Meeting Abstract
Snake venoms represent an adaptive trophic response to the challenges confronted by a limbless predator for overcoming fractious prey, and this chemical means of dispatching prey shows several dominant phenotypes. Many front-fanged snakes, particularly vipers, feed on a variety of vertebrate and invertebrate prey species, and some of their venom components (e.g., cobratoxin, metalloproteinases) appear to have been selected for “broad-brush” incapacitation of differing prey taxa. Using a number of proteomic and genomic-based techniques, the compositional diversity of front-fanged snakes is becoming well characterized; however, this is not the case for many rear-fanged colubroid snakes, which include a variety of diverse taxa world-wide. Because these species show a very high diversity of prey preferences, and because venoms are primarily a trophic adaptation, it is argued here that important clues for understanding specific selective pressures favoring venom component composition will be found among rear-fanged snake venoms. Rear-fanged snakes typically (but not always) produce venoms with lower complexity than front-fanged snakes, and there are even fewer dominant (and, arguably, biologically most relevant) venom protein families. We have demonstrated taxon-specific toxic effects, where lizards and birds show high susceptibility while mammals are largely unaffected, for both Old World and New World species of rear-fanged snakes, strongly indicating a causal link between toxin evolution and prey preference. Relatively few rear-fanged snake venoms have been characterized, and basic natural history data is often lacking, but directed sampling of specialized species indicates that novel compounds are likely among these specialists, particularly among those species feeding on archaic prey such as scorpions and centipedes.
