Evidence for Snake Venom Plasticity in a Long-Term Study with Individual Captive Bothrops atrox

Abstract

Variability in snake venom composition has been frequently reported and correlated to the adaptability of snakes to environmental conditions. Previous studies report plasticity for the venom phenotype. However, these observations are not conclusive, as the results were based on pooled venoms, which present high individual variability. Here we tested the hypothesis of plasticity by influence of confinement and single diet type in the venom composition of 13 adult specimens of Bothrops atrox snakes, maintained under captivity for more than three years. Individual variability in venom composition was observed in samples extracted just after the capture of the snakes. However, composition was conserved in venoms periodically extracted from nine specimens, which presented low variability restricted to the less abundant components. In a second group, composed of four snakes, drastic changes were observed in the venom samples extracted at different periods, mostly related to snake venom metalloproteinases (SVMPs), the core function toxins of B. atrox venom, which occurred approximately between 400 and 500 days in captivity. These data show plasticity in the venom phenotype during the lifetime of adult snakes maintained under captive conditions. Causes or functional consequences involved in the phenotype modification require further investigations.

Old World Vipers—A Review about Snake Venom Proteomics of Viperinae and Their Variations

“…Furthermore, age as well as regional separation affect the venom, most likely linked to the available diversity of prey [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. Sex, long-term captivity effects including stress [ 34 , 35 , 36 , 37 ], environmental conditions, like temperature, and the defense against primates are under discussion [ 38 , 39 ]. Venoms and their variations are of great scientific interest and can be seen as a model system for evolutionary biology, reaching from single genes to macroevolutionary contexts [ 40 , 41 , 42 ].…”

Gradual and Discrete Ontogenetic Shifts in Rattlesnake Venom Composition and Assessment of Hormonal and Ecological Correlates

“…We therefore suggest that one of the most important implications of our work is the need to record more detailed life history data, particularly body size, as venom is collected. The only comparably long-term study to ours involving another large pit viper ( Bothrops atrox ) provides a demonstration of the utility of considering body size information when making inferences about venom ontogeny [ 57 ]. These authors captured snakes in the wild classified as adults and used HPLC and enzymatics to profile change in venom during long-term captivity.…”

“…While minor compositional shifts were reported in all snakes, only 4 of 13 snakes showed shifts in venom proteins classified as “core function toxins”, and the authors provided several potential explanations for the major changes in these select individuals, including dietary shifts, collection during the rainy season, and that two of the four snakes were the two smallest females collected. Repeated measurements of body size were not provided in the study by Amazonas et al [ 57 ], but three of the four animals showing the large compositional shifts were indeed three of the four animals with the smallest body sizes at collection. Therefore, extrapolating our results in Crotalus to Bothrops leads us to hypothesize that these animals may have simply had the most opportunity for greater compositional change in venom, whereas the larger animals were already close to their terminal adult venom phenotype at first collection.…”

Armed stem to stinger: a review of the ecological roles of scorpion weapons

“…Venom is considered a fast-changing phenotype [ 248 ]. Snake venom, for example, has been seen to change in composition depending on factors like alterations in the animal’s physiological state and diet [ 249 , 250 ].…”