Males of the fossorial, communal bee Andrena agilissima (Scopoli 1770) typi
cally search for mates at flowers from which females collect pollen (WESTRI
CH 1989). To investigate whether communal nesting also affords mating oppor
tunities for adults freshly eclosed from brood cells, we collected and diss
ected females that were emerging for the first time in spring from their na
tal nests and examined the contents of their spermathecae. Circa 97% of fem
ales contained spermatozoa in their spermathecae, indicating a high Frequen
cy of preemergence intranidal mating. Bees also copulated above ground, bot
h near nest entrances and at flowers. In the latter situation, pollen-colle
cting females were seen to copulate, suggesting that A. agilissima females
mate repeatedly (polyandry) and are sexually receptive across adulthood. Th
e schedules of emergence of males and females from natal nest entrances in
spring overlapped to a large extent; the species was neither markedly prota
ndrous nor protogynous on the island of Elba, Italy, in 1998. These emergen
ce patterns are consistent with both pre-emergence intranidal mating and po
lyandry linked to female receptivity extended across adulthood. The sex rat
io at emergence was female biased (numerical proportion of males, MIM + F =
0.38), consistent with the view that pre-emergence intranidal mating gener
ates local mate competition amongst males, and that it is an important comp
onent of the mating biology of A. agilissima. The mating opportunities of s
ons within the nest may potentially provide a selective benefit to communal
nesting by females.