Miller-Struttmann NE, Galen C. High-altitude multi-taskers: Bumble bee food plant use broadens along an altitudinal productivity gradient. Oecologia 2014;176, 1033–1045.
This paper looks at extensive historical data on bumble bee host choice that was collected almost 50 years ago by L. W. Macior. The purpose is to see how bumble bee behavior, resource overlap between castes, and plant-bumble bee networks change with altitude. Results suggest that spatial variation in the different chosen resources is driven by a shift in the behavior of long-tongued bumble bees. Long-tongued bumble bees specialized in the subalpine but generalized in montane and alpine zones. The reanalysis of Macior's data shows that bumble bee behavior…show more content… Since bees are subject to numerous pressures in the modern world, the abundance and diversity of flowers has declined. Bees are chronically exposed to cocktails of agrochemicals, and they are simultaneously exposed to novel parasites accidentally spread by humans. Climate change is likely to exacerbate these problems in the future. What makes studying this difficult is that stressors do not act in isolation; for example, pesticide exposure can impair both detoxification mechanisms and immune responses, rendering bees more susceptible to parasites. They are more certain that chronic exposure to multiple interacting stressors is driving honey bee colony losses and declines of wild pollinators, but such interactions are not addressed by current regulatory procedures, and studying these interactions experimentally poses a major challenge. In the meantime, they believe that taking steps to reduce stress on bees would seem prudent; incorporating flower-rich habitat into farmland, reducing pesticide use through adopting more sustainable farming methods, and enforcing effective quarantine measures on bee movements are all practical measures that should be adopted. Effective monitoring of wild pollinator populations is urgently needed to inform management strategies into the…show more content… They especially looked at how interaction patterns covary with latitude, elevation, and insularity. They analyzed 29 complete plant–pollinator networks that encompass arctic, alpine, temperate, Mediterranean, and subtropical–tropical areas. After controlling for species richness, the residual connectance was significantly lower in highland than in lowland networks and differed marginally among biogeographic regions, with both alpine and tropical networks showing a trend for lower connectance. The two Mediterranean networks showed the highest residual connectance. After correcting for variation in network size, plant species were shown to be more generalized at higher latitude and lowland habitats, but showed increased specialization on islands. Oceanic island networks showed a lack of potential animal pollinators associated with this trend of increased specialization. Plants, but not their flower-visiting animals, supported the often-repeated statements about higher specificity in the tropics than at higher latitudes. They found the pattern of interaction build-up as diversity increases in pollination networks does not differ a lot from other mutualisms, such as plant–seed disperser networks or more complex food