Wing venation provides useful characters with which to classify extant and fossil insects. Recent... more Wing venation provides useful characters with which to classify extant and fossil insects. Recently, quantification of its shape using landmarks has increased the potential of wing venation to distinguish taxa. However, the use of wing landmarks in phylo-genetic analyses remains largely unexplored. Here, we tested landmark analysis under parsimony (LAUP) to include wing shape data in a phylogenetic analysis of hornets and yellow jackets. Using 68 morphological characters, nine genes and wing landmarks , we produced the first total-evidence phylogeny of Vespinae. We also tested the influence of LAUP parameters using simulated landmarks. Our data confirmed that optimization parameters, alignment method, landmark number and, under low optimization parameters, the initial orientation of aligned shapes can influence LAUP results. Furthermore, single landmark configurations never accurately reflected the topology used for data simulation, but results were significantly close when compared to random topologies. Thus, wing landmark configurations were unreliable phylogenetic characters when treated independently , but provided some useful insights when combined with other data. Our phylogeny corroborated the monophyly of most groups proposed on the basis of morphology and showed the fossil Palaeovespa is distantly related to extant genera. Unstable relationships among genera suggest that rapid radiations occurred in the early history of the Vespinae.
Supplementary Material: Perrard A., Baylac M., Carpenter, J.M. & Villemant C. 2014. Evolution of ... more Supplementary Material: Perrard A., Baylac M., Carpenter, J.M. & Villemant C. 2014. Evolution of wing shape in hornets: why is the wing venation efficient for species identification? Tables of classifications performed with different number of variables and excluding progressively the least sampled groups.
ABSTRACT The yellow-legged hornet, Vespa velutina, was accidentally introduced from Southeast Asi... more ABSTRACT The yellow-legged hornet, Vespa velutina, was accidentally introduced from Southeast Asia and then invaded France and Korea over the last 10 years. Since its introduction, its predation on honeybee colonies has rapidly become an economic problem in invaded countries. Using mitochondrial cytochrome C oxidase and 22 nuclear microsatellite loci, we showed that native hornet populations were well differentiated and highly diverse. In contrast, introduced populations from France and Korea suffered a genetic bottleneck, which did not prevent their rapid geographic expansion. Analysis of the genetic data indicates that French and Korean populations likely arose from two independent introduction events. The most probable source population is from an area between the Chinese provinces of Zhejiang and Jiangsu. This invasion route is in agreement with knowledge on trade and historical records. By studying colonies of V. velutina, we demonstrated its polyandry, which is very rare among Vespidae. This mating behavior could have favored the success of this Asian hornet in Europe and Korea. Combined, the population and colony results suggest that very few or possibly only one single multi-mated female gave rise to the invasion.
ABSTRACT Since its introduction in France 10 years ago, the yellow-legged hornet, Vespa velutina,... more ABSTRACT Since its introduction in France 10 years ago, the yellow-legged hornet, Vespa velutina, has rapidly spread to neighbouring countries (Spain, Portugal, Belgium, Italy and Germany). It showed efficient social traits facilitating its invasive success. Only scarce and incomplete natural history studies were known from its native distribution area. Studying the biology of this species in its invasive distribution range was thus a prerequisite to the implementation of efficient control methods in a near future. During a 3-year field survey, we collected 77 nests to investigate several of the species' key colony characteristics. Our results enabled us to accurately quantify each of the castes and to better understand their synchronicity throughout the season. Our study showed that mature nests are able to produce up to 13 000 individuals and that the size of mature nests is correlated to the number of individuals produced. This correlation enables the inference of one characteristic from the other. Furthermore, each mature nest can produce up to several hundreds of potential founder queens, a crucial datum in the light of today's unregulated spring queen trapping control campaigns. In addition, nest dissections enabled to record the incidence of nest relocation for the first time in this species. Results are discussed with regards to what is known in other Vespidae species, with a focus on Vespula species that are known to be invasive in many other countries worldwide.
ABSTRACT The relationships and ecology of Deccanolestes, a eutherian mammal from the Late Cretace... more ABSTRACT The relationships and ecology of Deccanolestes, a eutherian mammal from the Late Cretaceous of India that is known only from isolated dental, mandibular, and postcranial elements, have been a topic of considerable interest and debate. A recent comprehensive phylogenetic analysis has placed this taxon within Adapisoriculidae, a clade of otherwise Paleocene arboreal mammals, but unexpectedly resolved this expanded Adapisoriculidae near the base of the eutherian tree. Deccanolestes has been described as having an arboreal or scansorial lifestyle based on its ankle morphology. Here, we present a geometric morphometric study of the astragalus to test hypotheses pertaining to the ecomorphological affinities of Deccanolestes. Shape analyses were performed on extant eutherians and marsupials displaying a range of different lifestyles, but predominantly sampling arboreal forms, as well as relevant Cretaceous to Eocene taxa. In addition, we constructed a neighbor-joining tree based on the shape variables to identify similarities among taxa in astragalar morphology. Our results show that Cretaceous and Paleocene taxa, including Deccanolestes, cluster most closely and form a separate group distinct from extant mammal clades, including extinct Primates. Strong phylogenetic signal in astragalar morphology among extant taxa, as well as apparent phylogenetic clustering of extant and extinct taxa, complicates a straightforward interpretation of the locomotor ecology of Deccanolestes, but our results suggest that the astragalar morphology of Deccanolestes has no analogue among the sampled living species. However, this morphology appears prevalent among Cretaceous and Paleocene eutherian mammals.
Magazine R943 of the description, publication type, economic importance and country of origin of ... more Magazine R943 of the description, publication type, economic importance and country of origin of the new species were not found to be significantly correlated with the duration of shelf life .
The Yellow-legged hornet Vespa velutina nigrithorax has established viable populations in France ... more The Yellow-legged hornet Vespa velutina nigrithorax has established viable populations in France since an unintentional introduction before 2004, and the potential invasion risk of this bee-hawking hornet was estimated by modelling the species climatic suitability worldwide. By further projecting such models under 2100 future climate scenarios, we here estimated the predicted trends in invasion risk related to climate change. We performed eight different modelling techniques within an ensemble forecast framework using presence data from the native and the invaded ranges. We predicted an increase in the climatic suitability for the species in the Northern hemisphere, especially close to the already invaded range in Europe, in Spain and in Central and Eastern Europe -from Switzerland to Hungary up to Southern Sweden. Climate change should also increase the invasion risk in the United States except along the Eastern coast. Scenarios for future climates include predictions from five global circulation models and three special reports on emission scenarios. Standard deviations of the results obtained from the 13 different climate scenarios confirmed the low uncertainty of models to predict an increase in invasion risk across Central and Eastern Europe, close to the already invaded European range. These regions hold among the highest densities of bee-hives in Europe, and could suffer from the potential predation of the putative invading hornet on pollinators.
In recent years, five new species of Vespinae have been described from Yunnan Province, China. A ... more In recent years, five new species of Vespinae have been described from Yunnan Province, China. A thorough assessment of these taxa, including study of color differences and compilation of measurements of specimens from six entomological collections, shows that the new taxa are merely variants of existing, nominal species. Thus, all five are synonymized here, as follows: Vespa hekouensis Dong and Wang, and Vespa maguanensis Dong = Vespa analis Fabricius; Vespula yulongensis Dong and Wang = Vespula flaviceps (Smith); Vespula nujiangensis Dong and Wang = Vespula orbata (du Buysson); and Vespula gongshanensis Dong = Vespula rufa (Linnaeus), all NEW SYNONYMY. The synonymies bring the current number of vespine species recognized worldwide to 67.
Taxonomic notes are provided for several taxa of Vespinae. Vespula austriaca (Panzer, 1799) and V... more Taxonomic notes are provided for several taxa of Vespinae. Vespula austriaca (Panzer, 1799) and Vespula infernalis (de Saussure, 1854) can be distinguished by the sculpturing on the frons in the queen. Vespula yunlongensis Dong and Wang, 2003, is a synonym of V. flaviceps (Smith, 1870), NEW SYNONYMY, while V. yulongensis Dong and Wang, 2002, is not a synonym of that species, but of V. rufa (Linnaeus, 1758), NEW SYNONYMY. The type of Vespa peruana de Saussure, 1867, has been found in Geneva, and the species is confirmed as a synonym of Dolichovespula norwegica (Fabricius, 1781). Vespula shinanoensis Takamizawa, 2005, is a nomen nudum.
Social parasites exploit the brood-care behaviour and social
structure of one or more host specie... more Social parasites exploit the brood-care behaviour and social structure of one or more host species. Within the social Hymenoptera there are different types of social parasitism. In its extreme form, species of obligate social parasites, or inquilines, do not have the worker caste and depend entirely on the workers of a host species to raise their reproductive offspring. The strict form of Emery’s rule states that social parasites share immediate common ancestry with their hosts. Moreover, this rule has been linked with a sympatric origin of inquilines from their hosts. Here, we conduct phylogenetic analyses of yellowjackets and hornets based on 12 gene fragments and evaluate competing evolutionary scenarios to test Emery’s rule. We find that inquilines, as well as facultative social parasites, are not the closest relatives of their hosts. Therefore, Emery’s rule in its strict sense is rejected, suggesting that social parasites have not evolved sympatrically from their hosts in yellowjackets and hornets. However, the relaxed version of the rule is supported, as inquilines and their hosts belong to the same Dolichovespula clade. Furthermore, inquilinism has evolved only once in Dolichovespula.
Wing venation has long been used for insect identification. Lately, the characterization
of venat... more Wing venation has long been used for insect identification. Lately, the characterization of venation shape using geometric morphometrics has further improved the potential of using the wing for insect identification. However, external factors inducing variation in wing shape could obscure specific differences, preventing accurate discrimination of species in heterogeneous samples. Here, we show that interspecific difference is the main source of wing shape variation within social wasps. We found that a naive clustering of wing shape data from taxonomically and geographically heterogeneous samples of workers returned groups congruent with species. We also confirmed that individuals can be reliably attributed to their genus, species and populations on the basis of their wing shape. Our results suggested that the shape variation reflects the evolutionary history with a potential influence of other factors such as body shape, climate and mimicry selective pressures. However, the high dimensionality of wing shape variation may have prevented absolute convergences between the different species. Wing venation shape is thus a taxonomically relevant marker combining the accuracy of quantitative characters with the specificity required for identification criteria. This marker may also highlight adaptive processes that could help understand the wing’s influence on insect flight.
The wing venation is frequently used as a morphological marker to distinguish biological groups a... more The wing venation is frequently used as a morphological marker to distinguish biological groups among insects. With geometric morphometrics, minute shape differences can be detected between closely related species or populations, making this technique useful for taxonomy. However, the direct influence of genetic differences on wing morphology has not been explored within colonies of social insects. Here, we show that the father’s genotype has a direct effect on wing morphology in colonies of social wasps. Using geometric mor- phometrics on the venation pattern, we found significant differences in wing size and shape between patrilines of yellowjackets, taking allometry and measurement error into account. The genetic influence on wing size accounted for a small part of the overall size variation, but venation shape was highly structured by the differences between patrilines. Overall, our results showed a strong genetic influence on wing morphology likely acting at multiple levels of venation pattern development. This confirmed the pertinence of this marker for taxonomic purposes and suggests this phenotype as a potentially useful marker for phylogenies. This also raises doubts about the strength of selective pressures on this phenotype, which high- lights the need to understand better the role of wing venation shape in insect flight.
Coloration of stinging insects is often based on contrasted patterns of light and black pigmentat... more Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Mu¨ llerian mimicry than by abiotic pressures on melanism.
The only previous comprehensive phylogenetic analysis of the 22 species of the genus Vespa was ba... more The only previous comprehensive phylogenetic analysis of the 22 species of the genus Vespa was based on just 11 morphological characters and resulted in only limited resolution. In order to improve the phylogenetic inference, we carried out a simultaneous analysis with 45 morphological characters and data from four mitochondrial and two nuclear genes. The results support a number of the previously found relationships. The monophyly of the genus Vespa and the existence of a main clade excluding V. basalis and V. binghami are confirmed. The tropica group is supported. The affinis group is not supported; molecular data relate the previously unresolved V. orientalis to V. affinis + V. mocsaryana.
Caste shape dimorphism (CShD) has previously been studied in wasps through comparison of differen... more Caste shape dimorphism (CShD) has previously been studied in wasps through comparison of different body parts, originating from different imaginal discs. Using geometric morphometrics with a new protocol for measuring wings of pinned specimens from natural history collections, we tested CShD of three hornet species in an organ developed from a single imaginal disc: the forewing. Gaussian mixture models retrieved most castes and species levels, confirming that caste is an important component of wing variations in females of these hornets. Size and allometry – the influence of size on shape – contribution to wing dimorphism between castes was major, but failed to explain the entire shape dimorphism. This deviation from simple allometric scaling was not similar in the three species: in Vespa tropica, allometric directions in the shape space differed between castes, whereas in V. crabro and V. velutina, they were similar but a significant part of CShD resulted from lateral transpositions. These results clearly indicate that queens are not just enlarged workers. They also support that the different patterns of CShD may result from different developmental mechanisms. Finally, they highlight that even in a highly social group like hornets, there is still variation in caste dimorphism among species.
Wing venation provides useful characters with which to classify extant and fossil insects. Recent... more Wing venation provides useful characters with which to classify extant and fossil insects. Recently, quantification of its shape using landmarks has increased the potential of wing venation to distinguish taxa. However, the use of wing landmarks in phylo-genetic analyses remains largely unexplored. Here, we tested landmark analysis under parsimony (LAUP) to include wing shape data in a phylogenetic analysis of hornets and yellow jackets. Using 68 morphological characters, nine genes and wing landmarks , we produced the first total-evidence phylogeny of Vespinae. We also tested the influence of LAUP parameters using simulated landmarks. Our data confirmed that optimization parameters, alignment method, landmark number and, under low optimization parameters, the initial orientation of aligned shapes can influence LAUP results. Furthermore, single landmark configurations never accurately reflected the topology used for data simulation, but results were significantly close when compared to random topologies. Thus, wing landmark configurations were unreliable phylogenetic characters when treated independently , but provided some useful insights when combined with other data. Our phylogeny corroborated the monophyly of most groups proposed on the basis of morphology and showed the fossil Palaeovespa is distantly related to extant genera. Unstable relationships among genera suggest that rapid radiations occurred in the early history of the Vespinae.
Supplementary Material: Perrard A., Baylac M., Carpenter, J.M. & Villemant C. 2014. Evolution of ... more Supplementary Material: Perrard A., Baylac M., Carpenter, J.M. & Villemant C. 2014. Evolution of wing shape in hornets: why is the wing venation efficient for species identification? Tables of classifications performed with different number of variables and excluding progressively the least sampled groups.
ABSTRACT The yellow-legged hornet, Vespa velutina, was accidentally introduced from Southeast Asi... more ABSTRACT The yellow-legged hornet, Vespa velutina, was accidentally introduced from Southeast Asia and then invaded France and Korea over the last 10 years. Since its introduction, its predation on honeybee colonies has rapidly become an economic problem in invaded countries. Using mitochondrial cytochrome C oxidase and 22 nuclear microsatellite loci, we showed that native hornet populations were well differentiated and highly diverse. In contrast, introduced populations from France and Korea suffered a genetic bottleneck, which did not prevent their rapid geographic expansion. Analysis of the genetic data indicates that French and Korean populations likely arose from two independent introduction events. The most probable source population is from an area between the Chinese provinces of Zhejiang and Jiangsu. This invasion route is in agreement with knowledge on trade and historical records. By studying colonies of V. velutina, we demonstrated its polyandry, which is very rare among Vespidae. This mating behavior could have favored the success of this Asian hornet in Europe and Korea. Combined, the population and colony results suggest that very few or possibly only one single multi-mated female gave rise to the invasion.
ABSTRACT Since its introduction in France 10 years ago, the yellow-legged hornet, Vespa velutina,... more ABSTRACT Since its introduction in France 10 years ago, the yellow-legged hornet, Vespa velutina, has rapidly spread to neighbouring countries (Spain, Portugal, Belgium, Italy and Germany). It showed efficient social traits facilitating its invasive success. Only scarce and incomplete natural history studies were known from its native distribution area. Studying the biology of this species in its invasive distribution range was thus a prerequisite to the implementation of efficient control methods in a near future. During a 3-year field survey, we collected 77 nests to investigate several of the species' key colony characteristics. Our results enabled us to accurately quantify each of the castes and to better understand their synchronicity throughout the season. Our study showed that mature nests are able to produce up to 13 000 individuals and that the size of mature nests is correlated to the number of individuals produced. This correlation enables the inference of one characteristic from the other. Furthermore, each mature nest can produce up to several hundreds of potential founder queens, a crucial datum in the light of today's unregulated spring queen trapping control campaigns. In addition, nest dissections enabled to record the incidence of nest relocation for the first time in this species. Results are discussed with regards to what is known in other Vespidae species, with a focus on Vespula species that are known to be invasive in many other countries worldwide.
ABSTRACT The relationships and ecology of Deccanolestes, a eutherian mammal from the Late Cretace... more ABSTRACT The relationships and ecology of Deccanolestes, a eutherian mammal from the Late Cretaceous of India that is known only from isolated dental, mandibular, and postcranial elements, have been a topic of considerable interest and debate. A recent comprehensive phylogenetic analysis has placed this taxon within Adapisoriculidae, a clade of otherwise Paleocene arboreal mammals, but unexpectedly resolved this expanded Adapisoriculidae near the base of the eutherian tree. Deccanolestes has been described as having an arboreal or scansorial lifestyle based on its ankle morphology. Here, we present a geometric morphometric study of the astragalus to test hypotheses pertaining to the ecomorphological affinities of Deccanolestes. Shape analyses were performed on extant eutherians and marsupials displaying a range of different lifestyles, but predominantly sampling arboreal forms, as well as relevant Cretaceous to Eocene taxa. In addition, we constructed a neighbor-joining tree based on the shape variables to identify similarities among taxa in astragalar morphology. Our results show that Cretaceous and Paleocene taxa, including Deccanolestes, cluster most closely and form a separate group distinct from extant mammal clades, including extinct Primates. Strong phylogenetic signal in astragalar morphology among extant taxa, as well as apparent phylogenetic clustering of extant and extinct taxa, complicates a straightforward interpretation of the locomotor ecology of Deccanolestes, but our results suggest that the astragalar morphology of Deccanolestes has no analogue among the sampled living species. However, this morphology appears prevalent among Cretaceous and Paleocene eutherian mammals.
Magazine R943 of the description, publication type, economic importance and country of origin of ... more Magazine R943 of the description, publication type, economic importance and country of origin of the new species were not found to be significantly correlated with the duration of shelf life .
The Yellow-legged hornet Vespa velutina nigrithorax has established viable populations in France ... more The Yellow-legged hornet Vespa velutina nigrithorax has established viable populations in France since an unintentional introduction before 2004, and the potential invasion risk of this bee-hawking hornet was estimated by modelling the species climatic suitability worldwide. By further projecting such models under 2100 future climate scenarios, we here estimated the predicted trends in invasion risk related to climate change. We performed eight different modelling techniques within an ensemble forecast framework using presence data from the native and the invaded ranges. We predicted an increase in the climatic suitability for the species in the Northern hemisphere, especially close to the already invaded range in Europe, in Spain and in Central and Eastern Europe -from Switzerland to Hungary up to Southern Sweden. Climate change should also increase the invasion risk in the United States except along the Eastern coast. Scenarios for future climates include predictions from five global circulation models and three special reports on emission scenarios. Standard deviations of the results obtained from the 13 different climate scenarios confirmed the low uncertainty of models to predict an increase in invasion risk across Central and Eastern Europe, close to the already invaded European range. These regions hold among the highest densities of bee-hives in Europe, and could suffer from the potential predation of the putative invading hornet on pollinators.
In recent years, five new species of Vespinae have been described from Yunnan Province, China. A ... more In recent years, five new species of Vespinae have been described from Yunnan Province, China. A thorough assessment of these taxa, including study of color differences and compilation of measurements of specimens from six entomological collections, shows that the new taxa are merely variants of existing, nominal species. Thus, all five are synonymized here, as follows: Vespa hekouensis Dong and Wang, and Vespa maguanensis Dong = Vespa analis Fabricius; Vespula yulongensis Dong and Wang = Vespula flaviceps (Smith); Vespula nujiangensis Dong and Wang = Vespula orbata (du Buysson); and Vespula gongshanensis Dong = Vespula rufa (Linnaeus), all NEW SYNONYMY. The synonymies bring the current number of vespine species recognized worldwide to 67.
Taxonomic notes are provided for several taxa of Vespinae. Vespula austriaca (Panzer, 1799) and V... more Taxonomic notes are provided for several taxa of Vespinae. Vespula austriaca (Panzer, 1799) and Vespula infernalis (de Saussure, 1854) can be distinguished by the sculpturing on the frons in the queen. Vespula yunlongensis Dong and Wang, 2003, is a synonym of V. flaviceps (Smith, 1870), NEW SYNONYMY, while V. yulongensis Dong and Wang, 2002, is not a synonym of that species, but of V. rufa (Linnaeus, 1758), NEW SYNONYMY. The type of Vespa peruana de Saussure, 1867, has been found in Geneva, and the species is confirmed as a synonym of Dolichovespula norwegica (Fabricius, 1781). Vespula shinanoensis Takamizawa, 2005, is a nomen nudum.
Social parasites exploit the brood-care behaviour and social
structure of one or more host specie... more Social parasites exploit the brood-care behaviour and social structure of one or more host species. Within the social Hymenoptera there are different types of social parasitism. In its extreme form, species of obligate social parasites, or inquilines, do not have the worker caste and depend entirely on the workers of a host species to raise their reproductive offspring. The strict form of Emery’s rule states that social parasites share immediate common ancestry with their hosts. Moreover, this rule has been linked with a sympatric origin of inquilines from their hosts. Here, we conduct phylogenetic analyses of yellowjackets and hornets based on 12 gene fragments and evaluate competing evolutionary scenarios to test Emery’s rule. We find that inquilines, as well as facultative social parasites, are not the closest relatives of their hosts. Therefore, Emery’s rule in its strict sense is rejected, suggesting that social parasites have not evolved sympatrically from their hosts in yellowjackets and hornets. However, the relaxed version of the rule is supported, as inquilines and their hosts belong to the same Dolichovespula clade. Furthermore, inquilinism has evolved only once in Dolichovespula.
Wing venation has long been used for insect identification. Lately, the characterization
of venat... more Wing venation has long been used for insect identification. Lately, the characterization of venation shape using geometric morphometrics has further improved the potential of using the wing for insect identification. However, external factors inducing variation in wing shape could obscure specific differences, preventing accurate discrimination of species in heterogeneous samples. Here, we show that interspecific difference is the main source of wing shape variation within social wasps. We found that a naive clustering of wing shape data from taxonomically and geographically heterogeneous samples of workers returned groups congruent with species. We also confirmed that individuals can be reliably attributed to their genus, species and populations on the basis of their wing shape. Our results suggested that the shape variation reflects the evolutionary history with a potential influence of other factors such as body shape, climate and mimicry selective pressures. However, the high dimensionality of wing shape variation may have prevented absolute convergences between the different species. Wing venation shape is thus a taxonomically relevant marker combining the accuracy of quantitative characters with the specificity required for identification criteria. This marker may also highlight adaptive processes that could help understand the wing’s influence on insect flight.
The wing venation is frequently used as a morphological marker to distinguish biological groups a... more The wing venation is frequently used as a morphological marker to distinguish biological groups among insects. With geometric morphometrics, minute shape differences can be detected between closely related species or populations, making this technique useful for taxonomy. However, the direct influence of genetic differences on wing morphology has not been explored within colonies of social insects. Here, we show that the father’s genotype has a direct effect on wing morphology in colonies of social wasps. Using geometric mor- phometrics on the venation pattern, we found significant differences in wing size and shape between patrilines of yellowjackets, taking allometry and measurement error into account. The genetic influence on wing size accounted for a small part of the overall size variation, but venation shape was highly structured by the differences between patrilines. Overall, our results showed a strong genetic influence on wing morphology likely acting at multiple levels of venation pattern development. This confirmed the pertinence of this marker for taxonomic purposes and suggests this phenotype as a potentially useful marker for phylogenies. This also raises doubts about the strength of selective pressures on this phenotype, which high- lights the need to understand better the role of wing venation shape in insect flight.
Coloration of stinging insects is often based on contrasted patterns of light and black pigmentat... more Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Mu¨ llerian mimicry than by abiotic pressures on melanism.
The only previous comprehensive phylogenetic analysis of the 22 species of the genus Vespa was ba... more The only previous comprehensive phylogenetic analysis of the 22 species of the genus Vespa was based on just 11 morphological characters and resulted in only limited resolution. In order to improve the phylogenetic inference, we carried out a simultaneous analysis with 45 morphological characters and data from four mitochondrial and two nuclear genes. The results support a number of the previously found relationships. The monophyly of the genus Vespa and the existence of a main clade excluding V. basalis and V. binghami are confirmed. The tropica group is supported. The affinis group is not supported; molecular data relate the previously unresolved V. orientalis to V. affinis + V. mocsaryana.
Caste shape dimorphism (CShD) has previously been studied in wasps through comparison of differen... more Caste shape dimorphism (CShD) has previously been studied in wasps through comparison of different body parts, originating from different imaginal discs. Using geometric morphometrics with a new protocol for measuring wings of pinned specimens from natural history collections, we tested CShD of three hornet species in an organ developed from a single imaginal disc: the forewing. Gaussian mixture models retrieved most castes and species levels, confirming that caste is an important component of wing variations in females of these hornets. Size and allometry – the influence of size on shape – contribution to wing dimorphism between castes was major, but failed to explain the entire shape dimorphism. This deviation from simple allometric scaling was not similar in the three species: in Vespa tropica, allometric directions in the shape space differed between castes, whereas in V. crabro and V. velutina, they were similar but a significant part of CShD resulted from lateral transpositions. These results clearly indicate that queens are not just enlarged workers. They also support that the different patterns of CShD may result from different developmental mechanisms. Finally, they highlight that even in a highly social group like hornets, there is still variation in caste dimorphism among species.
Uploads
Papers by Adrien Perrard
and Wang, 2002, is not a synonym of that species, but of V. rufa (Linnaeus, 1758), NEW SYNONYMY. The type of Vespa peruana de Saussure, 1867, has been found in Geneva, and the species is confirmed as a synonym of Dolichovespula norwegica (Fabricius, 1781). Vespula shinanoensis Takamizawa, 2005, is a nomen nudum.
structure of one or more host species. Within the social
Hymenoptera there are different types of social parasitism.
In its extreme form, species of obligate social parasites, or
inquilines, do not have the worker caste and depend entirely
on the workers of a host species to raise their reproductive
offspring. The strict form of Emery’s rule states that social
parasites share immediate common ancestry with their hosts.
Moreover, this rule has been linked with a sympatric origin
of inquilines from their hosts. Here, we conduct phylogenetic
analyses of yellowjackets and hornets based on 12 gene
fragments and evaluate competing evolutionary scenarios to
test Emery’s rule. We find that inquilines, as well as facultative
social parasites, are not the closest relatives of their hosts.
Therefore, Emery’s rule in its strict sense is rejected, suggesting
that social parasites have not evolved sympatrically from
their hosts in yellowjackets and hornets. However, the relaxed
version of the rule is supported, as inquilines and their
hosts belong to the same Dolichovespula clade. Furthermore,
inquilinism has evolved only once in Dolichovespula.
of venation shape using geometric morphometrics has further
improved the potential of using the wing for insect identification. However,
external factors inducing variation in wing shape could obscure specific differences,
preventing accurate discrimination of species in heterogeneous
samples. Here, we show that interspecific difference is the main source of
wing shape variation within social wasps. We found that a naive clustering
of wing shape data from taxonomically and geographically heterogeneous
samples of workers returned groups congruent with species. We also confirmed
that individuals can be reliably attributed to their genus, species and
populations on the basis of their wing shape. Our results suggested that the
shape variation reflects the evolutionary history with a potential influence
of other factors such as body shape, climate and mimicry selective pressures.
However, the high dimensionality of wing shape variation may have prevented
absolute convergences between the different species. Wing venation
shape is thus a taxonomically relevant marker combining the accuracy of
quantitative characters with the specificity required for identification criteria.
This marker may also highlight adaptive processes that could help
understand the wing’s influence on insect flight.
polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental
constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a
polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within
the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Mu¨ llerian mimicry than by abiotic pressures on melanism.
and Wang, 2002, is not a synonym of that species, but of V. rufa (Linnaeus, 1758), NEW SYNONYMY. The type of Vespa peruana de Saussure, 1867, has been found in Geneva, and the species is confirmed as a synonym of Dolichovespula norwegica (Fabricius, 1781). Vespula shinanoensis Takamizawa, 2005, is a nomen nudum.
structure of one or more host species. Within the social
Hymenoptera there are different types of social parasitism.
In its extreme form, species of obligate social parasites, or
inquilines, do not have the worker caste and depend entirely
on the workers of a host species to raise their reproductive
offspring. The strict form of Emery’s rule states that social
parasites share immediate common ancestry with their hosts.
Moreover, this rule has been linked with a sympatric origin
of inquilines from their hosts. Here, we conduct phylogenetic
analyses of yellowjackets and hornets based on 12 gene
fragments and evaluate competing evolutionary scenarios to
test Emery’s rule. We find that inquilines, as well as facultative
social parasites, are not the closest relatives of their hosts.
Therefore, Emery’s rule in its strict sense is rejected, suggesting
that social parasites have not evolved sympatrically from
their hosts in yellowjackets and hornets. However, the relaxed
version of the rule is supported, as inquilines and their
hosts belong to the same Dolichovespula clade. Furthermore,
inquilinism has evolved only once in Dolichovespula.
of venation shape using geometric morphometrics has further
improved the potential of using the wing for insect identification. However,
external factors inducing variation in wing shape could obscure specific differences,
preventing accurate discrimination of species in heterogeneous
samples. Here, we show that interspecific difference is the main source of
wing shape variation within social wasps. We found that a naive clustering
of wing shape data from taxonomically and geographically heterogeneous
samples of workers returned groups congruent with species. We also confirmed
that individuals can be reliably attributed to their genus, species and
populations on the basis of their wing shape. Our results suggested that the
shape variation reflects the evolutionary history with a potential influence
of other factors such as body shape, climate and mimicry selective pressures.
However, the high dimensionality of wing shape variation may have prevented
absolute convergences between the different species. Wing venation
shape is thus a taxonomically relevant marker combining the accuracy of
quantitative characters with the specificity required for identification criteria.
This marker may also highlight adaptive processes that could help
understand the wing’s influence on insect flight.
polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental
constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a
polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within
the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Mu¨ llerian mimicry than by abiotic pressures on melanism.