By John Horne & Alison Horne
ABSTRACT A study of captive reared Lampyris noctiluca larvae confirms that the larval stage may last for one, two or three years, and that the sex ratio at the pupal stage is 1:1. The heaviest larvae at two months will continue to exhibit the highest growth rates for the remainder of the larval period and will pupate earlier than the lightest larvae. Males reach their pupation weight more rapidly than females. The resultant spread in the timing of pupation over three years may reduce levels of inbreeding, particularly in small colonies. Pupal weight is broadly proportional to the number of summers spent in the larval stage, which may explain the wide range of adult sizes (particularly of females) in the wild.
Keywords: Glow-worms, Lampyris noctiluca, sex ratio, larval weight, pupation weight