Ontogenetic Color Change Research Articles

The function of red and banded patterns in snakes: the ophiophagy hypothesis

Abstract The functions of bright bands in coral and other snakes have long been a puzzle. The most common opinion is that coral snakes display aposematic marks and that other red and black banded snakes in the Americas are mimics of coral snakes. I previously found that this prevailing opinion is weakly supported and unlikely, that red and bands had probably evolved independently or conjointly many times, and that a present selection for bands and red seems to exist in a significant fraction of the world. Here, I review the potential selective forces for red and bands in snakes. I find that snakes as predators are a priori plausible selective agents. I find that ophiophagy appears to be an exceptionally high risk in snakes that are themselves ophiophagous. Testing the working hypothesis that bands and red are protective against snake predators via their association with ophiophagy, as ophiophagous snakes are at higher risk, I find that the consumption of elongate vertebrates predicts band and red coloration with a very high level of confidence: red and bands are probably defensive against snake predators. Noting an apparent correlation of coloration with specific defensive behaviours and ontogenetic colour changes, I review both and find that ophiophagous snakes are remarkable for using stereotypical defences and not being aggressive, while ontogenetic colour changes seem to affect red and bands in snakes disproportionately. Defence against ophidian predators may be an unexpected natural selection shaping the appearance and behaviours of many snakes.

From masquerading to blending in: ontogenetic shifts in antipredator camouflage in Wallace’s flying frogs

A diversity of defence colourations that shift over time provides protection against natural enemies. Adaptations for camouflage depend on an organism’s interactions with the natural environment (predators, habitat), which can change ontogenetically. Wallace’s flying frogs (Rhacophorus nigropalmatus) are cryptic emerald green in their adult life stage, but juveniles are bright red and develop white spots on their back 1 month after metamorphosis. This latter conspicuous visual appearance might function as antipredator strategy, where frogs masquerade as bird or bat droppings so that predators misidentified them as inedible objects. To test this idea, we created different paraffin wax frog models—red with white spots, red without white spots, green, and unpainted—and placed them in equal numbers within a > 800 m2 rainforest house at the Vienna Zoo. This environment closely resembles the Bornean rainforest and includes several free-living avian predators of frogs. We observed an overall hit rate of 15.5%. A visual model showed that the contrast of red, green and control models against the background colouration could be discriminated by avian predators, whereas green models had less chromatic difference than red morphs. The attack rate was significantly greater for red but was reduced by half when red models had white spots. The data therefore supports the hypothesis that the juvenile colouration likely acts as a masquerade strategy, disguising frogs as animal droppings which provides similar protection as the cryptic green adult colour. We discuss the ontogenetic colour change as a possible antipredator strategy in relation to the different habitats used at different life stages.Significance statementPredation pressure and the evolution of antipredator strategies site at the cornerstone of animal-behaviour research. Effective antipredator strategies can change in response to different habitats that animals use during different life stages. We study ontogenetic shifts in colour change as dynamic antipredator strategy in juvenile and adult Wallace’s flying frogs. We show that the unusual colour pattern of juveniles (bright red with small white spots) likely functions as a masquerade of animal droppings. Specifically, we show that white dotting, which can be associated with animal faeces, acts as the main visual feature that turns an otherwise highly conspicuous individual into a surprisingly camouflaged one. To our knowledge, this is the first experimental exploration of a vertebrate masquerading as animal droppings.

Dots in the dark: dorsal polychromatism in the endemic Xingu Freshwater Stingray

AbstractPolychromatism refers to the presence of two or more color patterns within a species. Several species exhibit polychromatic patterns, including some elasmobranchs such as the Xingu Freshwater Stingray (Potamotrygon leopoldi), a threatened, endemic freshwater stingray species that is exploited in the international aquarium trade. Analysis of polychromatic patterns can provide insight into evolutionary mechanisms and be a useful tool for monitoring international trade. In this context, the present study analyzed intraspecific color variation in P. leopoldi. A total of 241 individuals collected in two areas along the Xingu River in Brazil were used for the study. Four dorsal color patterns of P. leopoldi were described. Size differences between color classes were statistically significant, suggesting that these color variations are associated with ontogenetic color changes. In addition, two color morphs specific to each locality were identified and described. Moreover, the occurrence of polychromatic forms in a Potamotrygoninae species may contribute to the understanding of diversification in this group, since some mechanisms of speciation are associated with polychromatism. Analysis of color variation in P. leopoldi is expected to help improve trade monitoring, especially given the existence of look‐alike species.

Ontogenetic color change in the tail of blue-tailed skinks (Plestodion elegans).

Ontogenetic color change in animals is an interesting evolution-related phenomenon that has been studied by evolutionary biologists for decades. However, obtaining quantitative and continuous color measurements throughout the life cycle of animals is a challenge. To understand the rhythm of change in tail color and sexual dichromatism, we used a spectrometer to measure the tail color of blue-tailed skink (Plestiodon elegans) from birth to sexual maturity. Lab color space was selected due to its simplicity, fastness, and accuracy and depends on the visual sense of the observer for measuring the tail color of skinks. A strong relationship was observed between color indexes (values of L*, a*, b*) and growth time of skink. The luminance of tail color decreased from juveniles to adults in both sexes. Moreover, we observed differences in color rhythms between the sexes, which may be influenced by different behavioral strategies used by them. This study provides continuous measurements of change in tail color in skinks from juveniles to adults and offers insights into their sex-based differences. While this study does not provide direct evidence to explain the potential factors that drive dichromatism between the sexes of lizards, our finding could serve as a reference for future studies exploring possible mechanisms of ontogenetic color change in reptiles.

Carotenoid intake during early life mediates ontogenetic colour shifts and dynamic colour change during adulthood

Carotenoids play an import role as one of the most prevalent pigments in animals. Carotenoid-based coloration accounts for striking sexually and naturally selected colour adaptations. Several anurans (frogs and toads) change body coloration either slowly and permanently between life stages (ontogenetic colour change), or rapidly and temporarily within minutes or hours (dynamic colour change). We investigated ontogenetic colour change from orange to green morphs in the Wallace's flying frog, Rhacophorus nigropalmatus , and tested the influence of dietary carotenoids on colour change during postmetamorphic development. At the age of 9 months, while all individuals still possessed orange-red body coloration, a 20-week-long feeding experiment was performed by supplying the frogs with either no carotenoid supplements or dietary carotenoids once or four times per week. A high carotenoid diet resulted in a faster increase in green colour chroma as well as higher levels of green and carotenoid chroma of back coloration. Less or no carotenoid supplementation led to an increase in UV-blue chroma, contributing to a dull turquoise appearance often observed in captive-bred and captive-raised anurans. In addition, we showed for the first time that Wallace's flying frogs also perform dynamic colour changes. We tested dynamic changes triggered either by 2 min tactile handling or varying 1 h dark and light conditions. Our results demonstrate that a high carotenoid diet facilitates rapid and reversible change of body coloration in response to a tactile stressor, an adaptation absent in frogs receiving no carotenoids. Dynamic colour changes were likewise observed in response to changing light conditions presumably camouflaging individuals and providing protection from UV irradiation. The ontogenetic and dynamic pigmentation changes are discussed in relation to mechanism and as a likely strategy to avoid predation both at different life stages and in different environments. • Dietary carotenoids impact the development of the green back coloration of frogs. • Lack of carotenoids increase UV-blue chroma, contributing to turquoise appearance. • Early life acquisition of carotenoids regulates dynamic colour change behaviour. • Light conditions mediate reversible full and partial body colour change of frogs.

Taxonomy, allometry, sexual dimorphism, and conservation of the trans-Andean watersnakeHelicops danieliAmaral, 1937 (Serpentes: Dipsadidae: Hydropsini)

The extensive lack of knowledge on the morphological aspects of South American watersnakes includes a poor understanding of phenotypic parameters, intraspecific variation, and conservation of the trans-Andean Helicops species, Daniel’s Keelback (Helicops danieli Amaral, 1937). For the first time, we provide a multidisciplinary view using key features (e.g., morphology and niche modeling) to improve the taxonomic recognition of this species, as well as describing ontogenetic color changes, allometry, sexual dimorphism, and the conservation status of this poorly studied snake. First, we emended the morphological diagnosis of H. danieli with 23 characters and detected that juvenile tail length is positively related to allometric growth, and that juveniles differ from adults through the presence of the white nuchal collar. Females are larger than males for snout–vent length, whereas males showed proportionally longer tails and smaller head length growth. Suitable areas for H. danieli are restricted to the trans-Andean regions from the Magdalena drainage to the Caribbean coast, which also showed high values of anthropic impacts. Our multidisciplinary approach provided new insights into this South American watersnake’s morphology, intraspecific variation, and distribution.

Does dietary β-carotene influence ontogenetic colour change in the southern corroboree frog?

Ontogenetic colour change occurs in a diversity of vertebrate taxa and may be closely linked to dietary changes throughout development. In various species, red, orange and yellow colouration can be enhanced by the consumption of carotenoids. However, a paucity of long-term dietary manipulation studies means that little is known of the role of individual carotenoid compounds in ontogenetic colour change. We know even less about the influence of individual compounds at different doses (dose effects). The present study aimed to use a large dietary manipulation experiment to investigate the effect of dietary β-carotene supplementation on colouration in southern corroboree frogs (Pseudophryne corroboree) during early post-metamorphic development. Frogs were reared on four dietary treatments with four β-carotene concentrations (0, 1, 2 and 3mgg-1), with frog colour measured every 8 weeks for 32 weeks. β-Carotene was not found to influence colouration at any dose. However, colouration was found to become more conspicuous over time, including in the control treatment. Moreover, all frogs expressed colour maximally at a similar point in development. These results imply that, for our study species, (1) β-carotene may contribute little or nothing to colouration, (2) frogs can manufacture their own colour, (3) colour development is a continual process and (4) there may have been selection for synchronised development of colour expression. We discuss the potential adaptive benefit of ontogenetic colour change in P. corroboree. More broadly, we draw attention to the potential for adaptive developmental synchrony in the expression of colouration in aposematic species.

The effectiveness of eyespots and masquerade in protecting artificial prey across ontogenetic and seasonal shifts.

When constraints on antipredator coloration shift over the course of development, it can be advantageous for animals to adopt different color strategies for each life stage. Many caterpillars in the genus Papilio exhibit unique ontogenetic color sequences: for example, early instars that masquerade as bird feces, with later instars possessing eyespots. I hypothesize that larvae abandon feces masquerade in favor of eyespots due to ontogenetic changes in signaler size. This ontogenetic pattern also occurs within broader seasonal shifts in background color and predator activity. I conducted predation experiments with artificial prey to determine how potential signaling constraints (specifically size and season) shape predation risk, and consequently the expression of ontogenetic color change in Papilio larvae. Seasonally, both predation and background greenness declined significantly from July to September, though there was little evidence that these patterns impacted the effectiveness of either color strategy. Caterpillar size and color strongly affected the attack rate of avian predators: attacks increased with prey size regardless of color, and eyespotted prey were attacked more than masquerading prey overall. These results may reflect a key size-mediated tradeoff between conspicuousness and intimidation in eyespotted prey, and raise questions about how interwoven aspects of behavior and signal environment might maintain the prevalence of large, eyespotted larvae in nature.

From matte banded to glossy black: structures underlying colour change in the caudal lures of southern death adders (Acanthophis antarcticus,Reptilia: Elapidae)

AbstractMany ambush-foraging snakes move their tails to entice prey within striking range (‘caudal luring’). During ontogeny, the conspicuous hues of caudal lures change to match the cryptic patterning of the body/head. This coincides with decreased luring behaviour and reflects the trade-off between prey acquisition and camouflage as the snake grows. Australo-Papuan death adders (Acanthophis, Elapidae) are unique in that both juveniles and adults use caudal luring, but ontogenetic colour change has not been investigated. We examined the spectral reflectance, microstructure and pigmentation of caudal skin in wild-sourced and captive bred Acanthophis antarcticus ranging in body size (snout-vent length 116–674 mm; mass 3–832 g; N = 33) to test whether colour properties change as snakes grow. We found that lure colour is distinct from the cryptic body skin across the life history, and changes from a matte banding pattern (grey/black) in neonates/juveniles, to uniform and glossy black with a yellow ventral stripe in larger snakes. These colour changes are caused by increases in dermal pigmentation and a transition to a smooth, interlocking epidermal microstructure. To understand the selection pressures that might be driving ontogenetic colour change in this species, further studies should test how different prey types respond to distinct lure morphologies.

Ultraviolet reflectance and pattern properties in leopard geckos (Eublepharis macularius)

Complex visual signaling through various combinations of colors and patterns has been well documented in a number of diurnal reptiles. However, there are many nocturnal species with highly sensitive vision, being able to discriminate colors in night conditions, as was shown in geckos. Because of their sensitivity to chromatic signals, including UV (ultraviolet), they may have potential hidden features in their coloration, which may play role in intraspecific communication (e.g. mate choice) or interspecific signals (e.g. antipredatory function). We explored this hypothesis in nocturnal Leopard geckos (Eublepharis macularius), a species using visual signals in both antipredation defense and courtship, having ontogenetic color change accompanied by a shift in behavior. We used UV photography and visual modeling in order to compare various aspects of their coloration (luminance, contrast, color proportions) between sexes, age groups and populations. We found that Leopard geckos have considerable UV reflectance in white patches on their tails (and on the head in juveniles). Though, no prominent differences were detected in their coloration between various groups. We hypothesize that the limitation of UV reflectance to the head and tail, which are both actively displayed during defense, especially in juveniles, might potentially boost the effect of antipredation signaling.

A further study on Franciscobasis Machado & Bedê, 2016 (Odonata: Coenagrionidae), a newly described genus from Minas Gerais, Brazil.

The genus Franciscobasis Machado & Bedê, 2016 is endemic to the Serra da Canastra National Park in Minas Gerais state, Brazil. Two species of Franciscobasis were described simultaneously with the genus description: F. franciscoi and F. sonia, the latter described only from females. Through morphological and molecular analysis, we investigated if F. sonia may represent the young female of F. franciscoi. Resulting data did not present adequate differences between females to characterize them as different species. Therefore, we suggest that F. sonia is a junior synonym of F. franciscoi, and the female of F. franciscoi goes through a complex ontogenetic color change.

Ontogenetic colour change signals sexual maturity in a non‐territorial damselfly

AbstractConspicuous colouration increases male reproductive success through female preferences and/or male–male competition. Despite the advantages of conspicuous colouration, inconspicuous male morphs can exist simultaneously in a population due to genetic diversity, condition dependence or developmental constraints. We are interested in explaining the male dichromatism in Xanthagrion erythroneurum damselflies. We reared these damselflies in outdoor insectaries under natural conditions and showed that this species undergoes ontogenetic colour changes. The younger males are yellow and change colour to red 6–7 days after their emergence. We took red and yellow male reflectance spectra and found that red males are brighter than yellow males. Next, we aimed to determine whether ontogenetic colour change signals sexual maturity with field observations and laboratory experiments. Our field observational data showed that red males are in higher abundance in the breeding territory, and they have a higher mating frequency than yellow males. We confirmed these field observations by enclosing a red and a yellow male with two females and found that yellow males do not mate in presence of red males. To determine whether colour change signals sexual maturity, we measured mating success of males before and after colour changes by enclosing a single male at different age (day 3‐day 7) and colour (yellow, intermediate and red) with a single female in a mating cage. Males did not mate when yellow but the same male mated after it changed colour to red, suggesting the ontogenetic colour change signals sexual maturity in this species. Our study shows that male dichromatism can be age‐dependent and ontogenetic colour change can signal age and sexual readiness in non‐territorial insects.

Phylogenetic systematics, ecology, and conservation of marsupial frogs (Anura: Hemiphractidae) from the Andes of southern Ecuador, with descriptions of four new biphasic species.

We review the systematics of the species of Gastrotheca (Anura: Hemiphractidae) in the highlands of the southern Ecuadorian Andes. We analyzed phylogenetic, morphological, ecological, and acoustic data from populations in the region. We provide an updated phylogenetic hypothesis inferred from a database that contains 42 species of Gastrotheca, and sequences from mitochondrial (12S, 16S, and ND1) and nuclear (POMC and RAG-1) genes. We describe four new endemic biphasic species for Ecuador (Gastrotheca cuencana, G. elicioi, G. turnerorum, and G. yacuri). In addition, we redefine G. lojana, recently resurrected from the synonymy of G. monticola, and redescribe G. litonedis. Furthermore, we describe the tadpoles and ontogenetic color changes in six species (G. cuencana, G. elicioi, G. litonedis, G. lojana, G. pseustes, and G. turnerorum). Also, we describe the calls of seven species (G. cuencana, G. elicioi, G. litonedis, G. lojana, G. pseustes, G. testudinea, and G. yacuri). The phylogenetic relationships estimated here are congruent with previous phylogenetic hypotheses for the group, except for the placement of G. galeata, G. plumbea, G. orophylax, G. nicefori, and G. griswoldi. Because most sister species in Gastrotheca are allopatric, the evolutionarly scenarios that likely have intervened in shaping the diversity are the uplift of the Andes and the formation of cross-Andean river valleys, which probably promoted conditions that acted as dispersal barriers that led to speciation. Many species of Gastrotheca (44%) are highly threatened. Most monophasic species have not been seen since the late 1980s, whereas the highland biphasic species have survived the catastrophic events that led to the disappearance of many other sympatric anurans. Research and conservation actions are urgently needed for all surviving species treated herein, five of which are either Critically Endangered or Endangered because of their restricted distributions (10-1600 km2), habitat destruction and fragmentation, climate change, and pathogens. Two of the new species, G. cuencana, and G. elicioi, mostly are known from the cities of Cuenca and Loja, respectively, where urbanization threatens their survival. In order to call attention to conservation issues, we name one new species to refer to the Yacuri National Park, and the other three in honor of the people from Cuenca, the Turner family, and Elicio E. Tapia, whose actions are helping to halt amphibian extinctions.

Improved camouflage through ontogenetic colour change confers reduced detection risk in shore crabs.

Animals from many taxa, from snakes and crabs to caterpillars and lobsters, change appearance with age, but the reasons why this occurs are rarely tested.We show the importance that ontogenetic changes in coloration have on the camouflage of the green shore crabs (Carcinus maenas), known for their remarkable phenotypic variation and plasticity in colour and pattern.In controlled conditions, we reared juvenile crabs of two shades, pale or dark, on two background types simulating different habitats for 10 weeks.In contrast to expectations for reversible colour change, crabs did not tune their background match to specific microhabitats, but instead, and regardless of treatment, all developed a uniform dark green phenotype. This parallels changes in shore crab appearance with age observed in the field.Next, we undertook a citizen science experiment at the Natural History Museum London, where human subjects (“predators”) searched for crabs representing natural colour variation from different habitats, simulating predator vision.In concert, crabs were not hardest to find against their original habitat, but instead, the dark green phenotype was hardest to detect against all backgrounds.The evolution of camouflage can be better understood by acknowledging that the optimal phenotype to hide from predators may change over the life history of many animals, including the utilization of a generalist camouflage strategy. A plain language summary is available for this article.

Reproductive behavior and development in Spilotes sulphureus (Serpentes: Colubridae) from Ecuador

Reproductive behavior and development in Spilotes sulphureus (Serpentes: Colubridae) from Ecuador. The Birdsnake Spilotes sulphureus is a large-sized species that occurs from the Amazon region to the Atlantic forest of South America. Despite the wide distribution little is known about its natural history. Here we report, for the frst time, reproductive behavior displayed by this species observed in a pair of Ecuadorian specimens in captivity. A ritualized pre-copulatory behavior followed a colubrine pattern similar to the congeneric species Spilotes pullatus. The repertoire included chin-rubbing, continuous tongue ficking, head raising, body jerking, cloacal gaping, and partial mounting. Oviposition occurred 86–98 days after of the frst copulation. Females lay clutches of 7–14 eggs. Juvenile coloration is remarkably different from adults. Newborns have a dorsum with transverse brown or gray bands, and white or pale gray interspaces; young of 1–2 years have green bands and yellow-green interspaces; adults have dark green bands. Ontogenetic color changes are presumably associated with antipredator strategies, change in size, vulnerability or habitat and microhabitat selection.

English

Abstract In crayfish, intraspecific coloration can vary due to a variety of factors such as diet, genetic variation, environment, and ontogeny. Ortmann (1906) hypothesized that the crayfish Cambarus bartonii bartonii and Faxonius obscurus exhibit an ontogenetic shift in color change, with greener coloration in younger individuals of both species diminishing with age in larger specimens. However, this hypothesis has never been quantitatively tested. This work incorporated digital image analysis to quantify coloration of samples of C. b. bartonii and F. obscurus collected from two locations, respectively, in an eastern Pennsylvania stream. Examination for relationships between coloration (percent “green dominance”, i.e., the proportion of green in comparison to blue and red in photographs) and body size did not reveal any significant relationship between these variables in either crayfish species. Therefore, this study does not support the presence of ontogenetic color change in C. b. bartonii and F. obscurus, and suggests intraspecific variation of color in both species may be primarily influenced by other factors.

Melanin deposition ruled out as cause of color changes in the red-eared sliders (Trachemys scripta elegans).

Animal coloration primarily depends on the presence of pigments and the mixing ratio of eumelanin and pheomelanin. The color of red-eared slider's carapace varies with age, from an olive green to a yellow green, and then to a yellow brown in juveniles, generally. The purpose of the present study was to investigate whether this color change is related to the difference in melanin expression. Melanin deposition levels were examined in the carapace, skin, eye and muscle of the three color-types using hematoxylin and eosin staining. Moreover, the full-length coding sequence (CDS) of red-eared slider turtle melanin biosynthesis regulatory genes TYR, TYRP1, MITF and SLC24A5 were cloned, sequenced and quantitatively analyzed. Both histological view of melanin deposition and quantitative real-time PCR test of melanin-regulated gene expressions showed that there are significant differences among different tissues of red-eared slider, but no significant difference among different color-types, indicating that melanin deposition is not associated with ontogenetic color change in the carapace of red-eared slider. This study initially explore the melanin deposition and the mRNA expression of melanin biosynthesis regulatory genes in red-eared slider, which serve as a foundation for further insight into the pigmentation patterns and the mechanism of body color change in turtles.

Female color polymorphism ofIschnura capreolusHagen, 1861 (Odonata: Coenagrionidae) with notes on behavior and ontogenetic color changes

Polymorphism in coenagrionids is widely known, mainly for Ischnura. Here, we present the case of I. capreolus, a Neotropical species of which, until now, little information concerning color polymorphism and ontogenetic color changes was known. We used a marking and recapture method to evidence ontogenetic coloration changes in females. We show that, in addition to the gynochrome morph, I. capreolus females also exhibit at least one additional morph: an androchrome color pattern. Gynochrome females (97.1% of marked females) are green-yellow when young and change to a brownish pattern with age, within a week. Androchrome females (2.9% of marked females) exhibit blue coloration, similarly to males. Our study provides the first evidence of ontogenetic color change in I. capreolus. Furthermore, field observations show that I. capreolus is similar to other Ischnura species regarding sexual harassment behavior.

Ontogenetic colour changes and male polymorphism in Mnais andersoni (Odonata: Calopterygidae)

Colour-based traits are widespread in flying species due to the importance of visual perception in their communication. Ontogenetic colour changes and reversible physiological colours occur in some species and are used as communication signals to conspecifics. The genus Mnais (Zygoptera: Calopterygidae) shows both genetic colour polymorphism and age-related colour changes, making challenging even the identification of species. Here we study three Chinese populations of Mnais andersoni during one month by mark-resighting methods. We describe the ontogenetic body and wing colour changes of male morphs (orange-winged and hyaline-winged) and females. With maturity, thoracic colour changes from metallic green to copper. The initially transparent wings of the hyaline winged males and females became light amber with age, while the orange-winged males show this colour since emergence to maturity. Whitish pruinosity covered all thorax in orange-winged males, while it remained limited to the ventral part of the tho...

The inheritance of female colour polymorphism in Ischnura genei (Zygoptera: Coenagrionidae), with observations on melanism under laboratory conditions.

Current research on female colour polymorphism in Ischnura damselflies suggests that a balanced fitness trade-off between morphotypes contributes to the maintenance of polymorphism inside populations. The genetic inheritance system constitutes a key factor to understand morph fluctuation and fitness. Ischnura genei, an endemic species of some Mediterranean islands, has three female colour morphs, including one androchrome (male-coloured) and two gynochromes. In this study, we reared two generations of I. genei under laboratory conditions and tested male behavioural responses to female colour morphs in the field. We recorded ontogenetic colour changes and studied morph frequency in three populations from Sardinia (Italy). Morph frequencies of laboratory crosses can be explained by a model based on an autosomal locus with three alleles and sex-restricted expression, except for one crossing of 42 families with unexpected offspring. The allelic dominance relationship was androchrome > infuscans > aurantiaca. Old individuals reared in the laboratory exhibited different levels of melanism in variable extent depending on sex and morph. Results of model presentations indicate a male preference for gynochrome females and the lack of recognition of androchromes as potential mates. Aurantiaca females were the most frequent morph in the field (63–87%). Further studies in other populations and islands are needed to understand the maintenance of this polymorphism.