Showing papers by "James H. Cane published in 1989"

Bees assess pollen returns while sonicating Solanum flowers

Abstract: Can bees accurately gauge accumulating bodily pollen as they harvest pollen from flowers? Several recent reports conclude that bees fail to assess pollen harvest rates when foraging for nectar and pollen. A native nightshade (Solanum elaeagnifolium Cavanilles) that is visited exclusively for pollen by both solitary and social bees (eg. Ptiloglossa and Bombus) was studied in SE Arizona and SW New Mexico. The flowers have no nectaries. Two experiments were deployed that eliminated “pollen feedback” to the bees by experimentally manipulating flowers prior to bee visits. The two methods were 1) plugging poricidal anthers with glue and 2) emptying anthers of pollen by vibration prior to bee visitation. Both experiments demonstrated that bees directly assess pollen harvest on a flower-by-flower basis, and significantly tailor their handling times, number of vibratile buzzes per flower and grooming bouts according to the ongoing harvest on a given flower. In comparison to experimental flowers, floral handling times were extended for both Bombus and Ptiloglossa on virgin flowers. Greater numbers of intrafloral buzzes and numbers of times bees groomed pollen and packed it into their scopae while still on the flower were also more frequent at virgin versus experimental flowers. Flowers with glued andreocia received uniformly brief visits from Bombus and Ptiloglossa with fewer sonications and virtually no bouts of grooming. Curtailed handling with few buzzes and grooms also characterized visits to our manually harvested flowers wherein pollen was artificially depleted. Sonicating bees respond positively to pollen-feedback while harvesting from individual flowers, and therefore we expect them to adjust their harvesting tempo according to the currency of available pollen (standing crop) within Solanum floral patches.

Novel pollen-harvesting behavior by the bee Protandrena mexicanorum (Hymenoptera: Andrenidae)

Abstract: A diverse guild of bees forages for pollen at silverleaf nightshade, Solanum elaeagnifolium Cavanilles, in southeastem Arizona (Linsley, 1962; Linsley and Cazier, 1963). The nectarless flowers shed their pollen through a pair of pores at the tip of each of the five sizeable yellow anthers. To harvest this pollen, bees sonicate the anthers using pulsed trains of rapid contractions from their flight muscles. Audible floral vibration (which we hereafter term '~ or \"buzz pollination\") has been reported for representatives of all major bee families and for representatives of an estimated 31 families and over 500 genera of flowering plants (Buchmann, 1983; Neff and Simpson, 1988). All studies to date report that, when female bees sonicate poricidally dehiscent anthers, they are positioned transversally astride the tip(s) of the anther(s), such that their thoracic or anterior abdominal venters are opposite the staminal pore(s) [Cassia fasciculata (Thorp and Estes, 1975); Cassia quiedondilla (Buchmann, 1974); Cochlospermum vitifolium (Snow and Roubik, 1987); Lycopersicon peruvianum (Brewer and Denna, 1980); Solanum section Geminata (Knapp, 1985); Solanum (Buchmann et al. , 1977); Vaccinium ashei (Cane and Payne, 1988); V. stamineum (Cane et al., 1985); Xiphidium caeruIeum (Buchmann, 1980)]. Females often curl into a partial \"C shape\" while buzzing flowers. This is true for bees that sonicate S. elaeagnifolium flowers, except for an uncommon desert panurgine, Protandrena (= Psaenythia) mexicanorum