Large variation in length of egg period in Psacothea hilaris (Coleoptera: Cerambycidae)

Abstract

To determine the difference in egg-period length and its effects on postembryonic development in Psacothea hilaris (Pascoe), 14 adult females, which were captured in Yayoi, Tokyo, and their offspring were reared at 25 °C under a photoperiodic regime of 16-h photophase and 8-h scotophase. When 1,486 eggs were placed on wet tissue paper within a day of oviposition, they took from 7 to >40 days to hatch, although 85.9 % of larvae hatched between 7 and 13 days following oviposition; 71 % of females produced larvae with long egg periods of 21 or more days. When 78 newly hatched larvae with different egg-period lengths were reared singly in sections of mulberry shoots, 39 emerged as adults between 57 and 117 days posthatching. Dissection showed two feeding larvae and a diapause pupa in shoot sections 141–168 days after larval hatching. A tradeoff was observed between the egg-period length and the time taken for postembryonic development in females, but not in males. Egg-period length did not affect adult body size. An increased amount of available food (volume of shoot sections) increased adult body size but did not affect the time for postembryonic development.