Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) oviposition on seven naturally co-occurring Eucalyptus species.

摘要

Gonipterus scutellatus is a significant insect pest of eucalypts in most countries where that genus has been introduced, but is usually only of minor significance in its native Australia. Because of this, much of the research on its biology and hostpreferences has been done outside Australia. This fact has the potential to produce misleading results as the insect may be forced to choose less preferred hosts, if normally preferred species are unavailable. In part of its native range, in Tasmania, oviposition of G. scutellatus was recorded on 7 naturally co-occurring Eucalyptus species that were planted in even aged, replicated plots. Among the species were the economically important E. globulus and E. viminalis, which have been previously reportedas highly preferred hosts. Within plots, oviposition occurred most commonly on 3 peppermint species (E. pulchella, E. tenuiramis and E. amygdalina) and was rare or absent on the other species (E. globulus, E. viminalis, E. ovata and E. obliqua). Of thepeppermints, E. pulchella was the most preferred species for oviposition at this site. A low percentage of peppermints in mixed forest (containing these 7 species) immediately adjacent to plots was always matched by low numbers of G. scutellatus eggs within plots, but high percentages of peppermints outside plots could either be matched by high or low numbers of eggs within plots. It is suggested that previous studies of G. scutellatus host range may have been limited because the insect was not exposedto hosts it naturally encounters.