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Many bumblebee species are declining at a rapid rate in the United Kingdom and elsewhere. This is commonly attributed to the decline in floral resources that has resulted from an intensification in farming practices. Here we assess growth of nests of the bumblebee, Bombus terrestris, in habitats providing different levels of floral resources. Experimental nests were placed out in conventional farmland, in farmland with flower-rich conservation measures and in suburban areas. Nests gained weight more quickly and attained a larger final size in suburban areas compared to elsewhere. The diversity of pollens gathered by bees was highest in suburban areas, and lowest in conventional farmland. Nests in suburban areas were also more prone to attack by the specialist bumblebee parasite Aphomia sociella, suggesting that this moth is more abundant in suburban areas than elsewhere. Overall, our results demonstrate that gardens provide a greater density and diversity of floral resources than farmland, and probably support larger populations of B. terrestris. Contrary to expectation, schemes deployed to enhance farmland biodiversity appear to have little measurable impact on nest growth of this bumblebee species. We argue that B. terrestris probably forage over a larger scale than that on which farms are managed, so that nest growth is determined by the management of a large number of neighbouring farms, not just that in which the nest is located.

Summary 1.Calyptrate flies include numerous species that are disease vectors and have a high nuisance value, notably Musca domestica . Populations are often associated with livestock farms and domestic waste disposal facilities such as landfill, where the accumulating organic matter provides suitable breeding conditions for a range of species. 2. We examined the relationship between fly numbers and weather conditions using a 4-year data set of weekly fly catches from six sites in southern UK, together with meteorological data. The first 3 years were used to develop predictive models, and these were then used to forecast fly populations in the fourth year. The accuracy of these predictions was assessed by comparison with the actual fly catches for that year. Separate models were developed for M. domestica , Calliphora spp. and all calyptrate flies combined. 3. Predictions based only on humidity, temperature and rainfall were strongly correlated with observed data ( r 2 values ranged from 0·52 to 0·84), suggesting that fly population changes are largely driven by the weather rather than by biotic factors. We can forecast fly populations so that control measures need only be deployed when weather conditions are suitable for a fly outbreak, reducing the need for prophylactic insecticide use. 4. Climate change was simulated using the most recent predictions of future temperature increases. Our models predicted substantial increases in fly populations up to 244% by 2080 compared with current levels, with the greatest increases occurring in the summer months. 5. Synthesis and applications. Models developed use weather data to predict populations of pestiferous flies such as M. domestica , which may prove valuable in integrated control programmes. These models predict substantial increases in fly populations in the future under likely scenarios of climate change. If this occurs we may expect considerable increases in the incidence of fly-borne disease.

No abstract

SummaryLantana camara, a woody shrub originating in south and central America, is among the most widespread and troublesome exotic weeds of the old-world tropics. It invades pasture, crops and native ecosystems, causing substantial economic losses and environmental degradation. In Australia alone, L. camara is currently estimated to cover approximately 40,000 km 2 . In glasshouse studies we demonstate that L. camara requires cross-pollination to set fruit, and that honeybee visits result in effective pollination. Field studies carried out in Queensland, Australia, suggest that fruit set is limited by pollinator abundance, and that the main pollinator of L. camara throughout a substantial portion of its Australian range appears to be the honeybee, Apis mellifera. Seed set was strongly correlated with honeybee abundance, and at many sites, particularly in southern Queensland, honeybees were the only recorded flower visitors. Of 63 sites that were visited, seed set was highest at five sites where only honeybees were present. Hives are frequently stationed within and adjacent to areas such as National Parks that are threatened by this noxious weed. Management of honeybee populations may provide a powerful tool for cost-effective control of L. camara that has previously been overlooked. We suggest that there are probably many other weeds, both in Australia and elsewhere, that benefit from honeybee pollination.