| comparison and examination of bombus occidentalis and bombus impatiens (hymenoptera: apidae) in tomato greenhouses. | experiments were conducted in commercial tomato, lycopersicon esculentum miller (solanaceae), greenhouses to compare the relative foraging effort of two bumble bee species, bombus occidentalis greene and bombus impatiens cresson, to examine interspecific competition between b. occidentalis and b. impatiens, and to determine whether bumble bee colonies grew to their full population potential in commercial tomato greenhouses. b. impatiens colonies had more brood and workers and made more foraging ... | 2004 | 15384352 |
| brain allometry and neural plasticity in the bumblebee bombus occidentalis. | brain plasticity is a common phenomenon across animals and in many cases it is associated with behavioral transitions. in social insects, such as bees, wasps and ants, plasticity in a particular brain compartment involved in multisensory integration (the mushroom body) has been associated with transitions between tasks differing in cognitive demands. however, in most of these cases, transitions between tasks are age-related, requiring the experimental manipulation of the age structure in the stu ... | 2010 | 20516659 |
| the effects of a bumble bee nectar robber on plant reproductive success and pollinator behavior. | interactions between a plant species (corydalis caseana), a bumble bee nectar robber (bombus occidentalis), and a bumble bee pollinator (b. appositus) were studied. there were no significant differences between naturally robbed and unrobbed flowers in fruit set or mean seed set per fruit. plots of c. caseana plants were subjected to treatments of robbing and no robbing using commercially available colonies of b. occidentalis. robbers did not pollinate the flowers. pollinator behavior was observe ... | 2001 | 21669629 |
| olfactory learning and memory in the bumblebee bombus occidentalis. | in many respects, the behavior of bumblebees is similar to that of the closely related honeybees, a long-standing model system for learning and memory research. living in smaller and less regulated colonies, bumblebees are physiologically more robust and thus have advantages in particular for indoor experiments. here, we report results on pavlovian odor conditioning of bumblebees using the proboscis extension reflex (per) that has been successfully used in honeybee learning research. we examine ... | 2009 | 19322551 |
| discrimination of the bumble bee species bombus occidentalis greene and b. terricola kirby by morphometric, colour and rapd variation. | the taxonomic status of b. terricola kirby and b. occidentalis greene has long been questioned. however recent coi gene sequence data suggests that b. occidentalis and b. terricola do represent good biological species. in this paper we test the hypothesis that b. terricola and b. occidentalis are conspecific by using independent morphometric and genetic (rapd) data. for comparison we also analyzed one consubgeneric species, b. moderatus (now b. crytptarum), and one non-consubgeneric species b. ( ... | 2013 | 24614474 |
| evidence for bombus occidentalis (hymenoptera: apidae) populations in the olympic peninsula, the palouse prairie, and forests of northern idaho. | since the mid-1990s, bombus occidentalis (green) has declined from being one of the most common to one of the rarest bumble bee species in the pacific northwest of the united states. although its conservation status is unresolved, a petition to list this species as endangered or threatened was recently submitted to the u.s. fish and wildlife service. to shed light on the conservation situation and inform the u.s. fish and wildlife service decision, we report on the detection and abundance of b. ... | 2016 | 26856817 |
| interspecific geographic distribution and variation of the pathogens nosema bombi and crithidia species in united states bumble bee populations. | several bumble bee (bombus) species in north america have undergone range reductions and rapid declines in relative abundance. pathogens have been suggested as causal factors, however, baseline data on pathogen distributions in a large number of bumble bee species have not been available to test this hypothesis. in a nationwide survey of the us, nearly 10,000 specimens of 36 bumble bee species collected at 284 sites were evaluated for the presence and prevalence of two known bombus pathogens, th ... | 2011 | 22119631 |
| Patterns of range-wide genetic variation in six North American bumble bee (Apidae: Bombus) species. | The increasing evidence for population declines in bumble bee (Bombus) species worldwide has accelerated research efforts to explain losses in these important pollinators. In North America, a number of once widespread Bombus species have suffered serious reductions in range and abundance, although other species remain healthy. To examine whether declining and stable species exhibit different levels of genetic diversity or population fragmentation, we used microsatellite markers to genotype popul ... | 2011 | 22035452 |
| effects of nosema bombi and its treatment fumagillin on bumble bee (bombus occidentalis) colonies. | we examined the effects of nosema bombi (microsporidia: nosematidae) on colonies of bumble bees, bombus occidentalis greene (hymenoptera: apidae), used to pollinate tomatoes in commercial greenhouses. we assessed methods of detecting n. bombi and tested the effectiveness of fumagillin to control this parasite. n. bombi did not affect adult population size or amount of brood in b. occidentalis colonies. fumagillin was not effective against n. bombi at the doses we tested, and frass samples did no ... | 2003 | 13678713 |
| interactions between nectar robbers and seed predators mediated by a shared host plant, ipomopsis aggregata. | animals that consume plant parts or rewards but provide no services in return are likely to have significant impacts on the reproductive success of their host plants. the effects of multiple antagonists to plant reproduction may not be predictable from studying their individual effects in isolation. if consumer behaviors are contingent on each other, such interactions may limit the ability of the host to evolve in response to any one enemy. here, we asked whether nectar robbing by a bumblebee (b ... | 2008 | 17965889 |
| comparative studies of pollen and fluorescent dye transport by bumble bees visiting erythronium grandiflorum. | in the colorado rocky mountains the glacier lily erythronium grandiflorum exhibits a striking dimorphism in pollen color and is commonly pollinated by the bumble bee bombus occidentalis. we induced bees to visit sequences of flowers in a flight cage, and compared dispersal of distinctively-colored pollen and fluorescent pigment ("dye") that the bee had picked up at a single donor flower. nonparametric and parametric analyses showed that dispersal properties of pollen and dye differed; consistent ... | 1986 | 28311616 |