1994/11/01 by Vincent J. Tepedino, V. J. Tepedino, P. F. Torchio +1 · 6 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Plant and animal studies #Insect and Pesticide Research #Insect and Arachnid Ecology and Behavior
paper · doi:10.1093/aesa/87.6.946
We examined usurpation of nest holes of four diameters in a greenhouse population of the xylophilous bee, Osmia lignaria propinqua Cresson. Although vacant holes were always in unlimited supply, ≈25% of all nests made were usurped. Of all females, ≈75% usurped at least one nest, 65% lost at least one nest to usurpation, and half were both usurpers and usurpees. Females tended to choose holes of the same diameter and in the same general area as their previous nest whether they were usurping or founding. Females usurped only when they encountered an active, but unattended, nest while they were searching for a new hole. Current occupants of a hole, whether founders or usurpers, were always successful in defending the hole, apparently because of the positional advantage of fighting from within the nest. Although no founder ever succeeded in regaining a nest that had been usurped, all founders contested ownership with intruders intermittently for ≈30 min before conceding defeat. In some cases, founders appeared to incur injury during their assaults on the intruder. The ratio of usurped to founded nests did not differ significantly from the ratio of occupied to vacant holes. Females differed greatly in the proportion of nests that they usurped. Large females were usurpers significantly more often than were small females. Usurping and founding were equivalent ways of producing progeny and either method yielded ≈1.5 live progeny per day.