Abstract:
In deep cave areas with loose substrate and sufficient moisture, the life history of Neaphaenops tellkampfii (Coleoptera: Carabidae, Trechinae) is synchronized with the seasonal pattern of its primary food sources, the eggs and first instar nymphs of the cave cricket Hadenoecus subterraneus (Orthoptera Gryllacridoidea, Rhaphidophoridae). Neaphaenops reproduction coincides with an order of magnitude increase in Hadenoecus egg input in the spring. Our 46 observations of predation by Neaphaenops suggest some switching to other cave animals as cricket egg and first instar nymph densities decrease during the summer. Neaphaenops life history in areas of Hadenoecus egg input is as follows: (1) female Neaphaenops reach maximum fecundity at the time of the maximum density of fìrst instar Hadenoecus nymphs; (2) early instar Neaphaenops larvae appear in late summer and fall; (3) last instar Neaphaenops larvae appear in early spring and pupation occurs shortly thereafter; (4) lightly coloured teneral adults emerge two to three months later, a time consistent with laboratory estimates of the length of the pupal stage. Seasonal changes in sex ratio due to differential mortality appear to be consistent with this seasonal pattern. A comparison of Neaphaenops with two other species of carabid cricket egg predators suggests the importance of seasonal food abundance in determining life history seasonality. Darlingtonea kentuckensis has a food resource pattern which appears identical to that of Neaphaenops, and the life history seasonality is also parallel. Rhadine subterranea, however, seems to have a much more equitable food input throughout the year, and appears to have an aseasonal life history.