2020 年 2020 巻 4 号 p. 11-16
The white grub beetle, Dasylepida ishigakiensis Niijima et Kinoshita (Coleoptera: Scarabaeidae), is an indigenous pest of sugarcane in the Miyako Islands, Okinawa, Japan. The mouthparts of the adult beetles are known to degenerate and they are assumed to have limited nutritional resources. On the basis of this, we studied changes in the quantity of stored lipids in the adult lifetime. For observing changes of stored lipid quantity, we adopt a commercial kit to conduct methylation of induced fatty acids in the whole insect body and purify them for analysis. We individually extracted and methylated whole lipids in the bodies of male beetles, both in laboratory-reared and feral individuals, and analyzed the methylated fatty acids by gas chromatography for quantification. In laboratory-reared males, we found no difference between newly eclosed beetles and those just after reproductive diapause, only the males who intensively flew for mating had lower levels of fatty acids. Feral males who have flown vigorously for mating possessed significant lower levels of fatty acid. From these results, we are able to know that there is certain relationship between male’s flight capability and stored lipids quantity in non-migratory insects.
