Fall field cricket

Description

Gryllus pennsylvanicus is known as the fall field cricket. G. pennsylvanicus is common in southern Ontario, is widespread across much of North America and can be found even into parts of northern Mexico. It tends to be absent in most of the southwestern United States including southern California. Within its geographic range this field cricket will burrow into soil in fields and forest edges. Individuals inhabit grassy disturbed areas and are often found around areas of human habitation. Adults reach 15-25 millimetres (0.6-1.0 in) and coloration ranges from dark black to dark brown, although some specimens show a slight reddish tint. The black antennae tend to be longer than the body span of the species. The cerci are longer than the head and prothorax, and the wings do not extend past the cerci. During the breeding season, the number of adult female G. pennsylvanicus captured in pitfall traps peaks approximately two weeks after the peak in the number of adult males captured, which seems to indicate protandry. Breeding in some areas also coincides with the seed rain from certain agricultural weeds, possibly providing females with food resources to increase their fecundity. Males call from the mouths of burrows or cracks in the ground into which they escape when scared. Calling males are separated from each other by approximately 7.7 to 10.3 m in the field, likely making it costly for females to sample large numbers of potential mates. Male G. pennsylvanicus calling song consists of short chirps roughly two to three per second each consisting of three to five pulses (each a single closure of the male forewings or tegmina). Like most other gryllines, females are attracted to male calling song and are attracted to higher calling effort at least when population density is low. In an elegant series of field experiments, Zuk showed that female G. pennsylvanicus were more attracted to calling song produced by older males than that of younger males. Males found paired with females in the field were also older than unpaired calling males nearby. However, in the earlier experiment higher calling effort explained a small, but statistically significant proportion of the variance in female attraction, raising the possibility that the apparent preference of females for the songs of older males might be due to differences in calling effort between older and younger males.