1998
Kupferberg, Sarah J.
Predator mediated patch use by tadpoles (Hyla regilla): Risk balancing or consequence of motionlessness? Journal Article
In: Journal of Herpetology, vol. 32, no. 1, pp. 84-92, 1998, ISBN: 0022-1511.
Abstract | Links | BibTeX | Tags: avoidance, behavior, differential predation, garter snakes, habitat use, larval anurans, locomotion, melanogaster, populations, stream-dwelling isopod, thamnophis
@article{Kupferberg1998,
title = {Predator mediated patch use by tadpoles (Hyla regilla): Risk balancing or consequence of motionlessness?},
author = {Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_Herpetology1998.pdf},
isbn = {0022-1511},
year = {1998},
date = {1998-03-00},
journal = {Journal of Herpetology},
volume = {32},
number = {1},
pages = {84-92},
abstract = {To quantify the impact of garter snakes (Thamnophis hydrophilus, formerly T. couchii) on tadpole prey (Hyla regilla), I experimentally examined whether: (1) garter snakes have greater impact on tadpole numbers or on behavior; (2) tadpole patch choice follows the rule of minimizing the ratio of mortality risk, μ, to foraging gain, g; and (3) predator-induced resource avoidance influences algal production. In replicated enclosed pools constructed on gravel bars of a northern California river, garter snakes did not significantly reduce the number of tadpoles but did alter patch choice. Tadpoles spent less time in high food quality algae mats (Cladophora glomerata with epiphytic diatoms) and more time in low food quality patches (Zygnematales algae mats and sediments) when garter snakes were present than when they were absent. In mortality risk experiments, however, there were no significant differences in the numbers of tadpoles consumed among patch types, and garter snakes were not size selective. Therefore, patch choice did not follow the rule of minimizing μ/g. The change in patch choice was likely a consequence of the sublethal effect of garter snakes in which tadpole activity is decreased. For negatively buoyant tadpoles, decreased activity results in sinking away from floating algal resources. This apparent resource avoidance by tadpoles did not affect algal mass over the relatively short duration of the experiments.},
keywords = {avoidance, behavior, differential predation, garter snakes, habitat use, larval anurans, locomotion, melanogaster, populations, stream-dwelling isopod, thamnophis},
pubstate = {published},
tppubtype = {article}
}
To quantify the impact of garter snakes (Thamnophis hydrophilus, formerly T. couchii) on tadpole prey (Hyla regilla), I experimentally examined whether: (1) garter snakes have greater impact on tadpole numbers or on behavior; (2) tadpole patch choice follows the rule of minimizing the ratio of mortality risk, μ, to foraging gain, g; and (3) predator-induced resource avoidance influences algal production. In replicated enclosed pools constructed on gravel bars of a northern California river, garter snakes did not significantly reduce the number of tadpoles but did alter patch choice. Tadpoles spent less time in high food quality algae mats (Cladophora glomerata with epiphytic diatoms) and more time in low food quality patches (Zygnematales algae mats and sediments) when garter snakes were present than when they were absent. In mortality risk experiments, however, there were no significant differences in the numbers of tadpoles consumed among patch types, and garter snakes were not size selective. Therefore, patch choice did not follow the rule of minimizing μ/g. The change in patch choice was likely a consequence of the sublethal effect of garter snakes in which tadpole activity is decreased. For negatively buoyant tadpoles, decreased activity results in sinking away from floating algal resources. This apparent resource avoidance by tadpoles did not affect algal mass over the relatively short duration of the experiments.