I am interested in the evolution of sexual dimorphism, which can reflect strong differences in the effects of sexual and natural selection on body size, morphological, life history, physiological and behavioral female and male traits. However, separate the evolutionary interactions between both selective forces represents a challenge for evolutionary biologists, and this is the main goal of my research group. Phone: +52 55 5623-1228 Address: FES Iztacala; UBIPRO; UNAM Av. de los Barrios No.1 Los Reyes Iztacala A.P. 314 Mexico 54090 Edo. de Mexico
In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing ... more In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing large spermatophores can increase female fecundity and lifespan, it may also decrease their sexual receptivity, benefiting male fitness. Allocating resources to these edible gifts may entail a lower apportionment of them to other functions, generating a trade-off between somatic and reproductive functions. Despite their effect on male and female fitness, little is known of the compounds associated with katydid spermatophores. Our study found 177 different putative proteins in the spermatophore of Conocephalus ictus, with no correlation between male body size with spermatophore mass, number, concentration and mass of proteins. However, we did observe a negative relationship between male forewing length and protein concentration, and a negative relationship between the mass of the spermatophore transferred to the females and their body size, suggesting a resource allocation tradeoff in males, but also strategic transference of resources based on female quality.
In many animal species, adult females and males often differ in characteristics other than primar... more In many animal species, adult females and males often differ in characteristics other than primary sexual traits. Thus, body size tends to be related to reproductive success through different pathw...
In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing ... more In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing large spermatophores can increase female fecundity and lifespan, it may also decrease their sexual receptivity, benefiting male fitness. Allocating resources to these edible gifts may entail a lower apportionment of them to other functions, generating a trade-off between somatic and reproductive functions. Despite their effect on male and female fitness, little is known of the compounds associated with katydid spermatophores. Our study found 177 different putative proteins in the spermatophore of Conocephalus ictus, with no correlation between male body size with spermatophore mass, number, concentration and mass of proteins. However, we did observe a negative relationship between male forewing length and protein concentration, and a negative relationship between the mass of the spermatophore transferred to the females and their body size, suggesting a resource allocation tradeoff in males, but also strategic transference of resources based on female quality.
We present the current understanding on the diversification of the Mesoamerican genus Sphenarium,... more We present the current understanding on the diversification of the Mesoamerican genus Sphenarium, a group of generalist-herbivorous grasshoppers that could play a major role on the evolution of defense mechanisms and life history traits of plants along to their distribution range. We discuss their phylogenetic relationships and how geological and climatic history, as well as environmental variation, could favor their expansion and diversification. Furthermore, in a phylogenetical framework, we considered future directions on the study of their interactions with the plants with which their populations have evolved.
Background matching and disruptive colouration are defense mechanisms of animals against visual p... more Background matching and disruptive colouration are defense mechanisms of animals against visual predators. Disruptive colouration tends to evolve in microhabitats that are visually heterogeneous, while background matching is favored in microhabitats that are chromatically homogeneous. This is one of the few comparative studies that have tested the relative impact of background matching and disruptive markings in the chromatic evolution. Controlling for the phylogeny, we explored the evolution of the colouration and the marking patterns in the sexual dichromatic and widely distributed Neotropical grasshoppers of the genus Sphenarium. These grasshoppers represent an excellent model to investigate the evolution of cryptic colouration on insects due to the heterogeneity of the environments where they have evolved. We found a correlation between the grasshoppers’ colouration and disruptive markings with the chromatic properties of their environments that was inferred by the levels of pre...
Entomologia Experimentalis Et Applicata, Feb 1, 2023
Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryp... more Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryptic through background matching and disruptive colouration, which breaks up the outlines of an animal because the pattern does not coincide with the shape and outline of the animal's body. Background matching could be advantageous in chromatically homogeneous microhabitats, whereas disruptive colouration can be favoured in visually heterogeneous microhabitats. Grasshoppers of the genus Sphenarium (Orthoptera: Pyrogomorphidae) inhabit very heterogeneous environments and exhibit both strategies. Adults show substantial continuous variation in colouration and longitudinal and transverse bands on the thorax and abdomen. However, males often exhibit considerably more variation in the number of longitudinal and transverse bands than females, which tend to have more uniform colouring (flatter patterns). In this study, we analysed the cryptic properties of the colour patterns of males and females of Sphenarium zapotecum Sanabria‐Urbán, H. Song & Cueva del Castillo and tested the effectiveness of background matching and disruptive colouration using humans as ‘predators’ in a computer detection experiment. We found that the females and males are dichromatic and seem to follow different cryptic strategies in their colouration: males are more disruptive to the background than females, whereas females have a higher level of background matching. In addition, in visually heterogeneous areas, predators spent most time searching for striped male morphs with lower background matching and higher disruptive properties, as well as for female morphs with high background matching, potentially increasing prey survival. As background matching is associated with females and disruptive colouration with males, our results could help explain the evolution of sexual dichromatism in this and other species of grasshoppers of the genus Sphenarium.
Cryptic coloration is an adaptative defensive mechanism against predators. Colour patterns appear... more Cryptic coloration is an adaptative defensive mechanism against predators. Colour patterns appear cryptic through general background coloration matching or disruptive coloration. Disruptive coloration might evolve in visually heterogeneous microhabitats, whereas background matching could be favoured in chromatically homogeneous microhabitats. In this study, we used digital photography to explore the potential use of disruptive coloration and background matching in males and females of the Neotropical grasshopper Sphenarium purpurascens in different habitats. We found chromatic differences in three habitats and sexual dichromatism that might be explained by local adaptation. Although females and males were sexually dichromatic, interpopulation differences were found in the magnitude of the sexual dichromatism. In a highly contrasting environment, both males and females seemed to follow a disruptive strategy, whereas in a heterogeneous environments males and females followed different...
Corbiculate bees offer the opportunity to analyse the evolution of differences in body size betwe... more Corbiculate bees offer the opportunity to analyse the evolution of differences in body size between sexes in relationship to the social environment, because this group of phylogenetically related taxa have contrasting levels of social organization, ranging from solitary to highly eusocial. Sexual size dimorphism evolves because body size is usually related to reproductive success through different pathways in females and males. Female body size is strongly correlated with fecundity, whereas in males the body size is correlated with mating success. Within a clade, if sexual selection on males has been stronger than selection on female fecundity, a sexual size dimorphism bias to males would be expected (Rensch’s rule), or an opposite trend when the fecundity of females has had a stronger effect. We tested these predictions by taking an allometric approach that considered differences in the capacity of a reproductive female to start a nest on her own or not. Phylogenetic analysis of th...
Corbiculate bees offer the opportunity to analyse the evolution of differences in body size betwe... more Corbiculate bees offer the opportunity to analyse the evolution of differences in body size between sexes in relationship to the social environment, because this group of phylogenetically related taxa have contrasting levels of social organization, ranging from solitary to highly eusocial. Sexual size dimorphism evolves because body size is usually related to reproductive success through different pathways in females and males. Female body size is strongly correlated with fecundity, whereas in males the body size is correlated with mating success. Within a clade, if sexual selection on males has been stronger than selection on female fecundity, a sexual size dimorphism bias to males would be expected (Rensch's rule), or an opposite trend when the fecundity of females has had a stronger effect. We tested these predictions by taking an allometric approach that considered differences in the capacity of a reproductive female to start a nest on her own or not. Phylogenetic analysis of the whole clade and another analysis including only species in which the females start nests on their own showed that the corbiculate bees do not seem to follow Rensch's rule. The males and reproductive females of the species in which the females have lost their capacity to start nests were smaller than the reproductive individuals of species in which the females start nests on their own, suggesting that selective pressures linked to the evolution of sociality might constrain the evolution of a large body size in both males and reproductive females.
Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryp... more Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryptic through background matching and disruptive colouration, which breaks up the outlines of an animal because the pattern does not coincide with the shape and outline of the animal's body. Background matching could be advanta
In insects, male mating success and female fecundity usually increase with body size. However, na... more In insects, male mating success and female fecundity usually increase with body size. However, natural selection favors faster maturation, reducing the risk of prereproductive death, when the reproductive season is short in habitats located at high altitudes or far from the equator. Also, if males that mature earlier than females under these conditions increase their mating opportunities, protandry may evolve in their
n insects, male mating success and female fecundity usually increase with body size. ... more n insects, male mating success and female fecundity usually increase with body size. However, natural selection favors faster maturation, reducing the risk of pre- reproductive death, when the reproductive season is short in habitats located at high altitudes or far from the equator. Also, if males that mature earlier than females under these conditions increase their mating opportunities, protandry may evolve in their populations. Nonetheless, as body size is strongly correlated with maturation time in insects, faster sexual maturation is reached at the expense of having a small body size. We analyzed the differences in adult body size of males and females of the grass-hopper Sphenarium histrio Gerstaecker (Orthoptera: Pyrgomorphidae) in three sites across an altitudinal gradient in southern Mexico. We also evaluated the possibility of protandry in these sampling sites using a common garden experiment. Male and female grasshoppers collected from low altitude sites in the field and reared in the laboratory were larger than those from a high altitude, suggesting genetic differentia-tion. Grasshoppers from a high altitude hatched earlier, had a shorter development time, presented fewer instars, and were smaller than grasshoppers from the other sampling sites. Moreover, development time in the three sampling sites was shorter in males than in females, suggesting protandry. Interestingly, the males from the three sites showed similar growth rates, but the females from low and high altitudes, re-spectively, had the fastest and slowest growth rates. In general, the adaptive value of the evolution of protandry has been focused on males. However, it may be that the growth rates of females in these sites could modify the degree of protandry as a response to their risk of pre-reproductive death and the potential benefits associated with multiple matings.
Male and female animals often exhibit differences in body size; this difference is known as sexua... more Male and female animals often exhibit differences in body size; this difference is known as sexual size dimorphism (SSD). Hummingbirds are an excellent model system to test functional hypotheses of SSD because they exhibit a wide range of body sizes and reproductive behaviour between the sexes. Here, using phylogenetic comparative methods, we tested whether mating system, male territoriality and agility predicted the evolution of SSD in this avian family. Our results first suggest that evolutionary increases in male-biased SSD are related to increases in lekking behaviour. Second, we found that male agility is positively related to increases in male biased-SSD albeit this is only likely to occur in males of territorial species. Finally, we found an allometric pattern for SSD consistent with Rensch’s rule that was not explained by our estimates of male competition and agility.
The genus Sphenarium Charpentier, 1842 comprises the most diverse group of the New World Pyrgomor... more The genus Sphenarium Charpentier, 1842 comprises the most diverse group of the New World Pyrgomorphidae. These grasshoppers show an extensive variation in external morphology, and are culturally and economically important for Mexican people since pre-Hispanic times. Nevertheless, the taxonomy of Sphenarium has been chaotic and remained incompletely resolved until now. Following an integrative taxonomic framework, we infer the number of species in this genus by species delimitation based on morphological, phylogenetic, and geographic information. Based on our results, we revise the genus and redefine 9 species and describe 8 new species (S. adelinae sp.n., S. crypticum sp.n., S. infernalis sp.n., S. miztecum sp.n., S. occidentalis sp.n., S. tarascum sp.n., S. totonacum sp.n. and S. zapotecum sp.n.). Moreover, we update the knowledge of the evolutionary relationships and biogeographic patterns of Sphenarium species. Our results also demonstrate the importance of historic geological an...
In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing ... more In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing large spermatophores can increase female fecundity and lifespan, it may also decrease their sexual receptivity, benefiting male fitness. Allocating resources to these edible gifts may entail a lower apportionment of them to other functions, generating a trade-off between somatic and reproductive functions. Despite their effect on male and female fitness, little is known of the compounds associated with katydid spermatophores. Our study found 177 different putative proteins in the spermatophore of Conocephalus ictus, with no correlation between male body size with spermatophore mass, number, concentration and mass of proteins. However, we did observe a negative relationship between male forewing length and protein concentration, and a negative relationship between the mass of the spermatophore transferred to the females and their body size, suggesting a resource allocation tradeoff in males, but also strategic transference of resources based on female quality.
In many animal species, adult females and males often differ in characteristics other than primar... more In many animal species, adult females and males often differ in characteristics other than primary sexual traits. Thus, body size tends to be related to reproductive success through different pathw...
In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing ... more In many katydids, the male feeds his mate with a large gelatinous spermatophore. While providing large spermatophores can increase female fecundity and lifespan, it may also decrease their sexual receptivity, benefiting male fitness. Allocating resources to these edible gifts may entail a lower apportionment of them to other functions, generating a trade-off between somatic and reproductive functions. Despite their effect on male and female fitness, little is known of the compounds associated with katydid spermatophores. Our study found 177 different putative proteins in the spermatophore of Conocephalus ictus, with no correlation between male body size with spermatophore mass, number, concentration and mass of proteins. However, we did observe a negative relationship between male forewing length and protein concentration, and a negative relationship between the mass of the spermatophore transferred to the females and their body size, suggesting a resource allocation tradeoff in males, but also strategic transference of resources based on female quality.
We present the current understanding on the diversification of the Mesoamerican genus Sphenarium,... more We present the current understanding on the diversification of the Mesoamerican genus Sphenarium, a group of generalist-herbivorous grasshoppers that could play a major role on the evolution of defense mechanisms and life history traits of plants along to their distribution range. We discuss their phylogenetic relationships and how geological and climatic history, as well as environmental variation, could favor their expansion and diversification. Furthermore, in a phylogenetical framework, we considered future directions on the study of their interactions with the plants with which their populations have evolved.
Background matching and disruptive colouration are defense mechanisms of animals against visual p... more Background matching and disruptive colouration are defense mechanisms of animals against visual predators. Disruptive colouration tends to evolve in microhabitats that are visually heterogeneous, while background matching is favored in microhabitats that are chromatically homogeneous. This is one of the few comparative studies that have tested the relative impact of background matching and disruptive markings in the chromatic evolution. Controlling for the phylogeny, we explored the evolution of the colouration and the marking patterns in the sexual dichromatic and widely distributed Neotropical grasshoppers of the genus Sphenarium. These grasshoppers represent an excellent model to investigate the evolution of cryptic colouration on insects due to the heterogeneity of the environments where they have evolved. We found a correlation between the grasshoppers’ colouration and disruptive markings with the chromatic properties of their environments that was inferred by the levels of pre...
Entomologia Experimentalis Et Applicata, Feb 1, 2023
Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryp... more Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryptic through background matching and disruptive colouration, which breaks up the outlines of an animal because the pattern does not coincide with the shape and outline of the animal's body. Background matching could be advantageous in chromatically homogeneous microhabitats, whereas disruptive colouration can be favoured in visually heterogeneous microhabitats. Grasshoppers of the genus Sphenarium (Orthoptera: Pyrogomorphidae) inhabit very heterogeneous environments and exhibit both strategies. Adults show substantial continuous variation in colouration and longitudinal and transverse bands on the thorax and abdomen. However, males often exhibit considerably more variation in the number of longitudinal and transverse bands than females, which tend to have more uniform colouring (flatter patterns). In this study, we analysed the cryptic properties of the colour patterns of males and females of Sphenarium zapotecum Sanabria‐Urbán, H. Song & Cueva del Castillo and tested the effectiveness of background matching and disruptive colouration using humans as ‘predators’ in a computer detection experiment. We found that the females and males are dichromatic and seem to follow different cryptic strategies in their colouration: males are more disruptive to the background than females, whereas females have a higher level of background matching. In addition, in visually heterogeneous areas, predators spent most time searching for striped male morphs with lower background matching and higher disruptive properties, as well as for female morphs with high background matching, potentially increasing prey survival. As background matching is associated with females and disruptive colouration with males, our results could help explain the evolution of sexual dichromatism in this and other species of grasshoppers of the genus Sphenarium.
Cryptic coloration is an adaptative defensive mechanism against predators. Colour patterns appear... more Cryptic coloration is an adaptative defensive mechanism against predators. Colour patterns appear cryptic through general background coloration matching or disruptive coloration. Disruptive coloration might evolve in visually heterogeneous microhabitats, whereas background matching could be favoured in chromatically homogeneous microhabitats. In this study, we used digital photography to explore the potential use of disruptive coloration and background matching in males and females of the Neotropical grasshopper Sphenarium purpurascens in different habitats. We found chromatic differences in three habitats and sexual dichromatism that might be explained by local adaptation. Although females and males were sexually dichromatic, interpopulation differences were found in the magnitude of the sexual dichromatism. In a highly contrasting environment, both males and females seemed to follow a disruptive strategy, whereas in a heterogeneous environments males and females followed different...
Corbiculate bees offer the opportunity to analyse the evolution of differences in body size betwe... more Corbiculate bees offer the opportunity to analyse the evolution of differences in body size between sexes in relationship to the social environment, because this group of phylogenetically related taxa have contrasting levels of social organization, ranging from solitary to highly eusocial. Sexual size dimorphism evolves because body size is usually related to reproductive success through different pathways in females and males. Female body size is strongly correlated with fecundity, whereas in males the body size is correlated with mating success. Within a clade, if sexual selection on males has been stronger than selection on female fecundity, a sexual size dimorphism bias to males would be expected (Rensch’s rule), or an opposite trend when the fecundity of females has had a stronger effect. We tested these predictions by taking an allometric approach that considered differences in the capacity of a reproductive female to start a nest on her own or not. Phylogenetic analysis of th...
Corbiculate bees offer the opportunity to analyse the evolution of differences in body size betwe... more Corbiculate bees offer the opportunity to analyse the evolution of differences in body size between sexes in relationship to the social environment, because this group of phylogenetically related taxa have contrasting levels of social organization, ranging from solitary to highly eusocial. Sexual size dimorphism evolves because body size is usually related to reproductive success through different pathways in females and males. Female body size is strongly correlated with fecundity, whereas in males the body size is correlated with mating success. Within a clade, if sexual selection on males has been stronger than selection on female fecundity, a sexual size dimorphism bias to males would be expected (Rensch's rule), or an opposite trend when the fecundity of females has had a stronger effect. We tested these predictions by taking an allometric approach that considered differences in the capacity of a reproductive female to start a nest on her own or not. Phylogenetic analysis of the whole clade and another analysis including only species in which the females start nests on their own showed that the corbiculate bees do not seem to follow Rensch's rule. The males and reproductive females of the species in which the females have lost their capacity to start nests were smaller than the reproductive individuals of species in which the females start nests on their own, suggesting that selective pressures linked to the evolution of sociality might constrain the evolution of a large body size in both males and reproductive females.
Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryp... more Cryptic colouration is an adaptative mechanism against predators. Colour patterns can become cryptic through background matching and disruptive colouration, which breaks up the outlines of an animal because the pattern does not coincide with the shape and outline of the animal's body. Background matching could be advanta
In insects, male mating success and female fecundity usually increase with body size. However, na... more In insects, male mating success and female fecundity usually increase with body size. However, natural selection favors faster maturation, reducing the risk of prereproductive death, when the reproductive season is short in habitats located at high altitudes or far from the equator. Also, if males that mature earlier than females under these conditions increase their mating opportunities, protandry may evolve in their
n insects, male mating success and female fecundity usually increase with body size. ... more n insects, male mating success and female fecundity usually increase with body size. However, natural selection favors faster maturation, reducing the risk of pre- reproductive death, when the reproductive season is short in habitats located at high altitudes or far from the equator. Also, if males that mature earlier than females under these conditions increase their mating opportunities, protandry may evolve in their populations. Nonetheless, as body size is strongly correlated with maturation time in insects, faster sexual maturation is reached at the expense of having a small body size. We analyzed the differences in adult body size of males and females of the grass-hopper Sphenarium histrio Gerstaecker (Orthoptera: Pyrgomorphidae) in three sites across an altitudinal gradient in southern Mexico. We also evaluated the possibility of protandry in these sampling sites using a common garden experiment. Male and female grasshoppers collected from low altitude sites in the field and reared in the laboratory were larger than those from a high altitude, suggesting genetic differentia-tion. Grasshoppers from a high altitude hatched earlier, had a shorter development time, presented fewer instars, and were smaller than grasshoppers from the other sampling sites. Moreover, development time in the three sampling sites was shorter in males than in females, suggesting protandry. Interestingly, the males from the three sites showed similar growth rates, but the females from low and high altitudes, re-spectively, had the fastest and slowest growth rates. In general, the adaptive value of the evolution of protandry has been focused on males. However, it may be that the growth rates of females in these sites could modify the degree of protandry as a response to their risk of pre-reproductive death and the potential benefits associated with multiple matings.
Male and female animals often exhibit differences in body size; this difference is known as sexua... more Male and female animals often exhibit differences in body size; this difference is known as sexual size dimorphism (SSD). Hummingbirds are an excellent model system to test functional hypotheses of SSD because they exhibit a wide range of body sizes and reproductive behaviour between the sexes. Here, using phylogenetic comparative methods, we tested whether mating system, male territoriality and agility predicted the evolution of SSD in this avian family. Our results first suggest that evolutionary increases in male-biased SSD are related to increases in lekking behaviour. Second, we found that male agility is positively related to increases in male biased-SSD albeit this is only likely to occur in males of territorial species. Finally, we found an allometric pattern for SSD consistent with Rensch’s rule that was not explained by our estimates of male competition and agility.
The genus Sphenarium Charpentier, 1842 comprises the most diverse group of the New World Pyrgomor... more The genus Sphenarium Charpentier, 1842 comprises the most diverse group of the New World Pyrgomorphidae. These grasshoppers show an extensive variation in external morphology, and are culturally and economically important for Mexican people since pre-Hispanic times. Nevertheless, the taxonomy of Sphenarium has been chaotic and remained incompletely resolved until now. Following an integrative taxonomic framework, we infer the number of species in this genus by species delimitation based on morphological, phylogenetic, and geographic information. Based on our results, we revise the genus and redefine 9 species and describe 8 new species (S. adelinae sp.n., S. crypticum sp.n., S. infernalis sp.n., S. miztecum sp.n., S. occidentalis sp.n., S. tarascum sp.n., S. totonacum sp.n. and S. zapotecum sp.n.). Moreover, we update the knowledge of the evolutionary relationships and biogeographic patterns of Sphenarium species. Our results also demonstrate the importance of historic geological an...
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Papers by Raul Cueva del Castillo