Effects of sublethal levels of the herbicide 2,4-D on foraging behaviors in the crayfish, Orconectes rusticus

Meeting Abstract

59.6  Sunday, Jan. 5 14:45  Effects of sublethal levels of the herbicide 2,4-D on foraging behaviors in the crayfish, Orconectes rusticus BROWNE, AM*; MOORE, PA; Bowling Green State University amandmb@bgsu.edu

The widespread use of herbicides across the globe has significantly increased the probability of synthetic chemicals entering freshwater habitats. Upon entering aquatic habitats, these chemicals target and disrupt both physiological and behavioral functioning in many different aquatic organisms. In particular, herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), can have negative impacts on the olfactory system because these receptor cells are in direct contact with water-soluble chemicals and stimuli in the environment. Studies focusing on LD50 concentrations can understate the impact of herbicides within aquatic habitats because damage to the olfactory receptors can result in modified behaviors or lack of appropriate responses to environmental or social cues. The purpose of this experiment was to determine whether exposure to sublethal levels of 2,4-D alters the foraging behaviors of crayfish, Orconectes rusticus. We hypothesized that crayfish exposed to greater concentrations of 2,4-D would be less successful in locating food, or would consume smaller amounts of food, possibly due to the inability to process the food odors in the contaminated waters. Crayfish were starved for a week to provide motivation to find food and were exposed to three sublethal levels of 2,4-D for 96 h. Animals were placed into a Y-maze system with a fish gelatin food source placed randomly in the right or left arm. Average walking speed, average time spent in the correct arm, and percent consumption were analyzed . Crayfish were impaired in their ability to forage effectively. These inabilities to locate and consume adequate amounts of food could further result in lower body weights and decreased fitness in the populations of crayfish exposed to sublethal levels of 2,4-D in natural habitats.

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