Challenges of the invasion front water balance, stress and immunity in the Guttural toad


Meeting Abstract

P3-44  Monday, Jan. 6  Challenges of the invasion front: water balance, stress and immunity in the Guttural toad BARSOTTI, AMG; MADELAIRE, CB*; WAGENER, C; TITON JR , B; GOMES, FR; MEASEY, J; University of São Paulo; Northern Arizona University; Stellenbosch University; University of São Paulo; University of São Paulo; Stellenbosch University cmadelaire@yahoo.com.br

Species introduced by human activities may comprise many ecosystems, however, some species may become invasive and rapidly expand their population size, indicating that these species have an adaptive capacity to new environments. In South Africa, the bufonid species Sclerophrys gutturalis was introduced in a periurban area with colder and drier climatic characteristics from those in which native populations occur. Our goal was to understand the adjustments made by this species in its new environment in terms of stress physiology and immunity. We assessed corticosterone (CORT), neutrophil:lymphocyte ratio (N:L), bacterial killing ability (BKA) and hematocrit (Htc) basal and after standardize stressors (dehydration and movement restriction), as well as body condition index (BCI) and field hydration level, in males from the native (Durban) and invasive population (Cape Town). Individuals from the native population presented higher basal BCI and BKA and lower N:L ratio. After the experiment, the native population presented higher BKA than the invasive population. Individuals from both populations showed increased CORT after dehydration. The results show that the native population presents higher immunocompetence and BCI, indicating a better conditions when compared to the invasive population. Dehydration represented stress for both populations, increasing CORT levels. Thus, our results corroborate that the BCI and dehydration level can generate major impacts on the physiological processes for this species.

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