University of Michigan
Department of Ecology and Evolutionary Biology

Three cheers to Jeremy Wright who received the American Society of Ichthyologists and Herpetologists’ 2011 Storer Award in Ichthyology for his poster, “Adaptive Significance of Venom Glands in the Tadpole Madtom (Noturus gyrinus).” 

Venom glands in fish have long been assumed to be anti-predatory adaptations. But direct examinations of their fitness benefits have been lacking and are confounded by the sharp, bony fin spines in many catfish species, which are also likely deterrents to predation. Wright’s experiment presented Tadpole Madtoms (Noturus gyrinus), a small catfish, with several fin spine phenotypes (intact, stripped, absent) to a potential natural predator (Largemouth bass - Micropterus salmoides). He found that the venom glands of this species do provide a significant fitness benefit relative to individuals having fin spines that lacked venom glands, or no spines at all.

Additionally, through comparative experiments using madtoms and a related catfish species, the Yellow Bullhead (Ameiurus natalis), Wright also found that particular venom components contribute disproportionately to predator deterrence. The lack of a single protein in the bullhead venom completely eliminated the fitness benefit provided by the madtom venom (even though injections of bullhead venom did induce signs of toxicity in the predator species). 

These findings provide new insights into the evolution of defensive venom toxicity in fishes and its possible relationship to tradeoffs in life history traits such as fecundity, body size and growth rate, as bullhead species reach much larger sizes, grow faster, and produce more offspring than do madtoms.

The poster was presented at the society’s annual meeting (attendance approximately 900) held in Minneapolis, Minn., July 6 - 11, 2011. The Storer Award is presented annually by ASIH for the best student poster. Wright also won in 2008 and 2009.