Survivorship, Fecundity, and Recruitment in a Mud Dauber Wasp, Sceliphron assimile (Hymenoptera: Sphecidae)

Abstract

A dense aggregation of 866 nests of a solitary mud daubing wasp, Sceliphron assimile Dahlbom, was censused at Hacienda La Pacifica near Caflas, Guanacaste Prov- ince, Costa Rica. The data were treated to yield both cohort and stage life tables. Nests had 1-26 cells. The number of cells per nest was used as an index of minimum female reproductive longevity. Reproducing females had a Type II (colstant probability of death) putt.ttr of survivorship. There was a72.IVo rate of successful adult emergence from nests. The rate of successful adult emergence did not vary as a function of nest size. Previously published data were used to estimate female-only fecundity values. Interval-spe_ciftc real- ized fecundity values were at a maximum in the first age interval and decreased pr_ogres- sively. A technique for calculating interval-specific recruitment values is introduced. Females living to produce l-LZ cells had higher recruitment (as a proportion of the population total) than did females producing either fewer or more cells. Interval-speci!c iecruitment values can be summed to yield a net recruitment rate (R,) that can be easily calculated, has fewer constraints than a net reproductive rate (Ro), and yields biologically meaningful information. An average female that initiated nesting produced 1.6 female offspring. The population can maintain constant size with 387o loss of emerged females to prereproductive death or emigration or both'