title: Super-Protective Child-Rearing by Japanese Bess Beetles, Cylindrocaulus patalis: Adults Provide Their Larvae with Chewed and Predigested Wood.
abstract: Beetles of the family Passalidae (Coleoptera: Scarabaeoidea) are termed subsocial. The insects inhabit rotten wood as family groups consisting of the parents and their offspring. The Japanese species Cylindrocaulus patalis has the lowest fecundity among passalids because siblicide occurs among the first-instar larvae; accordingly, parental care toward the survived larva is the highest among Passalidae. To clarify the nutritional relationships between the parents and their offspring, we investigated their ability to digest three types of polysaccharides that are components of wood (cellulose and β-1,4-xylan) and fungal cell walls (β-1,3-glucan). Although carboxymethyl-cellulase activity was barely detectable, β-xylosidase, β-glucosidase, β-1,4-xylanase and β-1,3-glucanase activities were clearly detected in both adults and larvae. Because the activities of enzymes that digest β-1,3-glucan were much higher than those for degrading β-1,4-xylan, in both adults and larvae, it is concluded that they are mainly fungivorous. Furthermore, these digestive enzymatic activities in second- and third-instar larvae were much lower than they were in adults. Although all larval instars grew rapidly when fed chewed wood by their parents, larvae ceased growing and died when fed only artificially ground wood meals. We conclude that the larvae are assumed to be provided with chewed predigested wood in which β-1,3-glucan is degraded by parental enzymes.
authors.affiliation: Biosystematics Laboratory, Graduate School of Social and Cultural Studies, Kyushu University, Fukuoka 819-0395, Japan. tatsuya_mishima0610@yahoo.co.jp.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Mishima
authors.affiliation: Laboratory of Biotechnology in Daily Life, Department of Bioscience in Daily Life, Nihon University, Fujisawa, Kanagawa 252-0880, Japan. wada.noriko@nihon-u.ac.jp.
authors.forename: Noriko
authors.initials: N
authors.lastname: Wada
authors.affiliation: Laboratory of Forest Zoology, Department of Forest Science and Resources, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan. iwata@brs.nihon-u.ac.jp.
authors.forename: Ryûtarô
authors.initials: R
authors.lastname: Iwata
authors.affiliation: Laboratory of Biotechnology in Daily Life, Department of Bioscience in Daily Life, Nihon University, Fujisawa, Kanagawa 252-0880, Japan. anzai.hiroshi@nihon-u.ac.jp.
authors.forename: Hirosi
authors.initials: H
authors.lastname: Anzai
authors.affiliation: Institute of Decision Science for a Sustainable Society, Kyushu University, Fukuoka 819-0395, Japan. tadatsugu.hosoya.848@m.kyushu-u.ac.jp.
authors.forename: Tadatsugu
authors.initials: T
authors.lastname: Hosoya
authors.affiliation: Biosystematics Laboratory, Graduate School of Social and Cultural Studies, Kyushu University, Fukuoka 819-0395, Japan. araya@scs.kyushu-u.ac.jp.
authors.forename: Kunio
authors.initials: K
authors.lastname: Araya
keywords: Cylindrocaulus patalis; bess beetles; chewed and predigested wood by the parents; glycanase activity; glycosidase activity; mycophagy; rotten wood; super-protective child-rearing