Happy New Year! The beautiful bright red berries of American holly attract many birds such as mocking birds, blue jays, and cardinals to a winter feast. The berries provide a nutritious meal for our feathered friends and, in return, the birds distribute the fruit of the holly to new places and deposit them with their droppings. While photographing the native holly leaf miner that we met in an earlier episode of Bug of the Week (The holly and the native holly leaf miner, December 11, 2006), I spotted several holly berries distinctly green rather than scarlet red. Inside these fruits I discovered tiny yellow maggots, the larvae of the holly berry midge. In the spring of last year while the holly still had blossoms, the adult holly berry midge, a small mosquito-like fly, deposited eggs into the developing fruit of the holly. These eggs hatched into larvae that fed within the berry. During the past growing season the maggots consumed tissue within the berry. When the warmth of spring returns, these maggots will complete development and become pupae from which emerge small midges that mate and deposit eggs into the developing berries, thus completing the life cycle. For a small maggot, life in a holly berry is precarious. Its fate is tied to a red berry that advertises "eat me" and hungry birds and squirrels could literally eat the holly berry midge out of house and home. However, the larva of the holly berry midge has a neat trick to lessen its risks of being consumed along with its fruity home. Berries infested by the holly berry midge and an associated fungus fail to turn red as do normal holly berries. They remain green all winter. Through a series of detailed observations researches found that green holly berries were much less likely to be eaten by squirrels and birds than red berries on the same tree. By preventing the berry from turning red and attracting fruit eating critters, holly berry midge has found a way to make its berry home and itself less likely to disappear down the gullet of an animal. How clever!

To learn more about the holly berry midge, please visit the following web sites.

Bug of the Week Archive