Consequences of divergent egg phenology to predation and coexistence in two sympatric, congeneric mantids (Orthoptera: Mantidae).

Two sympatric, congeneric mantid species, Tenodera sinensis (Saussure) and t. angustipennis (Saussure) exhibit intrinsically different temporal patterns of egg hatch in the spring. Tenodera sinensis hatches first, and begins to enter second instar by the time T. angustipennis starts to hatch. As a result, there is asynchrony in developmental times such that several different instars may be present during the first crucial month of life when mantid population densities are high and prey availability is low. The body length ratio of larger to smaller nymphs is most commonly ≥1.37, in favor of T. sinensis. This character divergence suggests allochronic niche separation which may alleviate competition for prey. However this same ratio appears to be the threshold for both interspecific predation and cannibalism among these bitrophic generalist predators. Therefore T. sinensis, which is nearly always larger, may have a selective advantage by utilizing its smaller congener and later-hatching conspecifics as prey in a food limited environment.