Download Crape myrtles are important to pollinating insects

Crape myrtles are important to pollinating insects
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 fifty 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 flowers
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 visited by bees. The cultivars Apalachee, Miami, Byers Wonderful White,
Osage, Acoma, Natchez, Yuma and Lipan were the cultivars most often used.
From this work it 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.
Larry Williams, UF/IFAS Extension Agent, Okaloosa County, April 12, 2012