Honey bee colony collapse syndrome has been widely publicized. Actually, honey bee populations have been declining for a long time. As pollinators, honey bees are important to agriculture, gardening, and food security.
Dr. Russ Mizell, UF/IFAS Extension entomologist, shares interesting findings concerning research with crape myrtles and pollinating insects in today’s article.
Honey bee populations have dwindled to about 50 percent of what they were 10-25 years ago both in commercial production and wild bees. As a result of this potential calamity, greater interest in other pollinators and particularly our native bees has increased. We have a large number of native bees that are important pollinators in Florida. The biology, ecology and behavior of many of these species remain unknown.
Many people are familiar with the widely planted ornamental crape myrtle as a result of its beautiful summer blooms in a variety of colors–white, lavender, pink, and red. Crape myrtle is a non-native and has been in the U.S. since colonial times. Bees and flowers would seem to go together and one might suppose given its beautiful summer glowers that crape myrtle has been studied for its use by pollinators. Surprisingly, until now it has not been. Recently, UF/IFAS researchers have been looking at pollinators on crape myrtle. They found that there are a number of native bee species as well as honey bees that use crape myrtle flowers.
Crape myrtles do not produce flower nectar but they are unusual in that they do have two types of anthers that produce two types of pollen. One of the pollens is for reproduction and the other is to feed the pollinators. If you examine the flowers you’ll see the brown pad-like reproductory anthers arranged higher above and over the bright yellow anthers providing food.
Including honey bees, the study found five major species and a number of minor species use crape myrtle flowers for pollen gathering. Bumble bees and two species of carpenter bees were the most prevalent native species observed. Most all crape myrtles in flower were visiting by bees. The cultivars Apalachee, Miami, Byers Wonderful White, Osage, Acoma, Natchez, Yuma, and Lipan were the cultivars most often used.
From this work its is clear that crape myrtles are important pollen sources for honey bees as well as native bees, Lots of other insects also use crape myrtle pollen including many predacious insects like syrphid flies.
Such insects will also consume the honeydew excreted by the crape myrtle aphid. Their usefulness to augment pollinators ties one more ecological service to this important landscape plant.