Feeding preference of Tomicus destruens progeny adults on shoots of five pine species

This paper presents the results of a two-year investigation on the preferences of Tomicus destruens (Wollaston) (Coleoptera Curculionidae) progeny adults for shoots of different pine species in three distinct trials. In the first one, cut shoots of four pine species (Pinus pinaster Aiton, P. pinea L., P. halepensis Mill. and P. nigra Arnold) were offered in cages to progeny adults that emerged from logs from two coastal pine forests (Tuscany and Basilicata), and one hilly pine forest (Tuscany). In the second trial, progeny adults from the Tuscan coastal pine forest were allowed to emerge in a mixed young plantation of P. pinea, P. nigra, P. pinaster and P. radiata D. Don. In the third trial, using cages, progeny adults that had emerged from logs taken from the Tuscan coastal pine forest were offered four-year-old potted trees of P. nigra and P. halepensis. In the first trial, progeny adults from the coastal pine forests preferred the pine species on which the larvae had developed, i.e., P. pinea and P. halepensis, while adults from the hilly pine forest favoured P. nigra. In the second one, this same trend occurred with progeny adults shoot-feeding heavily on both P. pinea (the pine species from which they emerged) and P. nigra. In the last trial with potted trees, no significant preferences were noted. In addition, in the tests with cut shoots, a high number of empty tunnels were recorded, particularly on P. halepensis