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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

A Thanksgiving feast served by green peach aphid, Myzus persicae

 

Hundreds of aphids partake in a Thanksgiving feast on the leaves of autumn clematis.

 

Climbing a lamppost in my front yard is a tangle of sweet autumn clematis, Clematis terniflora, one of the most delightful autumn bloomers. After rewarding me with fragrant blossoms for much of the fall, autumn clematis has one more treat just in time for Thanksgiving. Clematis serves as a nutritious food source for green peach aphids. Beneath each leaf, scores to hundreds of aphids suck nutritious sap that courses through the clematis and the horde is so abundant that the leaves drip with honeydew and sooty mold coats the lower leaves with a dark mantle of fungus. The saga of the green peach aphids on my clematis began earlier this year when winged aphids migrated to the vine clinging to my lamppost. These aphids survived last winter as eggs deposited on a cherry, peach, or other member of the genus Prunus. During summer and much of autumn female aphids abandon sexual reproduction and produce young without mating. This form of reproduction, called parthenogenesis, produces only females thus enabling aphid populations to increase rapidly. Another fact of life contributing to the explosion of aphids is their ability to eschew the usual insect-like business of laying eggs. While on their summer hosts, green peach aphids dispense with the egg stage and, like humans, give live birth to their babes. This blessed event takes only a few minutes but appears to be fraught with significant drama. Birthing aphids do lots of posturing and pushing. Fortunately, aphids have sucking mouthparts and loud vocalizations such as those accompanying human births are conspicuously absent. 

Breech births seem to be the rule for aphids.

 

To further accelerate the process of filling the world with their kind, female aphids carry embryos of their grandchildren within their bodies even before they are born. This also compresses the generation time for aphids and is part of the reason aphid populations rapidly grow from a few to thousands. As I examined my colony of aphids I noticed several winged adults mixed with the parthenogenetic females. In cold regions like Maryland, when temperatures turn chilly, winged adults leave clematis and return to Prunus to mate and lay eggs that spend the winter on the bark of the tree. In spring, eggs hatch and the complex life cycle of the aphid resumes. In warmer regions like Florida green peach aphids may cycle continuously on their hosts. 

Just as my clematis serves as a feast for green peach aphids on a mild Thanksgiving Day, so too will the aphids and their honeydew serve as dinner for guests higher up the food chain. Roaming around my clematis were dozens of multicolored Asian lady beetles. Their alligator-like larvae patrolled leaves and stems searching for tasty aphids. Without much stealth or finesse, larvae captured aphids in their jaws and proceeded to munch their hapless prey. Small aphids disappeared in just a minute or two, but large, plump aphids required several minutes to eat. A single larva of the multicolored Asian lady beetle may devour 1,200 aphids during the course of development. Adult beetles are also aphid-eating machines and may consume more than 250 aphids daily. Each female beetle may live more than one year and produce more than 700 eggs in a season. This ability to produce so many young with the potential for eating so many aphids makes the multicolored Asian lady beetle one of the most effective biological control agents in our gardens. One added surprise comes when multicolored Asian lady beetles enter homes for the winter (see Lady Bug, ladybug, fly away home).

After dining on aphids, the lady beetle takes a moment to groom

 

And what Thanksgiving feast would be complete without dessert? With gobs of sweet honeydew on leaves, and apparently on the menu, dozens of hungry yellow jackets visited the clematis to lap up the carbohydrate rich meal just in time to fatten up for their winter rest (see Unwanted picnic guests - Yellow Jackets, Vespula spp.). So on this merry Thanksgiving Day, while you munch turkey and savor pumpkin pie, reflect on the happy feasts underway wherever green peach aphids serve dinner. Happy Thanksgiving from Bug of the Week. 

A yellow jacket enjoys sweet honeydew for its Thanksgiving dessert

 

References

To learn more about green peach aphid, multicolored Asian lady beetle, and yellow jackets, please visit the following web sites:

http://entnemdept.ufl.edu/creatures/veg/aphid/green_peach_aphid.htm 


http://ohioline.osu.edu/hse-fact/1030.html 


http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7450.html