Does corticosterone mediate predator-induced responses of larval Hylarana indica?
Prey-predator interactions have been studied extensively in terms of morphological and behavioural responses of prey to predation risk using diverse model systems. However, the underlying physiological changes associated with morphological, behavioural or life historical responses have been rarely investigated. Herein, we studied the effect of chronic predation risk on larval growth and metamorphosis of Hylarana indica and the underlying physiological changes in prey tadpoles. In the first experiment, tadpoles were exposed to a caged predator from Gosner stage 25-42 to record growth and metamorphosis. Further, whole body corticosterone (CORT) was measured to determine the physiological changes underlying morphological and life historical responses of these prey tadpoles. Surprisingly, tadpoles experiencing continuous predation risk grew and developed faster and metamorphosed at a larger size. Interestingly, these tadpoles had significantly lower CORT levels. In the second experiment, tadpoles were exposed to predation risk (PR) or PR+CORT from stage 25-42 to determine the role of CORT in mediating predator-induced responses of H. indica. Tadpoles facing continuous predation risk grew and developed faster and metamorphosed at a larger size reinforcing the results of the first experiment. However, when CORT was administered along with predation risk, tadpoles grew and developed slowly leading to delayed metamorphosis. Interestingly, growth and metamorphic traits of tadpoles exposed to PR+CORT were comparable to those of the control group indicating that exogenous CORT nullified the positive effect of predation risk. Apparently, CORT mediates predator-induced morphological responses of H. indica tadpoles by regulating their physiology.
Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.
A M
AM
Joshi
Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.
N V
NV
Wadekar
Department of Zoology, Savitribai Phule Pune University, Pune 411007, India. Electronic address: naraharipg@unipune.ac.in.
N P
NP
Gramapurohit
D000704:Analysis of Variance; D000818:Animals; D001001:Anura / Q000502:physiology*; D001835:Body Weight / Q000187:drug effects; D003345:Corticosterone / Q000378:metabolism / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D010641:Phenotype; D011235:Predatory Behavior / Q000187:drug effects*
D003345:Corticosterone
Amphibia; Anti-predator response; Corticosterone; Hylarana indica; Predation risk; Tadpoles