| Popis: |
Invasive species threaten the success of native species worldwide. In order to protect at-risk ecosystems, we must understand the reasons behind the ecological success of introduced species. The weevil Naupactus cervinus, native to South America, is a particularly interesting model of invasive species success as it reproduces parthenogenetically, resulting in decreased genetic variability. We would expect such introduced populations to have decreased adaptive capabilities, but this is not the case for N. cervinus in its introduced range in the United States. We examine whether this introduced species experiences shifts in gene expression in association with the available food resources in the generalist niche they occupy. To better understand which gene functions are important to invasive species success, we compare gene expression across localities, host plants, life stages, and during an experimental host plant shift. We focus in particular on the upregulation of particular plant detoxification genes, and of effector genes that in turn can impact detoxification gene expression. Our transcriptome analyses of native and introduced weevils have shown that there is an increase in the number of upregulated detoxification genes in head and immature tissue samples. Additionally, more detoxification genes are upregulated in N. cervinus populations that consume legumes. No such upregulation occurs in populations feeding on most citrus host plants, with the exception of immatures and populations that consume organically grown orange trees. Regionally, more detoxification genes are upregulated in some localities relative to others. There is also an elevated detoxification response in the experimental host plant shift, which existed across all tissue types. Specific upregulation in larval tissue suggests that there may be a heritable epigenetic component in play; this takes the form of transgenerational priming of detoxification responses based on host plant, which may be associated with how this asexual species can successfully invade a new habitat. |
