Effects of Metals on Chemosensation in Non-Piscine Components of Aquatic Food Webs

Water’s unique chemical and physical properties provided the selective pressures that allowed for the development of a wide range of sophisticated and efficient chemical communication systems. Aquatic animals use chemosensory information to find food, avoid predators, and reproduce; that is, processes that are necessary to sustain healthy populations and ecosystems. Therefore, when chemosensory function becomes impaired from exposure to environmental contaminants, effects occur throughout the ecosystem. Most research involving contaminant effects on chemosensory function has been on fish; however, there is a growing body of evidence suggesting that similar effects occur in other non-piscine species. For example, freshwater leeches (Nephelopsis obscura) showed impaired chemosensation after a short-term exposure to copper concentrations as low as 5 μg/L. Moreover, copper-exposed leeches spent more time searching and less time actively feeding than controls. Chemosensory-impaired daphniids are unable to mount a kairomone-inducible anti-predator morphological defense against predatory midges, leaving them more vulnerable to predation than intact animals. Chemosensory-impaired daphniids also fail to make adaptive life history shifts (e.g., smaller body sizes) after being exposed to Cu. Despite the myriad effects documented under controlled laboratory conditions for daphniids, these effects do not easily extrapolate to real-world conditions where results are far more variable. This presentation will examine contaminant-impaired chemosensory function among non-piscine species and its consequences to aquatic ecosystems.