Meeting Abstract
Avoiding and defending oneself from predators is essential for survival; however, the behavioral changes and structures needed to do so can be energetically costly. Larvae of the dragonfly Leuchorhinia dubia can defend against predators behaviorally by reducing activity or hiding, or physically with defensive spines located on the abdomen. We investigated the tradeoffs between these physical and behavioral defenses in a field experiment. We placed individual larvae into floating behavioral arenas at Lake Hashawha in Westminster, Maryland containing two hiding places and an embedded grid system. We recorded the position of each larva every 10 minutes for 2 hours and calculated the activity level and the percent of time spent hiding. Body length and abdominal spine length were measured using photographs taken in the field. The percent of time larvae spent hiding appeared to be inversely correlated with spine length (P=0.1030) and body length (P=0.1062). Body and spine length did not affect activity level. Our data suggest that as dragonfly larvae grow, their increased size and morphological defenses may release them from the need to hide from predators, potentially increasing their foraging efficiency.
