Date: Mon, 19 Apr 2010 12:31:50 -0400
From: Al Cooke
Subject: Mysteries in the trees
It’s often misleading to identify insects or other mysteries based on general descriptions. But I recently had a call about a small caterpillar and black fecal pellets falling from a tree – oak I think. And there are reports across the state about fall cankerworms, small inchworms that hatch in the spring and are fond of oak and maple but may also feed on ash, boxelder, black cherry, and elms. For reasons entomologists do not understand, Charlotte has been a major center for this population since 1987, perhaps because of the large number of willow oaks that create a canopy for much of the city.
Anytime you have a lot of insects eating a lot of foliage, then they will create a lot of – umm – excrement, which will fall through the leaves below. Perhaps this is the source of Lynn’s “mystery noise.” From Kira’s report, it’s not clear to me if the leaves are being eaten or if they are falling off or both. But if they are being eaten, it’s possible that this or some similar insect is feeding in the canopy overhead.
Fortunately, mature trees can usually tolerate defoliation and leaf out again. They are so good at storing reserves of energy that it usually take them years to die. Certainly repeated defoliation year after year can lead to a deteriorating tree. On the other hand, most of us do not have the capacity to deal with insect pests in the canopies of large trees.
The good news is that these insects serve a significant role in the transfer of food up the food chain from plants (the source of all food) to higher animals. In a significant book published in 2007 (Bringing Nature Home), author Douglas Tallamy makes a good case that insects feeding on native plants are a major source of food for higher animals such as birds. Even seed eating birds need this high protein diet for raising young, something that many of them do about this time of year. Without this type of food transfer, the world in which we live would be a much different place. So if you ever wondered what value insects have, there is one.
alcooke