Time, Temperature, and Food as Determinants of Population Persistence in the Temperate Mantid \u3cem\u3eTenodera sinensis\u3c/em\u3e (Mantodea: Mantidae)

Characteristics of a well-established population of the mantid, Tenodera sinensis (Saussure), were examined during the adult portion of its life cycle, for three consecutive years (1990-1992). During the fall of 1992, changes in body mass of females in well-fed and starved experimental cohorts were compared with those in the open field, as a measure of food limitation in this population. The open field cohort maintained mean body mass at a level intermediate to the experimental cohorts. However, some individuals in the field did as well as those in the well-fed cohort, whereas none did as poorly as in the starved cohort. Ootheca production was greatly reduced in 1992 compared with the previous 2 yr. This could not be attributed to food limitation, because even well-fed experimental animals failed to oviposit. Lower temperatures in 1992 slowed development rate, reducing the number of females that reached imago in time to oviposit before killing frost. Thus, even when food limitation is not severe, stochastic reduction in degree-days could cause local or even regional extinction, especially in temperate univoltine species of low vagility such as T. Sinensis