Effect of the eucalypt lerp psyllid Glycaspis brimblecombei on adult feeding, oviposition-site selection, and offspring performance of the bronze bug, Thaumastocoris peregrinus

Abstract

Oviposition-site selection may be greatly affected by competitive plant-mediated interactions between phytophagous insects but these interactions have been poorly investigated on trees. Here, we evaluated the potential interaction between two invasive pests of Eucalyptus trees, the red gum lerp psyllid, Glycaspis brimblecombeiMoore (Hemiptera, Sternorrhyncha: Aphalaridae), and the bronze bug, Thaumastocoris peregrinusCarpintero et Dellapé (Heteroptera: Thaumastocoridae). We assessed the effect of the co-occurrence of G. brimblecombei on the selection of feeding and oviposition sites by T. peregrinus females using dual-choice bioassays. We compared developmental time and survival of the first instar of nymphs reared on healthy Eucalyptus tereticornisSmith (Myrtaceae) leaves and on leaves infested with the lerp psyllid, either with or without lerps (i.e., white conical sweet-tasting structures, secreted during the nymphal stage). Bronze bug females prefer to oviposit on lerp-carrying leaves but we found no difference in feeding preference when compared to healthy leaves. Infestation with the lerp psyllid hampered nymphal performance in terms of developmental time and survival, although the presence of lerps reverted the effect in survival and shortened the duration of the initial instar. These results display an interaction between these two insect species that affects both the oviposition preference of T. peregrinus females and the nymphal performance. Although there seems to be a discrepancy between mother preference and offspring performance, feeding on the lerps may prove beneficial to the offspring under long-term conditions and multiple infestation by other pests and diseases.