Showing papers by "Mathieu Joron published in 1999"
TL;DR: These contrasting patterns can be explained, in part, by the shape of a “number-dependent” selection function first modeled by Fritz Muller in 1879: Purifying selectio...
Abstract: ▪ Abstract Mimicry and warning color are highly paradoxical adaptations. Color patterns in both Mullerian and Batesian mimicry are often determined by relatively few pattern-regulating loci with major effects. Many of these loci are “supergenes,” consisting of multiple, tightly linked epistatic elements. On the one hand, strong purifying selection on these genes must explain accurate resemblance (a reduction of morphological diversity between species), as well as monomorphic color patterns within species. On the other hand, mimicry has diversified at every taxonomic level; warning color has evolved from cryptic patterns, and there are mimetic polymorphisms within species, multiple color patterns in different geographic races of the same species, mimetic differences between sister species, and multiple mimicry rings within local communities. These contrasting patterns can be explained, in part, by the shape of a “number-dependent” selection function first modeled by Fritz Muller in 1879: Purifying selectio...
497 citations
TL;DR: The mimetic polymorphism of the butterfly Heliconius numata Cramer is explained by means of multiple selection-migration clines at a single locus, a similar process to that which explains narrow hybrid zones between geographic races of other Heliconii butterflies.
Abstract: Polymorphism in aposematic animals and coexistence of multiple mimicry rings within a habitat are not predicted by classical Mullerian mimicry The butterfly Heliconius numata Cramer (Lepidoptera: Nymphalidae; Heliconiinae) is both polymorphic and aposematic The polymorphism is due to variation at a single locus (or `supergene') which determines colour patterns involved in Mullerian mimicry We sampled 11 sites in a small area (approx 60×30km) of North-eastern Peru for H numata and its co-mimics in the genus Melinaea and Athyrtis (Ithomiinae), and examined the role of temporal and spatial heterogeneity in the maintenance of polymorphism Colour-patterns of Melinaea communities, which constitute the likely `mimetic environment' for H numata, are differentiated on a more local scale than morphs of H numata, but the latter do show a strong and significant response to local selection for colour-pattern In contrast, analysis of enzyme polymorphism in H numata across the region revealed no spatial structure, which is consistent with a high mobility of this species Differences in spatial variability in the two taxa may have caused H numata to become polymorphic, while temporal variability, not significant in this study, probably has a lesser effect The mimetic polymorphism is therefore explained by means of multiple selection-migration clines at a single locus, a similar process to that which explains narrow hybrid zones between geographic races of other Heliconius butterflies
113 citations
01 Jan 1999
TL;DR: Mullerian and Batesian color patterns are often determined by relatively few pattern-regulating loci with major effects as discussed by the authors, which can be explained by the shape of a "number-dependent" selection function first modeled by Fritz Muller in 1879.
Abstract: ▪ Abstract Mimicry and warning color are highly paradoxical adaptations. Color patterns in both Mullerian and Batesian mimicry are often determined by relatively few pattern-regulating loci with major effects. Many of these loci are “supergenes,” consisting of multiple, tightly linked epistatic elements. On the one hand, strong purifying selection on these genes must explain accurate resemblance (a reduction of morphological diversity between species), as well as monomorphic color patterns within species. On the other hand, mimicry has diversified at every taxonomic level; warning color has evolved from cryptic patterns, and there are mimetic polymorphisms within species, multiple color patterns in different geographic races of the same species, mimetic differences between sister species, and multiple mimicry rings within local communities. These contrasting patterns can be explained, in part, by the shape of a “number-dependent” selection function first modeled by Fritz Muller in 1879: Purifying selectio...
18 citations
01 Jan 1999
TL;DR: At first sight, it seems most unlikely that Heliconius warning colour races have evolved by means of stochastic peak shift or shifting balance, but this is not the case.
Abstract: 1. At first sight, it seems most unlikely that Heliconius warning colour races have evolved by means of stochastic peak shift or shifting balance.
14 citations
TL;DR: The perspective dealt only with the paradox that mimicry rampantly diversifies in morphs, subspecies and species, even though simple theory explains only convergence in a reduction of diversity.
Abstract: There are many good general reviews of the evolution of mimicry1xMimicry in Plants and Animals. Wickler, W. See all References, 2xTurner, J.R.G. : 141–161See all References, including Edmunds's own excellent book3xDefence in Animals. Edmunds, M. See all References3. Our perspective dealt only with the paradox that mimicry rampantly diversifies in morphs, subspecies and species, even though simple theory explains only convergence in a reduction of diversity. (Also, we did refer to MacDougall and Dawkins, see Ref. 31 in our original article; however, their idea is now criticized4xSee all References4.) We concentrated on butterflies because most studies relating theory, field data and genetics are done in this group.We very much doubt the implication that butterflies are special; mimicry ought to work the same in less well known organisms. Edmunds and Golding suggest that female sex-chromosome heterogamety and female-limited mimicry in butterflies are related. However, mimetic sexual dimorphism in butterflies is due, in part, to sexual selection acting on males5xThe Descent of Man, and Selection in Relation to Sex (2nd edn). Darwin, C. See all References, 6xTurner, J.R.G. Biol. J. Linn. Soc. 1978; 10: 385–432CrossrefSee all References, 7xVane-Wright, R.I. : 251–253See all References, and similar dimorphisms are also common in male-heterogametic organisms, such as mammals. In only one case – Papilio glaucus in N. America8xHagen, R.H. and Scriber, J.M. J. Hered. 1989; 80: 179–195See all References8 – is a mimetic-switch gene linked to the female-specific W chromosome; most mimetic polymorphisms are inherited autosomally, with sex chromosomes merely serving to switch between mimetic and nonmimetic patterns through their effect on sex. Although no cases of female-limited mimicry are known in organisms other than butterflies, we don't see a good reason for this: where ecologically feasible, there are cases of male-limited mimicry in Lepidoptera9xVane-Wright, R.I. J. Zool. 1975; 177: 329–337CrossrefSee all References9, for instance in diurnal male moths that search for females that rest by day.The assertion that butterflies have become diurnal because of unpalatability is clearly wrong. Basal groups like Hesperiidae are chiefly palatable, and the palatability of most Dismorphiinae, Coliadinae, Lycaenidae and Libytheinae argues for unpalatability evolving within the Pieridae and Nymphalidae, rather than before their radiation. Mimicry is associated with diurnality in Lepidoptera; but this is hardly surprising given that nocturnal predators rarely use details of colour and pattern when hunting prey. Rapid and unpredictable flight (Castniidae, Hesperiidae and Charaxinae), low profitability (Satyrinae and Lycaenidae), and camouflaged undersides (many Nymphalidae) are among other common attributes of Lepidoptera that allow diurnality. Unpalatability, warning colour and mimicry are clearly among adaptations that permit diurnality, but they are neither required nor unique to butterflies. Anyone who has been stung by a Paraponera and swarmed over by Crematogaster will be able to inform about great differences in the unpleasantness of ants, and it seems probable that similar palatability spectra exist in spiders and Diptera. Mimetic butterflies are better studied, rather than having special kinds of palatability or mimicry.Gordon and Smith resent our correct citation of their group's earlier ideas on Batesian overload in Danaus. However, we also reported (p. 463 in our original article) their current hypothesis: ‘recent contact… of previously isolated geographical races has been suggested as a nonadaptive cause of polymorphism in these species’. Although we did not say so in the perspective, secondary contact is not a good deus ex machina for explaining mimetic polymorphism. It has recently been found that in both Acraea encedon10xSee all References10 and Danaus chrysippus (F. Jiggins, pers. commun.) sex ratio distortion is a result of infection by male-killing bacteria rather than hybrid breakdown. We have no doubt that similar nonhistorical ideas will explain other puzzling features of the genetics of Danaus and Acraea. In any case, geographic isolation in a refuge cannot by itself cause an initially unfavourable colour pattern to spread; drift and/or fluctuating selection are required initially, and these could also take place during parapatric contact, as in Heliconius11xMallet, J. and Turner, J.R.G. : 262–280See all References11, making allopatry unparsimonious. The Danaus anomaly also stubbornly refuses to disappear via an accusation of beanbag genetics. We must still explain an area larger than Europe with unexpected mimetic polymorphism. We suggest that this and other Mullerian polymorphisms might be maintained by spatiotemporal heterogeneity, as described in our article. Mimetic selection in Danaus may be fairly weak in the area of polymorphism, and balanced by fairly strong gene flow (large-scale migrations), leading to a wide band of polymorphism between areas of stable relative purity. Similar patterns of current selection are a likely source of widespread polymorphism in Mullerian mimetic ladybirds12xMelanism. Majerus, M.E.N. See all References12.
1 citations