Ventral Coloration Research Articles

Phenotypic and genetic divergence in reed frogs across a mosaic hybrid zone on São Tomé Island

AbstractAlthough naturally heterogeneous environments can lead to mosaic hybrid zones, human-induced habitat fragmentation can also lead to environmental heterogeneity and hybridization. Here we quantify phenotypic and molecular divergence across a reed frog mosaic hybrid zone on São Tomé Island as a first step towards understanding the consequences of hybridization across this heterogeneous landscape. The São Tomé giant reed frog (Hyperolius thomensis) is strongly tied to cool, wet, forest habitats whereas the distribution of Moller’s reed frog (H. molleri) spans cool, wet, forests to warm, dry, disturbed habitats. Correspondingly, hybridization is concentrated in the more forested, cool, wet sites relative to non-forested, warmer, drier habitats. Four of six sites with hybrid frogs are artificial water bodies near the forest edge, indicating that both breeding habitat and broader scale environmental variation are probably important for understanding interspecific interactions and the extent of hybridization in this system. Phenotypic variation (body size and ventral coloration) largely tracks genetic and environmental variation across the hybrid zone with larger and more pigmented frogs occurring in forested, cool, wet habitats. Understanding whether human-induced changes in habitat break down reproductive barriers will be essential for conservation management of the less abundant, forest-associated H. thomensis in the face of rampant hybridization.

Selection on multiple sexual signals in two Central and Eastern European populations of the barn swallow.

Variation in intensity and targets of sexual selection on multiple traits has been suggested to play a major role in promoting phenotypic differentiation between populations, although the divergence in selection may depend on year, local conditions or age. In this study, we quantified sexual selection for two putative sexual signals across two Central and East European barn swallow (Hirundo rustica rustica) populations from Czech Republic and Romania over multiple years. We then related these differences in selection to variation in sexual characters among barn swallow populations. Our results show that tail length and ventral coloration vary between populations, sexes, and age classes (first‐time breeders vs. experienced birds). We found that selection on tail length was stronger in first‐time breeders than in experienced birds and in males than in females in the Romanian population, while these differences between age groups and sexes were weak in Czech birds. We suggest that the populational difference in selection on tail length might be related to the differences in breeding conditions. Our results show that ventral coloration is darker (i.e., has lower brightness) in the Romanian than in the Czech population, and in experienced birds and males compared with first‐time breeders and females, respectively. The sexual difference in ventral coloration may suggest sexual selection on this trait, which is supported by the significant directional selection of ventral coloration in first‐time breeding males on laying date. However, after controlling for the confounding effect of wing length and tarsus length, the partial directional selection gradient on this trait turned nonsignificant, suggesting that the advantage of dark ventral coloration in early breeding birds is determined by the correlated traits of body size. These findings show that ventral coloration may be advantageous over the breeding season, but the underlying mechanism of this relationship is not clarified.

A new species of terrestrial frog of the genus Noblella Barbour, 1930 (Amphibia: Strabomantidae) from the Llanganates-Sangay Ecological Corridor, Tungurahua, Ecuador.

We describe a new species of terrestrial frog of the genus Noblella from the eastern versants of the Ecuadorian Andes in the upper Pastaza watershed. Noblella naturetrekii sp. n. differs from its Ecuadorian congeners by the presence of a differentiated tympanic membrane and a weakly defined tympanic annulus, and eyelids with rounded tubercles. In addition, the new species is characterized by its blackish–dark brown ventral coloration scattered with little white dots and the absence of papillae at the tip of the fingers and toes. We provide a detailed description of the call and osteology of the new species. Finally, we present the most complete phylogeny of the genus, which confirms that Noblella is a non-monophyletic group.

A new species of Pristimantis (Anura: Craugastoridae) from the cloud forests ofColombian western Andes.

The frogs of the genus Pristimantis are recognized for their characteristic reproductive mode and for their incredible diversity of species, becoming the genus with the highest number of species within tetrapod vertebrates. We describe here a new species of Pristimantis from the northwestern Andes of Colombia. The species was found between 2000-2500 m.a.s.l., mostly within moss hanging of tree branches in a tropical cloud forest. It can be easily distinguished from other Pristimantis species of the western Andes by the unique black and white patterning in the ventral surface and the flanks, the hourglass-shaped dorsal folds, and the prominent conical tubercles on eyelids, heels, and outer edge of tarsus. A phylogenetic analysis further supports its status of a lineage reciprocally monophyletic to P. satagius and separated by a genetic distance of 0.03; the latter species bear whitish rather than predominantly black ventral coloration. To the best of our knowledge, this species is only known from the 2,500 ha nature reserve Mesenia-Paramillo, despite other research on this area of the country. Therefore, the species is declared vulnerable while new evidence on its distribution range is accumulated.

Genetic delimitation of Pristimantisorestes (Lynch, 1979) and P.saturninoi Brito et al., 2017 and description of two new terrestrial frogs from the Pristimantisorestes species group (Anura, Strabomantidae).

In the genus Pristimantis, species are often combined into taxonomic units called species groups. The taxonomy of these groups is frequently inaccurate due to the absence of genetic data from type series and repeated misidentifications generated by high morphological resemblance between taxa. Here, we focus on the P.orestes species group, providing the first genetic assessment of P.orestes sensu stricto from individuals collected from the type locality, with a reviewed diagnosis and description of advertisement calls. We find that two lineages previously named P.orestes are genetically distinct and should be separated into two different species. Based on genetic and morphological data, we name one of these species P.cajanumasp. nov. This new species is morphologically distinct from other members of the group by having shagreen dorsal skin, evident dorsolateral folds, broader discs on toes and fingers and pale gray ventral coloration. Additionally, P.saturninoi is placed within the P.orestes species group based on genetic data from its type series. However, we find that one of its paratypes is genetically distinct and belongs to a clade containing a new species we name P.quintanaisp. nov. This new species is morphologically distinguished by lacking a tympanic membrane and vocal sacs in males, and by having expanded discs on toes and fingers, finely tuberculated dorsal skin and irregular white or cream spots in the groin and concealed surfaces of thighs. Our findings highlight the importance of providing genetic characterization and placement from the type series in taxonomic challenging groups, such as Pristimantis. We also suggest that the diversity of species within the P.orestes group will increase as more sampling is achieved in the southern Andes of Ecuador.

Pachnoda iskuulka (Coleoptera: Scarabaeidae: Cetoniinae), a new species from Somaliland, including description of its mature larva.

Pachnoda iskuulka Král, Sommer Šípek, new species from the Sanaag region of north-eastern Somaliland is described. The new species is compared with the morphologically similar taxa Pachnoda abyssinica abyssinica Reiche, 1847, P. a. meriteti Di Gennaro, 2017, P. massajae Gestro, 1881, and P. werneri Beinhundner, 1992, all of which occur in the Horn of Africa. Relevant diagnostic characters (e.g., dorsal and ventral surface color pattern, male external genitalia) are illustrated. The third instar larva of the new species is described and biological notes are provided.

Genetic differentiation predicts body size divergence between island and mainland populations of common wall lizards (Podarcis muralis)

AbstractSmall-bodied vertebrates sometimes evolve gigantism on islands, but there is a lack of consistent association with ecological factors or island characteristics. One possible reason is that, even if the ecological conditions are right, body size might fail to diverge on islands that were isolated recently or if there is gene flow between islands and the mainland. We studied body size, ventral colour polymorphism and genetic structure across nine islands and adjacent mainland populations of common wall lizards (Podarcis muralis) off the western coast of France. Population genetic data suggested that island populations might have maintained gene flow after their geographical isolation from the mainland. Island lizards were larger and heavier than mainland lizards on average, but the extent of gigantism varied substantially between islands. Island size and distance from the mainland were poor predictors of body size, but lizards from populations that were highly genetically differentiated from the mainland were larger than lizards from less differentiated populations. Colour morphs that were rare on the mainland tended to be more common on islands. We propose that genetic isolation or bottlenecks promote body size evolution in island lizards, which makes it challenging to identify ecological causes of island gigantism without complementary genetic information.

Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia

Manta rays (Mobula spp.) are highly valued in nature-based tourism globally. In Indonesia, although manta rays are protected, critical information is lacking on their habitat use, population dynamics and movements. We investigate the population structure and residency patterns of reef manta rays (Mobula alfredi) in the Nusa Penida Marine Protected Area (MPA). From photo-identification data logged by citizen scientists and trained observers (mantamatcher.org), we identified 624 reef manta rays from 5,913 sightings (January 2012–April 2018) based on their unique ventral coloration patterns. Year-round records were collected from two shallow (<20 m) reefs – Manta Bay (MB; n = 3,029 sightings) and Manta Point (MP; n = 3,058) – that are used frequently by tourism operators. Maximum likelihood techniques and a Markov movement analysis were used to model residency patterns and movement between these sites within the MPA. Manta rays at MB were predominantly male (64%, n = 261 individuals), with immature males (14%, n = 59) being sighted most frequently (39%, n = 1,170). In contrast, few immature individuals were sighted at MP (6%, n = 28), and they were sighted on few occasions (2%, n = 45), while mature female manta rays comprised 26% (n = 127) of the MP community and were the most frequently sighted (48%, n = 1,413). Lagged identification rates indicated high site fidelity at each location. However, 44% (n = 278) of individuals moved between the two sites and cumulative discovery curves showed a continued recruitment of individuals over the 6 years of the study. In addition, the behaviors displayed by the manta rays differed markedly between the two sites: MB appears to be a foraging ground, especially for juveniles, and potentially a nursery, while MP is used mainly for cleaning and courtship, indicating a social and reproductive site. Reproductive behavior coincided with the peak annual sightings in May. To prevent disturbance to this threatened species by tourism, regulations for the number of boats and interactions, especially during key reproductive times should be considered. Further, strict fishing regulation in the area is recommended as fishing gear entanglement was identified as a threat to this population.

Resurrection of an East African house bat species Scotophilus altilis Allen, 1914 (Chiroptera: Vespertilionidae).

Several house bat specimens superficially resembling the white-bellied house bat Scotophilus leucogaster (Cretzschmar, 1830), were recently captured in southwestern Ethiopia and southern South Sudan. These S. cf. leucogaster differed from typical S. leucogaster by their slightly smaller size and ventral coloration, conforming instead with the original description of S. altilis Allen, 1914. Scotophilus altilis is an overlooked taxon known from the Blue Nile region in Sudan that is currently considered a junior synonym of S. leucogaster. Phylogenetic analysis of mitochondrial cytochrome b gene (cytb) sequences revealed S. cf. leucogaster as a sister clade to S. leucogaster with a genetic distance of ca. 10%. Comparative specimens of questionable S. nigritellus de Winton, 1899 from northwestern Ethiopia and a wing biopsy sample of another S. cf. leucogaster from western Kenya also fell within this clade. Sequence data from two nuclear markers (zfy and fgb7) corroborated the distinction of S. cf. leucogaster from S. leucogaster. Likewise, morphometric analysis of cranial data largely supported this distinction, as well as taxonomic affiliation with S. altilis based on comparison with the only available paratype specimen. The position of this paratype specimen within the new Scotophilus clade, inferred from analysis of a short fragment of cytb, confirmed its taxonomic identity. Based on the presented evidence, the overlooked East African taxon S. altilis should be resurrected as a full species within the genus Scotophilus.

Seasonal and interpopulational phenotypic variation in morphology and sexual signals of Podarcis liolepis lizards.

Widespread species often show extensive phenotypic variation due to the contrasting abiotic and biotic factors that shape selective pressures in different environments. In this context, the gradual and predictable patterns of variation in climatic and environmental conditions found in mountain areas offer a great opportunity to explore intraspecific phenotypic variation. For instance, temperature is negatively correlated with altitude and virtually all aspects of the behavior and physiology of ectotherms are sensitive to body temperature. In this work, we tested the hypothesis that morphology, dorsal and ventral coloration and the chemical profile of femoral secretions show interpopulational and seasonal variation in the lacertid lizard (Podarcis liolepis). We compared lizards from three populations inhabiting lowland and highland habitats in the French Pyrenees that were closely related genetically. We found that highland lizards were larger, stockier, had longer heads and more femoral pores and had a darker dorsal coloration than lowland ones. In addition, we detected interpopulational differences in both the abundance and the richness of chemical compounds in the glandular secretions, and we also found seasonal variation in the overall chemical composition. Dorsal and ventral coloration differed seasonally and between populations. Ventral and dorsal brightness were higher in lowland than in highland lizards in the reproductive season whereas the reversed trend was found in the non-reproductive season but only for dorsal brightness. In addition, all lizards had browner dorsal coloration in the non-reproductive season, and lowland lizards were greener in the reproductive season. By integrating information from both visual and chemical systems, our works offers a comprehensive view of how these lizards communicate in a multimodal context.

Body Color and Morphological Correlates of Fitness in Eastern Fence Lizards (Sceloporus undulatus): A Spectrophotometric Approach

Many lizards use colorful badges in displays with conspecifics during courtship and aggressive interactions. In Eastern Fence Lizards (Sceloporus undulatus), males and females reveal sexually dimorphic ventral abdominal coloration during social interactions and use these features to signal sex and perhaps other characteristics. However, the extent to which ventral badges or other chromatic features of males and females signal quality remains unresolved in this species. Additionally, adult S. undulatus exhibit temperature-dependent color change of their abdominal badges, a potential confounding variable in studies of the function of these badges. Here, we examined the relationship between spectral variables of ventral and dorsal skin color and morphometric traits linked to fitness in adult male and female S. undulatus under standardized temperature conditions. For males, ventral patch hue tended to decrease (i.e., was blue-shifted) as body size increased, whereas dorsal hue was unrelated to male size. In contrast, there was no relationship between ventral hue and body size in females, and dorsal hue increased (i.e., was red-shifted) with body size. In males, lower ultraviolet (UV) chroma and greater blue chroma of ventral abdominal badges predicted increasing body size. In females, UV chroma of the ventral abdomen was inversely related to body size and better body condition, whereas blue chroma was inversely related to body condition only. Dorsal UV chroma decreased with increasing body size in both males and females, but brightness was not a significant predictor of any morphometric trait in either sex. Overall, these results indicate that both blue and UV reflectance of ventral and dorsal abdominal skin are indices of size and thus age, and could therefore serve as indices of signaler quality in this species.

Colour variation between different lineages of a colour polymorphic lizard

AbstractColour polymorphic animals offer useful models to study the evolution of polymorphisms and studies with colour polymorphic lizards have contributed many advances in this field. Unfortunately, few studies address basic questions such as how observers (e.g. conspecifics) perceive the polymorphism or whether there is chromatic variability among evolutionary lineages or distant geographic areas within a species' range. The common wall lizard (Podarcis muralis) shows a striking colour polymorphism in its ventral surface, presenting up to five alternative colour morphs, that is white, yellow and orange/red (depending on the lineage), and two intermediate mosaic morphs: white‐orange and yellow‐orange. Here we compare this polymorphism in two geographically distant areas, the Po valley (Northern Italy) and the Eastern Pyrenees (Iberian Peninsula), corresponding to separate phylogeographic lineages. Using objective techniques of colour measurement and lizard vision models, we examine the chromatic differences between these two polymorphic lineages. We also search for chromatic differences in other colour traits present in P. muralis: the cryptic dorsal coloration and the ultraviolet‐blue spots of the outer ventral scales (UV‐blue OVS) used for intraspecific communication. Although we detected significant differences among lineages in colour variables, the main variation was found between the alternative ventral colour morphs. The most striking inter‐lineage divergence was between the orange Pyrenean morph and the red Italian morph, mainly caused by achromatic (but not chromatic) differences. In addition, although the UV‐blue OVS show strong chromatic and achromatic variation between lineages, the dorsal coloration shows the smallest degree of variation, and mainly between localities rather than lineages. Overall, the ventral colour pattern of P. muralis is shared by at least two geographically and phylogenetically distant lineages. Nevertheless, body coloration also shows signs of historical divergence (Pyrenean orange vs. Italian red) and local adaptation (mainly in the dorsal pattern).

A new species ofEptesicus(Chiroptera, Vespertilionidae) from Argentina

Eight species of the bat genus Eptesicus are distributed in South America of which four are known from Argentina. Here, we describe a new species, based on specimens collected from La Rioja Province, and one specimen from Mendoza Province, Argentina, deposited in a museum collection. This new species of Eptesicus can be distinguished from other congeners by its golden to yellowish-brown coloration, strong contrast between dorsal and ventral fur color, long forearm (> 41 mm), and by the relatively short (∼ 6 mm) dorsal fur. A detailed description of the external and cranial morphology of the new species, as well as comparisons with other species of similar size, and present in the same distributional area, are included. A Wilcoxon–Mann–Whitney test and a discriminant linear function analysis were performed to assess the morphometric differences among species of Eptesicus. The phylogenies obtained by different criteria, as well as those obtained independently from different genes, are in agreement with regard to the relationships of the new species.

Two new species of lotic breeding salamanders (Amphibia, Caudata, Hynobiidae) from western Japan.

Two new species of lotic-breeding salamanders, Hynobius sematonotos and H. oyamai, are described from Chugoku district and northeastern Kyushu district, respectively, western Japan. They are members of the so-called H. naevius group and are phylogenetically close to H. naevius, H. katoi, and H. hirosei but divergent from them with large genetic distances. These new species have been treated as Chugoku and northeastern Kyushu lineages, respectively, of H. naevius to which they are morphologically very similar. However, these new species can be differentiated from H. naevius by several morphological traits. Hynobius sematonotos is characterized and discriminated from other species by combination of small body size, a shallow vomerine teeth series with small number of vomerine teeth, small number of upper and lower jaw teeth, relatively long head and snout, and large upper eyelid, relatively short axilla-groin, reddish purple ground color with grayish brown marking on the dorsum, and reddish to bluish gray ventral ground color with relatively large markings varying from pale-white to white. Hynobius oyamai is characterized and discriminated from other species by large body size, moderately deep vomerine teeth series with a medium number of vomerine teeth, large number of upper and lower jaw teeth, relatively wide internarial and long fifth toe, bluish purple ground color sometimes with pale white marking on dorsum. Hynobius sematonotos occurs in Honshu, disjunct from H. naevius and H. oyamai that occur allopatrically in Kyushu.

A giant on the ground: another large-bodied Atractus (Serpentes: Dipsadinae) from Ecuadorian Andes, with comments on the dietary specializations of the goo-eaters snakes.

Body-size is significantly correlated with the number of vertebrae (pleomerism) in multiple vertebrate lineages, indicating that somitogenesis process is an important factor dictating evolutionary change associated to phyletic allometry and, consequently, species fitness and diversification. However, the role of the evolution of extreme body sizes (dwarfism and gigantism) remains elusive in snakes, mainly with respect to postnatal ontogeny in dietary preferences associated with evolution of gigantism in many lineages. We described herein a new species in the highly diversified and species-rich genus Atractus on the basis of four specimens from the southeastern slopes of the Ecuadorian Andes. The new species is morphologically similar and apparently closely related to two other allopatric giant congeners (A. gigas and A. touzeti), from which it can be distinguished by their distinct dorsal and ventral coloration, the number of supralabial and infralabial scales, the number of maxillary teeth, and relative width of the head. In addition, we discuss on the ontogenetic trajectories hypotheses and dietary specializations related to evolution of gigantism in the goo-eaters genus Atractus.

Male Bicyclus anynana Butterflies Choose Females on the Basis of Their Ventral UV-Reflective Eyespot Centers.

Butterflies often use their dorsal and ventral wing color patterns for distinct signaling functions. Color patterns on hidden dorsal wing surfaces are often used in sexual signaling, while exposed ventral patterns are often used to ward off predator attacks. At rest, however, part of the ventral forewings are often hidden by the hindwings, allowing individuals to also use the patterns on this wing surface for sexual signaling. Here, we test this hypothesis in Bicyclus anynana (Butler, Lepidoptera, Nymphalidae) butterflies by first determining the degree of sexual dimorphism in ventral forewing patterns, focusing on the eyespots, from both wet and dry season forms, and then testing the role of the larger ventral forewing eyespots of dry season females in male mate choice. We also test male investment in reproduction. We show that ventral forewing UV-reflective eyespot centers, in addition to dorsal forewing eyespot centers previously examined in this species, play a role in sexual signaling as males preferentially mated with females with their ventral eyespot centers intact instead of blocked with black paint. This male preference, however, did not translate into a detectable higher reproductive investment via a single mating toward ornamented females. This study provides an example of how ventral forewing patterns, often hidden by hindwings, are used in sexual communication, in this case by females to attract males.

The wooden breast condition results in surface discoloration of cooked broiler pectoralis major

Published studies have shown that the wooden breast (WB) condition affects the macroscopic appearance, quality, and functionality of raw broiler breast fillets (pectoralis major) as well as the texture of both raw and cooked fillets. In this study, we demonstrated for the first time that the WB condition also significantly affects the color and appearance of cooked breast fillets. Fresh broiler breast fillets (deboned at 3h post-mortem) were collected from a commercial plant and sorted into normal (no WB) and severe WB condition categories based on palpable hardness and rigidity throughout the breast fillets. The fillets were either cooked directly from a fresh state, after marination with a target concentration of 0.75% NaCl and 0.45% phosphate at the end, or after storage at -20°C. Samples were cooked to 76°C in individual cooking bags in a combi-steam oven. Color measurements (CIEL*a*b*) on both the ventral and dorsal surfaces of cooked fillets were assessed using a Minolta spectrophotometer CM-700d. There were no significant CIE color value differences on the dorsal surfaces (bone side) of cooked fillets (P > 0.01). However, on the cooked ventral surfaces (skin side), the WB condition caused increases (P < 0.01) in a* and b* values and a decrease (P < 0.01) in the L* value regardless of marination treatment or frozen storage. The average L* values of cooked WB fillets were more than 6 units lower than in cooked normal fillets. After cooking, WB fillets showed higher a* and b* values by more than 0.5 and 2 units, respectively, than normal fillets. Data demonstrate that the WB condition can negatively influence the ventral surface color of cooked broiler breast fillets. The cooked surface of WB fillets was darker, redder, and more yellow than that of fillets without the WB condition. The detrimental effect of WB on the surface color and appearance of cooked breast fillets was noticeable and was not eliminated by marination or frozen storage.

Morphological and Genetic Diversity of Sea Buckthorn (Hippophae rhamnoides L.) in the Karakoram Mountains of Northern Pakistan

Sea buckthorn (Hippophae rhamnoides L.) is a dioecious, wind-pollinated shrub growing in Eurasia including the Karakoram Mountains of Pakistan (Gilgit-Baltistan territory). Contrary to the situation in other countries, in Pakistan this species is heavily underutilized. Moreover, a striking diversity of berry colors and shapes in Pakistan raises the question: which varieties might be more suitable for different national and international markets? Therefore, both morphological and genetic diversity of sea buckthorn were studied to characterize and evaluate the present variability, including hypothetically ongoing domestication processes. Overall, 300 sea buckthorn individuals were sampled from eight different populations and classified as wild and supposedly domesticated stands. Dendrometric, fruit and leaf morphometric traits were recorded. Twelve EST-SSRs (expressed sequence tags-simple sequence repeats) markers were used for genotyping. Significant differences in morphological traits were found across populations and between wild and village stands. A significant correlation was found between leaf area and altitude. Twenty-two color shades of berries and 20 dorsal and 15 ventral color shades of leaves were distinguished. Mean genetic diversity was comparatively high (He = 0.699). In total, three distinct genetic clusters were observed that corresponded to the populations’ geographic locations. Considering high allelic richness and genetic diversity, the Gilgit-Baltistan territory seems to be a promising source for selection of improved germplasm in sea buckthorn.

Now you see me, now you don't: dynamic flash coloration as an antipredator strategy in motion

Animals employ a diverse array of colorations to avoid being consumed by predators. While much research has focused on patterns that work when the animal remains stationary, studies examining the role of colour patterns that function when it moves to avoid predation remain scarce. Here, I propose and test the hypothesis that striking colorations that change dynamically through time, for example bright colours on the dorsal wing surface in combination with cryptic/contrasting ventral coloration (or vice versa) as seen in many insects and birds, serve to protect the moving animal from predation. This idea is analogous to a well-known visual illusion termed the flash lag effect which occurs because of the constraints in estimating the instantaneous position of a moving object due to the inherent neural processing delay. I performed a virtual predation experiment using a touch screen where human participants were asked to capture a moving stimulus that changed colour dynamically through time or remained constant. I found stimuli with dynamic colour change were caught less often and less accurately than a colour-static white or background-matching stimulus but were equally difficult to capture as a colour-static average grey under certain conditions. These results suggest that dynamic colour change is effective in lowering the probability of capture, but this benefit is not unique, as the colour-static average grey stimulus had a similar advantage. Overall, the study thus presents the first clear evidence that animals that change colours during movement could gain significant protection against predation, probably by misrepresenting the prey's location.

Barn swallow antipredator behavior covaries with melanic coloration and predicts survival

Conspecific individuals often consistently differ in their behavioral responses to specific exogenous stimuli. Such individual differences in have been shown to be heritable, suggesting that selection maintains variation in personality. However, survival selection on a major personality trait, antipredator behavior, and its sex-dependency, has been seldom measured in the wild. Here, we found that yearling barn swallows (Hirundo rustica) showed consistency in agitation upon repeated exposure to a restraint-handling protocol, probably reflecting antipredator behavior, and that males were more agitated than females. Females that exhibited larger antipredator behavior were more likely to survive until the next breeding season with no variation among 3 study years nor across 7 breeding colonies, suggesting that variation in antipredator behavior is not maintained by spatiotemporal variation in viability selection on antipredator behavior. In both sexes, the intensity of melanin-based ventral plumage coloration positively covaried with antipredator behavior, consistent with previous observations from diverse vertebrate species. In some barn swallow populations, male coloration is targeted by directional intersexual selection, suggesting that melanization signals antipredator behavior to prospecting females and that sexual selection for antipredator behavior, or other correlated personality traits, can drive the evolution of sexual color dimorphism in barn swallows. Thus, we showed that viability selection occurs on antipredator behavior and that spatiotemporal variation in selection has no major role in promoting variation in antipredator behavior. More melanized individuals were more agitated, implying that melanization may signal personality in a sexual communication context in a species where male coloration is an epigamic trait.