A common mode of attraction of larvae and adults of insect predators to the sex pheromone of their prey (Hemiptera: Matsucoccidae) M. Branco 1 * , J.C. Franco 2 , E. Dunkelblum 3 , F. Assael 3 , A. Protasov 3 , D. Ofer 3 and Z. Mendel 3 1 Departamento de Engenharia Florestal, Instituto Superior de Agronomia, 1349-017 Lisboa, Portugal: 2 Departamento de Protecc ¸a ˜o das Plantas e de Fitoecologia, Instituto Superior de Agronomia, 1349-017 Lisboa, Portugal: 3 Department of Entomology, Agricultural Research Organization, the Volcani Center, Bet Dagan, 50250, Israel Abstract The attraction of several adult predators, genera Elatophilus, Hemerobius and Sympherobius, to the sex pheromones of pine bast scales, Matsucoccus Cockerell, has already been demonstrated. Here, the hypothesis that the larvae of these predators are similarly attracted to the host prey sex pheromone is tested. The response of predators was tested in field trials using pine tree arenas baited with the sex pheromones of M. josephi Bodenheimer & Harpaz, M. feytaudi Ducasse and M. matsumurae Kuwana. Experiments were conducted in Israel in stands of Pinus halepensis infested by M. josephi and in Portugal in stands of P. pinaster infested by M. feytaudi, respectively. The selectivity of larvae for the three sex pheromones was tested in Petri dish arenas in the laboratory. In the field, the larval stages exhibited similar modes of attraction to those of the conspecific adults: Elatophilus hebraicus Pericart in Aleppo pine forest, E. crassicornis Reuter and Hemerobius stigma Stephens in the maritime pine forests. Laboratory choice tests confirmed the kairomonal selectivity of larvae. Both forest and laboratory tests demonstrated the response of a coccinellid of the genus Rhyzobius to the sex pheromones of M. feytaudi and M. matsumurae. A unique chemical communication system among several taxa of predators of Matsucoccus spp. was highlighted that may be attributed to their coevolution on a geological time scale. Keywords: kairomone, response, sex pheromone, Matsucoccus, predator, Elatophilus, Hemerobius stigma, Rhyzobius, Pinus Introduction The members of the genus Matsucoccus Cockerell (Hemi- ptera: Matsucoccidae) feed exclusively on pines. The genus Matsucoccus includes the oldest known scale insect fossils: species from the lower Cretaceous, aged about 125 million years (Koteja, 1990; Foldi, 2004). Several Matsucoccus species are severe pests; these include M. feytaudi Ducasse in southeastern Europe (Covassi & Binazzi, 1992; Jactel et al., 1998), M. josephi Bodenheimer & Harpaz in the Middle East (Mendel et al., 1994), and M. matsumurae Kuwana and M. acalyptus Herbert in North America (McClure, 1976; Kosztarab, 1996). Currently, the sex pheromones of three Matsucoccus species are known, those of M. matsumurae, M. feytaudi and M. josephi, which are ketones that share a common ketodiene moiety (Dunkelblum et al., 2000). Recent * Fax: 351 213645000 E-mail: mrbranco@isa.utl.pt Bulletin of Entomological Research (2006) 96, 179–185 DOI: 10.1079/BER2005415