Insects and Bacteria Appear to Team Up Against a Pesticide

Multiple Choice

Insects and bacteria appear to team up against a pesticide that is commonly sprayed on crops. The bean bug Riptortus pedestris is a common soybean pest and in a recent study was shown to acquire resistance to a common insecticide. This resistance is related to the presence of bacteria ( Burkholderia sp.) living within its gut. In this mutually beneficial relationship, more than 100 million bacteria can live within the insect's gut. Evidence suggests that these bacteria are able to break down the pesticide into carbon dioxide, which is used by the bacteria, and harmless waste products are then secreted. In a recent study, researchers fed bacteria-infested bean bugs and bacteria-free bean bugs a diet of soybean seedlings that had been treated with the pesticide. Most of the bacteria-infested bean bugs survived after eating the treated soybeans, but 80 percent of the bacteria-free bean bugs died. In the experiment, what would be considered the control group?

A) the bacteria-free bean bugs
B) the bacteria-infested bean bugs
C) the use of pesticides on the soybean plants
D) the number of deaths caused by eating the plants