TY - JOUR
T1 - Invader danger
T2 - Lizards faced with novel predators exhibit an altered behavioral response to stress
AU - Trompeter, Whitney P.
AU - Langkilde, Tracy
N1 - Funding Information:
We thank N. Freidenfelds and J. Marden for comments on a previous version of this manuscript, N. Freidenfelds for statistical and lab assistance, and R.L. Rosier for providing data on the effect of time of day on CORT levels. This research was funded in part by a Pennsylvania State University undergraduate research grant (to W. P. Trompeter) and the National Science Foundation ( DEB-0949483 to T. Langkilde).
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/7
Y1 - 2011/7
N2 - Animals respond to stressors by producing glucocorticoid stress hormones, such as corticosterone (CORT). CORT acts too slowly to trigger immediate behavioral responses to a threat, but can change longer-term behavior, facilitating an individual's survival to subsequent threats. To be adaptive, the nature of an animal's behavior following elevated CORT levels should be matched to the predominant threats that they face. Seeking refuge following a stressful encounter could be beneficial if the predominant predator is a visual hunter, but may prove detrimental when the predominant predator is able to enter these refuge sites. As a result, an individual's behavior when their CORT levels are high may differ among populations of a single species. Invasive species impose novel pressures on native populations, which may select for a shift in their behavior when CORT levels are high. We tested whether the presence of predatory invasive fire ants (Solenopsis invicta) at a site affects the behavioral response of native eastern fence lizards (Sceloporus undulatus) to elevated CORT levels. Lizards from an uninvaded site were more likely to hide when their CORT levels were experimentally elevated; a response that likely provides a survival advantage for lizards faced with native predatory threats (e.g. birds and snakes). Lizards from a fire ant invaded site showed the opposite response; spending more time moving and up on the basking log when their CORT levels were elevated. Use of the basking log likely reflects a refuge-seeking behavior, rather than thermoregulatory activity, as selected body temperatures were not affected by CORT. Fleeing off the ground may prove more effective than hiding for lizards that regularly encounter small, terrestrially-foraging fire ant predators. This study suggests that invasive species may alter the relationship between the physiological and behavioral stress response of native species.
AB - Animals respond to stressors by producing glucocorticoid stress hormones, such as corticosterone (CORT). CORT acts too slowly to trigger immediate behavioral responses to a threat, but can change longer-term behavior, facilitating an individual's survival to subsequent threats. To be adaptive, the nature of an animal's behavior following elevated CORT levels should be matched to the predominant threats that they face. Seeking refuge following a stressful encounter could be beneficial if the predominant predator is a visual hunter, but may prove detrimental when the predominant predator is able to enter these refuge sites. As a result, an individual's behavior when their CORT levels are high may differ among populations of a single species. Invasive species impose novel pressures on native populations, which may select for a shift in their behavior when CORT levels are high. We tested whether the presence of predatory invasive fire ants (Solenopsis invicta) at a site affects the behavioral response of native eastern fence lizards (Sceloporus undulatus) to elevated CORT levels. Lizards from an uninvaded site were more likely to hide when their CORT levels were experimentally elevated; a response that likely provides a survival advantage for lizards faced with native predatory threats (e.g. birds and snakes). Lizards from a fire ant invaded site showed the opposite response; spending more time moving and up on the basking log when their CORT levels were elevated. Use of the basking log likely reflects a refuge-seeking behavior, rather than thermoregulatory activity, as selected body temperatures were not affected by CORT. Fleeing off the ground may prove more effective than hiding for lizards that regularly encounter small, terrestrially-foraging fire ant predators. This study suggests that invasive species may alter the relationship between the physiological and behavioral stress response of native species.
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U2 - 10.1016/j.yhbeh.2011.04.001
DO - 10.1016/j.yhbeh.2011.04.001
M3 - Article
C2 - 21549122
AN - SCOPUS:79959560115
SN - 0018-506X
VL - 60
SP - 152
EP - 158
JO - Hormones and Behavior
JF - Hormones and Behavior
IS - 2
ER -