Xeromelecta larreae
(By K. James Hung)
Spring has arrived in San Diego again! As native bees emerge from their natal nests underground or in wood stems, I, too, shall emerge from my long writing hiatus and begin photographing and writing about bees again. Rain is hitting San DiegoCounty hard as I write, and for the first time since I began my workdocumenting the diversity of bees in the county, we may have a productivespring with lots of flowers in both the mountains and deserts.
The photo above is a cleptoparasitic bee (i.e., cuckoo bee), Xeromelecta larreae. In our deserts, it can be easily recognized by the reddish to yellow thorax, nearly all black abdomen, very dark wings, and a somewhat lazy, slow flight. Like other cleptoparasitic species, the females do not collect pollen, but find nests of other bee species (their “hosts”) and lay their eggs on the pollen balls therein. Historical records that I could find seem to indicate that this species is primarily active in April; thus my seeing this species at the end of February this year may be caused by the strange climate pattern this year (early rains, and then a period of hot, dry weather). But then again, it seems like there’s no such thing as “strange” or “typical” climate patterns for Southern California anymore these days.
Finding and infiltrating the nests of other bee species is probably risky for these parasites, who may be attacked and vehemently ejected by their hosts should they be discovered. An encounter with an angry host (likely a digger bee in the genus Anthophora) is perhaps the reason that the bee photographed above is missing her antennae (that’s why she looks so odd). Many cleptoparasitic species have adapted specialized morphological structures to aid in just such situations; I look forward to discussing some of these adaptations in another post in the near future :).
