Buczkowski, G. | Search bioRxiv

bioRxiv2025

Distribution and efficacy of ingested dsRNA targeting tissue-specific genes in the Argentine ant, Linepithema humile

1With the increasing availability of genomic and transcriptomic information within Formicidae, the investigation of gene function has become possible within ants. However, eusocial life history renders the generation of transgenic strains of ants difficult outside of specific ant lineages that can induce reproductive behavior in workers. RNA interference (RNAi) remains a practical option to investigate gene function within their genomic context in ant lineages that do not exhibit reproductive behavior in workers. This method can be leveraged to investigate the large odorant receptor (OR) gene families present in ant clades. However, ORs tend to be expressed in a tissue-specific fashion, and the capability of dsRNA to achieve knockdown of genes exhibiting localized expression remains uncertain. In this study, we use fluorescently labelled dsRNA to track the spread of dsRNA through the worker body, qPCR to verify that dsRNA can knockdown gene expression in the antennae, and behavioral trials to verify that knockdown of ORs affects nestmate recognition. We found that orally-administered dsRNA is capable of being spread systemically and knocking down tissue-specific genes. Additionally, we found that RNAi may be useful in investigating the influence of ORs in eusocial insect nestmate recognition.

molecular biology↗

bioRxiv2021

Consistent signatures of urban adaptation in a native, urban invader ant Tapinoma sessile

Biological invasions are becoming more prevalent due to the rise of global trade and expansion of urban areas. Ants are among the most prolific invaders, with many exhibiting a multi-queen colony structure, dispersal through budding and a lack of inter-nest aggression. Although these characteristics are generally associated with the invasions of exotic ants, they may also facilitate the spread of native ants into novel habitats (e.g., urban areas). Native to North American forests, the odorous house ant Tapinoma sessile has become abundant in urban environments throughout the United States. Forest-dwelling colonies typically have a small workforce, inhabit a single nest, and are headed by a single queen, whereas urban colonies tend to be several orders of magnitude larger, inhabit multiple nests and are headed by multiple queens. Here, we explore and compare the population genetic and breeding structure of T. sessile within and between urban and natural environments in several localities across its distribution range. We found the social structure of a colony to be a plastic trait in both habitats, although extreme polygyny (i.e., nests with multiple queens) was confined to urban habitats. Additionally, polydomous colonies (i.e., nests lacking genetic differentiation and behavioral antagonism) were only present in urban habitats, suggesting T. sessile can only achieve unicoloniality within urbanized areas. Finally, we identified strong differentiation between urban and natural populations in each locality and continent-wide, indicating cities may restrict gene flow and exert intense selection pressure. Overall, our study highlights urbanizations influence in charting the evolutionary course for species.

evolutionary biology↗