Timing of adult mortality, oviposition, and hatching during the underground phase of Forficula auricularia (Dermaptera : Forficulidae)

We studied the effects of frost on the survival rare of European earwigs, F orficula auricularia L., during the underground phase of their cycle and de termined the timing of oviposition, hatching, and death of the adults: we s elected couples and inserted them into the ground to a depth of 150 cm in a n open area and along the foundations of a heated suburban house in the Mon treal area. Oviposition occurred in November and December, and eggs hatched between January and early June, after an average incubation period of 79-1 89 d depending on experimental conditions. In the open area all adults and eggs at ground surface died, killed by frost, whereas those in the soil alo ng the house foundation did not die. Males died during the fall and early w inter; their longevity was shorter than that of females, which survived unt il shortly after egg hatch. Females and eggs survived temperatures as low a s -3 and -2 degreesC, respectively. For successful reproduction, females mu st keep their developing eggs at a temperature low enough to delay hatching until mid-April.