Dynamic changes in host–virus interactions associated with colony founding and social environment in fire ant queens (Solenopsis invicta)

Abstract

The dynamics of host–parasite interactions can change dramatically over the course of a chronic infection as the internal (physiological) and external (environmental) conditions of the host change. When queens of social insects found a colony, they experience changes in both their physiological state (they develop their ovaries and begin laying eggs) and the social environment (they suddenly stop interacting with the other members of the mother colony), making this an excellent model system for examining how these factors interact with chronic infections. We investigated the dynamics of host–viral interactions in queens of Solenopsis invicta (fire ant) as they transition from mating to colony founding/brood rearing to the emergence of the first workers. We examined these dynamics in naturally infected queens in two different social environments, where queens either founded colonies as individuals or as pairs. We hypothesized that stress associated with colony founding plays an important role in the dynamics of host–parasite interactions. We also hypothesized that different viruses have different modalities of interaction with the host that can be quantified by physiological measures and genomic analysis of gene expression in the host. We found that the two most prevalent viruses, SINV‐1 and SINV‐2, are associated with different fitness costs that are mirrored by different patterns of gene expression in the host. In fact SINV‐2, the virus that imposes the significant reduction of a queen's reproductive output is also associated with larger changes of global gene expression in the host. These results show the complexity of interactions between S. invicta and two viral parasites. Our findings also show that chronic infections by viral parasites in insects are dynamic processes that may pose different challenges in the host, laying the groundwork for interesting ecological and evolutionary considerations.

Foodborne Transmission and Clinical Symptoms of Honey Bee Viruses in Ants Lasius spp.

“…Since adult mortality was not observed, removal/cannibalism of diseased brood [74,75], resulting in fewer emerging adults, underlies the observed smaller sizes of infected colonies. This would be analogous to the Solenopsis invicta virus 1 (SINV-1), which can also cause increased larval mortality and a loss of body weight in queens [76]. However, our data do not suggest any effect of ABPV on bodyweight, either for queens or workers, which may due to differences between viruses and/or hosts.…”

The Association between Virus Prevalence and Intercolonial Aggression Levels in the Yellow Crazy Ant, Anoplolepis Gracilipes (Jerdon)

“…Numerous positive-sense, single-strain RNA viruses have been reported in multiple invasive ant species [17,32,33] with a wide range of effects on their host ants spanning from the reduction of foraging activity [34] and fitness costs [35], to colony mortality [36,37], allowing the utilization of these viruses as biocontrol agents to become feasible and promising [38]. One necessary piece of information to evaluate the biocontrol potential of viruses lies in how these viruses are transmitted between colonies, yet most of the mechanism studies are largely based on a single ant system (i.e., red imported fire ant) and its viruses [39,40].…”

Pollutants and Their Interaction with Diseases of Social Hymenoptera

“…Viruses are often transmitted horizontally among individuals and between species or genera. Depending on the host-virus pair, the health effects can range from asymptomatic to symptomatic infections, with individuals suffering from altered behavior, higher mortality, or morphological deformations [147][148][149][150], and some viruses have been shown to have higher virulence in stressed individuals [51,151]. Both, the microsporidian Nosema spp.…”