GRIFFITH UNIVERSITY
Fruit Flies – Lessons in Research and Politics
Professorial Lecture
By
Professor Richard Arthur Ian Drew AM FTSE PhD, DSc
Tropical Fruit Fly Research Group
Australian School of Environmental Studies
Delivered on
Thursday, 26 April 2001
5.30 pm
Central Theatre 1
Nathan Campus, Griffith University
Fruit Flies – Lessons in Research and Politics
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Fruit Flies – Lessons in Research and Politics
C ON T E N T S
Introduction
….…………………………………………………………………….
Background
to
Current
….…………………………………………
Projects 9
Taxonomic
Research
….…………………………………………………………
•
Morphology
…..………………………………………………………
•
Biology
..…...…………………….………………………………
……
•
Isozyme
and
DNA
Studies
…..……………………………………
•
Pheromone
Chemistry
….…………………………………………
•
Behaviour
…..………………………………………………………..
Ecological
….………………………..…………………………………
Speciation
in
the
..………………….…………………………………
5
10
11
12
14
14
15
Research 17
Dacinae 23
Applications
of
the
Research 24
….………………………………………………
•
Problems caused by pest fruit fly species ....…………………… 25
−
Preharvest crop losses
−
New incursions
−
Export trade losses
−
Pressures and added costs on national quarantine services
•
Some
solutions
to
the
problems 28
…..……………………………..
−
Field pest management
−
Eradication of new incursions
−
Quarantine Programs
§ Off-shore
§ Border
§ On-Shore
−
Training Workshops
Conclusions
…..…………………………………….….……………………………
i
32
Fruit Flies – Lessons in Research and Politics
Acknowledgements
….……………………………….….………………………
34
References
….……………………………………………………………………….
35
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Fruit Flies – Lessons in Research and Politics
Bactrocera umbrosa (Fabricius) – the breadfruit fly, feeding on fruit tissue from
wounds on fruit surface of Artocarpus altilis (breadfruit), in Vanuatu
(Photograph courtesy of Meredith Romig)
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Fruit Flies – Lessons in Research and Politics
The best thing…is to learn…Learn why the world wags and what wags it…you can learn astronomy
in a lifetime, natural history in three, literature in six…you can start to make a cartwheel out of the
appropriate wood,…After that you can start on mathematics, until it is time to learn to plough.
(T.H. White, The Sword in the Stone, p.254)
INTRODUCTION
It is with much gratitude and pleasure that I place on record my thanks to Professor
Roy Webb (Vice-Chancellor) and his senior staff for the opportunity to work at Griffith
University, a forward-thinking organisation unhindered by unnecessary bureaucratic
processes and over-management. I have appreciated the freedom to establish the fruit
fly research program, the opportunities to interact with other staff and work directly
with funding groups when negotiating new projects. In the years to come the University
will, I trust, be rewarded. The signs are certainly good at this time.
In a career that has spanned some thirty years and many more years to come, I hope, it
has given me some great experiences in collaborative research, appreciation of different
cultures and of course – almost to the point of surfeit – travel. I have conducted
fieldwork in many South East Asian and South Pacific countries and found great
personal enrichment in building collaborative teams and working closely with the
various host country personnel, from leading bureaucrats to all-important project staff.
Growing into an understanding of other countries and their cultures is an experience of
great value. I am deeply grateful for this and especially to the Australian Centre for
International Agricultural Research (ACIAR) for its project support (Drew and Allwood
1997).
I had the privilege of studying Entomology and beginning my research career in the late
l960s. These were halcyon days for science in Australia, and Entomology was a high
profile discipline. Its recognition as a key discipline operating at the intersection of
human health and agriculture saw it attracting not only eager young scientists but
others, frequently medical practitioners, as amateur entomologists acquiring substantial
collections and knowledge through passionate interest and observation.
The University of Queensland boasted an outstanding Entomology Department with
excellent academic staff and a truly rigorous curriculum which spawned many
prominent scientists still making an impact today. The teaching program was based on
that taught at Imperial College, University of London, by O.W. Richards. The
cornerstones of the teaching program were Systematics, Biology and Ecology of the
Insecta. Like all students, I based my research on what I was taught and was free to
observe in the field through guided learning, and these foundations undoubtedly have
been seminal to all of my research endeavour since.
At the beginning, I want to put the need for agricultural research in context.
On 15 August 2000, in Canberra, there was a one-day Crawford Fund Symposium
entitled ‘Food, water and war: security in a world of conflict’ (Anon 2000). Some
interesting statistics were presented by military, political and government leaders –
♦ Between 1989 and 1999, there were 108 armed conflicts worldwide, 90% of
the casualties being women and children, in the poorest countries
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Fruit Flies – Lessons in Research and Politics
♦ The main causes of conflicts today are poverty, lack of food and lack of
land and water.
It is generally believed that 38% of the world’s arable lands are now rated as seriously
degraded and that this represents some two billion hectares laid waste. In the
developing world, poor farmers are slashing and burning forests by moving higher up
the mountains. By the year 2020, world food output must rise by 70% or we will see
large portions of humanity suffering Ethiopian-proportion famines (Cribb 1997).
Consequently, extra food must be produced on less land, using less water. We cannot
separate poverty, political chaos, economic failure and environmental devastation, and
today the environment has become the major international security issue of the 21st
century. Indeed, agricultural research has a key role to play in engendering international
collaboration, goodwill and peace, through enhancing environmentally sustainable
world food production. This is why areas of agricultural research are so important, and
it is why I believe Griffith University’s fruit fly program is so well-placed to contribute
significantly. It behoves us to focus globally, not locally, in working to achieve
sustainable, environmentally safe agricultural practices, especially in the developing
world.
Those who know me, know that it is possible to be passionate about fruit flies. Fruit
flies are insects belonging to one family, the Tephritidae. Worldwide, there are several
subfamilies and some 4500 known species. The subfamily Dacinae is the one with
which I have been most involved. This subfamily is primarily subtropical to tropical in
its distribution where the endemic habitat in South East Asia and the Pacific region is
comprised of our magnificent rainforests. In the forests the fly species breed in the
fleshy fruits growing on a wide range of plant families. The unique combination of large
numbers of species belonging to the rainforest ecosystem and a few species being major
pests of fruit and vegetable crops, makes the Dacinae extremely interesting and
valuable subjects for both basic and applied research. In reflecting on thirty years of
fruit fly research I aim to review some of the basic principles that I have employed and
concepts generated, and I guess, express my opinion as to what constitutes worthwhile
scientific research.
The Dacinae have two main genera, Dacus and Bactrocera. Dacus is of African origin with
a few species extending into South East Asia and the South Pacific as far as
northeastern Australia and Vanuatu. The genus Bactrocera has proliferated from South
East Asia to the South Pacific region with Papua New Guinea having the largest
number of species of any single land mass (Drew and Hancock 1999). Our present
project in PNG is discovering some exciting undescribed species in the undisturbed
rainforests, especially in East New Britain. We now have enough data on the endemic
species of most island groups, from India to French Polynesia, to be able to undertake
valid biogeography research, especially when we can relate the species to the taxonomy
and biogeography of the rainforests. In May 2001 we will have published a revision of
the Dacinae of the Solomon Islands and Vanuatu (Drew and Romig, 2001).
Henry David Thoreau, author of the famed Walden and archetypical observer of nature,
once complained that Harvard taught him ‘all of the branches and none of the roots’
(Atkinson 1937). Clearly, the roots are essential and many researchers are criticised for
what is considered an unnecessary concentration on ‘the roots’. In this lecture I want to
illustrate that we can and should combine both, basic and applied research, to the
2
Fruit Flies – Lessons in Research and Politics
benefit of all. Also, I will suggest that our research must have a strong element of
creativity that stretches our understanding and engenders a more lateral and contextual
exploration of our subjects. Thought can be a many-faceted concept and perhaps
tonight you will place me in the category described by William James that ‘a great many
people think they are thinking when they are merely rearranging their prejudices’. All I
can say in defence is that I am passionate about biology, excited over finding new
information or synthesis, and convinced beyond doubt that science always has and will
be a cornerstone of society.
Bactrocera (Paradacus) decipiens
(Drew)
(Photograph courtesy of Steve Wilson, Allan Allwood & Luc Leblanc)
3
Worldwide distribution of the genera Dacus and Bactrocera (hand shaded on student map)
Fruit Flies – Lessons in Research and Politics
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Fruit Flies – Lessons in Research and Politics
BACKGROUND TO CURRENT PROJECTS
In addition to research in Australia, I have carried out field and laboratory
investigations in Peninsular Malaysia, Thailand, Bhutan, East Malaysia (Sabah,
Sarawak), Papua New Guinea, Cook Islands, Tahiti, Fiji, Tonga, Solomon Islands,
Vanuatu, Western Samoa, and New Zealand. Much of this has been in collaboration
with Allan Allwood who was stationed in Fiji for 10 years from 1990. I have also
studied in the Natural History Museum (London), the University of Vermont, and
University of Massachusetts (Amherst).
As noted above, the Tephritidae are exciting insects to study and extremely valuable
subjects for basic research. Across the family, they show amazing biological diversity
that is expressed in aspects of their morphology, habitat utilisation and behaviour. In
my own research I have undertaken investigations in Taxonomy, Ecology, Behaviour
and Pest Management and I have found that these areas are interconnected, each
providing mutually illuminating data that reflects values of the other.
The discovery of insecticides such as DDT and the organophosphates set back basic
biological research on insects for many decades. It was too easy to recommend
pesticide cover sprays as a panacea for all problems, to the detriment of our
environment. Entomologists now realise, perhaps too late in some situations, that basic
biological research, with understanding of rich naturally occurring complementarities,
are essential to sustainable pest management systems.
As a result of the fruit fly research set out below, it has been possible to develop and
promote environmentally safe field control and eradication systems, provide data for
Australian quarantine security against incursion of exotic fruit fly pest species and
develop coursework for teaching and training programs.
Presently, at Griffith University, we are conducting major ACIAR fruit fly projects in
Papua New Guinea and Bhutan. In 2001, Vietnam will be included with collaborative
support from ACIAR and The Crawford Fund. Also, we have an ARC large grant to
evaluate phylogenies within the Dacinae based on DNA and a project for the
Californian Department of Agriculture to establish an electronic key to species of major
quarantine threat to the USA. These projects are enabling us to undertake wide-ranging
research into taxonomy, aspects of genetics using DNA, ecology and pest management.
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Fruit Flies – Lessons in Research and Politics
TAXONOMIC RESEARCH
In 1996 we were conducting a training workshop in Queensland for quarantine and
agriculture officers from fifteen South Pacific countries (Drew and Romig 1996). As is
the case in many of our workshops, identification of fruit fly specimens to species level
was requested. At the conclusion of the course a local university professor and leader
said to me, ‘Dick, I am impressed to see that taxonomic research has a genuine
application’. Frankly, I have always been amazed that so many of our academic and
government leaders miss this point and fail to understand the connection between
sound taxonomic research leading to accurate definition of species and concomitant
issues of biological research and pest control. In CSIRO, and in a number of our
universities and government departments of agriculture, we have witnessed a turn,
might I say a rush, to the albeit important neoscience areas such as molecular biology at
the expense of the insect taxonomy research programs. Is it coincidental that this has
happened – perhaps it is why it has happened – during the phase where entomology
itself has wandered somewhat from its earlier concentration on taxonomic research and
its intriguing scientific outcomes.
Taxonomic research is fundamental to all aspects of biology. Unless we can define and
identify species we cannot understand the environment in which we live and/or work.
Elucidation of environmental impacts, pest management programs, ecological and
molecular biology research is all built on knowledge of species. For these reasons I have
always found taxonomic research exciting and rewarding.
While taxonomic research and descriptions of species are usually based on
morphological studies, and this indeed is how I began my research, I realised in the
early years that a true biological definition of species based on genetic, ecological and
behavioural characteristics was needed. As a result I launched into the program of
research, often in collaboration with other scientists, that is discussed below. Suffice to
state here that I have used a range of biological characters to define species, in addition
to standard morphological ones. In summary, the following areas have contributed to
the taxonomic research –
♦
♦
♦
♦
♦
Morphology of adults
Biology, especially rainforest host studies
Isozyme and DNA studies
Chemistry of male pheromones
Behaviour, particularly responses to male lures.
This combination of studies was applied to our research of the dorsalis-complex of
species in South East Asia (Drew and Hancock 1994). There are 8 major pest species
in the complex and some have been spread to countries beyond that region. These pest
species are listed in Table 1.
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Fruit Flies – Lessons in Research and Politics
Table 1. The known pest species of fruit flies in the Bactrocera dorsalis -complex
of South East Asia
Species
B. caryeae (Kapoor)
Distribution
India
B. dorsalis (Hendel)
Sri Lanka, India to S. China,
Taiwan, Hawaii, Northern
Thailand to Bangkok, Laos,
Vietnam, Cambodia
Philippines, Sabah, Palau
Andaman Is, Southern
Thailand, Malaysia, Borneo,
Indonesia, Singapore
Malaysia, Borneo, Indonesia,
Southern Thailand,
Singapore
Philippines, Palau
B. occipitalis (Bezzi)
B. carambolae
(Drew and Hancock)
B. papayae
(Drew and Hancock)
B. philippinensis
(Drew and Hancock)
B. kandiensis
(Drew and Hancock)
B. pyrifoliae
(Drew and Hancock)
Pest Status
mango, guava, citrus,
champedak
a wide range of edible fruits
mango
a wide range of fruits
a wide range of fruits
a wide range of edible fruits
Sri Lanka
mango
Northern Thailand
peach, guava, Chinese pear
Morphology
For Ornithologists and Entomologists alike, it is exciting to study species and observe
the remarkable morphological diversity that is present. In the Dacinae in Papua New
Guinea, we have collected, and currently are collecting, and studying, some remarkable
species collected in undisturbed rainforests. Some are rare species, probably breeding in
only one rainforest plant species. To describe such species and relate them to their
endemic host plants is a privilege that very few biologists experience today.
I have described over 300 species and revised many more, using standard
morphological descriptions (Norrbom et al. 1998). Like all groups of organisms, some
species are easy to distinguish while others are extremely difficult. The close or similar
species, termed ‘sibling’ or ‘cryptic’ species, are the ones whose deciphering require the
biological research.
The morphological definition of species within the subfamily Dacinae is particularly
complex as the majority of distinguishing characteristics are colour patterns and body
bristles (setae) (Drew 1989a). Unlike many other insect families, male and female
genitalia have only limited application in differentiating between species.
The value of morphological characters is best emphasised by explaining that even when
sibling species are defined through basic biological techniques, we still require the use
of morphological characters in routine identifications. For example, many countries
conduct ongoing quarantine surveillance programs and specimens collected have to be
identified using standard light microscopy.
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Fruit Flies – Lessons in Research and Politics
Electron microscopy is of some value in distinguishing female specimens of some
groups (Drew 1989b), and in identification of larvae to species level (Elson-Harris
1992). Considering that immature stages are the ones that cause the damage to
commercial crops, and the stages that usually break quarantine barriers, more research
effort needs to be applied to taxonomy of eggs and larvae.
Some researchers have made a career out of defining morphological terms, even
producing dictionaries to add to their publication lists. I have found this most
frustrating, not only because it is another form of ‘bean counting’ but also because we
can never settle upon consistent use of terms. In some instances we have changed
several times only to return to those terms used thirty to forty years earlier. The large
number of agriculture and quarantine officers in many countries, who identify fruit flies
for their surveillance programs, find name changing extremely difficult.
A current concept or term that I find meaningless is ‘morphospecies’. This infers that
some species defined on morphological criteria are not true genetic species but can still
be regarded as species. It is my opinion that taxonomic researchers must work to define
true genetic species using morphology as a significant tool. However, given the
limitations of morphological characters, we must expand our thinking and incorporate
other facets of biological research in the determination of species.
Biology
To me, a genuine biological definition of species has to be based on more than the
Dobzhansky (1937) ‘reproductive isolation’ principle. In the Tephritidae there are a
number of examples of species that interbreed under laboratory situations, even across
subgenera. Under the Dobzhansky laboratory experimental procedures, these would not
qualify as ‘good’ species. For example, Bactrocera (Afrodacus) jarvisi (Tryon) and Bactrocera
(Bactrocera) tryoni (Froggatt) interbreed and produce fertile offspring in laboratory
experiments (Cruickshank et al., in press). Also, fertile hybrid progeny resulting from
crosses between Bactrocera (Bactrocera) tryoni (Froggatt) and Bactrocera (Bactrocera)
neohumeralis (Hardy) occur in the laboratory and can be found in the field (Gibbs 1968).
Further, in my early taxonomic research, I encountered a wide range of sibling species
complexes and many species which could not be defined on morphology alone.
Biological characters clearly were, and are, essential.
One simple but extremely valuable set of biological taxonomic data is the endemic
rainforest host plant records. I was first introduced to host plant surveys by Allan
Allwood, who pioneered areas of Entomology in the Northern Territory between 19701990 era. Allan’s passion for host surveys rubbed off and has provided sought-after
data for several aspects of fruit fly Entomology throughout the region from South East
Asia to the Pacific. The host plant specificity of most dacine species provides valuable
differentiating characters.
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Fruit Flies – Lessons in Research and Politics
Collecting wild fruits near Hanoi, Vietnam, for fruit fly host records
(March 1999)
(Photograph courtesy of Meredith Romig)
Isozyme and DNA Studies
Since 1977, I have invested considerable resources in genetic studies in order to
identify sibling species. I established a laboratory at QDPI, Indooroopilly, to use
isozymes to identify a species in the dorsalis-complex in the Northern Territory. When
9
Fruit Flies – Lessons in Research and Politics
first discovered, this species was thought to be one of the dorsalis-complex pest species
from South East Asia. After isozyme, cytological and host plant studies, the fly was
identified as an undescribed species, endemic to northwestern Australia. We described
it as Bactrocera opiliae (Drew and Hardy 1981).
In recent years I have supported work and collaborated with DNA researchers at the
Natural History Museum (London), University of Sydney, Queensland University of
Technology and now at Griffith University. The most valuable results have come from
the research of Associate Professor Jane Hughes and Jing Ma here at Griffith
University. We have successfully separated six species in the Bactrocera musae-complex of
Papua New Guinea. This is particularly relevant for the intrinsic value of the research
and extremely useful because one species, B.musae (Tryon), is a serious pest that causes
crop production losses and restrictions on trade in that country.
Some other studies, successfully completed, were on the Bactrocera tryoni-complex (Drew
and Lambert 1986) in Australia and Bactrocera xanthodes-complex (Hoeben et al. 1996) in
the South Pacific.
Pheromone Chemistry
In the mid-1980s, collaboration was established with Professor William Kitching at the
University of Queensland Chemistry Department. My own interest was to see if there
were differences between species in the chemical composition of the male sex
pheromones. I collected specimens, excised pheromone glands and placed them in
tubes of solvent, during field trips to many countries. The samples were analysed at
Professor Kitching’s laboratory. This led to over a decade of valuable research in which
chemistry studies were carried out on some twenty-four species of Bactrocera from South
East Asia, Australia and the South Pacific. A considerable number of papers have been
published and summarised in Fletcher and Kitching (1995).
In studying the most difficult sibling species in the dorsalis-complex of South East Asia,
we found that each species had unique and different chemical components in the male
pheromones (Drew and Hancock 1994). For example, Bactrocera carambolae (Drew and
Hancock) and Bactrocera papayae (Drew and Hancock), two sympatric species of major
pest status in South East Asia, have markedly different pheromones. At the same time,
field studies showed that these species did not interbreed and had a range of different
endemic rainforest host plants.
The male pheromones are released during courtship and mating. The males occupy
positions on the underside of leaves and atomise the pheromone through a process of
high-speed wing vibrations over bristles on the abdomen (Kuba and Sokei 1988).
Species-specific pheromones would seem essential, particularly in cases where sibling
species occupy the same host plants.
Behaviour
Courtship and mating behaviour in the Tephritidae has been observed for at least 50
species. Zwolfer (1974) noted that species of Tephritinae exhibit characteristic
rendezvous behaviour where the males use the larval host plants as species-specific
territories for courtship and mating. To date, all records of courtship and mating have
been in or on the respective host plants of species. For example, studies by Zwolfer
10
Fruit Flies – Lessons in Research and Politics
(1974) on Tephritinae and Drew and Lloyd (1987) on B. tryoni mating on the leaves of
host plants. Also, Rhagoletis pomonella mates on the host fruit (Prokopy et al. 1971).
Mating pair of the Queensland fruit fly, Bactrocera tryoni (Froggatt) on the
lower leaf surface of a peach tree
One little known aspect of dacine behaviour is the response to the male attractants, cue
lure and methyl eugenol. We have found that a species will respond to one of these
lures but not both. Usually, within a group of sibling species, some are attracted to cue
lure while others respond to methyl eugenol. These differences are useful in separating
some species in the dorsalis-complex and musae-complex.
The sources of cue lure and methyl eugenol in nature, particularly within the Dacinae
habitat, and their involvement in behavioural strategies of fruit flies, have long been the
subject of enquiry and debate. Methyl eugenol has been detected in a range of plants
representing ten families (Metcalf 1979) but cue lure has not been found in any plant
species. The known methyl eugenol containing plants do not occur in the rainforest
ecosystem in which the Dacinae have originated and speciated, other than some
orchids. Recent field surveys in Papua New Guinea have recorded specimens of
twenty-four species of Dacinae having orchid pollinaria (pollen sacs) (Clarke et al., in
review). Some of these orchids are thought to contain methyl eugenol which may be the
essential cue to attract the flies to the flowers for pollination to proceed. Chemistry
research in Malaysia on two species of orchid, Spathiphyllum cannaefolium and Dendrobium
anosmum, revealed that they contained chemicals attractive to male fruit flies that
respond to both methyl eugenol and cue lure (Yong 1992, Toong and Tan 1994). It was
also recorded that unpollinated flowers produced the attractants and that the secretion
of them coincided with the active period of the fly. A number of other concepts have
been proposed for methyl eugenol, including stimulation of male mating activity and
deterring predators.
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Fruit Flies – Lessons in Research and Politics
The cue lure molecule has 2-butanone as a component and this is common to a range of
chemicals that attract cue lure responding dacine species. In studies on B.tryoni, Drew
(1987a) found that 2-butanone, cue lure and volatile metabolites of bacteria species
associated with fruit flies, attracted sexually mature males and immature females. Given
that 2-butanone is emitted by ripening fruit and some bacteria species, Drew (1987a)
proposed that it may be an important rendezvous stimulant to bring mature male flies
into the host plants, to ensure mating encounters.
RESEARCH INTO ECOLOGY & BEHAVIOUR
SPECIATION
TAXONOMY
PEST CONTROL STRATEGIES
BIOGEOGRAPHY
ENVIRONMENTAL INTERACTIONS
A framework for ecological and behavioural research
12
Fruit Flies – Lessons in Research and Politics
ECOLOGICAL RESEARCH
Ecological research, combined with a strong knowledge of taxonomy, is of great value
in understanding environmental issues, biodiversity, research and development in pest
management, developing quarantine systems, collating data on biogeography and
elucidating concepts on possible processes of speciation. This combination of research
areas on the Dacinae, and the resulting outcomes have been most rewarding and
stimulating.
Worldwide, most ecological research on species of Dacinae has been conducted on pest
species introduced into new countries and/or habitats (e.g. Fletcher 1973, 1974, Meats
1981). This is because fruit fly pest species are often transferred between countries and
there is a plethora of funding support for work on these new invaders. Examples are
Bactrocera tryoni (Queensland fruit fly) in southern Australia, Bactrocera dorsalis (Oriental
Fruit Fly), Bactrocera cucurbitae (Melon fly) and Ceratitis capitata (Medfly), all in Hawaii.
Consequently, much of our ecological understanding of Bactrocera species has arisen
from research on the above species in Australia and Hawaii. This has resulted in a
blurred picture. In Australia, studies on B.tryoni in southern New South Wales have
emphasised that climatic factors are the main population regulatory mechanisms.
In the late 1970s I became convinced that it was essential to research the ecology of
dacine species in their endemic habitat, if we were going to have any understanding of
their life systems and make prognoses relevant to pest management. Consequently,
ecological research was initiated in some South-East Queensland rainforests,
particularly Cooloola and Mt Glorious. These locations are within the original
distribution of most eastern Australian Bactrocera species and the rainforests comprise
the endemic habitat. In this research, we were able to study some of the seasonal and
geographic distributions, host plant records, altitudinal effects and vertebrate predation
(Drew and Hooper 1983, Drew et al. 1984, Zalucki et al. 1984). While this research
raised considerably more questions than were answered, it became clear that a range of
biological parameters had significant influences on the distribution and seasonal
abundance of species. In particular, the distribution and fruiting seasons of host plants
were significant factors governing the distribution and seasonal abundance of fruit fly
species, with climatic factors having a more indirect influence.
Another significant finding was the influence of fruit feeding vertebrates as population
reducing mechanisms in the rainforests (Drew 1987b). The direct ingestion of eggs and
larvae in fruit and destruction of female fly oviposition resources led to some 70%
reduction in Bactrocera cacuminata populations in Solanum mauritianum fruit and similar
levels for Bactrocera halfordiae in Planchonella australis fruits at Mt Glorious. Fruit fly
parasitoids suffered the same fate as the flies and it would appear that the parasitoids
are not major factors in the rainforests in reducing the fly populations. Generally,
parasitism peaks at above 10% and has little effect on reducing infestation levels in
food crops as well as in wild host plants.
An extension of the vertebrate feeding research was the finding that fruit fly infested
fruit provided a rich protein source for the fruit feeding animals (Drew 1988). Infested
fruit tissue contains higher levels of amino acids than uninfested tissue, in addition to
the protein available in eggs and larvae.
13
Fruit Flies – Lessons in Research and Politics
One significant contribution over the past fifteen years has been the extensive and
systematic collection of host plant records from South East Asia, Australia and many
South Pacific islands. Collections of wild and edible/commercial fruits were taken at
regular time intervals over a number of years in Peninsular Malaysia, Thailand,
Vietnam, Sabah, Sarawak, Indonesia, Australia and Pacific Island countries from Papua
New Guinea to French Polynesia. A major side benefit from the Asian Papaya Fruit Fly
eradication program in North Queensland was the extensive host fruit surveys that were
carried out over a large area of rainforest. I was instrumental in organising these and
participating in some of the early fieldwork. Given that these field collections were
non-selective, with any available fruiting body collected, the flies reared provided a
good assessment of host fruit ranges. They also have given a reasonable measure of the
pest status of most fruit fly species. Records from Australia and South East Asia have
been published (Allwood et al. 1999, Hancock et al. 2000) but those from the South
Pacific islands remain in databases.
Some interesting features of the host records are as follows ♦ 51 endemic rainforest families in Australia and 63 in South East Asia were found to
be hosts of dacine species
♦ Of 42 species of Dacinae in Australia, reared from endemic wild (mostly rainforest)
fruits, 18 were monophagous, 15 oligophagous (having 2 to 7 host species) and 9
were polyphagous (8 or more host species)
♦ Of 67 species of Dacinae in South East Asia, reared from endemic wild fruits, 23
were monophagous, 31 oligophagous (2 to 7 host species) and 13 polyphagous (8 or
more host species)
♦ The species recorded as polyphagous in the forests are, primarily, the pest species in
cultivated ecosystems
♦ The genus Dacus originated in Africa and contains 95% of all African Dacinae and
is represented by many fewer species in South East Asia and the Pacific Region.
However, the species in both Africa and South East Asia to the Pacific share the
same host plant families
♦ Many dacine species, and subgenera, are restricted to one plant family. In some
such instances, e.g. the family Gnetaceae, speciation of fruit fly species can be
traced across wide geographic zones.
Probably, the most significant and interesting area of ecological research that I have
been involved in over the past two decades has been the bacteria relationships in the
life cycle of some Bactrocera species. This has been summarised by Drew and Lloyd
(1991) and has stimulated a considerable number of theses and research papers,
worldwide (see Lauzon et al. 1998, Epsky et al. 1998, Lauzon et al. 2000, Vijaysegaran
et al. 1997).
The first records of bacteria associated with tephritid fruit flies were published by Petri
(1910). Both he and subsequent workers considered the bacteria to be obligate
mutualistic symbionts that produce important nutrients for both adult flies and larvae
(Girolami 1983, Hagen 1966, Luthy et al. 1983, Miyazaki et al. 1968). A number of
14
Fruit Flies – Lessons in Research and Politics
more recent researchers have questioned this symbiotic relationship including Drew et
al. 1983, Fitt and O’Brien 1985, Howard et al. 1985, Lloyd et al. 1986.
In Queensland, using aseptic dissection techniques, the bacteria associated with four
species of Bactrocera (B.neohumeralis and B.tryoni collected on trees of guava, mulberry
and peach, B.cacuminata from trees of wild tobacco and B.musae from banana), were
isolated and identified. In particular, bacteria were identified from the adult fly crop,
mid-gut, oesophageal bulb, faeces, fruit surfaces, oviposition sites and larval fruit rot
(Lloyd et al. 1986).
The predominant bacertia were species of Enterobacteriaceae, particularly Klebsiella
oxytoca, Erwinia herbicola and Enterobacter cloacae (Lloyd et al. 1986). Laboratory feeding
experiments showed that adult B.tryoni survived and reproduced on a diet of ‘fruit fly
type’ bacteria alone (Drew et al. 1983). Drew and Lloyd (1987) developed a double
antibiotic resistant strain of Klebsiella oxytoca as a ‘marked’ strain that could be used in
laboratory and field cage experiments.
Subsequently, considerable laboratory and field research has been conducted in the
following areas (Drew and Lloyd 1987, 1991, Vijaysegaran 1995, Vijaysegaran et al.
1997) –
♦ Observations on regurgitation of crop fluids, and colour of alimentary canal
contents, of B.cacuminata and B.tryoni feeding on fruiting mulberry trees
♦ Isolation of bacteria distributed by adult B.tryoni during feeding and regurgitation
processes
♦ Determination of the origin of bacteria that were distributed by flies
♦ Fate of bacteria ingested by adult B.tryoni and transfer on to host plant surfaces,
using the ‘marked’ strain of Klebsiella oxytoca
♦ Comparison of bacteria colonies on fruiting, field nectarine trees, caged (excluding
fruit flies) and uncaged
15
Fruit Flies – Lessons in Research and Politics
Bactrocera (Bactrocera) papayae Drew & Hancock (Asian Papaya fruit fly)
(Photograph courtesy of Steve Wilson)
Bactrocera (Zeugodacus) cucurbitae
(Coquillett)(Melon fly)
(Photograph courtesy of Steve Wilson)
16
Fruit Flies – Lessons in Research and Politics
Bactrocera (Bactrocera) tryoni (Froggatt) (Queensland fruit fly)
(Photograph courtesy of Steve Wilson)
Bactrocera (Notodacus) xanthodes
(Broun)(Pacific fruit fly)
(Photograph courtesy of Steve Wilson)
17
Fruit Flies – Lessons in Research and Politics
♦ A study of the fruit fly activity, and associated bacteria, in a fruiting peach tree for
an eleven-week period, from three weeks before flies arrived in the tree
♦ A study of the anatomy of the adult fly mouth-parts, observations on feeding
processes, mechanisms for filtering particles from liquid food substances and
associated laboratory feeding experiments to elucidate the functional morphology of
the mouth-part structures.
In addition to the Queensland-based studies, research has been carried out in the USA
on Rhagoletis pomonella and Anasterpha species, on bacteria relationships and attraction of
adult flies to the volatile bacteria metabolites (Lauzon et al. 1998, MacCollom et al.
1992, MacCollom et al. 1994, Martinez et al. 1994). However, the Queensland-based
studies, particularly on the interaction between Bactrocera species, their host plants and
bacteria are the only ones, to date, where this multitrophic relationship has been
investigated in some detail.
In summary, good data are now available on ♦ The utilisation of certain bacteria as an adult fly food
♦ The transfer of the same bacteria species into fruit with eggs during the oviposition
process and the establishment of homogenous bacteria colonies in association with
the fruit rot on which the fruit fly larvae feed
♦ The attraction of adult Bactrocera species to fruit fly-type bacteria odours both in the
laboratory and under field situations
♦ The availability and activity of fruit fly-type bacteria on host plants, particularly on
fruit surfaces
♦ The transmission of the bacteria across generations of a fruit fly species
♦ The influence of some bacteria species on adult fly foraging behaviour
♦ The role of bacteria and host plant odours on the interaction between fruit flies and
their host plants
Fruits and the host plants, in general, have many important ecological effects on the
insects that live on them (Sallabanks and Courtney 1992). Tephritidae, in particular,
utilise their host plants as resting sites, sites for host-specific matings, adult and larval
food sites. Pupation may occur in the decomposed fruit but more often in the soil
beneath the host plant. Tephritid fruit-feeding larvae cannot move from one fruit to
another and so the oviposition site selection by egg-laying females must be efficient, if
the subsequent immature stages are destined to survive.
18
Fruit Flies – Lessons in Research and Politics
SPECIATION IN THE DACINAE
Both the general host fruit surveys and the ecological studies described above indicate
that dacine species have a dependent relationship with specific host plants. Given that
the host plants provide a source of adult food, oviposition sites, larval food, sites for
courtship, mating and pupation, and that approximately 80% of dacine species are
monophagous or oligophagous, there is a strong argument for a theory of co-evolution
of rainforest plant species and species of Dacinae. That is, there are strong ecological
and evolutionary links between dacine species and their host plants.
The distribution of the tropical and subtropical rainforests (outside of tropical central
America) match the distribution of the Dacinae. This forest distribution includes West
Africa, coastal East Africa, Madagascar, Mascarene Islands, southwest India, Southeast
Asia, Papua New Guinea, northeastern Australia and some South Pacific islands
(Whitmore 1986).
The rainforests of Southeast Asia possess the greatest species richness. Papua New
Guinea also contains a large flora that includes Indo-Malayan elements. There is
decreasing floristic richness eastwards from PNG into Melanesia (e.g. Solomon Islands).
Data from the Queensland Herbarium show that the rainforests of PNG are
considerably richer than their counterparts in northeastern Australia (Table 2).
Table 2. Number of plant genera and species in PNG and Australian rainforests
No. Genera
No. Species
PNG
716
8000
Australia
545
1600
The rainforest floras of these two landmasses show
♦ Close relationships at the generic level, indicating a common phylogenetic ancestry
♦ Low numbers of shared species and numerous species endemic to each area,
suggesting more recent independent speciation which has been more vigorous in
PNG
♦ Some evidence of close relationship between the two areas at species level, when
similar environmental units are compared (e.g. similar soil types and rainfall)
♦ Within Australia, the composition of flora changes markedly from North to South
along the east-coast
♦ The floras of PNG and Australia are probably the result of long climatic sifting of a
single ancestral stock. The Indo-Malayan element has become a strong influence in
the PNG flora but not as much in Australia
♦ During the last glacial period the PNG-Australia land bridge would have been as
arid as is the Gulf of Carpentaria today.
Factors that have contributed to the large number of plant species in the rainforests
include the following ♦ Considerable localised evolution of species, after the combining of the Laurasian
and Gondwanan elements through continental drift
19
Fruit Flies – Lessons in Research and Politics
♦ The long, stable history of tropical rainforests and their large numbers of ecological
niches are conditions that lead to coevolution of plants and animals.
The Dacinae of PNG and Australia exhibit a similar pattern of distribution and
relationships to that described above for the rainforests. Also, there are large numbers
of sibling species in genera of rainforest plants that are hosts of fruit flies, and similarly
large numbers of dacine sibling species associated with these plants.
As far as history can reveal, evidence indicates that there has been considerable
coevolution of dacine species and their host plants in the rainforests. As noted above,
this is also indicated on ecological grounds.
There are large numbers of sibling species of Dacinae in Southeast Asia and Papua New
Guinea, particularly in the dorsalis-complex. In this complex there are some 70 known
species, some of which today exist in sympatric situations and some in allopatry. The
Recognition Concept of Speciation (Paterson 1985) is a considerably better fit than the
Reproductive Isolation Concept (Dobzhansky 1937, Mayr 1942), for the Dacinae. It is
more conceivable that geographic isolation, or isolation by means of populations being
confined to specific plant species, has led to changes in courtship and mating systems
(or mate recognition systems) which, in turn, resulted in reproductively isolated
populations (species). This concept of Speciation accommodates changes in speciation
in the rainforest flora which then influence changes in the fruit fly courtship and mating
behaviour.
In presenting a short discussion on the relationship between our understanding of
taxonomy, behaviour, ecology and biogeography of the Dacinae and a resulting concept
of Speciation, I believe we need considerably more data on other influential aspects.
These include influences of the host plant, in different localities at different fruiting
stages, on fruit fly behaviour patterns such as courtship and mating, adult feeding and
oviposition. These will be areas of exciting research for postgraduate students in years
to come.
APPLICATIONS OF THE RESEARCH
No insect disturbs the lives of politicians and bureaucrats like fruit flies, such is their
impact on horticultural production throughout the world. When the dreaded Asian
Papaya Fruit Fly was discovered near Cairns, North Queensland, in November 1995, a
colleague in the United States Department of Agriculture in Hawaii, Dr Jack
Armstrong, said to me, ‘Dick, now you will find out that fruit flies are politics’. In the
ensuing months and years, the fruit fly scientists discovered that politicians from the
Premier to cabinet ministers in Queensland and the Prime Minister, federal ministers
and local members in several States, ducked for cover and protected themselves with
any means possible. In Queensland, press and industry bans were placed on scientists,
while departmental managers with no understanding of the technical aspects of the
problem attempted to provide answers to the press and public.
On the positive side, the results from years of research in Australia and South East
Asia, long-term collaboration with fruit fly scientists worldwide, and belief in vital
taxonomic underpinning, paid dividends in seeing the fly completely eradicated by
1998. It has been equally pleasing to see the results of our research being used in field
and pest management, trade and quarantine security programs. This is discussed below.
20
Fruit Flies – Lessons in Research and Politics
In addition to new incursions, there are continuing strong political interactions in areas
of international trade and quarantine security.
Problems caused by pest fruit fly species
(a)
Preharvest crop losses
In all countries where fruit flies occur, the crop losses experienced by suburban
gardeners, subsistence growers and commercial producers, are varied but often
extensive. In countries like Australia, field control has been achieved by applications of
insecticide cover sprays of dimethoate or fenthion which are common
organophosphates. These activities have caused, in turn, obvious environmental
problems. In situations where regular control strategies are not applied, severe crop
losses are experienced. Some examples of crop losses measured during overseas project
work are given in Table 3 (McGregor 1999, Allwood pers. comm., Drew unpublished
data).
Fallen fruit in carambola orchard resulting from fruit fly infestation
21
Fruit Flies – Lessons in Research and Politics
Table 3. Percentage losses to fruit fly for some crops in countries in South East
Asia and the South Pacific
Country
Crop
Bhutan
Vietnam
Mandarine
Peach
Guava
Waterapple
Carambola
Rose Apple
Mango
Cantaloupe
Bitter Gourd
Breadfruit
Carambola
Guava
Pumpkin
Snake Gourd
Pumpkin Squash
Guava
Mango
Cumquat
Capsicum
Papaya
Guava
Bananas
Malaysia
Thailand
Papua New Guinea
Solomon Islands
Vanuatu
Nauru
Fiji
Tonga
Western Samoa
Palau
(b)
%
Crop Loss
70
65
99
76
100
100
65
94
95
75
90 – 95
70 – 96
44
>90
60 – 87
95
95
60
97 – 100
19 – 37
45 – 99
80
Fruit Fly Species
B. minax
B. pyrifoliae
B. correcta
B. correcta
B. carambolae
B. dorsalis-complex
B. dorsalis
B. cucurbitae
B. cucurbitae
B. umbrosa
B.frauenfeldi/B. papayae
B. frauenfeldi
B. cucurbitae/B. decipiens
B. cucurbitae/D. solomonensis
B. cucurbitae
B. trilineola
B. dorsalis/B. frauenfeldi
B. passiflorae
B. facialis
B. xanthodes
B. kirki
B. dorsalis-complex
New incursions
Worldwide, fruit flies are being spread to new countries on a regular basis. Each year
new records occur. Some of the most recent introductions or outbreaks are ♦ Bactrocera papayae (Asian Papaya fruit fly) in Papua New Guinea
♦ * Bactrocera papayae in north Queensland in 1995
♦ * Bactrocera philippinensis in Darwin, Australia and Palau
♦ Bactrocera dorsalis (Oriental fruit fly) in Mauritius and Tahiti
♦ Bactrocera zonata and Dacus ciliatus into Egypt and Israel
♦ Several species into California
♦ * Ceratitis capitata in Auckland, New Zealand, March 1996
♦ Bactrocera tryoni in Auckland, New Zealand, March 1996, detected but not
established
(* = subsequently eradicated)
There are many older records of major introductions to a number of countries.
As noted above, the introduction of pest species into new countries causes major
political upheaval and trauma for industry. Immediate cessation of export trade from
the affected area and generally the country, is the most unpalatable and worst possible
result.
22
Fruit Flies – Lessons in Research and Politics
Most new incursions can be traced to passenger travel and not commercial trade.
Consequently, with the ever-increasing international air traffic, and people carrying
fruits and vegetables in baggage, this problem will be forever with us.
In addition to the industry losses through trade bans, the costs of eradication programs
are large. For example, the north Queensland program against B. papayae cost $35
million over three years.
(c)
Export trade losses
Countries that have endemic pest fruit fly species, or established introduced species,
will suffer bans on the export of fresh horticultural produce. When new incursions are
found, temporary export bans are applied until the fruit fly is proven not to be
established or, if it had become established, totally eradicated.
In order to overcome export bans on fresh produce there has been considerable
investigation into postharvest technologies since the early 1900s. The most reliable
period for export was the 1970s and 1980s with the use of Ethylene Dibromide (EDB)
as a postharvest fumigant. When EDB was banned in the late 1980s many countries
lost their export markets.
With the current move to world trade liberalisation under the GATT agreement, there
has been an upsurge in interest in quarantine matters. The world leaders, in formulating
the agreement, did not consider the biological implications of free trade in agricultural
commodities and now we are confronted with a maze of difficult quarantine issues.
Within this area there are also accusations of some countries using a potential fruit fly
threat as a trade barrier to protect their own industries. This represents a potential
minefield for politicians and business leaders and will provide much business for
lawyers.
Within Australia, fruit flies in some of the northern states inhibit or prevent interstate
trade to ‘fruit fly free’ states, unless postharvest treatments have been applied.
Queensland industries, in particular, suffer in this area. For some years, the problem
within Australia has been compounded by the different importing states having
different requirements. These inconsistencies have generally made it difficult for
exporters to obtain access to more than one market. A national, uniform set of rules for
interstate trade would be helpful, though difficult to achieve.
(d)
Pressures and added costs on national quarantine services
As a result of the movement of major pest fruit fly species between countries, there has
been increasing pressure on national quarantine services. Whilst no country can have a
quarantine system that will guarantee complete exclusion of fruit flies, all can ensure
early detection of new introductions. Consequently, many countries now have
established quarantine surveillance programs for fruit flies, which add costs to their
annual budgets. Also, many countries have had to upgrade their port of entry detection
systems to identify fruits and vegetables in passengers’ baggage.
Some solutions to the problems
(a)
Field pest management to prevent preharvest losses
23
Fruit Flies – Lessons in Research and Politics
The discovery of DDT in the 1940s, and subsequent insecticides, led insect pest
control, and fruit fly pest management in particular, into pesticide cover spray
programs. These have many deleterious effects including the killing of pollinators and
biocontrol agents, leaving pesticide residues in food crops and the environment, and
health hazards for farm workers.
Our fruit fly research has steadily pursued studies on the ecology of species, pheromone
chemistry, colour and protein attractancy, with the aim of developing field pest
management with markedly reduced pesticide usage. While we have made some
progress in the colour response studies with Queensland fruit fly, the major success has
been in the development of a new formulation of protein bait.
The bacteriological research in the 1980s showed that flies were attracted to bacteriaproduced volatile metabolites and when the bacteria were added to the standard
autolysed yeast mixture, they increased the attractancy of the bait. The bacteria species
involved cannot be produced commercially in a form that will maintain their viability.
Consequently, the next step was to test gelatinous bait formulations that may encourage
bacteria growth once they are applied to foliage. Our first experiments utilised carboxy
methyl cellulose in autolysed yeast protein. The resulting gel spray proved to be more
attractive than the standard protein mixture.
Protein gel formulation on foliage of citrus
(Photography courtesy of Richard Bull)
24
Fruit Flies – Lessons in Research and Politics
Since joining Griffith University in 1997, we have worked closely with Richard Bull
(Aventis) to develop a new formulation of yeast protein, gel and fipronil insecticide.
Laboratory bioassays, field trials to assess efficacy in commercial orchards and
applications in large-area suppression/eradication, have been conducted. The final
result has been a protein bait formulation that is a great improvement on previous
commercial mixtures and provides high levels of field control, with applications as low
as 2.5 litres per hectare (or 10 ml per tree).
Clearly, the combination of the gel and fipronil enhance the attraction and feeding
responses of the fruit flies. Fipronil is a rare insecticide in having no apparent repellency
effect when added to insect food baits.
In the coming year, we will be commencing a project on aspects of feeding behaviour of
fruit flies with the support of an ARC SPIRT grant. These studies will provide
additional data on the food nutrient requirements and hopefully help in planning
protein bait application strategies. In particular, information is required on the ‘how,
when and where’ of protein bait application for the protection of fruit and vegetable
crops.
(b)
Eradication of new incursions
The science of fruit fly eradication has been a specialised area of research since the
mid-1900s. It went through a marked progression when the United States Department
of Agriculture established specialist fruit fly laboratories in Hawaii in 1947-48,
following the introduction of B.dorsalis (Oriental fruit fly). The primary focus of the
USDA Hawaiian effort was to eradicate all three pest species that had been introduced
into what was a fruit fly free environment, i.e. Ceratitis capitata (Medfly), B.cucurbitae
(Melon fly) and B.dorsalis. This was never attempted but the USDA research results
have been successfully applied to eradication programs in other countries. Eradication
is not recommended to obtain field control of endemic pest populations.
In recent years, the FAO-IAEA laboratories in Vienna have made major investments
into eradication technology, particularly the Sterile Insect Technique (SIT). The United
States government also contributed extensive funding into the eradication of Medfly
from Mexico during the 1980s (probably in the order of $100 million (US) per year for
ten years). This program was also used to investigate and refine techniques.
As a result of the activities described above, there is extensive published literature on
the science and business management of fruit fly eradication campaigns. For the
eradication of Asian Papaya fruit fly in north Queensland we were able to draw upon
the technology developed in Hawaii, especially the methyl eugenol Male Annihilation
technique.
The main aspects of an eradication program are ♦ detection and monitoring to determine the distribution and size of the invading fruit
fly population
♦ choice of correct eradication strategy, usually Male Annihilation and/or SIT
supplemented with specific protein bait applications
♦ specific population monitoring to determine progress of eradication
♦ ongoing monitoring after completion of eradication to ensure early identification of
any new incursion.
25
Fruit Flies – Lessons in Research and Politics
Our fruit fly research in Queensland and South East Asia provided an important basis
upon which the B.papayae eradication program in north Queensland could proceed. The
research in Malaysia and Thailand provided data on B.papayae in its endemic
environment, host plant ranges and methods of field monitoring. This enabled us to
rapidly set up a field surveillance program to detect the distribution of the outbreak,
locate breeding areas and recommend an eradication strategy. An independent
economic analysis has shown that the research carried out with the assistance of
ACIAR led to a saving in the overall eradication campaign of some $10 million dollars
(Collins 1998).
The success of the eradication program in North Queensland proved the high level
efficacy of the Male Annihilation technique, especially for methyl eugenol responding
species.
Eradication programs are extremely expensive and have always been funded by
governments or UN-FAO backed programs. As noted, they tend to become extremely
political and difficult to manage.
A positive political side is in the eradication program on Medfly in Israel and Jordan
where the US government is providing funds to ensure its continuation. Workers from
Israel, Jordan and Palestine are collaborating and moving freely over both territories to
maintain the program.
(c)
Quarantine Programs
Quarantine security measures with regard to fruit flies have become a major endeavour
in many countries. The primary aims are to prevent new incursions, or detect them early
if introduced, and guarantee to trading partners that certain production areas are fruit
fly free.
The quarantine strategies can be classified into three categories –
(i) Off-shore quarantine. There are two off-shore methods by which a country like
Australia can prevent introductions of exotic fruit fly species, i.e. applying
requirements for Market Access Technologies on fresh horticultural produce
imports and assisting neighbouring countries from where regular travellers arrive to
remain free of major exotic pest species.
The Market Access Technologies available are –
♦ Non-host status produce which can be imported when it has been proven
not to be a host to any fruit fly species
♦ Area-free status produce which is grown in locations free of pest fruit flies
♦ Physical postharvest treatments whereby produce after harvest is subjected
to cold or heat to kill fruit fly eggs and/or larvae
♦ Chemical postharvest treatments, primarily methyl bromide fumigation or
dipping in dimethoate insecticide, to kill eggs and/or larvae.
26
Fruit Flies – Lessons in Research and Politics
Our fruit fly research in Australia and a number of South East Asian and South
Pacific countries has provided data upon which host fruits have been selected for
the various categories of Market Access Technologies.
Through the combined efforts of ACIAR supported projects and the Regional Fruit
Fly Projects (RFFP), countries such as Papua New Guinea, Solomon Islands,
Vanuatu and Fiji now have ongoing fruit fly quarantine surveillance programs. This
has involved support for equipment and training of staff (see Training Workshops
below). As long as these surveys are maintained, major exotic pest fruit fly species
should not become established and add further pressure on Australian and New
Zealand ports of entry.
(ii) Border quarantine. There is, at present, enhanced quarantine surveillance at ports
of entry into Australia, New Zealand and other countries in the region. These
programs invoke passenger profiling by knowing the routes that are of highest risk,
fruit detecting dogs, special x-ray machines and baggage inspections. Also, imported
commercial produce is sub-sampled and examined.
The data from our fruit fly projects have been invaluable in enabling quarantine
authorities to make sound decisions in border quarantine, especially in the selection
of high-risk transport routes and passenger profiling.
(iii) On-shore quarantine. The major on-shore quarantine strategy for fruit flies is to
establish a surveillance program based on trapping and host fruit collecting. In
1976, our fruit fly research program provided data that indicated that Australia
should have a permanent quarantine detection survey across the northern coastline,
especially to provide an early detection of any new incursion of exotic species.
Consequently, Allan Allwood (then an entomologist in Darwin) and I were
instrumental in having Australian Plant Quarantine support the establishment of the
northern Australian quarantine fruit fly survey. This was later expanded into the
NAQS program and the fruit fly part was maintained until 1988 when Australian
government fund cutting to quarantine caused the downsizing of the fruit fly
surveillance effort. This was done without reference to fruit fly scientists and turned
out to be a very costly decision as the outbreak of Asian Papaya fruit fly in Cairns,
detected in November 1995, had been present undetected for several years.
The value of the early detection surveys was proven in New Zealand in MarchApril 1996. In Auckland, a Medfly infestation was detected, probably within six to
eight weeks of its introduction, and then eradicated within two months. Also, in
Darwin in December 1998, a new introduction of Bactrocera philippinensis was
detected early and quickly eradicated. Whereas the B.papayae eradication program in
North Queensland cost $35 million over three years, the programs in Auckland and
Darwin were just a fraction of this cost and time.
In-country quarantine surveillance programs for exotic fruit flies have the potential
to become political footballs as governments look for cost savings in their
expenditures. The fruit fly survey across northern Australia was rebuilt after the
B.papayae outbreak in North Queensland and it will be most surprising if any
Federal or State government allows this to be downsized again. Certainly, industry
and fruit fly scientists will be watching closely.
27
Fruit Flies – Lessons in Research and Politics
An important follow-up to the surveys is to establish Eradication Contingency
Plans. Because the major fruit fly threats to the Pacific Region are from South East
Asia, a considerable amount of our fruit fly ecology data from ACIAR projects have
been used in the eradication contingency plans that have been developed in
Australia and South Pacific island countries. These plans are essential to the rapid
introduction of efficient eradication programs. Clearly, it is better to have the
management and design of eradication programs well defined and in the hands of
those that are scientifically, rather than managerially, equipped to make the
technical decisions with a minimum of bureaucratic and hierarchical process.
(d)
Training Workshops
Our fruit fly research data has been used in some sixteen training workshops for
agriculture officers from many countries in South East Asia, the South Pacific Region,
Australia, California and New Zealand. The workshops have provided training in
quarantine programs, preharvest field control and market access technologies. They
have utilised a considerable amount of the taxonomic and field ecology data and
techniques that have been developed in the protein bait spray programs. At every
workshop, there has been a demand for training in fruit fly species identifications,
covering taxonomic data from Asia to the Pacific. This has justified the emphasis that
we have placed on our taxonomic research over a 30 year period.
There will be an ongoing demand for training workshops for all countries that have
quarantine programs for fruit flies. Staff changes, changes in distributions of pest fruit
fly species and new introductions or outbreaks will dictate an ongoing need for training.
CONCLUSIONS
In my opinion, the impact of insects on human habitation is so significant that the
discipline of Entomology is one of the major and most important facets of the
Biological Sciences. Insects affect human and animal health, food and fibre production
and play a key role in biological diversity. Fruit flies are only one of many important
and intriguing areas of entomology and, in the future, some universities will have to
return to intensive entomological teaching and research.
A nation’s competitive advantage is directly related to its scientific expertise. If we
place too much emphasis on basic research we lose touch with reality, if too much
emphasis is placed on applied research we are in danger of losing our gene pool of
valuable scientists. The key, therefore, is to establish basic research endeavour and
bring these results to bear on real problems, to offer real solutions to society.
The most valuable ecological research will always be dependent on accurate
determination of species and investigations at a multidisciplinary level. Areas of
research such as chemistry, microbiology, molecular biology, history and even sociology
make important contributions to the ecological understanding of our environment. This
clearly requires a deal of lateral thought in our scientists. Genuine research is the
creative activity of creative individuals. If creativity does not exist, there is no point in
pretending that genuine research is taking place. Today, in Biology, we have a serious
problem where just about anyone with a laptop and a little data can write and publish
short papers and purport to be scientists, without leaving the office or laboratory.
Whether I am biased, or wedged in a time warp, I cannot see that this approach
28
Fruit Flies – Lessons in Research and Politics
enlightens us with a sufficiently deep understanding of the biological relationships,
processes and behavioural patterns of organisms. Sadly, also, this more insular approach
seems to engender negative attitudes to life and others’ work and forfeits the
excitement and open-mindedness of enquiry and discovery. In the words of Peter
Ustinov, ‘there can be no intelligence without flexibility of mind. This does not, for a
moment, mean that profound conviction should be betrayed, merely that an open mind
is far more likely to have a balanced view of both doubts and convictions than a closed
one’.
We urgently need scientists who see biological research as probing into the complex
web of life of species and become excited over exploring new and intricate aspects of
biology. This is a much deeper and more meaningful approach that does not take away
from data gathering and storing. The latter should be a derivative result of the
investigation ‘on the ground’ and not become a kind of end in itself.
Michelangelo once said, ‘we criticise by creating’. This clear statement can be aptly
applied to scientific research.
In my fruit fly research, I have held the view that basic research into systematics,
ecology and behaviour of species, with its synthesis and analysis, provides the allimportant foundation for major contributions to world food production, while
preserving our environment. I am happy, tonight, for you the listeners and readers to be
the judge. I am happy to be within a University that fosters science and that seeks to
‘manage creativity’ in the best academic traditions.
As Ursula Le Guin writes in Earthsea Trilogy ‘We must learn to keep the balance. Having
intelligence we must not act in ignorance. Having choice, we must not act without
responsibility’ (p.361). It is my opinion that we need universities that free their
researchers and teachers as far as possible, to practice their art of research and to
inspire students with their scholarship. We need Faculties that propound the splendid
nexus between research and teaching, imbuing students with the love of enquiry and
lifelong learning. Above all, we need researchers that are positive, with a passion for
biology, energy and enthusiasm for their work and an ability to plan and focus on
worthwhile goals. We cannot buy commitment, dedication and perseverance, it, like
leadership, is born, but we can cultivate the seeds of these attributes when present in
our next generation. Just as our teaching programs should be designed to educate and
enlighten, our research endeavour should contribute to society with kind and caring
attitudes.
ACKNOWLEDGEMENTS
On the occasion of this Professorial Lecture, I wish to thank the following University
staff members for their help and support in organising this event; Jan Benjamin, Petney
Dickson and Meredith Romig.
What one achieves over a period of research is always the result of collaboration with
co-workers. Meredith Romig has worked with extreme dedication for over 30 years and
made enormous contributions in scientific artwork, field experimental research and
operational co-ordination. Allan Allwood has been a long-time collaborator in research,
both within Australia and in overseas project activities, and has contributed enormously
to fruit fly work in the region.
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Fruit Flies – Lessons in Research and Politics
I have collaborated with many other scientists from Australian and overseas
institutions, covering Entomology and other scientific disciplines. Such collaboration is
always rewarding, not only for the direct research outcomes but also for the inspiration
one receives from working in, and understanding, other facets of science.
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Fruit Flies – Lessons in Research and Politics
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Fruit Flies – Lessons in Research and Politics
Professor Richard Arthur Ian Drew AM FTSE PhD, DSc
Tropical Fruit Fly Research Group
Australian School of Environmental Studies
Griffith University,
Nathan, QLD 4111, Australia
Phone: (07) 3875 3696; Fax: (07) 3875 3697
Email: [email protected]
Webpage: http://www.ens.gu.edu.au/fruitfly/drew/drew.htm
Research Interests : Taxonomy, Biology/ Ecology, Speciation,
Biogeography, control of fruit flies in the family Tephritidae
Recent Distinctions
1990 – Awarded the Ian Mackerras Medal by the Australian Entomological
Society for contributions to Australian Entomology
1995 – Elected a member in the General Division of the Order of Australia
2000 – Clunies Ross National Science and Technology Award
2000 – Elected Fellow of the Australian Academy of Technological Sciences
and Engineering
Publications
3
11
74
3
1
Books/ Monographs
Book Chapters
Journal Articles
Conference Proceedings (refereed only)
Invited Lecture
36