Within-clutch variation in venoms from hatchlings of Deinagkistrodon acutus (Viperidae).

We used 17 hatchling five-paced pit-vipers snakes (Deinagkistrodon acutus) to study within-clutch variation in snake venoms. We measured venom yield and total protein content, and examined the correlations between venom yield and hatchling size [snout-vent length (SVL) and body mass]. We also analyzed the electrophoretic profiles and enzymatic activities of venoms from hatchlings. Lyophilized venom mass was not correlated with SVL, nor with body mass. Liquid venom mass and total protein content were not correlated with body mass, but were positively correlated with SVL. Venom composition, as shown in SDS-PAGE chromatograms did vary among individuals but there were biochemical differences in activity which had to be due to subtle venom composition differences between the sexes. Female hatchlings showed higher esterolytic and fibrinogenolytic activities but lower proteolytic, collagenolytic, phosphomonoesterase and fibrinolytic activities than male hatchlings. We did not find sexual differences in 5' nucleotidase, phospholipase A(2) and hyaluronidase activities, and l-amino acid oxidase activities in either female or male hatchlings. Within-clutch variation in venoms from D. acutus hatchlings should be attributed to the individual-based differences in presence or absence, and the relative amount of the protein components, and might have a genetic basis.