Amendment of a thermophile-fermented compost to humus improves the growth of female larvae of the Hercules beetleDynastes hercules(Coleoptera: scarabaeidae)

Abstract

AbstractAimsHercules beetle is a popular pet and large adult individuals are considered valuable. Incorporating compost prepared from marine animals and fermented by thermophilic bacteria into the humus benefits the gut microflora of several livestock. Here, we evaluated whether this compost improves the growth of the Hercules beetle (Dynastes hercules hercules) larvae.Methods and ResultsWe mixed the compost grains with the humus at a final concentration of 1% (w/w) and transferred ∼90 days old Hercules beetle larvae to fresh humus with or without the compost. After 72 days rearing period, only the female larvae reared in the humus with compost exhibited superior growth, compared with those grown in compost-free humus. The gut bacterial composition was determined at 0 and 46 day after transferring the larvae to humus with or without compost. Improved growth of the female larvae was associated with increased abundance of Mollicutes and decreased abundance of Gammaproteobacteria.ConclusionThe thermophile-fermented compost has a probiotic effect on the female Hercules beetle larvae that is mediated by altered gut microflora.