【生態】女王バチにふさわしい生息地

The survival and persistence of bumblebee family lineages increases substantially with the proportion of high-quality foraging habitat within 250-1,000 m of the colony, an analysis of three bumblebee species reveals. The findings, published online in Nature this week, support the idea that conservation measures that boost floral resources at a landscape level throughout the season can have positive effects on wild pollinators in agricultural settings.

Habitat loss due to agricultural intensification is a major cause of the global decline in insect pollinators, including bumblebees. Although various initiatives to restore pollinator habitats and populations have been developed, an understanding of the effects of landscape changes on key population-level parameters, such as survival between lifecycle stages, is lacking for bumblebees.

Claire Carvell and colleagues studied three common bumblebee (Bombus) species within 20 km2 of mixed agricultural landscape (comprising farmland, grassland, woods and villages) in Buckinghamshire, UK, over two years. They conducted land-use and habitat surveys, and sampled DNA from 537 spring queens and 2,101 worker bees to analyse relationships within and between generations in the colony. The authors then used demographic and spatial modelling to evaluate the between-year survival of family lineages in the field populations. They find that colonies located close to high-value foraging habitats, including spring flower resources, are more likely to produce daughter queens that survive winter hibernation and spring emergence.

In an accompanying News & Views, Jeffrey Lozier concludes that the study provides a framework that could be used “to investigate the effects of pesticides, pathogens and other factors on multigenerational life-cycle dynamics, with the goal of identifying a realistic way to optimize land-use heterogeneity for bumblebee populations.”