Time perception-based decision making in a parasitoid wasp

The capacity of animals to measure time and adjust their behaviors accordingly has been a topic of interest in vertebrates, but little evidence is currently available for insects. This capacity has yet to be properly investigated in parasitoid wasps, even though they are frequently used to test ecological models. Here, using associative learning between odors and time intervals, we show that the parasitoid wasp Microplitis croceipes (Hymenoptera: Braconidae) has the capacity to measure time. When released in a wind tunnel, females flew toward an odor associated with the time interval they had just experienced. We also found that reducing energy expenditure by restraining parasitoid wasp movement during the training interval prevented time perception. This serves as experimental evidence of time perception in a parasitoid wasp, provides both a rare example of learning associated to a time interval in an insect and a mechanism by which these animals could optimize their behaviors, as well as suggesting a role for energy expenditure in its time perception mechanism.