POLLINATOR SCIENCE
making more bees, and how many? A partial substitute for reproductive success is examining growth parameters, which correlate with an increased or decreased ability to thrive in an environment. Looking at size is a good surrogate for bees, as their body size often varies with the abundance of food We found that there was some evidence that the presence
of managed honey bees caused reduced reproductive output in some native bee populations in the limited number of both better quality and more quantity of studies. So what do we know? There are more than 20,000 species
of bees. With such a huge diversity of species, a simple, universal answer to the outcome of interactions is unlikely. Feeding habits vary greatly across bee families, genera, and species. Some species exhibit specialization for one host plant species, what scientists call monolectic bees, a relatively rare habit. The majority of bees forage on multiple species within one plant genus (oligolectic) or multiple species in similar plant genera (mesolectic). Some have a much broader repertoire and visit multiple species within multiple genera and families, they are considered polylectic to various degrees.2
which are considered broadly polylectic or generalist feeders, can forage on a wide spectrum of food resources within a landscape. With such a varied diet, what wild bees are they competing with? There are two alternative theories regarding the segment
of the bee community that would potentially be subjected to the greatest negative impacts in the presence of honey bees. One suggests that oligolectic or mesolectic bees with narrower
“To understand if there are
winners and losers in this race for food, we have to first define the different types of interactions. Not all of them are lose/lose. Sometimes interactions are mutually beneficial.”
This image: Wild bees are vastly understudied. For many of the solitary species, we know few details of their reproductive biology and how they may be impacted by competition. Left: As generalist foragers, bumble bees have the closest overlap to honey bees in their foraging preferences. But their longer tongues and buzz pollination ability, means they can access sources honey bees can not.
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interactions within their narrow niche space. With a more limited diet, these species would also be less able to shift to feed on other plants. The other suggests that generalist polylectic feeders, like bumble bees, would experience the most resource overlap with honey bees and be more likely to directly compete for the same resources, though they would have the capacity to shift or share their resources. Oligolectic
not preferred by generalist feeders, and therefore exist in a separate niche space not used by honey bees. Many beekeepers ascribe to this point of view, describing the feeding preferences of their charges as general, but targeted toward nectar rich plants that dominate the landscape.3,4 Studies of honey bee foraging support the view that these generalists exploit the most abundant and most nectar- 5,6
Winners and Losers? To understand if there are winners and losers in this race interactions. Ecological interactions between species are diverse. We categorize them to understand the impacts one has on the other. There are six common ways that bee species can interact. Not all of them are lose/lose. Sometimes Much of what we in the bee community have called competition is more likely ammensalism, an interaction in which one species experiences a negative impact, while the other one is unaffected. This term applies when one bee that was there is now gone.
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