Insects with Personality

Many people look on insects as objects and fail to appreciate that insects are living creatures with “personality”. The average aphid does not possess a complex personality worthy of a homecoming queen or even a class clown. However, the biological definition of personality includes the “behavioral response patterns”.

Aphids do more than suck plant phloem. Aphids possess a repertoire of defensive behaviors to respond to threats from predators and parasitoids. Individuals may vary in their “behavioral response patterns”. Thus, under the above definition, we can say that individual aphids have personalities.

In the ongoing debate over nature, nurture, or nature & nurture, scientists have used twin studies to correlate genetics with behavior. Identical twins possess identical genes. Behavioral differences between twins can be attributed to the influence of the environment (nurture). Aphids, not only produce twins, they produce clones, multiple individuals with identical genes during their asexual reproductive phase. Recently, members of the Experimental Ecology Group at the University of Osnabrueck in Germany used aphid clones to study the contribution of nurture to “personality”.

In their study, a lady beetle was allowed to terrorize groups of aphid clones. Indinvidual aphids displayed a “flighty” or an “oblivious” personality. “Flighty” aphids dropped off the plants at the first sign of trouble. “Oblivious” aphids remained on the plant. In repeated tests, the “flighty” individuals are the ones that drop off the plant each time while the “oblivious” individuals remain.

Since the “flighty” and “oblivious” aphids are genetically identical, their personality must be influenced by environment.” Which environmental factors lead to “flighty” personality and which lead to “oblivious” personality? The answer will require further study. The study also found that aphid personality has a genetic component as well as a nurture effect. Some clones had higher ratios of fearful to oblivious personalities than others.

Insects present numerous opportunities to research behavioral questions. Like humans, aphids, personality is influenced by both nature and nurture. Insights about insect personality may have some clues for personality development in humans and a greater appreciation for human personality differences.

Red Aphids
The aphids in the above experiments were pea aphids