Comparison of clay and charcoal as feed additives for Protaetia brevitarsis (Coleoptera: Scarabaeidae)

The white-spotted chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae), has been traditionally used in Korea as a medicine for preventing liver-related diseases and suppressing liver cancer. Therefore, this insect is economically important and is commercially reared and sold in Korea. Recently, P. brevitarsis was listed as a temporal food ingredient by the Korean Ministry of Food and Drug Safety. Given the increasing economic importance of this beetle, we have sought to improve rearing conditions for its commercial production. In this study, we compared the effects of two food supplements, clay and charcoal, on the growth of second instar larvae of P. brevitarsis . Clay and charcoal are generally known as good adsorbent for removal of contaminating substances in insect feed. We fed second instar P. brevitarsis larvae a commercial diet consisting of fermented sawdust with seven different combinations of clay and/or activated charcoal, and measured their effects on weight gain for approximately 17 wk until larvae pupated. We found that addition of clay at 2.5% w/w of the fermented sawdust diet had no negative effect on weight gain of second instar P. brevitarsis larvae and thus may improve the quality of P. brevitarsis as a commercial food.