Joseph F. Phillips
April 13, 1998
To understand the protection capacity of the aphid, a study was conducted using popular aphid infested trees. On certain leaves, William Foster and Philip Rhoden conducted a study in which 50 soldier aphids and 50 non-soldier aphids were compared to other leaves, which contained 100 non-soldier aphids (Foster and Rhoden 761).
The experiment was conducted in Cambridge, U.K. on two separate occasions. The dates of this experiment were September 16-25, 1993 and September 8-21, 1994. Twigs were chosen from the same trees in both cases. The twigs were swabbed and cleaned with all aphids removed. In a laboratory setting, one of the twigs was covered with 50 soldier and 50 non-soldier aphids. On another twig, only non-soldier aphids were placed on the twig.
The experiments measured aphid survivorsí (762). This is due to the fact that when aphids attack other aphids, there may be no remains to measure. During the two years, there was no significant difference in attack frequency. The only difference between the two years was the number of cohabiting aphids.
The experiment showed that soldier aphids did help defend aphid colonies from natural predators, however, the researchers warned against the limits of the experiment and recommended further aphid studies.
Foster, William A. and Philips K. Rhoden. "Soldiers Effectively Defend Aphid Colonies Against Predators in the Field." Animal Behavior. Mar 1998. Vol. 3, Pp. 761-765.