Pollinator biodiversity and floral resource use in Ecballium elaterium 
(Cucurbitaceae), a Mediterranean endemic

AbstractIntegration of pollinator-dependent invasive plants into native pollination networks can have direct and indirect effects on local plant and pollinator communities. Impacts on local plants are well documented; however effects on native pollinators have gained less attention. We examine these issues in habitat fragments of the endangered oak-savannah ecosystem in British Columbia, Canada. We measured pollen collection by native bumble bees (Bombus Latreille; Hymenoptera: Apidae) and the introduced honey bee (Apis mellifera Linnaeus; Hymenoptera: Apidae) foraging on two common native plants in habitat fragments with varying invasive (Cytisus scoparius (Linnaeus) Link; Fabaceae) density. The Bombus species with the largest workers had higher proportions of invasive pollen on their bodies and in their corbiculae than smaller workers. Honey bees rarely collected C. scoparius pollen. While some native bumble bees species collect an increasing proportion of C. scoparius pollen with increasing C. scoparius density, this did not translate into an increased potential for pollination. Rather, measures of effective pollination decline with C. scoparius density. Overall, our results suggest that some bee species may be better at finding resources at highly invaded sites. Apis mellifera is likely not playing a major role in facilitating the spread of C. scoparius in our region. Rather C. scoparius is visited by a complement of native bumble bees that are similar to pollinators in the native range of this plant.

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Floral resource use and interactions between Apis mellifera and native bees in cucurbit crops in Yucatán, México

The Canadian Entomologist ◽

10.4039/n04-043 ◽

2005 ◽

Vol 137 (4) ◽

pp. 441-449 ◽

Cited By ~ 17

Author(s):

Miguel Angel Pinkus-Rendon ◽

Víctor Parra-Tabla ◽

Virginia Meléndez-Ramírez

Keyword(s):

Apis Mellifera ◽

Resource Use ◽

Interspecific Interactions ◽

Citrullus Lanatus ◽

Niche Overlap ◽

Fruit Production ◽

Floral Resources ◽

Native Bees ◽

Native Bee ◽

Floral Resource

AbstractDespite the importance of native pollinators in agricultural systems, little is known about the potential competitive interactions among them or the way they exploit crops' floral resources. This study determines the temporal use of floral resources by, and interspecific interactions between, native bees and Apis mellifera L. (Hymenoptera: Apidae) in experimental plots of squash, Cucurbita moschata (Duchesne ex Lam.) Duchesne ex Poir. (Cucurbitaceae), and watermelon, Citrullus lanatus (Thunb.) (Cucurbitaceae). General and specific niche overlap analyses were done to determine whether temporally differential use of floral resources occurred. Direct displacement interactions at the floral level were quantified. The species with the greatest abundances were Peponapis limitaris Cockerell (Apidae), Partamona bilineata Say (Apidae), and A. mellifera. Overall, the niche overlap analyses in both crops suggested that floral resources are not used simultaneously by different bee species. Winner events during aggressive encounters suggested a hierarchy among bee species, with A. mellifera being one of the species with more winner encounters in both crops. It is suggested that those deciding whether or not to introduce A. mellifera into crops should consider whether the abundance of native bee species is sufficient to ensure efficient fruit production.

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