Biology and rearing technique for the mangrove firefly, Pteroptyx valida (Coleoptera: Lampyridae) Olivier, with discussion of additional instar in female

With increasing pressure from many threats including firefly tourism and urbanization, rearing of Pteroptyx fireflies and reintroducing the species to habitats with low populations is a conservation challenge. Here we report a novel rearing technique for P. valida Olivier, 1909 to develop on an artificial substrate, sodium polyacrylate, together with biological observations on the egg and pupa, stages which are typically difficult to observe. The life span of P. valida under the technique was 152.7 ± 5.2 days and did not differ between sexes. Mated females laid 202.9 ± 17.0 eggs per female with 84% hatching rate. The highest larval mortality rate occurred in the first and second instars with 32% and 25%, respectively. The larvae needed four to six instars to develop to adults. The developmental time of the first to sixth larval instars ranged from 22−32 days, with the pupal stage lasting 9 days. Larvae with additional instars were observed in lab culture, and these most often became female adults, resulting in female-biased sexual size dimorphism as discussed in this study.