18 Feb 2022

Microbiome Perturbations During Domestication of the Green June Beetle (Cotinis nitida)

Abstract: Animal-associated microbiomes are critical to the well-being and proper functioning of the animal host, but only limited studies have examined in-sect microbiomes across different developmental stages. These studies revealed large shifts in microbiome communities, often because of significant shifts in diet during insects’ life cycle. Establishing insect colonies as model laboratory organisms and understanding how to properly feed and care for animals with complex and dynamic life cycles requires improved data. This study examined laboratory-raised green June beetles (Cotinis nitida) captured from the field upon emergence from pupae. Starting with wild-caught adults, two generations of beetles were reared in the laboratory, ending with an entirely laboratory-raised generation of larvae. The study compared the microbiomes of each generation and the microbiomes of larvae to adults. This study suggests that a diet of commercial, washed fruit for adults and commercial, packaged, organic alfalfa meal for larvae resulted in depauperate gut microbiome communities. Fermentative yeasts were completely absent in the laboratory-raised adults, and major bacterial population shifts occurred from one generation to the next, coupled with high morbidity and mortality in the laboratory-raised generation. Providing laboratory-raised beetles fresh-collected fruit and the larvae field-harvested detritus may therefore vastly improve their health and survival.