Differences in morphology and parotoid gland secretion (composition and release) of introduced cane toads (Rhinella marina) from established populations in Florida, USA


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


42-10  Sat Jan 2  Differences in morphology and parotoid gland secretion (composition and release) of introduced cane toads (Rhinella marina) from established populations in Florida, USA Gardner, S*; Kepas, M; Simons, C; Horne, LM; Savitzky, A; Mendonça, M; Auburn University; Utah State University; Utah State University; University of Texas at El Paso; Utah State University; Auburn University stg0015@auburn.edu

Cane toads are invasive in several locations throughout the world. We collected cane toads from populations spanning the invasion range in FL to assess morphological changes to parotoid glands and secretion likelihood, to determine how establishment northward has affected these parameters. We also collected secretion samples from individuals occurring in representative southern and northern populations and compared toxicity and the effects of increasing epinephrine doses on the likelihood of poison secretion in lab-acclimated toads. Residual body indices increased with increasing latitude, and parotoid gland size increased with increasing toad size. We found no effect of latitude on gland size or toad size, but secretion likelihood increased with increasing latitude. Marinobufagenin concentrations in cane toad secretions were not different between populations. Lab-acclimated cane toads were more likely to secrete poison with increasing epinephrine dose, although there was no difference between south and north population individuals. Quantities of epinephrine released upon disturbance in the field were likely responsible for secretion increasing with latitude.

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