An official website of the United States government
Comparing the diversity of gut microbiota between and within social insect colonies can illustrate interactions between bacterial community composition and host behaviour. In many eusocial insect species, different workers exhibit different task behaviours. Evidence of compositional differences between core microbiota in different worker types could suggest a microbial association with the division of labour among workers. Here, we present the core microbiota ofAphaenogaster piceaant workers with different task behaviours. The genusAphaenogasteris abundant worldwide, yet the associated microbiota of this group is unstudied. Bacterial communities fromAphaenogaster piceagut samples in this study consist of 19 phyla, dominated by Proteobacteria, Cyanobacteria and Firmicutes. Analysis of 16S rRNA gene sequences reveals distinct similarity clustering ofAphaenogaster piceagut bacterial communities in workers that have more interactions with the refuse piles. Though gut bacterial communities of nurse and foraging ants are similar in overall composition and structure, the worker groups differ in relative abundances of dominant taxa. Gut bacterial communities from ants that have more interactions with refuse piles are dominated by amplicon sequence variants associated with Entomoplasmataceae. Interaction with faecal matter via refuse piles seems to have the greatest impact on microbial taxa distribution, and this effect appears to be independent of worker type. This is the first report surveying the gut microbiome community composition ofAphaenogasterants.
more »
« less
Trachymyrmex septentrionalis Ant Microbiome Assembly Is Unique to Individual Colonies and Castes
ABSTRACT Within social insect colonies, microbiomes often differ between castes due to their different functional roles and between colony locations. Trachymyrmex septentrionalis fungus-growing ants form colonies throughout the eastern United States and northern Mexico that include workers, female and male alates (unmated reproductive castes), larvae, and pupae. How T. septentrionalis microbiomes vary across this geographic range and between castes is unknown. Our sampling of individual ants from colonies across the eastern United States revealed a conserved T. septentrionalis worker ant microbiome and revealed that worker ant microbiomes are more conserved within colonies than between them. A deeper sampling of individual ants from two colonies that included all available castes (pupae, larvae, workers, and female and male alates), from both before and after adaptation to controlled laboratory conditions, revealed that ant microbiomes from each colony, caste, and rearing condition were typically conserved within but not between each sampling category. Tenericute bacterial symbionts were especially abundant in these ant microbiomes and varied widely in abundance between sampling categories. This study demonstrates how individual insect colonies primarily drive the composition of their microbiomes and shows that these microbiomes are further modified by developmental differences between insect castes and the different environmental conditions experienced by each colony. IMPORTANCE This study investigates microbiome assembly in the fungus-growing ant Trachymyrmex septentrionalis , showing how colony, caste, and lab adaptation influence the microbiome and revealing unique patterns of mollicute symbiont abundance. We find that ant microbiomes differ strongly between colonies but less so within colonies. Microbiomes of different castes and following lab adaptation also differ in a colony-specific manner. This study advances our understanding of the nature of individuality in social insect microbiomes and cautions against the common practice of only sampling a limited number of populations to understand microbiome diversity and function.
more »
« less
- Award ID(s):
- 1656475
- PAR ID:
- 10377287
- Editor(s):
- Imperiale, Michael J.
- Date Published:
- Journal Name:
- mSphere
- Volume:
- 7
- Issue:
- 4
- ISSN:
- 2379-5042
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Many species have evolved alternate phenotypes, thus enabling individuals to conditionally produce phenotypes that are favorable for reproductive success. Examples of this phenomenon include sexual dimorphism, alternative reproductive strategies, and social insect castes. While the evolutionary functions and developmental mechanisms of dimorphic phenotypes have been studied extensively, little attention has focused on the evolutionary covariance between each phenotype. We extend the conceptual framework and methods of morphological integration to hypothesize that dimorphic traits tend to be less integrated between sexes or social castes. In the case of social insects, we describe results from our recent study of an ant genus in which workers have major and minor worker castes that perform different behavioral repertoires in and around the nest. In the case of birds, we describe a new analysis of a family of songbirds that exhibits plumage coloration that can differ greatly between males and females, with apparently independent changes in each sex. Ant head shape, which is highly specialized in each worker caste, was weakly integrated between worker castes, whereas thorax shape, which is more monomorphic, was tightly integrated. Similarly, in birds, we found a negative association between dimorphism and the degree of integration between sexes. We also found that integration decreased in fairy wrens (Malurus) for many feather patches that evolved greater dichromatism. Together, this suggests that the process of evolving increased dimorphism results in a decrease in integration between sexes and social castes. We speculate that once a mechanism for dimorphism evolves, that mechanism can create independent variation in one sex or caste upon which selection may act.more » « less
-
Sharma, Prashant (Ed.)The ant subfamily Leptanillinae (Hymenoptera: Formicidae) consists of minute soil-dwelling species, with several genera within this clade being based solely upon males, including Yavnella Kugler. The dissociation of males and workers has resulted in taxonomic confusion for the Leptanillinae. We here describe the worker caste of Yavnella, facilitated by maximum-likelihood and Bayesian inference from 473 partitioned ultra-conserved element loci, this dataset including 49 other leptanilline species, both described and undescribed. Yavnella laventa sp. nov. is described from seven worker specimens collected in south-western Iran from the Milieu Souterrain Superficiel, a subterranean microhabitat consisting of air-filled cavities among rock and soil fragments, which is subject to similar environmental conditions as caves. This species has bizarrely elongated appendages, which suggests that it is confined to cavities, in contrast with the soil-dwelling behaviour observed in other leptanilline ants. Based on its gracile phenotype relative to other Leptanillinae, Y. laventa shows remarkable adaptations for subterranean life, making it one of a very few examples of this syndrome among the ants. Moreover, the discovery of the worker caste of Yavnella expands our morphological knowledge of the leptanilline ants. We provide worker- and male-based diagnoses of Yavnella, along with a key to the genera of the Leptanillinae for which workers are known. The worker caste of Yavnella as known from this species is immediately recognisable, but the possibility must be noted that described workers of Leptanilla may in fact belong to Yavnella. Further molecular sampling is required to test this hypothesis. ZooBank: urn:lsid:zoobank.org:pub:A54A5766-F35A-4074-9353-1C70FE3955D3more » « less
-
Eusocial insects, such as bees, ants, and wasps of the Hymenoptera and termites of the Blattodea, are able to generate remarkable diversity in morphology and behavior despite being genetically uniform within a colony. Most eusocial insect species display caste structures in which reproductive ability is possessed by a single or a few queens while all other colony members act as workers. However, in some species, caste structure is somewhat plastic, and individuals may switch from one caste or behavioral phenotype to another in response to certain environmental cues. As different castes normally share a common genetic background, it is believed that much of this observed within-colony diversity results from transcriptional differences between individuals. This suggests that epigenetic mechanisms, featured by modified gene expression without changing genes themselves, may play an important role in eusocial insects. Indeed, epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNAs, have been shown to influence eusocial insects in multiple aspects, along with typical genetic regulation. This review summarizes the most recent findings regarding such mechanisms and their diverse roles in eusocial insects.more » « less
-
Abstract Ants are significant structural and agricultural pests, generating a need for human-safe and effective insecticides for ant control. Erythritol, a sugar alcohol used in many commercial food products, reduces survival in diverse insect taxa including fruit flies, termites, and mosquitos. Erythritol also decreases longevity in red imported fire ants; however, its effects on other ant species and its ability to be transferred to naïve colony members at toxic doses have not been explored. Here, we show that erythritol decreases survival in Tetramorium immigrans Santschi (Hymenoptera: Formicidae) in a concentration-dependent manner. Access to ad-libitum water reduced the toxic effects of erythritol, but worker mortality was still increased over controls with ad-lib water. Foraging T. immigrans workers transferred erythritol at lethal levels to nest mates that had not directly ingested erythritol. Similar patterns of mortality following erythritol ingestion were observed in Formica glacialis Wheeler (Hymenoptera: Formicidae), Camponotus subarbatus Emery (Hymenoptera: Formicidae), and Camponotus chromaiodes Bolton (Hymenoptera: Formicidae). These findings suggest that erythritol may be a highly effective insecticide for several genera of ants. Erythritol’s potential effectiveness in social insect control is augmented by its spread at lethal levels through ant colonies via social transfer (trophallaxis) between workers.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1128/msphere.00989-21
