RESUMO
Gene expression research is a valuable tool for investigating how gene regulation and expression control the underlying behaviors that structure a eusocial insect colony. However, labs that focus on ant research frequently keep ant colonies in the lab for ease of sampling. It is typically impractical to accurately emulate the field conditions where ants are collected from, so laboratory colonies can be exposed to drastically different environmental conditions and food sources than they are naturally exposed to in the wild. These shifts in diet and environment can cause changes in the gene expression of the ants, affecting downstream behavioral and physiological systems. To examine the nature of these changes, colonies of the Argentine ant, Linepithema humile (Mayr, 1868), were excavated from North Carolina and transferred to the lab, where they were sampled monthly. Illumina and qPCR analyses were conducted on forager samples to detect any changes in gene expression. Approximately six percent of the Argentine ant genome, which represents 765 genes, showed changes in gene regulation after six months in the laboratory environment. The subset of these genes examined via qPCR show that the expression of many genes are correlated with each other, indicating that these genes might be a part of a regulatory network. These findings showed that ant colonies kept in the lab experience changes in gene expression, resulting in downstream effects. Therefore, lab ant colonies are not necessarily representative of wild colonies when conducting experiments on the gene expression, behavior, and physiology of these colonies.
Assuntos
Formigas/metabolismo , Domesticação , Transcriptoma , Animais , Fatores de TempoRESUMO
The Argentine ant (Linepithema humile) is an invasive species that disrupts the balance of natural ecosystems by displacing indigenous ant species throughout its introduced range. Previous studies that examined the mechanisms by which Argentine ants attain ecological dominance showed that superior interference and exploitation competition are key to the successful displacement of native ant species. The objective of this research was to test the hypothesis that effective interference competition by Argentine ants may also be detrimental to the survival of Argentine ant colonies where Argentine ants and native ants compete at toxic baits used to slow the spread of Argentine ants. To study this hypothesis, we examined the competitive interactions between Argentine ants and native odorous house ants, Tapinoma sessile, in the presence and absence of toxic baits. Results showed that Argentine ants aggressively outcompete T. sessile from toxic baits through efficient interference competition and monopolize bait resources. This has severe negative consequences for the survival of Argentine ants as colonies succumb to the toxic effects of the bait. In turn, T. sessile avoid areas occupied by Argentine ants, give up baits, and consequently suffer minimal mortality. Our results provide experimental evidence that highly efficient interference competition may have negative consequences for Argentine ants in areas where toxic baits are used and may provide a basis for designing innovative management programs for Argentine ants. Such programs would have the double benefit of selectively eliminating the invasive species while simultaneously protecting native ants from the toxic effects of baits.