5.04 Bee Ecology
- Explain the evolutionary relationship between bees and flowering plants.
- Describe three nesting strategies for bees.
- Give examples of generalist and specialist bees.
- Use the recent scientific literature to identify threats to native bee populations.
While honey bees get a lot of attention because of their unique relationship to people, they could actually be considered an invasive species. Honey bees (Apis mellifera) were first brought to North America in the 17th century and have since have established populations outside of managed beehives. These colonies are called “feral” or “wild” colonies and along with managed colonies compete for resources with many of the approximately 4000 bee species native to North America.
Whether honey bees negatively impact native bees is controversial, and despite much research the impact of competition is not entirely understood.  Some of the confounding effects may be a result of native bees and honey bees having different nesting and foraging strategies. Some species of bees are solitary, laying eggs with food stores and leaving the young to care for themselves. These nests can be in the ground (like miner bees) or in wood (like carpenter bees). Often, but not always, these bees are specialists, meaning that they limit their food to a single species or a few species of flowers. Generalist bees (like honey bees and bumble bees) forage on a wide variety of species, but often prefer visiting a single species in a given day, which has the side effect of improving pollination. Some native bees, like bumble bees, are eusocial and form colonies. Due to their increased space needs they sometimes inhabit cavities like abandoned rodent burrows.
While the rate of honey bee colony loss has increased in recent years, it is unclear what effects habitat loss, pesticide exposure, and disease are having on native bees. This video describes work being done by Same Droege and US Geological Survey to address this issue. Check out Sam Droege’s amazing photos here.
Bees provide an important ecological service, providing genetic mixing by transporting pollen from one stationary plant to another. Bees evolved from carnivorous wasp ancestors some time after angiosperms (flowering plants) appeared. It has long been thought bees and other pollinators are a driving force behind the evolution of the incredible variety of angiosperm species, but there are still gaps in our understanding of this process.  Maybe you could help solve this biological mystery!
- Jane C. Stout and Carolina L. Morales, Ecological impacts of invasive alien species on bees, Apidologie, 40 3 (2009) 388-409
- Timotheüs Van der Niet, Rod Peakall, and Steven D. Johnson, Pollinator-driven ecological speciation in plants: new evidence and future perspectives Ann Bot (2014) 113 (2): 199-21