Outline
Animal Communication
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Katydid Calling song:
A case study
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Patrick A. Guerra
Div. of Life Sciences, UTSC
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Communication
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The cooperative transfer of
information from a signaler to a
receiver
Information contained within the
message
Multimodal signals
Multicomponent signals
Communication
Bioacoustics
Katydids – Natural History
Katydid communication – Calling song
My research on Conocephalus brevipennis
Female responses to song
Male responses to song
The Agora Effect
Bioacoustics
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The study of sound in animals
Animal communication and
associated behaviour
Sound production anatomy and
neurophysiology of animals
Auditory capacities and auditory
mechanisms of animals
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Katydid – Natural History
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Habitat: grassland areas and forests
Diet: Leaves, stems, flowers, and fruits of
plants; some are carnivorous (e.g.
subfamily Listroscelidiae)
Predators: Bats, birds, snakes, shrews,
and monkeys; important in the food web
chain
A key feature: They have antennae, which
can be 2-3 times as long as their body
Diversity: some 4,000 species of katydids
in the world; e.g. Amazon rain forests =
about 2,000 katydid species
Katydids – Natural History
Panacanthus cuspidatus
showing anti-predator
response
Neoconocephalus
nebrascensis, a
coneheaded katydid
A Leaf Mimic
Subfamily: Pseudophyllinae
Katydids – Natural History
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Life cycle:
Have incomplete metamorphosis (egg(eggnymphnymph-adult)
Lay eggs in many places (e.g. soil, in
stems of plants, and in bark of trees)
Nymphs are very similar to adults, but are
smaller and lack fully developed wings.
The nymph goes through several molts
(generally five), gradually developing into
an adult.
Katydids – Natural history
An Airplane
katydid. The
widely-spread rear
legs resemble the
wings on a plane.
Lichen-colored
katydid. A highly
camouflaged
insect.
A wasp-like katydid. Notice the
grasshopper-like legs which
give it away. It is a type of bush
katydid or Phaneropterinae.
Orchelimum
vulgare, a meadow
katydid
Pterophylla camellifolia, a
true katydid
Photos: Dr. James Castner
Photos: Glenn K. Morris and Thomas J. Walker
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Katydid Communication: Calling
Song
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„ Functions
Intersexual:
Intersexual: e.g.,
mate attraction,
callcall-reply systems
Intrasexual:
Intrasexual: e.g.,
malemale-male
competition
Aggregate
behaviour:
behaviour: e.g.,
habitat selection
Katydid Calling song: Hearing
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Ear
Ear
Katydid Calling song: Stridulatory
apparatus
Hearing: the
hearing organ, an
"ear" (tympanum(tympanumcovered auditory
structure), is found
at the base of each
front leg’s second
segment (tibia)
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Wing structure of
C.brevipennis
male
Song production:
sound created by
rubbing a scraper
on one forewing
against a file on
the other front
wing (stridulation
(stridulation))
Conocephalus brevipennis
The Short-winged meadow katydid
Male
Female
Conocephalus brevipennis
Ovipositor
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C. brevipennis Calling song
Sympatric and syntopic
Conocephalus nigropleurum
Comparison
Buzz-tick-gap AM pattern
Continuous buzz
AM pattern
Experiments
Problems faced in nature
by C. brevipennis
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Species recognition
Localization of sound source
Evaluation of a singer
Signal interference
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Present signals to animals that may
be relevant to them in the field
No choice phonotaxis trials:
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The song of an individual conspecific male (C.
(C. brevipennis)
brevipennis)
The song of a single sympatric and syntopic heterospecific (C.
nigopleurum)
nigopleurum)
The song of a single sympatric heterospecific (Conocephalus
attenuatus)
attenuatus)
Simulated aggregate song
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Two choice phonotaxis trials:
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The choice between an individual and a group
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Methods: Phonotactic bioassays
Results: No choice
Hanging
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1. Individual singer
2. Simulated aggregate song
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F
50 cm
E
70 cm
F
90 cm
A
Females (p < 0.0005)
and males (p < 0.025)
approach conspecific
song
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B
C
Results: Two choice
Simulated aggregate song
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VS.
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F
58 dB
M
Females approach a single singer (p < 0.005)
while males approach a group if it is more
quiet than the individual singer (p < 0.02)
F
M
Females (p < 0.05) and
males (p < 0.01) both
approach simulated
aggregate song
Female responses to song
Individual singer
70 dB
M
M
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No choice results
Group song = evaluate males
Conspecific song = choose appropriate
mates
SpeciesSpecies-specific features of calling song
aid approaching appropriate mates
Two choice results
Choose signals that facilitate finding an
appropriate mate
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Aggregate song response and the
Agora effect
Male responses to song
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No choice results
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Attracted to group song and conspecific
song
Aggregative behaviour favoured by
conspecific females
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Two choice results
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Space themselves within groups in order
to be perceived by females
Calling song: a mediating factor for interintermale spacing within groups
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A problem?
1. Intermingled
aggregations
2. Contiguous
aggregations
C. brevipennis and C. nigropleurum approach
aggregate signals
Males benefit by joining forces with other
males, regardless of species
Produce a stronger signal and attract more
females
Just a lottery as to which species a female
belongs to
Future Research
How do ♂s form
appropriate groups?
„ Determine actual
distributions of signalling
males in aggregations
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Summary
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C. brevipennis aggregative behaviour
Females choose signals aiding mate
choice
Males choose signals aiding aggregate
formation & proper interinter-male spacing
within groups
Context-dependent functions of
C. brevipennis calling song
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