Effects of spatio‐temporal intervals between newly‐hatched larvae on larval survival and development in Monochamus alternatus (Coleoptera: Cerambycidae)

Abstract The effects of distance between hatching larvae on survival and development were investigated in Monochamus alternatus. Two newly‐hatched larvae were inoculated into Pinus densiflora bolts at a distance of 2.5 cm or 10 cm, simultaneously or at an interval of 2 weeks. Some larvae were inoculated singly as a control. When larvae were inoculated simultaneously, mortality of the closely‐inoculated larvae was significantly higher than that of distantly‐inoculated larvae. Such high mortality was identified as due to conspecific bites. When the two larvae were inoculated asynchronously, the first‐inoculated larvae killed some second‐inoculated larvae but were never killed by them. Consequently, mortality was higher in second‐inoculated larvae than in first‐inoculated larvae. In particular, there was a significant difference in mortality between them when the larvae had been inoculated closely. The mortality of second‐inoculated larvae was higher in the closely‐inoculated group than in the distantly‐inoculated group although there was no significant difference between them. In the case of two simultaneously‐inoculated larvae, the initial distance between them had no significant effect on the development and growth in the early larval stage. When the larvae were inoculated asynchronously, the first‐inoculated larvae grew more quickly than singly‐inoculated control larvae.