Biology of the Predaceous Earwig Labidura riparia (Dermaptera: Labiduridae)1,2

Abstract

The striped earwig, Labidura riparia (Pallas), was successfully reared for the first time on an oligidic medium in the laboratory and we studied the earwig's biology. Eggs hatched in 8 days at 26.7±1.1°C, and development time through the nymphal stages for females and small male morphotypes was 33.27 and 33.06 days, respectively. Head-capsule sizes and weights of smaller adult males and females were not significantly different. Females and smaller males passed through 5 stadia. The larger male morphotype had 6 nymphal stages. Females with permanent mates produced an average of 10 egg batches totaling 440 eggs during their adult life (114.8 days). Fertility and fecundity were reduced when females were paired with males for only 24 hours and then separated. Predatory activity and functional response studies were carried out using larvae of the wireworm, Melanotus communis (Gyllenhal). Locomotor and mating activity were nocturnal. Investigations of subsocial behavior using 32P indicated possible exchange of materials from the female parent to its offspring.