Sunflower pollen protects bees from parasites

http://www.eurekalert.org/pub_releases/2016-06/uocp-spp061416.php

Public Release: 14-Jun-2016
Sunflower pollen protects bees from parasites
Why eat nasty things? Because your enemy finds it even nastier
University of Chicago Press Journals

Plant pollens vary in quality as food sources for bees, and pollen from the sunflower family (the family that includes dandelions, daisies, and thistles) is known to have some unpleasant qualities. Bees fed exclusively sunflower pollen often develop poorly, slowly, or not at all. Yet many bee species collect pollen exclusively from this family; in fact, specialization on sunflower pollen has evolved multiple times in bees. Research by Dakota Spear and colleagues suggests that parasites could be part of the explanation.

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Sarah Silverman, ... noticed that bee species specializing on sunflower pollen were not attacked by a common brood-parasitic wasp, Sapyga. The wasp frequently lays eggs in the nests of other mason bee species, where its larvae kill bee eggs and eat their pollen provisions. Silverman and Forrest hypothesized that the wasp might be unable to develop on the pollen provisions of sunflower specialists.

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To test the hypothesis, she forced wasp larvae to feed on different types of pollen provisions, including those of sunflower specialists, and monitored their development and survival. As suspected, wasp survival was much lower on the sunflower provisions.

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