Field studies of growth, reproduction, and mortality in the burrowing wolf spider Geolycosa domifex (Hancock)

Abstract

A population of burrowing wolf spiders (Geolycosa domifex (Hancock)) was studied near Toronto, Canada, from 1974 to 1977. By following the life history of individuals in marked burrows, it was found that females produce one brood when they are 3 years old. Juveniles leave their mothers during July and August, after which they search for suitable burrow sites, establish burrows, and overwinter. During this period approximately 85% of the juveniles die and the average burrow diameter increases from 1 mm in August to 2–3 mm in October. In the second summer approximately 9% of the original cohort die and the average burrow diameter is 7 mm when the remaining individuals overwinter. In the third summer 4–5% of the original cohort die and burrow diameters average 13 mm when the remaining individuals overwinter. In the fourth summer the remaining 1 or 2% of the original cohort reproduce and more than 99% of these are killed by acrocerid flies (Pterodontia flavipes Grey) and pompilid wasps (Anoplius relativus (Fox)). Because < 0.008% of the original cohort survive to reproduce in their 4th year of life, three separate cohorts occupy the same habitat with little (< 1%) gene flow between them.