刺桐釉小蜂(Quadrastichus erythrinae Kim)的產卵選擇與造癭偏好

Abstract

The erythrina eulophid wasp, Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae), is a new invasive species on coral trees (Erythrina spp.) in Taiwan. The oviposition of female wasps induces galls on the young shoots and stems of the coral trees. A serious infection could cause the death of the host tree. Cecidogenesis, the forming of galls, involves a series of complicated processes and the galling insects must induce galls within the right phenological phase of the host plant. This study attempts to clarify the oviposition preference of the erythrina eulophid wasps for the different phenological phases of the coral tree, and also to compare the location preference for the gall forming. The oviposition of the female wasps can be recorded throughout the daylight hours, but with a higher frequency from 8 am to 1 pm. We divided the phenological phase the leaves of the coral tree into 5 phases, and found that the oviposition frequency was highest in phase B, while no oviposition took place in phase E. The gall abundance, recorded 10 days after oviposition, was highest in stage A (during oviposition). The female erythrina eulophid wasps tend to prefer ovipositing in the new shoots from phase A-C, yet we could not find a location preference. We suggest that more protection efforts are needed in spring and summer when the new shoots emerge, to avoid population outbreak of the erythrina eulophid wasp.