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Liselotte Sundström - One of the best experts on this subject based on the ideXlab platform.
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the first draft genomes of the ant Formica Exsecta and its wolbachia endosymbiont reveal extensive gene transfer from endosymbiont to host
BMC Genomics, 2019Co-Authors: Kishor Dhaygude, Helena Johansson, Abhilash Nair, Yannick Wurm, Liselotte SundströmAbstract:Background Adapting to changes in the environment is the foundation of species survival, and is usually thought to be a gradual process. However, transposable elements (TEs), epigenetic modifications, and/or genetic material acquired from other organisms by means of horizontal gene transfer (HGTs), can also lead to novel adaptive traits. Social insects form dense societies, which attract and maintain extra- and intracellular accessory inhabitants, which may facilitate gene transfer between species. The wood ant Formica Exsecta (Formicidae; Hymenoptera), is a common ant species throughout the Palearctic region. The species is a well-established model for studies of ecological characteristics and evolutionary conflict.
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Genome organization and molecular characterization of the three Formica Exsecta viruses-FeV1, FeV2 and FeV4.
PeerJ, 2019Co-Authors: Kishor Dhaygude, Helena Johansson, Jonna Kulmuni, Liselotte SundströmAbstract:We present the genome organization and molecular characterization of the three Formica Exsecta viruses, along with ORF predictions, and functional annotation of genes. The Formica Exsecta virus-4 (FeV4; GenBank ID: {"type":"entrez-nucleotide","attrs":{"text":"MF287670","term_id":"1444544064","term_text":"MF287670"}}MF287670) is a newly discovered negative-sense single-stranded RNA virus representing the first identified member of order Mononegavirales in ants, whereas the Formica Exsecta virus-1 (FeV1; GenBank ID: {"type":"entrez-nucleotide","attrs":{"text":"KF500001","term_id":"563616038","term_text":"KF500001"}}KF500001), and the Formica Exsecta virus-2 (FeV2; GenBank ID: {"type":"entrez-nucleotide","attrs":{"text":"KF500002","term_id":"563616050","term_text":"KF500002"}}KF500002) are positive single-stranded RNA viruses initially identified (but not characterized) in our earlier study. The new virus FeV4 was found by re-analyzing data from a study published earlier. The Formica Exsecta virus-4 genome is 9,866 bp in size, with an overall G + C content of 44.92%, and containing five predicted open reading frames (ORFs). Our bioinformatics analysis indicates that gaps are absent and the ORFs are complete, which based on our comparative genomics analysis suggests that the genomes are complete. Following the characterization, we validate virus infection for FeV1, FeV2 and FeV4 for the first time in field-collected worker ants. Some colonies were infected by multiple viruses, and the viruses were observed to infect all castes, and multiple life stages of workers and queens. Finally, highly similar viruses were expressed in adult workers and queens of six other Formica species: F. fusca, F. pressilabris, F. pratensis, F. aquilonia, F. truncorum and F. cinerea. This research indicates that viruses can be shared between ant species, but further studies on viral transmission are needed to understand viral infection pathways.
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stress responses upon starvation and exposure to bacteria in the ant Formica Exsecta
PeerJ, 2019Co-Authors: Dimitri Stucki, Nick Bos, Dalial Freitak, Liselotte SundströmAbstract:Organisms are simultaneously exposed to multiple stresses, which requires regulation of the resistance to each stress. Starvation is one of the most severe stresses organisms encounter, yet nutritional state is also one of the most crucial conditions on which other stress resistances depend. Concomitantly, organisms often deploy lower immune defenses when deprived of resources. This indicates that the investment into starvation resistance and immune defenses is likely to be subject to trade-offs. Here, we investigated the impact of starvation and oral exposure to bacteria on survival and gene expression in the ant Formica Exsecta. Of the three bacteria used in this study, only Serratia marcescens increased the mortality of the ants, whereas exposure to Escherichia coli and Pseudomonas entomophila alleviated the effects of starvation. Both exposure to bacteria and starvation induced changes in gene expression, but in different directions depending on the species of bacteria used, as well as on the nutritional state of the ants.
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Genome organization and molecular characterization of the three Formica Exsecta viruses—FeV1, FeV2 and FeV4
PeerJ Inc., 2019Co-Authors: Kishor Dhaygude, Helena Johansson, Jonna Kulmuni, Liselotte SundströmAbstract:We present the genome organization and molecular characterization of the three Formica Exsecta viruses, along with ORF predictions, and functional annotation of genes. The Formica Exsecta virus-4 (FeV4; GenBank ID: MF287670) is a newly discovered negative-sense single-stranded RNA virus representing the first identified member of order Mononegavirales in ants, whereas the Formica Exsecta virus-1 (FeV1; GenBank ID: KF500001), and the Formica Exsecta virus-2 (FeV2; GenBank ID: KF500002) are positive single-stranded RNA viruses initially identified (but not characterized) in our earlier study. The new virus FeV4 was found by re-analyzing data from a study published earlier. The Formica Exsecta virus-4 genome is 9,866 bp in size, with an overall G + C content of 44.92%, and containing five predicted open reading frames (ORFs). Our bioinformatics analysis indicates that gaps are absent and the ORFs are complete, which based on our comparative genomics analysis suggests that the genomes are complete. Following the characterization, we validate virus infection for FeV1, FeV2 and FeV4 for the first time in field-collected worker ants. Some colonies were infected by multiple viruses, and the viruses were observed to infect all castes, and multiple life stages of workers and queens. Finally, highly similar viruses were expressed in adult workers and queens of six other Formica species: F. fusca, F. pressilabris, F. pratensis, F. aquilonia, F. truncorum and F. cinerea. This research indicates that viruses can be shared between ant species, but further studies on viral transmission are needed to understand viral infection pathways
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Ants reign over a distinct microbiome in forest soil
Soil Biology and Biochemistry, 2019Co-Authors: Stafva Lindstrom, Liselotte Sundström, Sari Timonen, Helena JohanssonAbstract:Abstract Biotic and abiotic characteristics shape the microbial communities in the soil environment. Manipulation of soil, performed by ants when constructing their nests, radically changes the soil characteristics and creates a unique environment, which differs in its composition, frequency and abundance of microbial taxa, from those in the reference soils. We sampled nests of the mound-building ant Formica Exsecta, and the surrounding reference soils over a three-month period, and generated NGS (Illumina MiSeq), and T-RFLP data of the bacterial and fungal communities. We used ordination techniques and network analysis to disclose the community structure, and we assessed the variation in diversity, evenness and enrichment of taxa between the two environments. We also used indicator analysis to identify the potential core microbiome of the nests. Our results show that the bacterial and fungal communities, in the rigorously curated nest environment, are significantly different from those in the reference soils, in terms of community structure and enrichment of characteristic indicator taxa. We demonstrate that the nests represent a niche, where microbial species can adapt and diverge from the communities in the surrounding soils. Our findings contribute to our understanding of the composition and function of microbiomes in fragmented habitats.
Laurent Keller - One of the best experts on this subject based on the ideXlab platform.
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Conditional Manipulation of Sex Ratios by Ant Workers: A Test of Kin Selection Theory
2016Co-Authors: Liselotte Sundstrm, Michel Chapuisat, Laurent KellerAbstract:Variable queen mating frequencies provide a unique opportunity to study the resolution of worker-queen conflict over sex ratio in social Hymenoptera, because the conflict is maximal in colonies headed by a singly mated queen and is weak or nonexistent in colonies headed by a multiply mated queen. In the wood ant Formica Exsecta, workers in colonies with a singly mated queen, but not those in colonies with a multiply mated queen, altered the sex ratio of queen-laid eggs by eliminating males to preferentially raise queens. By this conditional response to queen mating frequency, workers enhance their inclusive fitness. Social insects provide some of the most striking examples of elaborate cooperative behavior, yet life within colonies also en-tails conflicts (1, 2). For example, in euso-cial Hymenoptera such as ants, wasps, and bees, diploid females develop from fertilized eggs and haploid males from unfertilize
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Reproductive specialization in multiple-queen colonies of the ant Formica Exsecta
2015Co-Authors: Laurent KellerAbstract:In polygynous (multiple queens per nest) colonies of social insects, queens can increase their reproductive share by laying more eggs or by increasing the proportion of eggs that develop into reproductive individuals instead of workers. We used polymorphic microsatellite loci to determine the genetically effective contribution of queens to the production of gynes (new queens), males, and 2 different cohorts of workers in a polygynous population of the ant Formica Exsecta. For this purpose, we developed a new method that can be used for diploid and haplodiploid organisms to quantify the degree of reproductive specialization among breeders in societies where there are too many breeders to ascertain parentage. Using this method, we found a high degree of reproductive specialization among nest-mate queens in both female- and male-producing colonies (sex ratio is bimodally distributed in the study population). For example, a high effective proportion of queens (25 % and 79%, respectively) were specialized in the production of males in female- and male-producing colonies. Our analyses further revealed that in female-producing colonies, significantly fewer queens contributed to gyne production than to worker production. Finally, we found significant changes in the identity of queens contributing to different cohorts of workers. Altogether, these data demonstrate that colonies of F. Exsecta, and probably those of many other highly polygynous social insect species, are composed of reproductive individuals differing in their investment to gynes, males, and workers. These findings demonstrate a new aspect of the highly dynamic social organization of complex animal societies. Key words: ants, breeding system, polygyny, reproductive skew, repro-ductive specialization, social insects. [Behav Ecol 18:375–383 (2007)
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© 2007 The Authors Journal compilation © 2007 Blackwell Publishing Ltd Blackwell Publishing LtdContrasting population genetic structure for workers and queens in the putatively unicolonial ant Formica Exsecta
2015Co-Authors: Rolf Kümmerli, Laurent KellerAbstract:The theory of inclusive fitness provides a powerful explanation for reproductive altruism in social insects, whereby workers gain inclusive fitness benefit by rearing the brood of related queens. Some ant species, however, have unicolonial population structures where multiple nests, each containing numerous queens, are interconnected and individuals move freely between nests. In such cases, nestmate relatedness values may often be indis-tinguishable from zero, which is problematic for inclusive fitness-based explanations of reproductive altruism. We conducted a detailed population genetic study in the polygynous ant Formica Exsecta, which has been suggested to form unicolonial populations in its native habitat. Analyses based on adult workers indeed confirmed a genetic structuring consistent with a unicolonial population structure. However, at the population level the genetic struc-turing inferred from worker pupae was not consistent with a unicolonial population struc-ture, but rather suggested a multicolonial population structure of extended family-based nests. These contrasting patterns suggest limited queen dispersal and free adult worker dis-persal. That workers indeed disperse as adults was confirmed by mark–recapture measure
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Foreign ant queens are accepted but produce fewer offspring.
Oecologia, 2008Co-Authors: Barbara Holzer, Michel Chapuisat, Laurent KellerAbstract:Understanding social evolution requires us to understand the processes regulating the number of breeders within social groups and how they partition reproduction. Queens in polygynous (multiple queens per colony) ants often seek adoption in established colonies instead of founding a new colony independently. This mode of dispersal leads to potential conflicts, as kin selection theory predicts that resident workers should favour nestmate queens over foreign queens. Here we compared the survival of foreign and resident queens as well as their relative reproductive share. We used the ant Formica Exsecta to construct colonies consisting of one queen with workers related to this resident queen and introduced a foreign queen. We found that the survival of foreign queens did not differ from that of resident queens over a period of 136 days. However, the genetic analyses revealed that resident queens produced a 1.5-fold higher number of offspring than introduced queens, and had an equal or higher share in 80% of the colonies. These data indicate that some discrimination can occur against dispersing individuals and that dispersal can thus have costs in terms of direct reproduction for dispersing queens.
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Reproductive parameters vary with social and ecological factors in the polygynous ant Formica Exsecta
Oikos, 2008Co-Authors: Rolf Kümmerli, Laurent KellerAbstract:Due to their haplo-diploid sex determination system and the resulting conflict over optimal sex allocation between queens and workers, social Hymenoptera have become important model species to study variation in sex allocation. While many studies indeed reported sex allocation to be affected by social factors such as colony kin structure or queen number, others, however, found that sex allocation was impacted by ecological factors such as food availability. In this paper, we present one of the rare studies that simultaneously investigated the effects of social and ecological factors on social insect nest reproductive parameters (sex and reproductive allocation, nest productivity) across several years. We found that the sex ratio was extremely male biased in a polygynous (multiple queens per nest) population of the ant Formica Exsecta. Nest-level sex allocation followed the pattern predicted by the queen-replenishment hypothesis, which holds that gynes (new queens) should only be produced and recruited in nests with low queen number (i.e. reduced local resource competition) to ensure nest survival. Accordingly, queen number (social factor) was the main determinant on whether a nest produced gynes or males. However, ecological factors had a large impact on nest productivity and therefore on a nest's resource pool, which determines the degree of local resource competition among co-breeding queens and at what threshold in queen number nests should switch from male to gyne production. Additionally, our genetic data revealed that gynes are recruited back to their parental nests after mating. However, our genetic data are also consistent with some adult queens dispersing on foot from nests where they were produced to nests that never produced queens. As worker production is reduced in gyne-producing nests, queen migration might be offset by workers moving in the other direction, leading to a nest network characterized by reproductive division of labour. Altogether our study shows that both, social and ecological factors can influence long-term nest reproductive strategies in insect societies.
Sundström Liselotte - One of the best experts on this subject based on the ideXlab platform.
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Genome organization and molecular characterization of the three Formica Exsecta viruses—FeV1, FeV2 and FeV4
'PeerJ', 2019Co-Authors: Dhaygude, Kishor Uttam, Johansson Helena, Kulmuni, Jonna Katharina, Sundström LiselotteAbstract:We present the genome organization and molecular characterization of the three Formica Exsecta viruses, along with ORF predictions, and functional annotation of genes. The Formica Exsecta virus-4 (FeV4; GenBank ID: MF287670) is a newly discovered negative-sense single-stranded RNA virus representing the first identified member of order Mononegavirales in ants, whereas the Formica Exsecta virus-1 (FeV1; GenBank ID: KF500001), and the Formica Exsecta virus-2 (FeV2; GenBank ID: KF500002) are positive single-stranded RNA viruses initially identified (but not characterized) in our earlier study. The new virus FeV4 was found by re-analyzing data from a study published earlier. The Formica Exsecta virus-4 genome is 9,866 bp in size, with an overall G + C content of 44.92%, and containing five predicted open reading frames (ORFs). Our bioinformatics analysis indicates that gaps are absent and the ORFs are complete, which based on our comparative genomics analysis suggests that the genomes are complete. Following the characterization, we validate virus infection for FeV1, FeV2 and FeV4 for the first time in field-collected worker ants. Some colonies were infected by multiple viruses, and the viruses were observed to infect all castes, and multiple life stages of workers and queens. Finally, highly similar viruses were expressed in adult workers and queens of six other Formica species: F. fusca, F. pressilabris, F. pratensis, F. aquilonia, F. truncorum and F. cinerea. This research indicates that viruses can be shared between ant species, but further studies on viral transmission are needed to understand viral infection pathways.Peer reviewe
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Stress responses upon starvation and exposure to bacteria in the ant Formica Exsecta
'PeerJ', 2019Co-Authors: Stucki Dimitri, Bos Nick, Freitak Dalial, Sundström LiselotteAbstract:Organisms are simultaneously exposed to multiple stresses, which requires regulation of the resistance to each stress. Starvation is one of the most severe stresses organisms encounter, yet nutritional state is also one of the most crucial conditions on which other stress resistances depend. Concomitantly, organisms often deploy lower immune defenses when deprived of resources. This indicates that the investment into starvation resistance and immune defenses is likely to be subject to trade-offs. Here, we investigated the impact of starvation and oral exposure to bacteria on survival and gene expression in the ant Formica Exsecta. Of the three bacteria used in this study, only Serratia marcescens increased the mortality of the ants, whereas exposure to Escherichia coli and Pseudomonas entomophila alleviated the effects of starvation. Both exposure to bacteria and starvation induced changes in gene expression, but in different directions depending on the species of bacteria used, as well as on the nutritional state of the ants.Peer reviewe
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The first draft genomes of the ant Formica Exsecta, and its Wolbachia endosymbiont reveal extensive gene transfer from endosymbiont to host
'Springer Science and Business Media LLC', 2019Co-Authors: Dhaygude Kishor, Johansson Helena, Nair Abhilash, Wurm Yannick, Sundström LiselotteAbstract:Abstract Background Adapting to changes in the environment is the foundation of species survival, and is usually thought to be a gradual process. However, transposable elements (TEs), epigenetic modifications, and/or genetic material acquired from other organisms by means of horizontal gene transfer (HGTs), can also lead to novel adaptive traits. Social insects form dense societies, which attract and maintain extra- and intracellular accessory inhabitants, which may facilitate gene transfer between species. The wood ant Formica Exsecta (Formicidae; Hymenoptera), is a common ant species throughout the Palearctic region. The species is a well-established model for studies of ecological characteristics and evolutionary conflict. Results In this study, we sequenced and assembled draft genomes for F. Exsecta and its endosymbiont Wolbachia. The F. Exsecta draft genome is 277.7 Mb long; we identify 13,767 protein coding genes, for which we provide gene ontology and protein domain annotations. This is also the first report of a Wolbachia genome from ants, and provides insights into the phylogenetic position of this endosymbiont. We also identified multiple horizontal gene transfer events (HGTs) from Wolbachia to F. Exsecta. Some of these HGTs have also occurred in parallel in multiple other insect genomes, highlighting the extent of HGTs in eukaryotes. Conclusion We present the first draft genome of ant F. Exsecta, and its endosymbiont Wolbachia (wFex), and show considerable rates of gene transfer from the symbiont to the host. We expect that especially the F. Exsecta genome will be valuable resource in further exploration of the molecular basis of the evolution of social organization
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Changes in gene DNA methylation and expression networks accompany caste specialization and age-related physiological changes in a social insect
'Wiley', 2019Co-Authors: Morandin Claire, Sundström Liselotte, Brendel, Volker P., Helantera Heikki, Mikheyev, Alexander S.Abstract:Social insects provide systems for studying epigenetic regulation of phenotypes, particularly with respect to differentiation of reproductive and worker castes, which typically arise from a common genetic background. The role of gene expression in caste specialization has been extensively studied, but the role of DNA methylation remains controversial. Here, we perform well replicated, integrated analyses of DNA methylation and gene expression in brains of an ant (Formica Exsecta) with distinct female castes using traditional approaches (tests of differential methylation) combined with a novel approach (analysis of co-expression and co-methylation networks). We found differences in expression and methylation profiles between workers and queens at different life stages, as well as some overlap between DNA methylation and expression at the functional level. Large portions of the transcriptome and methylome are organized into "modules" of genes, some significantly associated with phenotypic traits of castes and developmental stages. Several gene co-expression modules are preserved in co-methylation networks, consistent with possible regulation of caste-specific gene expression by DNA methylation. Surprisingly, brain co-expression modules were highly preserved when compared with a previous study that examined whole-body co-expression patterns in 16 ant species, suggesting that these modules are evolutionarily conserved and for specific functions in various tissues. Altogether, these results suggest that DNA methylation participates in regulation of caste specialization and age-related physiological changes in social insects.Peer reviewe
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Caste-dependent brood retrieval by workers in the ant Formica Exsecta
'Elsevier BV', 2018Co-Authors: Pulliainen, Outi Unni Inkeri, D'ettorre Patrizia, Bos, Nicky Peter Maria, Sundström LiselotteAbstract:The ability to distinguish friends from foe is a widespread phenomenon among social animals. In ants, recognition of intruders is important for the maintenance of colony integrity and survival. Intruders are typically adult, but the acceptance of non-nestmate brood could result in severe fitness costs, depending on the caste of the brood. Accepting non-nestmate worker brood may not carry a cost, as they should not drain resources of the adoptive colony but may instead add to the workforce. Sexual brood, however, would typically not contribute to colony performance, yet require resources, and should thus be rejected. Here, we tested whether workers of the narrow-headed ant, Formica Exsecta, which strongly discriminate between adult nestmates and non-nestmates, also discriminate between nestmate and non-nestmate pupae. Furthermore, we investigated whether the caste of the brood (workers/sexuals) affects discrimination. We carried out analysis of surface chemicals to investigate whether the chemical distance between colonies was associated with the propensity to accept non-nestmate pupae. We show that worker pupae were retrieved irrespective of their origin, whereas nestmate sexual pupae were retrieved at a slightly higher rate than non-nestmates. Our chemical data, however, suggest that both the reproductive and the worker brood carry sufficient chemical information for discrimination, as they both express colony signatures. However, this information is acted upon only in the case of sexual brood. Our results thus suggest that workers selectively capitalize on the chemical information in agreement with fitness predictions, albeit to a lower extent than during discrimination between adult individuals.Peer reviewedPeer reviewe
Dalial Freitak - One of the best experts on this subject based on the ideXlab platform.
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stress responses upon starvation and exposure to bacteria in the ant Formica Exsecta
PeerJ, 2019Co-Authors: Dimitri Stucki, Nick Bos, Dalial Freitak, Liselotte SundströmAbstract:Organisms are simultaneously exposed to multiple stresses, which requires regulation of the resistance to each stress. Starvation is one of the most severe stresses organisms encounter, yet nutritional state is also one of the most crucial conditions on which other stress resistances depend. Concomitantly, organisms often deploy lower immune defenses when deprived of resources. This indicates that the investment into starvation resistance and immune defenses is likely to be subject to trade-offs. Here, we investigated the impact of starvation and oral exposure to bacteria on survival and gene expression in the ant Formica Exsecta. Of the three bacteria used in this study, only Serratia marcescens increased the mortality of the ants, whereas exposure to Escherichia coli and Pseudomonas entomophila alleviated the effects of starvation. Both exposure to bacteria and starvation induced changes in gene expression, but in different directions depending on the species of bacteria used, as well as on the nutritional state of the ants.
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Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population.
Royal Society open science, 2016Co-Authors: Nick Bos, Liselotte Sundström, Unni Pulliainen, Dalial FreitakAbstract:Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica Exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tissue-specific changes in gene expression, but inbreeding had little effect on most of the genes studied. Our results illustrate the importance of studying stress responses in different tissues instead of entire organisms.
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Inbreeding-related trade-offs in stress resistance in the ant Formica Exsecta.
Biology letters, 2014Co-Authors: Dalial Freitak, Nick Bos, Dimitri Stucki, Liselotte SundströmAbstract:Inbred individuals and populations are predicted to suffer from inbreeding depression, especially in times of stress. Under natural conditions, organisms are exposed to more than one stressor at any one time, highlighting the importance of stress resistance traits. We studied how inbreeding- and immunity-related traits are correlated under different dietary conditions in the ant Formica Exsecta. Its natural diet varies in the amount and nature of plant secondary compounds and the level of free radicals, all of which require detoxification to maintain organismal homeostasis. We found that inbreeding decreased general antibacterial activity under dietary stress, suggesting inbreeding-related physiological trade-offs.
Nick Bos - One of the best experts on this subject based on the ideXlab platform.
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stress responses upon starvation and exposure to bacteria in the ant Formica Exsecta
PeerJ, 2019Co-Authors: Dimitri Stucki, Nick Bos, Dalial Freitak, Liselotte SundströmAbstract:Organisms are simultaneously exposed to multiple stresses, which requires regulation of the resistance to each stress. Starvation is one of the most severe stresses organisms encounter, yet nutritional state is also one of the most crucial conditions on which other stress resistances depend. Concomitantly, organisms often deploy lower immune defenses when deprived of resources. This indicates that the investment into starvation resistance and immune defenses is likely to be subject to trade-offs. Here, we investigated the impact of starvation and oral exposure to bacteria on survival and gene expression in the ant Formica Exsecta. Of the three bacteria used in this study, only Serratia marcescens increased the mortality of the ants, whereas exposure to Escherichia coli and Pseudomonas entomophila alleviated the effects of starvation. Both exposure to bacteria and starvation induced changes in gene expression, but in different directions depending on the species of bacteria used, as well as on the nutritional state of the ants.
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caste dependent brood retrieval by workers in the ant Formica Exsecta
Animal Behaviour, 2018Co-Authors: Unni Pulliainen, Nick Bos, Patrizia Dettorre, Liselotte SundströmAbstract:Abstract The ability to distinguish friends from foe is a widespread phenomenon among social animals. In ants, recognition of intruders is important for the maintenance of colony integrity and survival. Intruders are typically adult, but the acceptance of non-nestmate brood could result in severe fitness costs, depending on the caste of the brood. Accepting non-nestmate worker brood may not carry a cost, as they should not drain resources of the adoptive colony but may instead add to the workforce. Sexual brood, however, would typically not contribute to colony performance, yet require resources, and should thus be rejected. Here, we tested whether workers of the narrow-headed ant, Formica Exsecta, which strongly discriminate between adult nestmates and non-nestmates, also discriminate between nestmate and non-nestmate pupae. Furthermore, we investigated whether the caste of the brood (workers/sexuals) affects discrimination. We carried out analysis of surface chemicals to investigate whether the chemical distance between colonies was associated with the propensity to accept non-nestmate pupae. We show that worker pupae were retrieved irrespective of their origin, whereas nestmate sexual pupae were retrieved at a slightly higher rate than non-nestmates. Our chemical data, however, suggest that both the reproductive and the worker brood carry sufficient chemical information for discrimination, as they both express colony signatures. However, this information is acted upon only in the case of sexual brood. Our results thus suggest that workers selectively capitalize on the chemical information in agreement with fitness predictions, albeit to a lower extent than during discrimination between adult individuals.
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Starvation resistance and tissue-specific gene expression of stress-related genes in a naturally inbred ant population.
Royal Society open science, 2016Co-Authors: Nick Bos, Liselotte Sundström, Unni Pulliainen, Dalial FreitakAbstract:Starvation is one of the most common and severe stressors in nature. Not only does it lead to death if not alleviated, it also forces the starved individual to allocate resources only to the most essential processes. This creates energetic trade-offs which can lead to many secondary challenges for the individual. These energetic trade-offs could be exacerbated in inbred individuals, which have been suggested to have a less efficient metabolism. Here, we studied the effect of inbreeding on starvation resistance in a natural population of Formica Exsecta ants, with a focus on survival and tissue-specific expression of stress, metabolism and immunity-related genes. Starvation led to large tissue-specific changes in gene expression, but inbreeding had little effect on most of the genes studied. Our results illustrate the importance of studying stress responses in different tissues instead of entire organisms.
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Inbreeding-related trade-offs in stress resistance in the ant Formica Exsecta.
Biology letters, 2014Co-Authors: Dalial Freitak, Nick Bos, Dimitri Stucki, Liselotte SundströmAbstract:Inbred individuals and populations are predicted to suffer from inbreeding depression, especially in times of stress. Under natural conditions, organisms are exposed to more than one stressor at any one time, highlighting the importance of stress resistance traits. We studied how inbreeding- and immunity-related traits are correlated under different dietary conditions in the ant Formica Exsecta. Its natural diet varies in the amount and nature of plant secondary compounds and the level of free radicals, all of which require detoxification to maintain organismal homeostasis. We found that inbreeding decreased general antibacterial activity under dietary stress, suggesting inbreeding-related physiological trade-offs.