Showing papers by "James H. Cane published in 2007"

Importance of pollinators in changing landscapes for world crops

Abstract: The extent of our reliance on animal pollination for world crop production for human food has not previously been evaluated and the previous estimates for countries or continents have seldom used primary data. In this review, we expand the previous estimates using novel primary data from 200 countries and found that fruit, vegetable or seed production from 87 of the leading global food crops is dependent upon animal pollination, while 28 crops do not rely upon animal pollination. However, global production volumes give a contrasting perspective, since 60% of global production comes from crops that do not depend on animal pollination, 35% from crops that depend on pollinators, and 5% are unevaluated. Using all crops traded on the world market and setting aside crops that are solely passively self-pollinated, wind-pollinated or parthenocarpic, we then evaluated the level of dependence on animal-mediated pollination for crops that are directly consumed by humans. We found that pollinators are essential for 13 crops, production is highly pollinator dependent for 30, moderately for 27, slightly for 21, unimportant for 7, and is of unknown significance for the remaining 9. We further evaluated whether local and landscape-wide management for natural pollination services could help to sustain crop diversity and production. Case studies for nine crops on four continents revealed that agricultural intensification jeopardizes wild bee communities and their stabilizing effect on pollination services at the landscape scale.

Substrates and Materials Used for Nesting by North American Osmia Bees (Hymenoptera: Apiformes: Megachilidae)

Abstract: Nesting substrates and construction materials are compared for 65 of North America’s 139 described native species of Osmia bees. Most accounts report Osmia bees nesting in preexisting cavities in dead wood or pithy stems such as elderberry (Sambucus spp.), with cell partitions and plugs made from a pulp of finely masticated leaf tissue. Mud is widely used by species constructing free-form clumps of nest cells against stone surfaces. Some Osmia bees adopt abandoned nests of other Hymenoptera, particularly those of mud dauber wasps (Sceliphron spp.) and larger ground-nesting bees (e.g., Anthophora spp.). Reports of subterranean nesting by Osmia species are uncommon but possibly under-represent the habit, because subterranean nests are obscure and likely to be scattered. Ground- or surface-nesting habits are suspected for species that are absent from intensive trap-nesting programs in their native ranges but that otherwise have been commonly taken at flowers. The range of nesting habits and material...