Xyleborus volvulus (Coleoptera: Curculionidae): Biology and Fungal Associates.

The ambrosia beetle Fabricius has been reported as a potential vector of the plant pathogen T.C. Harr., Fraedrich & Aghayeva that is affecting avocado orchards in South Florida. In this study, we examined its life cycle, process of gallery formation, gallery structure, and fungal associates by rearing one generation on avocado sawdust medium under control conditions. The adult foundress excavated a vertical tunnel that constituted the main gallery with a length of 2.5 cm, followed by the construction of up to six secondary galleries with a total length of 4.4 cm. The time period for one generation (egg to adult) was 28 days. Teneral males emerged 3 days after the emergence of the first females. The F generation did not significantly contribute to gallery expansion. Four species of and nine yeast species were recovered from galleries and beetles. and were the most frequent symbionts recovered from new adults and galleries. dominated during the early stages of the gallery development, whereas was most frequent in later stages. Other species were inconsistently isolated from galleries, which suggests a strong association between and both and These results suggest that is the primary nutritional symbiont of and that yeast species may be pioneer colonizers that assist with the growth of fungal symbionts. Ambrosia beetles cultivate fungi in tunnels bored into weakened host trees. This obligate interaction is required for their survival as beetles feed on these symbiotic fungi, and the fungi benefit from transportation by the beetles. carries many nonpathogenic symbionts; however, recently the acquisition of (the causal agent of a lethal vascular disease of lauraceous trees) by this beetle has altered its status from wood degrader to potential pest in avocado. We conducted a study to understand the relationship of this beetle and its fungal associates. Our results show that has a multipartite flexible association with different species. The lack of fidelity in the mutualistic association may explain the acquisition of Knowing the beetle biology and its mutualistic interactions furthers an understanding of the beetle's role as a potential vector and in disease transmission.