Effects of Body Size, Diet, and Mating on the Fecundity and Longevity of the Goldspotted Oak Borer (Coleoptera: Buprestidae)

Abstract

Abstract The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is an invasive wood-borer that was recently introduced into southern California from southern Arizona, and has caused the rapid mortality of thousands of native oaks. Biological control of A. auroguttatus is a management strategy of high interest, but is in its early stages, which is due, in part, to a lack of information on the basic biology and life history of this beetle. To address this shortcoming, studies were conducted in quarantine on the realized lifetime fecundity of A. auroguttatus, which was determined by comparing oviposition and larval emergence rates of females subjected to different dietary and mating treatments. Longevity and body size were also recorded for male and female adults under these treatments. Mean A. auroguttatus lifetime oviposition and larval emergence were similar in females that were continuously paired with either one or two males. Virgin females laid significantly fewer eggs and no larval emergence resulted from unfertilized eggs. The number of mates did not affect mean A. auroguttatus adult longevity, but a carbohydrate-enriched diet increased both mean longevity and lifetime oviposition by as much as 46 and 250%, respectively. There was no correlation between adult body size and lifetime oviposition, days to initial oviposition, larval emergence, and adult longevity. However, hind tibia length was marginally correlated with total oviposition period. For mass rearing A. auroguttatus eggs in the laboratory, pairing females with one male and providing adults with a continuous diet of 10% honey-water and oak foliage is recommended.