Abstract
The recent discovery of multiple viruses in ants, along with the widespread infection of their hosts across geographic ranges, provides an excellent opportunity to test whether viral prevalence in the field is associated with the complexity of social interactions in the ant population. In this study, we examined whether the association exists between the field prevalence of a virus and the intercolonial aggression of its ant host, using the yellow crazy ant (Anoplolepis gracilipes) and its natural viral pathogen (TR44839 virus) as a model system. We delimitated the colony boundary and composition of A. gracilipes in a total of 12 study sites in Japan (Okinawa), Taiwan, and Malaysia (Penang), through intercolonial aggression assay. The spatial distribution and prevalence level of the virus was then mapped for each site. The virus occurred at a high prevalence in the surveyed colonies of Okinawa and Taiwan (100% infection rate across all sites), whereas virus prevalence was variable (30%–100%) or none (0%) at the sites in Penang. Coincidentally, colonies in Okinawa and Taiwan displayed a weak intercolonial boundary, as aggression between colonies is generally low or moderate. Contrastingly, sites in Penang were found to harbor a high proportion of mutually aggressive colonies, a pattern potentially indicative of complex colony composition. Our statistical analyses further confirmed the observed correlation, implying that intercolonial interactions likely contribute as one of the effective facilitators of/barriers to virus prevalence in the field population of this ant species.
Highlights
A number of traits, such as shifts in social structure, inbreeding tolerance, and adaptability to human-disturbed habitats, are disproportionally presented in invasive ants [1,2,3]
One would predict that a population comprised of mutually tolerant colonies likely has a higher level of viral prevalence as a result of intensive intercolonial interactions, while variations of prevalence should be registered in a population with mixed supercolonial groups
We inoculated three virus-free A. gracilipes colonies by feeding them with a 10% virus-contaminated honey solution, and all the colonies were invariably found positive to TR44839 virus infection as both positive and negative strands of the virus were detected at Day 7 after feeding
Summary
A number of traits, such as shifts in social structure, inbreeding tolerance, and adaptability to human-disturbed habitats, are disproportionally presented in invasive ants [1,2,3]. The “vulnerable supercolony hypothesis” was proposed by Ugelvig and Cremer [8] and has been empirically tested by Tragust et al In [7], supercolony structure was shown to be more susceptible to fungal infections due to the high frequency of intercolonial interactions in the invasive garden ant, Lasius neglectus. Such a pattern is likely more profound for viral pathogens because viruses are generally more readily transmitted horizontally than other pathogen groups [9,10,11,12]. To assess such transmission dynamics, a critical step is to understand if intercolonial interactions serve as a potential transmission pathway of a given virus
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
