30,781 research outputs found
The Molecular Clockwork of the Fire Ant Solenopsis invicta
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
Gene expression differences in relation to age and social environment in queen and worker bumble bees
Eusocial insects provide special insights into the genetic pathways influencing aging because of their long-lived queens and flexible aging schedules. Using qRT-PCR in the primitively eusocial bumble bee Bombus terrestris (Linnaeus), we investigated expression levels of four candidate genes associated with taxonomically widespread age-related pathways (coenzyme Q biosynthesis protein 7, COQ7; DNA methyltransferase 3, Dnmt3; foraging, for; and vitellogenin, vg). In Experiment 1, we tested how expression changes with queen relative age and productivity. We found a significant age-related increase in COQ7 expression in queen ovary. In brain, all four genes showed higher expression with increasing female (queen plus worker) production, with this relationship strengthening as queen age increased, suggesting a link with the positive association of fecundity and longevity found in eusocial insect queens. In Experiment 2, we tested effects of relative age and social environment (worker removal) in foundress queens and effects of age and reproductive status in workers. In this experiment, workerless queens showed significantly higher for expression in brain, as predicted if downregulation of for is associated with the cessation of foraging by foundress queens following worker emergence. Workers showed a significant age-related increase in Dnmt3 expression in fat body, suggesting a novel association between aging and methylation in B. terrestris. Ovary activation was associated with significantly higher vg expression in fat body and, in younger workers, in brain, consistent with vitellogenin's ancestral role in regulating egg production. Overall, our findings reveal a mixture of novel and conserved features in age-related genetic pathways under primitive eusociality
Short Neuropeptide F Receptor in the Worker Brain of the Red Imported Fire Ant (Solenopsis invicta Buren) and Methodology for RNA Interference
The red imported fire ant (Solenopsis invicta Buren) is one of the worst invasive species in the United States. Investigating their physiology to understand its molecular basis could lead to the discovery of new gene targets for fire ant control. Neuropeptides are involved in the regulation of important physiological processes, and in insects the short neuropeptide F (sNPF) plays an important role as regulator of feeding, and involved in mechanisms of nutrient sensing, growth and reproduction. This study is focused into unveiling the physiological role of the sNPF and its receptor (sNPFR) in fire ants. In workers, we found a total of nine clusters of immunoreactive-sNPFR cells located near important neuropiles in the brain. These sNPFR-expressing cells are sensitive to the presence/absent of brood, perhaps in correlation with changes in the nutritional status of the colony. Also, these cell clusters are differentially expressed among worker subcastes, suggesting the sNPF/sNPFR pathway could be associated with mechanisms of division of labor. To discover where sNPF is synthesized, we attempted to localize the sNPF-expressing cells in the brain of queens and workers through in situ hybridization, unfortunately without success; thus, the site of synthesis of sNPF in the brain still remains unknown. Finally, we tried to elucidate the role of the sNPFR in social context by silencing its gene expression trough feeding of dsRNA using small laboratory colonies. We found differential effects when delivering the sNPFR-dsRNA through heat-killed dsRNA-producing bacteria or by delivering dsRNA purified from these bacterial cultures. Also, the type of food used as carrier and the concentration of dsRNA were crucial for gene silencing success. Our results showed that feeding a large concentration of dsRNA in liquid and solid foods is required to induce RNAi in the queen midgut; and that the silencing of the sNPFR in this organ did not induce mortality in these queens, but instead it appears to increase larval mortality. In summary, our results are consistent with the sNPF/sNPFR signaling pathway in fire ants being involved in the regulation of division of labor and in sensing the nutritional status, and suggest its function is fundamental for larval development
Short Neuropeptide F Receptor in the Worker Brain of the Red Imported Fire Ant (Solenopsis invicta Buren) and Methodology for RNA Interference
The red imported fire ant (Solenopsis invicta Buren) is one of the worst invasive species in the United States. Investigating their physiology to understand its molecular basis could lead to the discovery of new gene targets for fire ant control. Neuropeptides are involved in the regulation of important physiological processes, and in insects the short neuropeptide F (sNPF) plays an important role as regulator of feeding, and involved in mechanisms of nutrient sensing, growth and reproduction. This study is focused into unveiling the physiological role of the sNPF and its receptor (sNPFR) in fire ants. In workers, we found a total of nine clusters of immunoreactive-sNPFR cells located near important neuropiles in the brain. These sNPFR-expressing cells are sensitive to the presence/absent of brood, perhaps in correlation with changes in the nutritional status of the colony. Also, these cell clusters are differentially expressed among worker subcastes, suggesting the sNPF/sNPFR pathway could be associated with mechanisms of division of labor. To discover where sNPF is synthesized, we attempted to localize the sNPF-expressing cells in the brain of queens and workers through in situ hybridization, unfortunately without success; thus, the site of synthesis of sNPF in the brain still remains unknown. Finally, we tried to elucidate the role of the sNPFR in social context by silencing its gene expression trough feeding of dsRNA using small laboratory colonies. We found differential effects when delivering the sNPFR-dsRNA through heat-killed dsRNA-producing bacteria or by delivering dsRNA purified from these bacterial cultures. Also, the type of food used as carrier and the concentration of dsRNA were crucial for gene silencing success. Our results showed that feeding a large concentration of dsRNA in liquid and solid foods is required to induce RNAi in the queen midgut; and that the silencing of the sNPFR in this organ did not induce mortality in these queens, but instead it appears to increase larval mortality. In summary, our results are consistent with the sNPF/sNPFR signaling pathway in fire ants being involved in the regulation of division of labor and in sensing the nutritional status, and suggest its function is fundamental for larval development
Chemosensory sensitivity reflects reproductive status in the ant Harpegnathos saltator.
Insects communicate with pheromones using sensitive antennal sensilla. Although trace amounts of pheromones can be detected by many insects, context-dependent increased costs of high sensitivity might lead to plasticity in sensillum responsiveness. We have functionally characterized basiconic sensilla of the ant Harpegnathos saltator for responses to general odors in comparison to cuticular hydrocarbons which can act as fertility signals emitted by the principal reproductive(s) of a colony to inhibit reproduction by worker colony members. When released from inhibition workers may become reproductive gamergates. We observed plasticity in olfactory sensitivity after transition to reproductive status with significant reductions in electrophysiological responses to several long-chained cuticular hydrocarbons. Although gamergates lived on average five times longer than non-reproductive workers, the shift to reproductive status rather than age differences matched the pattern of changes in olfactory sensitivity. Decreasing sensillum responsiveness to cuticular hydrocarbons could potentially reduce mutually inhibitory or self-inhibitory effects on gamergate reproduction
Pretender punishment induced by chemical signalling in a queenless ant
Animal societies are stages for both conflict and cooperation. Reproduction is often monopolized by one or a few individuals who behave aggressively to prevent subordinates from reproducing (for example, naked mole-rats, wasps and ants). Here we report an unusual mechanism by which the dominant individual maintains reproductive control. In the queenless ant Dinoponera quadriceps, only the alpha female reproduces. If the alpha is challenged by another female she chemically marks the pretender who is then punished by low-ranking females. This cooperation between alpha and low-rankers allows the alpha to inflict punishment indirectly, thereby maintaining her reproductive primacy without having to figh
Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus
PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication
Direct and indirect genetic effects of a social supergene.
Indirect genetic effects describe phenotypic variation that results from differences in the genotypic composition of social partners. Such effects represent heritable sources of environmental variation in eusocial organisms because individuals are typically reared by their siblings. In the fire ant Solenopsis invicta, a social supergene exhibits striking indirect genetic effects on worker regulation of colony queen number, such that the genotypic composition of workers at the supergene determines whether colonies contain a single or multiple queens. We assessed the direct and indirect genetic effects of this supergene on gene expression in brains and abdominal tissues from laboratory-reared workers and compared these with previously published data from field-collected prereproductive queens. We found that direct genetic effects caused larger gene expression changes and were more consistent across tissue types and castes than indirect genetic effects. Indirect genetic effects influenced the expression of many loci but were generally restricted to the abdominal tissues. Further, indirect genetic effects were only detected when the genotypic composition of social partners differed throughout the development and adult life of focal workers, and were often only significant with relatively lenient statistical cutoffs. Our study provides insight into direct and indirect genetic effects of a social supergene on gene regulatory dynamics across tissues and castes in a complex society
The Genome and Methylome of a Subsocial Small Carpenter Bee, Ceratina calcarata
Understanding the evolution of animal societies, considered to be a major transition in evolution, is a key topic in evolutionary biology. Recently, new gateways for understanding social evolution have opened up due to advances in genomics, allowing for unprecedented opportunities in studying social behavior on a molecular level. In particular, highly eusocial insect species (caste-containing societies with nonreproductives that care for siblings) have taken center stage in studies of the molecular evolution of sociality. Despite advances in genomic studies of both solitary and eusocial insects, we still lack genomic resources for early insect societies. To study the genetic basis of social traits requires comparison of genomes from a diversity of organisms ranging from solitary to complex social forms. Here we present the genome of a subsocial bee, Ceratina calcarata. This study begins to address the types of genomic changes associated with the earliest origins of simple sociality using the small carpenter bee. Genes associated with lipid transport and DNA recombination have undergone positive selection in C. calcarata relative to other bee lineages. Furthermore, we provide the first methylome of a noneusocial bee. Ceratina calcarata contains the complete enzymatic toolkit for DNA methylation. As in the honey bee and many other holometabolous insects, DNA methylation is targeted to exons. The addition of this genome allows for new lines of research into the genetic and epigenetic precursors to complex social behaviors
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