| DatasetID | 287 |
|---|---|
| Name | Competitive interactions and foraging path selection in bumblebees |
| Description | Foraging Path Selection in Bumblebees Hindsight or Foresight? Abstract: Inflorescence richness and density did not affect the magnitude or variation in magnitude of the turning angles between inflorescences in the paths of foraging bumblebees. The pooled data indicated that bumblebees tended to move straight through the Vicia patch regardless of raceme density. The angular distributions from the field data were similar to those derived from a computer model in which consumers just visited the nearest inflorescences provided that they revisited few flowers. These results imply that the foraging paths of bumblebees may be determined, in part, by a tendency to visit nearest inflorescences. The distribution of turning angles from individual rather than pooled data, however, suggest that active selection of inflorescences with between two and six flowers may also play a role in determining the foraging path. I found no evidence for area-restricted foraging. This may be due to the heterogeneity of the natural resource patches. From early April, to the end of June, during the spring seasons of 1980 and 1981, I censured and collected morphological and foraging data on all species of bees collecting nec- tar from a patch of ViciadasycarpusTen. (Leguminosae), at Hastings Natural History Reservation, Carmel Valley, California. Interspecific Competition and Resource Utilization between Bumblebees. Abstract: The competitive interactions of bumblebees (Bombus spp.) on a patch of nectar-producing Vicia dasycarpus [Leguminosae] at Hastings' Natural History Reservation, Monterey County, California [USA], were studied during the spring of 1979 and 1980. Characteristics of selected racemes, handling time per raceme, number of flowers visited per raceme, transit time between racemes, and thoroughness of nectar removal from flowers were determined in the field for each bee species. These parameters were compared to the production and standing crop of nectar sampled throughout the day. An experimental removal and subsequent reintroduction of the most numerous, longest tongued bees was performed in order to reveal its influence upon the remaining species. The depth to which each species could extract nectar was determined in the lab by an artifical flower apparatus where bees removed a sugar solution from wells of various depths. Eight species of bees commonly foraged for nectar in Vicia during 1979 but only two species, Bombus californicus queens and Synhalonia frater, were present in 1980. These were the species that, in 1979, had the longest and one of the shortest measured proboscides. Racemes of Vicia had about one-third fewer flowers in 1980 than in 1979 and fewer flowers produced nectar in 1980 when compared to 1979. This led to a 13-fold reduction of potentially nectar producing flowers and a four-fold reduction in consumer biomass in 1980. When the long-tongued species. B. californicus queens were removed from the patch in 1980, other bumblebee queens (B. vosnesenskii and B. caliginosis) appeared in the patch for the first time that year. B. vosnesenskii and B. caliginosis queens showed nearly perfect density compensation in biomass with the removed species. When B. californicus queens were reintroduced into the patch, the other bumblebee species abandoned the patch. The foraging ecology of S. frater in the patch was relatively unaffected by these experiments. No aggressive interactions were observed between any species. These data suggest that exploitative interspecific competition for limiting nectar resources was a major influence upon the presence and behavior of bumblebees exploiting the nectar of the Vicia patch in 1980 but not in 1979. The longer tongued B. californicus queens passively excluded B. vosnesneskii and B. caliginosis queens during the resource limited 1980 season. The superior ability of B. californicus queens to remove nectar from flowers was due to their greater speed in processing and traveling between influorescences as well as their ability to withdraw nectar at greater depths when compared to the other species. Total probiscis length (glossa + prementum), rather than tongue length alone appears to be a truer approximation of the depth to which these species are able to withdraw nectar. |
| Physical Location | |
| Publisher/Owner | Roberta L. Soltz, Central Washington University, soltzr@cwu.edu, 509-936-3163 |
| Publication Date | |
| Permissions | Undetermined |
| Source | Mark Stromberg NRS file |
| Contact | Mark Stromberg |
| Type | Biological Survey - Experimental |
| Subject | Animal |
| Geo. Extent | Hastings Reserve |
| URL | https://berkeley.app.box.com/files/0/f/372726297/1/f_3020735891 |
| NRS Registry? | yes |
| Format | |
| Timespan Start | 1979 |
| Timespan End | 1981 |
| Total Items | |
| Databased Items | 0 (as of 2012-08-28) |
| Comments | Links refer to: Soltz, R. L. (1986). "Foraging Path Selection in Bumblebees Hindsight or Foresight?" Behaviour 99(1-2): 1-21. AND Soltz, R. L. (1987). "Interspecific Competition and Resource Utilization between Bumblebees." Southwestern Naturalist 32(1): 39-52. |
| Entered By | Jessica Rothery |
| Last Updated | 2017-11-12 13:17:32 |