Miolri~irfil.Jourtm1of
the Linnenn Sociely (198l), 16: 33-40.
Only connect
R. I . VANE-WRIGHT
Department of Entomology, British Museum (Natural History),
London SW7 5BD
Accepted far publication February 1981
Despite the fact that it has been said that the only people interested in definitionsare those who wish
to criticize them, I thank the five commentators. It has also been said that “the Linnean Society has
been the medium for the publication of classical Memoirs upon Mirniay” (Poulton, 1898). I hope
History will continue to be generous in its judgment on this latest round.
THE GREAT UNCLASSIFIED
To Edmunds and Cloudsley-Thompson,whose criticism is primarily a litany of
fascinating, hard-to-classify examples, I offer no excuses-in all cases we are
unable to decide if the organisms concerned are normally involved in mimicry
because we lack sufficient information. But all of us should remember (myself
included, as I have at times perpetrated the mistake), that while we may talk of ‘a
mimic’ as convenient shorthand for ‘anindividual or species in a situation controlled by the dynamics of mimicry’, we should not foster the error of insisting
that we must decide on a given species or individual being, or not being, mimetic
in some absolute sense. Essentialism or typology has no place in modern biology.
NEUTRAL AND USEFUL
Endler’s survey is interesting and stimulating. However, I would like to make
two small points in self justification. Endler claims that an important and overlooked criterion for separating phenomena which involve crypsis from those
involving mimicry is that, in crypsis, mistakes in discrimination by the operator
have no effect on the population dynamics of the primary signal generator
(model).To be fair, he does say that I made this distinction indirectly in the paper
under discussion (Vane-Wright, 1980) but categorically denies that I made the
distinction in my 1976 paper. I think I got pretty close. “A neutral interactive role
between model and mimic may be indicative of a cryptic resemblance; it is intended to discuss this aspect in a more generalized treatment” (Vane-Wright,
1976: 31).
My second point at issue may indicate thin skin in addition to a bruised ego.
Endler concludes that the confusion by an operator between model and mimic
0024-4066/8 1/050033 + 08S02.00/0
3
33
Q 198 1 The Linnean Society of London
R. 1. VANE-WRIGHT
54
can give rise to many classes of phenomena: “Calling most or all of them
‘mimicry’ is not very useful” (Endler, 1981). My original attempt at a general
definition was introduced in the context of trying to define 40 theoretically different types of mimicry and to separate them from all possible types of crypsis. I
have exhorted biologists that “although the ‘old war-horses’ of Batesian and
Miillerian mimicry still offer much sco e, it is time for other types of mimicry to
be studied comparatively” (Vane-Wrig t, 198 1). If Endler is suggesting that I am
wasting breath because my proposals are not complex enough, I can only refer
him to the criticisms of Bees (1977).
R
DEFINITIONS AND THEORIES
With Robinson, and to a lesser extent Rothschild, I must take more serious
issue. Not surprisingly, it would seem that differences in assumptions about
metaphysics lie behind our disagreements. I will discuss some of these aspects,
starting with something of little significance and leading up to more fundamental
matters.
An ambigui8
Robinson claims that I quote him of “concluding that plant-part mimicry is part
of crypsis” (my italics). What I actually said, in its entirety, w a s “I do not think it
appropriate to include these exam les of resemblance by mantids under the term
mimicry, as suggested by Edmun s (1976); they are examples of crypsis, as dealt
with by Robinson ( 1969)” (Vane-Wright, 1980). And again, “Robinson (1969) has
made a notable attempt to classify cryptic resemblances” (Vane-Wright, 1976:
49). What I meant by these statements was that Robinson had provided a good
classification of the phenomena I consider to be examples of cxypsis. I fully
accept the biological importance of Robinson’s separation of backgrounddependent and background-independent resemblances. As this distinction does
not affect mimicry as I have defined it, I have not specificall discussed the topic.
However, I was at fault for using ambiguous language an not making it clear
that Robinson and I used the terms mimicry and crypsis in different ways.
B
dy
Reductio ad absurdam
Robinson takes me to task for applying reductio ad absurdam to a series of
statements by Edmunds (19761, connected with the idea that “mimetic animals
. . are detected by predators”. In defining a concept, one is necessarily concerned with semantics. The problem comes down, ultimately, to whether or not
you choose to label leaves as primary signal generators in the general context of
mimicry and crypsis. I do not think it meaningful to do so-unless the leaves
happen to be petals. Are Robinson’s leaves ‘signalling’ that they are leaves for
some mystic purpose connected with overloading the minds of predators with
information about inedible objects? Are there, normally, signal-based interactions between insectivores and sticks? The implication is that ‘signal’ and any
selection of the light rays, volatile chemicals or other emanations arising from an
object have the same meaning. Robinson apparently does not make the distinction made by most behaviourists, of signals and sign stimuli; or that made by
psychologists, of potential and effective stimuli. Of course, an animal may attend
.
ONLY CONNECT
35
to sticks-and stones-but a stone surely does not signuf that it is a stone? Thus,
to say that a leaf-insect is ‘detected’ and then that it ‘signals that it is a leaf seems
to use words without due regard to their semanticcontent.
Dictionaries-a game for two
Despite concern for semantic accuracy, the use of dictionaries rarely helps
when it comes to arguments over the use of words within science. Robinson uses
the O.E.D. to define the verb ‘to mimic’, but overlooks the fact that the principal
word under discussion is the noun ‘mimicry’and that this word is now regarded as
having a special, biologic4 meaning. Here are two dictionary‘definitions: “an
advantageous superficial resemblance to some other species or object ( b i d 1’’
(Macdonald, 197 7); “protective similarity in appearance of one species of animal
to another” (Abercrombie,Hickman &Johnson, 1966). At least Dr Robinson and
I can agree to disagree with both of these!
In the present context, it is necessary to search for lexicons which define
mimicry in some way differently from crypsis. Most are not very helpful. Beadnell
( 1938), for example, defines ‘mimicry’as “assumption of colour resemblance as a
means of self-protection” and ‘cryptic’ as “protective coloration for condalInent”. The O.E.D., Robinson’s choice, gives mimicry (in the biological sense) as
“a close external resemblance which a living creature (or sometimes a nest, etc.)
bears to a different animal, or to some inanimate object” but gives no special
biological meaning for the word cryptic (“hidden, secret, occult, mystical”). In
fact, it is difficult to find the noun ‘crypsis’ in dictionaries; Holmes (1979) defines
it as “the phenomenon of being c v t i c especially in the sense of camouflaged to
resemble part of the environment , against which she gives for mimicry, “the
resemblance of one animal (the mimic) to another, so that a third animal is
deceived into confusing them; the resemblance of an animal or plant to an
inanimate object”.
In my opinion (see below), I consider all these definitions woefully inadequate
for the concept of mimicry, as originally introduced by H. W.Bates (1862: 509)
and as more or less understood in biology ever since.
Mimicry is a theory
Mimicry is, historically, a description of particular examples of what evolutionists call ‘convergences’, or what cladists now call ‘false characters’. Bates was
impressed by the remarkable similarity in outward appearance of certain rare
Dismorphiinae (“Lepta1ides”-six-legged butterflies with a unique type of
forewing radial venation) and some abundant Nymphalidae (“Acraeoid and
Danaoid He1iconidae”-‘four-legged’ butterflies with commonplace forewing
radial venation), all of which flew together in the Amazonian forests. Using the
then new theory of evolution by natural selection, advanced by his friends
Charles Darwin and Alfred Russel Wallace, Bates fashioned an explanation. First,
he assumed that the common nymphalids were somehow intrinsically protected
from insectivorous birds and that such birds recognized and actively avoided
them. Secondly, he assumed that the rare Dismorphia were not intrinsically protected. He then suggested that some initial similarity between the two sorts of
butterfly had been enhanced through the agency of generations of differential
R. I. VANE-WRIGHT
36
predation by the birds: the most nymphalid-like Dismorphias tended to survive
best at each generation.
Alternatives to this theory of mimicry are that similarities (or homeochromtismsee Poulton, 1897:iX) have arisen through:
(a) the actions of a [beneficent or capricious?] creator to ensure survival
(Kirby, 18 17);
(b) individual organisms ‘miming’, involving some conscious act of will
(Distant, 1899);
(c) parallel evolutionary modifications in response to some common local
abiotic factor (Blandford, 1897);
(d) a response to the chemistry or structure of food (Acworth, 1947);
(el orthogenesis (Eimer, 18971;
(0 determination by dynamic autonomic and choronomic laws (effectively a
combination of ‘c’ and ‘e’: Berg, 1922);
(g)sexual selection (Poulton, 1898) and
(h) pure chance, requiring no explanation whatsoever (McLachlan, 1897).
Into the wilderness
Samuel Butler defined definition as the act of “enclosing a wilderness of idea
within a wall of words”. But if we must also define our words, are we not faced
with mere tautology, or infinite regress?
Ghiselin ( 1966a, b) states that the meaning of a word has nothing to do with
the practical roblems of identif)ing examples that fit the definition. Definitions
are “simply iscussions of how words happen to be used, entailing an analysis of
the concept the words symbolize, or are proposals to use the words in a particular
way” (Ghiselin, 1966a). The same author goes on to point out that while it is
desirable that we employ an operational definition of meaning (“propositions are
meaningful only if it is possible, inprimjde, to verifj them by empirical test”), it is
all too easy to “oversimplif) theories in seeking an easy route to their operational
testing”, Butler and Ghiselin agree: definitions are about ideas.
In the light of these comments, I assert that my definition of mimicry (VaneWright, 1980) is valid in that it is about the meaning of a word; stems from an
analysis of what the word symbolizes; proposes to use the word in a particular
way and is operational in Ghiselin’s sense. Although I accept Robinson’s criticism
that my ideas about predator behaviour and perception may be gross oversimplifications of physiology, Robinson’s “improved” definition is an unacceptable
oversimplification of Bates’ theory. Robinson seeks to remove two component
ideas: evolution by natural selection and perception. Both of these are essential to
a complete, modern statement of the theory-that their inclusion may cause
subse uent inconvenience when we try to assign putative examples to categories
is irre evant.
To the possible objection that we need not be bound by Bates’ original formulation of the theory (whichhas, indeed, been both restricted and generalized since
1862-most notably b the introduction of Wickler’s concept of intraspecific
mimicry), I would say xis: remove ‘fitness’(= evolution by natural selection)and
investigationsof mimicry become impotent in considering the merits of the alternative explanations given above. This emasculation would have delighted
Darwin’s critics and is a misrepresentation of what Bates was trying to do.
B
4
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31
Remove perception and the meaning of’mimicry becomes trivial. Any notion of‘
mimicry as an explanation of a class of convergences or false characters having as
a common cause “mistaken identity”, “false information”, “confusion”, “deception” or simply “identification”, demands the involvement of some sentient,
perceiving being or agency-be this a creator, birds choosing this or that, or one
organism consciously copying the actions of another. Mimicry is a logical necessity arising from the signal-based interactions that we know (believe) to exist in
nature, regardless of whether or not there are any real examples. Mimicry theory
describes the possibilities for the evolution of parasitism and mutualism inherent
in the establishment of communication. A concept of communication which does
not embrace perception is, I believe, impossible.
I f lqe is an illusion, then so is death
An essential aspect of mimicry theory is the concept of alternative prey, most
fully discussed by Holling (1965).Mimicry cannot work, cannot evolve through
natural selection, without there being some choice open to the operators.
Mimicry (and crypsis: Vane-Wright, 1976: 49) describes a set of relations between
organisms-it does not describe the organisms themselves (which is why I am at
fault for insisting that leaf or stick insects are necessarily cryptic-in high density
conditions, such as occurred with de Ruiter’s jays, such animals do function as
mimics, in my sense). According to Ghiselin ( 1966b),“in [describing]a relation . . .
all the terms must be supplied”. Ghiselin goes on to examine the statements
“Socrates is similar”, which is obviously meaningless and “birds are more similar
to each other than mammals are to each other”-which he shows to be equally,
although less obviously, vacuous. So it is with a statement of the type which
Robinson seeks to incorporate into his “improved” definition. “Mimics gain
food”-in relation to what? If the incompleteness of this statement is not
obvious, consider the third alternative which Robinson gives-“mimics gain a
mating advantage”-in relation, presumably, to non-mimetic individuals of the
same species, which must be at some disadvantage. What can “gain a mating
advantage” be other than some measure of relative fitness?
Logical traps
Rothschild (p. 22) observes that cuckoos change their feeding habits as they
grow older, the adult birds eating caterpillars formerly unacceptable to them as
fledglings. She suggests that this predator thus “upsets the whole conventional
concept of mimics, models and fitness”. Fitness is a dynamic property, not a fixed
attribute of individual organisms. Likewise, a single organism can readily take on
the role of model or mimic, depending on the particular operator involved; the
terms model and mimic describe functional entities in a schematized biological
interaction: they are not fixed properties of individuals. Thus, the waywardness
of the cuckoo’s appetite cannot invalidate any reasonable definitions of models,
mimics or fitness.
Wickler (1968) and Wiens (1978) appear to have had a similar problem with
regard to the often expressed view that “Miillerian mimicry is not mimicry”.
Because, it is argued, a single object (individual) can fulfil two roles, either the
division into models and mimics is impossible (Wiens), or no ‘deception’ is
R. I. VANE-WRIGHT
38
involved (Wickler).All such objections seem to relate to the misplaced desire to
define individuals. What can be defined are the functional roles of models and
mimics (Vane-Wright, 1976:48); the observation that a single organism can
fulfil two roles at different times is not unique to Milllerian interactions; it is
potentially the case for all types of mimicry system.
A related matter is the widespread confusion over the demonstrable existence
of a palatability spectrum and the conclusion that, therefore, a mimicry spectrum
also exists. This idea, most recentl reiterated by Huheey (1980:1213), has
correctly been dismissed as illogical y Rothschild (1980:8?3). In any particular
interaction, an organism must either fulfil the role of mimic, or model, not both
(and it cannot be a ‘70% mimic’ or a ‘45% model’). Naturally, a particular species
or population might in some way be measured as showing, say, 70% Batesian
mimic interactions. In such a case the 70% might be made up by 70% of the
individuals all behaving in a standard way, or all of the individuals might all show
70% interactions of the Batesian type, or the figure might represent any possible
combination of fixed or variable individual interactions.
Thus I retain my conviction that, logically, models and mimics can be defined
but only as interactive elements-they are not ‘labels’ to be applied in a fixed or
permanent way to individuals, populations or species.
i
The use oftruth is like the use ofwords; both truth and words depend greatly upon custom
This Butler aphorism illuminates a tricky point about words and mimicry. As I
have already stated (Vane-Wright, 1976, 19801, I do not think it advisable to use
the word ‘deception’ in deliberative writings about mimicry; likewise, the concept
of ‘false information’ is suspect. The terms are unnecessary and their anthropocentrism predisposes us to think about mimicry in a narrow way. “We like to
judge animals in the same way as our fellow men, and the more they are like us
the more we do this. It can be carried to the point where, quite unfairly, even
human moral standards are applied to them” (Burkhardt 8c Schleidt, 1967).
Custom can also lead us astray in other ways. Endler’s table 1 shows that the
idea that crypsis is to do with objects of “no interest” to an operator goes back to
Poulton (1898:565) and the wording was incorporated by Cott (1940) into his
definitions. Martin’s translation of Wickler ( 1968) uses, for mimicry, the hrase
“signals of interest” which I have, in turn, incorporated into my own de nition
(Vane-Wright, 1980). As I have already discussed, a ‘signal’ is necessarily always
of interest, because it can only be defined in relation to a tuned signal receiver. A
“signal of no interest” is manifestly no signal at all-it is background nois-r
a
potential stimulus at most. Thus, a refined version of m definition would indeed
remove the words “of interest”, as pro osed by Ro inson-but not for his
reason. In the full context they are re undant words, the information they
contain being already conveyed by the proper notion of ‘signals’.
R
B
L
Why does m i m i q still excite?
After 120 years, Bates’ theory still excites the imagination and still gives rise to
wild enthusiasm or total disbelief. Even an attempt to define it attracts attention.
To understand wh mimi arouses our interest so, I think we must look outside
the narrower con nes of e subject.
h ” X
ONLY CONNECT
39
Gregory ( 1980),in trying to demonstrate similarities between preceptions and
the hypotheses of science, suggests that “hypotheses are selections of signalled and
postulated data organized to be effective in typical (and some novel) situations” and
that they “are effective in having powers to predict future events, and further
hypotheses. They may also predict what is not true”. On this basis, the perceptions of operators, with respect to models and mimics, could be seen as directly
comparable to scientific hypotheses. The study of mimicry is so fascinating and
gives rise to such debate because, in a single system, it combines paradigms for
theories of evolution and of epistemology. What could be more interesting than
that?
Is Robinson’s improvement an improvement ?
I do not believe so. I have demonstrated that the attempt to remove the
concepts of fitness and perception is both historically and scientifically ill-conceived. In fact, these concepts are not actually removed from the ‘improved’
definition. They are merely subsumed by some of the remaining words, in particular, “signal properties”,. “confused” and “gains”. Kirby ( 181?), speaking of
the wasp- and bee-like flies of the genus Volucella, commented “thus has the
Author of nature provided that they may enter those nests and deposit their eggs
undiscovered. Did these intruders venture themselves amongst the humble-bees
in a less kindred form, their lives would probably pay the forfeit of their presumption”. Of the nine theories about homeochromatism that I have listed
above, I think the spirit of Robinson’s definition comes closest to Kirby and the
kindly intrusions of the Wisdom of Providence and the Author of Nature. Even if
neo-Darwinism is inadequate to h l l y explain nature (Gould, 1981),even if much
of it is no more than “empty rhetoric’’ (Patterson, 19801, let us not strip mimicry
from its true place in science: at the very heart of Darwinism.
ACKNOWLEDGEMENTS
I would like to thank Chris Humphries, Laurence Mound and Colin Patterson
for some helpful suggestions.
REFERENCES
ABERCROMBIE, M., HICKMAN, C. J. &JOHNSON, M. L., 1966. A Dictionafy ofliology, 5th edn., 284 pp.
Harmondsworth: Penguin.
ACWORTH, B., 1947. Eulfer/Zy Miracles and Mysfe’es: xii + 260 pp. London: Eyre & Spottiswoode.
BATES, H. W., 1862. Contributions to an insect fauna of the Amazon Valley. Lepidoptera: Heliconidae.
Transactions of the Linnean Society of London, 23: 495-566.
BEADNELL, C. M., 1938. Dictionary of Scienlific T e r n : x + 235 pp. London: Watts & co.
BEES, J., 1977. Terminal terminology. A n t m , London, I : 35.
BERG, L. S., 1922. Nornogenesis or Euolulion Deteminedby Law [original in Russian]. Consulted in English translation by J. N. Rostovtsov, 1969 edition, xxiv + 477 pp. Cambridge, Mass.& London: MIT Press.
BLANDFORD, W. F. H., 1897. [Discussion of paper by F. A. Dixey.1 Proncdings ofthc Enlomologicd S d e t y of
London, 1897: xx-xxxii, xxxiv-xlvii.
BURKHARDT, D. & SCHLEIDT, W.,1967. In Burkhardt, Schleidt & H. Altner(Eds1,Si&s inlhe Animal World,
translated Irom German by K. Morgan, 150 pp. London: George Allen & Unwin.
C o n , H. B.. 1940. Adaptive colorationin animals, xxxii + 508 pp. London: Methuen.
DISTANT, W. L., 1899-1900. Biological suggestions. Mimicry. The Zoologist, (4Y: 289-315,341-363,443-470,
529-553; (4M: 116-130.
EDMUNDS, M., 1976. The defensive behaviour of Ghanaian praying mantids with a discussion of territoriality.
Zoological Journal of the Linnean Society, 58: 1-37.
R. I. VANE-WRIGHT
40
ELMER, C. H. T., 1897. Orthogmsis der Schmtterlinge: xvi + 513 pp. Leipzig: W. Engelmann.
ENDLER, J. A., 1981. An overview of the relationships between mimicry and crypsis. Biological Journal ofthe
Linnean Society, 16: 25-31.
CHISELIN, M. T., 1966a. An application of the theory of definitions to systematicprinciples. SystematicZoology,
15: 127-130.
CHISELIN, M. T., 1966b. On psychologism in the logic of taxonomic controversies. Systematic Zoology, 1 5 : 207215.
COULD, S. J., 1981. The chance that shapes our ends. New Scientist, 89 (1239): 347-349.
HOLLING, C. S., 1965. The functional response of predators to prey density, and its role in mimicry and
population regulation. M m h of the Entornologicid Society of Canada, 45 : 1-60.
HOLMES, S., 1979. Henderson's Dictionary ofBiological Trrmc,9th edn.: xi + 510 pp. London: Longman.
HUHEEY, J. E., 1980. Batesian and Miillerian mimicry: semantic and substantive differences of opinion.
Evolution, 34: 1212-1215.
KIRBY, W., 18 17. In W. Kirby & W. Spence, An Introduction to Entmnology, 2: 529 pp. London: Longman, Hurst,
Rees, Orme & Brown.
1652 pp.
MACDONALD, A. M., 1977. Chambers Twentieth Century Duhnary (with supplement): xii
Edinburgh: Chambers.
McLACHLAN, R., 1897. [Discussion of paper by F. A. Dixey]. Proceedings ofthe Entmnologicid Society ofLondon,
1897: xx-Xxxii, xxxiv-xlvii.
PATTERSON, C., 1980. Ckdistics. Biologist, 27: 234-240.
POULTON, E. B., 1897. [Discussion of paper by F. A. Dixey]. Proceedings ofthe Entomological Society ofLondon,
1897: xx-Xxxii, xxxiv-xlvii.
POULTON, E. B., 1898. Natural selection the cause of mimetic resemblance and common warning colours.
Linnean Society's Journal, Zoology, 26: 558-612.
ROTHSCHILD, M., 1980. Mimicry, buttertlies and plants. Symbolar Botanicac Upsalicnris, 22: 82-99.
VANE-WRIGHT, R. I., 1976. A unified classification of mimetic resemblances. Biological Journal ofthe Linnean
+
SoCiCty, 8: 25-56.
VANE-WRIGHT, R. I., 1980. On the definition of mimicry. Biological J o u d ofthe Linnean Society, 13: 1-6.
VANE-WRIGHT, R. I., 1981. Mimicry and its unknown ecological consequences. In P. H. Greenwood 8c P. L.
Forey (Eds), C k c , Change and ChaUenge-tht? Evolving Bws@re: 157-168. London: CUP 8c BMNH.
WICKLER, W., 1968. Miming in Plrmts and A n i d , translated from German by R. D. Martin, 255 pp. London:
Weidenfeld & Nicholson.
WIENS, D., 1978. Mimicry in plants. EvoluZioMry Biology, 11: 365-403.