The effect of antibiotic treatment and diet on life history traits and virus susceptibility in an insect

The microbiome of insects is subject to disruption and proliferation as demonstrated in other animal models, and such changes may affect the normal life history traits of the host. Likewise, such changes in the microbial composition may increase or decrease pathogen susceptibility of the host. Here I examine firstly the effects of antibiotic consumption on the cabbage looper (Trichoplusia ni) to a wide range of antibiotics routinely used in the maintenance of laboratory colonies, and then tested whether there were negative effects on the parental generation exposed to them, and if lingering effects were observed in an offspring generation with the addition of a baculovirus (TnSNPV). In the final chapter, I examined the effect of host plant diet, along with site, in combination of antibiotic therapy, on overall insect survival, viral-induced mortality, viral reproducibility, as well as life history traits. Larvae fed cabbage experienced reduced overall survival and increased rates of viral-induced mortality in comparison to those fed kale. Likewise, larvae fed kale had consistently heavier pupal and larval weights in comparison to cabbage-fed larvae. We suggest that host plant diet plays an important role in pathogen susceptibility and life history traits in a much stronger fashion than antibiotic treatment.