Mating Behavior and Sex Attraction of Eucera palestinae Friese (Hymenoptera: Anthophoridae)

Eucera palestinae is a ground-nesting solitary bee that lives in dense aggre gations. Males emerge up to a week before females, and cruise in the nesting site. Upon emergence, a female is usually spotted by several males that compete aggressively to cop ulate with her. Soon after mating the females become unreceptive. Field experiments have demonstrated that although the initial attraction toward a female is by sight, a virgin female is also distinguished by her scent. Bioassays using tethered males that were scented with different female odors were conducted, recording the mounting attempts by cruising males upon the tethered male. Of all the extracts used, whole abdomens and especially the abdominal tergites most often induced mounting attempts by cruising males. The source of this sex attractant is thought to be small glands that are attached to the abdominal tergites. Hymenoptera males use various strategies in searching for mates. Some species search in the nesting area while others search near feeding regions or landmarks. The choice of a particular mating strategy by males is influenced by two major factors; (1) finding a receptive female, and (2) increasing the chances that its sperm will successfully fertilize that female. Thus, aspects of the ecology of a species, such as nesting and feeding habits, influence the evolution of the searching pattern of the males for their mates (Alcock et al., 1978). Independent of the strategy employed, the seeking behavior of either sex is directed largely by communicative signals. Males may be attracted towards fe males by one or a combination of up to three types of cues; visual, auditory or chemical signals (Eickwort and Ginsberg, 1980 and references therein). Experi ments with the halictine bee Augochlora pura demonstrated that males were not attracted to a piece of filter paper which was impregnated with fresh female odor nor to dead dried females, but were attracted to dried females scented with fresh female odor (Barrows, 1975), suggesting that A. pura males are attracted by a combination of olfactory and visual cues. On the other hand, males of Andrena flavipes seem to be attracted by the conspicuous orange hair on the females' legs, removal of which reduces the females' attractivity to a large extent (Butler, 1965). We here describe the mating behavior and the occurrence of a sex attractant in E. palestinae.