Post hoc assessment of host plant use in a generalist invader: implications for understanding insect–plant interactions and weed biocontrol

Species limits, quarantine risk and the intrigue of a polyphagous invasive pest with highly restricted host relationships in its area of invasion

“…Further, field surveys in the area of S. aurantii incursion within Australia demonstrated conclusively that under natural conditions, S. aurantii in Australia is consistently present on B. delagoense (Rafter et al. ; Rafter and Walter ). This contrasts strongly with the polyphagous habits of this species in its native range in Africa.…”

“…Paradoxically, this generalist horticultural pest has not displayed the expected polyphagous tendencies in its incursive range. It is restricted in host use to plants in the family Crassulaceae in Australia (Anonymous 2003;Rafter et al 2008;Rafter and Walter 2013a).…”

“…When restricted to a single host species growing in the laboratory, S. aurantii collected from B. delagoense in Australia will feed, with some delay, on macadamia (Macadamia integrifolia) and mango (Mangifera indica). In contrast, it readily feeds on the crassulaceous ornamental Kalanchoe blossfeldianna (Rafter et al 2008;Rafter and Walter 2013a). However, when presented with two or more species simultaneously (one of them B. delagoense), they always colonize B. delagoense rather than the alternative species presented (Rafter and Walter 2013a).…”

“…It is restricted in host use to plants in the family Crassulaceae in Australia (Anonymous 2003 ; Rafter et al. 2008 ; Rafter and Walter 2013a ).…”

“…In contrast, it readily feeds on the crassulaceous ornamental Kalanchoe blossfeldianna (Rafter et al. 2008 ; Rafter and Walter 2013a ). However, when presented with two or more species simultaneously (one of them B. delagoense ), they always colonize B. delagoense rather than the alternative species presented (Rafter and Walter 2013a ).…”