Mismatched outcomes for biodiversity and ecosystem services: testing the responses of crop pollinators and wild bee biodiversity to habitat enhancement.

Supporting ecosystem services and conserving biodiversity may be compatible goals, but there is concern that service-focused interventions mostly benefit a few common species. We use a spatially replicated, multiyear experiment in four agricultural settings to test if enhancing habitat adjacent to crops increases wild bee diversity and abundance on and off crops. We found that enhanced field edges harbored more taxonomically and functionally abundant, diverse, and compositionally different bee communities compared to control edges.

Summer Flowering Cover Crops Support Wild Bees in Vineyards.

Agricultural expansion and intensification negatively affect pollinator populations and has led to reductions in pollination services across multiple cropping systems. As a result, growers and researchers have utilized the restoration of local and landscape habitat diversity to support pollinators, and wild bees in particular. Although a majority of studies to date have focussed on effects in pollinator-dependent crops such as almond, tomato, sunflower, and watermelon, supporting wild bees in self-pollinated crops, such as grapes, can contribute to broader conservation goals as well as provide other indirect benefits to growers.

Temporal dynamics influenced by global change: bee community phenology in urban, agricultural, and natural landscapes.

Urbanization and agricultural intensification of landscapes are important drivers of global change, which in turn have direct impacts on local ecological communities leading to shifts in species distributions and interactions. Here, we illustrate how human-altered landscapes, with novel ornamental and crop plant communities, result not only in changes to local community diversity of floral-dependent species, but also in shifts in seasonal abundance of bee pollinators. Three years of data on the spatio-temporal distributions of 91 bee species show that seasonal patterns of abundance and species richness in human-altered landscapes varied significantly less compared to natural habitats in which floral resources are relatively scarce in the dry summer months.

Investigating temporal patterns of a native bee community in a remnant North American bunchgrass prairie using blue vane traps.

Native bees are important ecologically and economically because their role as pollinators fulfills a vital ecosystem service. Pollinators are declining due to various factors, including habitat degradation and destruction. Grasslands, an important habitat for native bees, are particularly vulnerable.

Survey of bumble bee (Bombus) pathogens and parasites in Illinois and selected areas of northern California and southern Oregon.

Pathogens have been implicated as potential factors in the recent decline of some North American bumble bee (Bombus) species, but little information has been reported about the natural enemy complex of bumble bees in the United States. We targeted bumble bee populations in a state-wide survey in Illinois and several sites in California and Oregon where declines have been reported to determine presence and prevalence of natural enemies. Based on our observations, most parasites and pathogens appear to be widespread generalists among bumble bee species, but susceptibility to some natural enemies appeared to vary.

Nest site selection influences mortality and stress responses in developmental stages of Megachile apicalis Spinola (Hymenoptera: Megachilidae).

We examined stress responses and survival in developmental stages of the invasive solitary bee Megachile apicalis Spinola during two nesting seasons in the Central Valley of California to consider whether abiotic stress tolerance of its offspring contributes to this species' successful colonization of the western United States. In 2001 and 2003, artificial nesting cavities were affixed to vertical plywood boards oriented to maximize nest cavity temperature and humidity differences: one side faced south (exposed to direct sun) and the other one faced north (shaded). After several weeks of nesting activity, we measured heat shock protein 70 (HSP70) concentrations in adults and offspring on 1 d in both years and offspring survival and mortality sources in 2003.

Bursaphelenchus anatolius n. sp. (Nematoda: Parasitaphelenchidae), an Associate of Bees in the Genus Halictus.

Bursaphelenchus anatolius n. sp., a phoretic associate of Halictus bees from Ankara, Turkey, is described and illustrated.

Crop pollination from native bees at risk from agricultural intensification.

Ecosystem services are critical to human survival; in selected cases, maintaining these services provides a powerful argument for conserving biodiversity. Yet, the ecological and economic underpinnings of most services are poorly understood, impeding their conservation and management. For centuries, farmers have imported colonies of European honey bees (Apis mellifera) to fields and orchards for pollination services.

Maternal investment and size-number trade-off in a bee, Megachile apicalis, in seasonal environments.

Maternal investment in offspring size and number differed between spring- and summer-emerging individual females of Megachile apicalis, a solitary multivoltine bee. Data from experimentally initiated female populations indicated that spring-emerging females produced a relatively large number of progeny but allocated a small amount of food to each, resulting in small progeny. Adult females of larger body sizes provisioned food at a greater rate than did smaller females, and this body-size effect was significant in spring-emerging females.