Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recogniti...Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recognition cues on adult individu- als are from a mixture of genetic and environmental sources, but the ontogeny and use of recognition cues on eggs has not been previously assessed. We studied recognition by workers of eggs that were either nestmates or non-nestmates, and the ontogeny of recognition cues on eggs in the ant Formica fusca, a species with precise egg recognition abilities. Workers were able to dis- criminate among freshly laid eggs with no nest derived cues on them, and the egg surface chemicals varied among nests in these eggs, suggesting that queen derived cues are used in nestmate recognition. The results are discussed in the light of their implica- tions on deceptive social parasite strategies and within colony conflicts展开更多
Insect cuticular hydrocarbons(CHCs)serve as communication signals and protect against desiccation.They form complex blends of up to 150 different compounds.Due to differences in molecular packing,CHC classes differ in...Insect cuticular hydrocarbons(CHCs)serve as communication signals and protect against desiccation.They form complex blends of up to 150 different compounds.Due to differences in molecular packing,CHC classes differ in melting point.Communication is especially important in social insects like ants,which use CHCs to communicate within the colony and to recognize nestmates.Nestmate recognition models often assume a homogenous colony odor,where CHCs are collected,mixed,and redistributed in the postpharyngeal gland(PPG).Via diffusion,recognition cues should evenly spread over the body surface.Hence,CHC composition should be similar across body parts and in the PPG.To test this,we compared CHC composition among whole-body extracts,PPG,legs,thorax,and gaster,across 17 ant species from 3 genera.Quantitative CHC composition differed between body parts,with consistent patterns across species and CHC classes.Early-melting CHC classes were most abundant in the PPG.In contrast,whole body,gaster,thorax,and legs had increasing proportions of CHC classes with higher melting points.Intraindividual CHC variation was highest for rather solid,late-melting CHC classes,suggesting that CHCs differ in their diffusion rates across the body surface.Our results show that body parts strongly differ in CHC composition,either being rich in rather solid,late-melting,or rather liquid,early-melting CHCs.This implies that recognition cues are not homogenously present across the insect body.However,the unequal diffusion of different CHCs represents a biophysical mechanism that enables caste differences despite continuous CHC exchange among colony members.展开更多
Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pathways. This complexity provides the opportunity to evaluate the ecological and social conditions that favor the evoluti...Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pathways. This complexity provides the opportunity to evaluate the ecological and social conditions that favor the evolution of complex signaling. We investigated how the chemical signatures of three populations of the social paper wasp Polistes biglumis differed in terms of concentration of hydrocarbons, proportions of branched hydrocarbons and overall variation. We tested whether the variation in chemical signatures among populations could be explained by the prevalence of social parasites or whether this was just an effect of local abiotic conditions which influenced the composition of the hydrocarbon cuticular layer. We studied the chemical signa- ture in three populations in which obligate social parasites differed in the selection pressures they imposed on host populations. Within each population, we restricted our analyses to non-parasitized hosts, to avoid potential short-term effects of parasite pres- ence on the host chemical signatures. We found that host colonies in parasitized populations had more diverse profiles than the parasite-free population. Moreover, the overall concentration of hydrocarbons and the relative proportion of branched hydrocar- bons were larger in the parasitized populations, relative to the non-parasitized one. This is to our knowledge the first evidence in favour of the hypothesis that different traits in the host chemical signatures as a whole undergo evolutionary changes resulting from directional or balancing selection imposed by social parasites. We conclude that obligate social parasites act as ＇engines of diversity＇ on host chemical signatures and operate in favor of a geographic mosaic of diverging communication codes展开更多
The invasive white-footed ant Technomyrmex difficilis has emerged as a rising pest in several regions,yet its invasion dynamics remain underexplored.This species outcompetes native ants and causes agricultural losses ...The invasive white-footed ant Technomyrmex difficilis has emerged as a rising pest in several regions,yet its invasion dynamics remain underexplored.This species outcompetes native ants and causes agricultural losses by tending pest insects,including aphids and mealybugs.This study provides the first integrated analysis of the species'behavioral,chemical,and genetic variation across Texas and Florida populations.Observations suggest that the recently discovered Texas population of white-footed ants originated from Florida.Microsatellite and mitochondrial DNA analyses revealed low genetic diversity in both populations,with a shared haplotype consistent with the Texas population originating from Florida.STRUCTURE analysis further supported genetic clustering between the two regions.Despite similar within-colony coefficients of relatedness for workers,the populations differed in reproductive strategy:Florida colonies showed signs of inbreeding and high inter-colony aggression,whereas Texas colonies exhibited potential localized outbreeding,low aggression,and more uniform cuticular hydrocarbon profiles.Aggression was positively correlated with chemical divergence but not with genetic differentiation.This study establishes a foundational understanding and highlights the importance of integrating multiple types of data to understand the invasion biology of Technomyrmex difficilis.展开更多
Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life history.While some species are active slave-makers with many workers and others are workerless...Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life history.While some species are active slave-makers with many workers and others are workerless‘murder-parasites,’Myrmoxenus kraussei is considered as a‘degenerate slave-maker’because of its very low worker numbers.Here,we document that Temnothorax recedens host workers in single colonies of M.kraussei from Lago di Garda,Italy,exhibit significantly more genetic diversity than workers in unparasitized colonies.This raises the possibility that,despite its low worker numbers,M.kraussei may actively engage in slave raids in nature.展开更多
文摘Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recognition cues on adult individu- als are from a mixture of genetic and environmental sources, but the ontogeny and use of recognition cues on eggs has not been previously assessed. We studied recognition by workers of eggs that were either nestmates or non-nestmates, and the ontogeny of recognition cues on eggs in the ant Formica fusca, a species with precise egg recognition abilities. Workers were able to dis- criminate among freshly laid eggs with no nest derived cues on them, and the egg surface chemicals varied among nests in these eggs, suggesting that queen derived cues are used in nestmate recognition. The results are discussed in the light of their implica- tions on deceptive social parasite strategies and within colony conflicts
基金This study was funded by a Heisenberg fellowship of the German Research Foundation to FM(Deutsche Forschungsgemeinschaft,grant no.ME 3842/6-1).
文摘Insect cuticular hydrocarbons(CHCs)serve as communication signals and protect against desiccation.They form complex blends of up to 150 different compounds.Due to differences in molecular packing,CHC classes differ in melting point.Communication is especially important in social insects like ants,which use CHCs to communicate within the colony and to recognize nestmates.Nestmate recognition models often assume a homogenous colony odor,where CHCs are collected,mixed,and redistributed in the postpharyngeal gland(PPG).Via diffusion,recognition cues should evenly spread over the body surface.Hence,CHC composition should be similar across body parts and in the PPG.To test this,we compared CHC composition among whole-body extracts,PPG,legs,thorax,and gaster,across 17 ant species from 3 genera.Quantitative CHC composition differed between body parts,with consistent patterns across species and CHC classes.Early-melting CHC classes were most abundant in the PPG.In contrast,whole body,gaster,thorax,and legs had increasing proportions of CHC classes with higher melting points.Intraindividual CHC variation was highest for rather solid,late-melting CHC classes,suggesting that CHCs differ in their diffusion rates across the body surface.Our results show that body parts strongly differ in CHC composition,either being rich in rather solid,late-melting,or rather liquid,early-melting CHCs.This implies that recognition cues are not homogenously present across the insect body.However,the unequal diffusion of different CHCs represents a biophysical mechanism that enables caste differences despite continuous CHC exchange among colony members.
文摘Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pathways. This complexity provides the opportunity to evaluate the ecological and social conditions that favor the evolution of complex signaling. We investigated how the chemical signatures of three populations of the social paper wasp Polistes biglumis differed in terms of concentration of hydrocarbons, proportions of branched hydrocarbons and overall variation. We tested whether the variation in chemical signatures among populations could be explained by the prevalence of social parasites or whether this was just an effect of local abiotic conditions which influenced the composition of the hydrocarbon cuticular layer. We studied the chemical signa- ture in three populations in which obligate social parasites differed in the selection pressures they imposed on host populations. Within each population, we restricted our analyses to non-parasitized hosts, to avoid potential short-term effects of parasite pres- ence on the host chemical signatures. We found that host colonies in parasitized populations had more diverse profiles than the parasite-free population. Moreover, the overall concentration of hydrocarbons and the relative proportion of branched hydrocar- bons were larger in the parasitized populations, relative to the non-parasitized one. This is to our knowledge the first evidence in favour of the hypothesis that different traits in the host chemical signatures as a whole undergo evolutionary changes resulting from directional or balancing selection imposed by social parasites. We conclude that obligate social parasites act as ＇engines of diversity＇ on host chemical signatures and operate in favor of a geographic mosaic of diverging communication codes
基金supported by Invasive Ant Research and Management Project from Texas A&M Agrilife and the Urban Entomology Endowment at Texas A&M University.
文摘The invasive white-footed ant Technomyrmex difficilis has emerged as a rising pest in several regions,yet its invasion dynamics remain underexplored.This species outcompetes native ants and causes agricultural losses by tending pest insects,including aphids and mealybugs.This study provides the first integrated analysis of the species'behavioral,chemical,and genetic variation across Texas and Florida populations.Observations suggest that the recently discovered Texas population of white-footed ants originated from Florida.Microsatellite and mitochondrial DNA analyses revealed low genetic diversity in both populations,with a shared haplotype consistent with the Texas population originating from Florida.STRUCTURE analysis further supported genetic clustering between the two regions.Despite similar within-colony coefficients of relatedness for workers,the populations differed in reproductive strategy:Florida colonies showed signs of inbreeding and high inter-colony aggression,whereas Texas colonies exhibited potential localized outbreeding,low aggression,and more uniform cuticular hydrocarbon profiles.Aggression was positively correlated with chemical divergence but not with genetic differentiation.This study establishes a foundational understanding and highlights the importance of integrating multiple types of data to understand the invasion biology of Technomyrmex difficilis.
基金We thank Daniela Schulz for technical assistance and DFG(He1623/24)for financial support.
文摘Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life history.While some species are active slave-makers with many workers and others are workerless‘murder-parasites,’Myrmoxenus kraussei is considered as a‘degenerate slave-maker’because of its very low worker numbers.Here,we document that Temnothorax recedens host workers in single colonies of M.kraussei from Lago di Garda,Italy,exhibit significantly more genetic diversity than workers in unparasitized colonies.This raises the possibility that,despite its low worker numbers,M.kraussei may actively engage in slave raids in nature.
