Distribution of the Chuuk Islands Giant Millipede ,

The spirobolidan millipede Acladocrieus setigerus (Silvestri, 1897) grows to at least 155 mm long and is so far known only from Chuuk Islands, Micronesia. It occurs mainly in well-shaded habitats, usually on the forest floor and on tree trunks. It sprays defensive secretions from paired, lateral ozopores on trunk segments; the major compounds, identified here for the first time, are benzoquinones. The secretion stains human skin a reddish brown and causes a slight burning sensation, occasionally followed by slight blistering and exfoliation. AMONG THE MORE than 600 islands composing the Federated States of Micronesia (FSM), only six of the larger islands of Chuuk (formerly Truk) Lagoon are known to harbor a millipede exceeding 100 mm in length. Taxonomic and phylogenetic relationships of this and other millipedes in the Pacific are incompletely studied and we follow Jeekel (2001) in treating the giant millipede on Chuuk as Acladocrieus setigerus (Silvestri, 1897) pending a systematic review of the genus. Although A. setigerus was described over 100 yr ago, almost nothing is known of its biology. The scanty and widely scattered literature consists largely of morphological descriptions and briefly if at all annotated listings in faunal survey reports. This study provides new information on the distribution and habitat preferences of A. setigerus together with the first report on the composition of its defensive compounds and the clinical manifes1 Manuscript accepted 5 February 2004. 2 Division of Natural Sciences and Mathematics, College of Micronesia-FSM, P.O. Box 159, Kolonia, Pohnpei, Federated States of Micronesia 96941 (e-mail: [email protected]). 3 Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030 (e-mail: aattygal@ stevens-tech.edu). 4 Corresponding author. Pacific Science (2004), vol. 58, no. 4:625-636 © 2004 by University of Hawai'i Press All rights reserved tations of human contact with them. The study is based largely on specimens, field observations, and anecdotal information from local residents obtained during visits to Weno, Tonoas, Fefan, Uman, and Tol islands, 20 June-1 July 2003.