Bornean caterpillar (Lepidoptera) constructs cocoon from Vatica rassak (Dipterocarpaceae) resin containing multiple deterrent compounds William O.C. Symondson a *, Jeremy D. Holloway b , Benoit Goossens a,c and Carsten T. Müller a a Cardiff School of Biosciences, Cardiff University, Cardiff, UK; b Department of Life Sciences, Natural History Museum, London, UK; c Danau Girang Field Centre, c/o Sabah Wildlife Department, Wisma Muis, 88100 Kota Kinabalu, Sabah, Malaysia (Received 9 January 2014; accepted 12 June 2014; first published online 15 August 2014) Many Lepidoptera larvae use pieces of vegetation bound with silk to construct or disguise their cocoons. Here we report the first known case of a caterpillar building its cocoon entirely out of fragments of resin, broken away from sheets of dried resin on the trunk of a tree and held together with silk. The behaviour of the larva (possibly Negritothripa sp. in the Nolidae), from the Kinabatangan Wildlife Sanctuary in Sabah, Borneo, is described. The cocoon was constructed on the trunk of Vatica rassak (Dipterocarpaceae). Analysis of resin from the cocoon, using gas chromatography-mass spectrometry, revealed a complex mixture of 260 components, dominated by sesquiterpenes and triterpenes. Many of these com- pounds have defensive properties, protecting the tree from herbivores and fungi. The larva appears to have evolved an elaborate and possibly unique behaviour, allowing it to harness the defensive properties of the resin to protect its pupa from predators and/or entomopathogenic fungi. Keywords: defensive chemicals; Dipterocarpaceae; eligmine Nolidae; sesquiterpenes; terpenes; Vatica rassak Introduction Many Lepidoptera construct their cocoons by using their silk to bind together materials (e.g. sticks, leaves, bark) collected from the surrounding environment. Some of the best known examples are the bagworms (Psychidae), whose larvae collect together loose pieces of vegetation bound with silk to make a well-camouflaged mobile refuge, later fixed to a substrate and used as a site for pupation (Rhainds et al. 2009). Species in at least 10 other families of Lepidoptera do something similar (Rhainds et al. 2009). Some species are more selective than others but the case is built out of materials scavenged from the immediate area. As far as we are aware there are no previous reports of Lepidoptera larvae exclusively using potentially toxic resins collected from tree trunks for this purpose. In 2011 an unidentified caterpillar was found on the trunk of a Vatica rassak tree (Dipterocarpaceae) near the Danau Girang Field Centre on the Kinabatangan River in Eastern Sabah. Vatica rassak is found in Malaysia, Indonesia, the Philippines, Papua New Guinea and elsewhere (Uphof 1968; Soerianegara and Lemmens 1994). This tree, locally known as rasak, produces abundant resin from wounds, which dries *Corresponding author. Email: symondson@cardiff.ac.uk Journal of Natural History, 2015 Vol. 49, Nos. 9–10, 553–560, http://dx.doi.org/10.1080/00222933.2014.939731 © 2014 Taylor & Francis Downloaded by [University of Cambridge] at 05:04 08 April 2016