Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) use of Opuntia host species in Argentina

VARONE, LAURA; LOGARZO, GUILLERMO A.; BRIANO, JUAN A.; HIGHT, STEPHEN M.; CARPENTER, JAMES E.

BIOLOGICAL INVASIONS

SPRINGER

Lugar: Berlin; Año: 2014 vol. 16 p. 2367 - 2380

1387-3547

A central aspect in biology and ecology isto determine the combination of factors that influencethe distribution of species. In the case of herbivorousinsects, the distribution of herbivorous species isnecessarily associated with their host plants, a patternoften referred to as ??host use??. Novel interactions thatarise during a biological invasion can have importanteffects on the dynamics of that invasion, especially if itis driven by only a subset of the genetic diversity of theinvading species. This is the case of the wellknownSouth American cactus moth, Cactoblastis cactorum,a successfully used biological control agent of nonnativeOpuntia cacti in Australia and South Africa, butnow threatening unique cactus diversity and agriculturein North America. We studied the patterns of hostplant usage by and host plant availability for C.cactorum under field conditions in Argentina, coveringthe geographical range of the four C. cactorumphylogroups and the recently documented southerndistribution. We also assessed female preference andlarval performance under laboratory conditions.Cactoblastis cactorum showed a geographical patternof host use in its native range that was related to hostavailability. Laboratory assays of female preferenceshowed some degree of preference to oviposit on O.ficus-indica, O. leucotricha and O. quimilo, but it wasnot positively correlated with the performance oflarvae. These findings contribute to the further comprehensionof the host use dynamics of C. cactorum inthe insects? native range, and could provide usefulinformation for assessing the risk and future spread ofthis insect in North America.