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Four talks at SICB

07 January 2020

Three different talks for Society for Integrative and Comparative Biology (SICB) 2020

Austin, Texas USA: JAN 03-07, 2020

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

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

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.


Invasive toads shift behavioral traits to find water

43-7  Sunday, Jan. 5 09:15 – 09:30  Invasive toads shift behavioral traits to find water MADELAIRE, CB*; BARSOTTI, AMG; WAGENER, C; SUGANO, Y; BAXTER-GILBERT, J; GOMES, FR; MEASEY, J; Northern Arizona University; University of São Paulo; Stellenbosch University ; University of São Paulo; Stellenbosch University; University of São Paulo; Stellenbosch University

The adaptive nature of invasive species is becoming recognized as facilitating their survival in conditions that differ from their native range. Behavioral changes in invasive populations have been poorly explored but offer a wide potential when combined with physiological traits. For anurans invading xeric habitats, the importance of finding water is relevant for reproduction, to maintain hydration to function optimally and not experience dehydration stress. The water-finding hypothesis (WFH) states that survival can be enhanced through the behavioral ability to find water. We tested the WFH in Sclerophrys gutturalis from their native population in Durban and an invasive population in Cape Town Additionally, we tested if artificially elevated levels of corticosterone (CORT), which is known to increase during dehydration stress, affect water-finding behaviors. In a labyrinth experiment, we observed the toads’ ability to find water in different hydration states (100%, 90% and 80%). We found that individuals from the invasive population took longer to engage in water-searching behavior and spent more time near to the water source after finding it. Also, toads from the invasive population were more active and at 90% dehydration they show higher number of attempts to find water. Moreover, elevation of CORT in fully hydrated toads increased the success of finding water. Our experiment suggests that rapid adaptative water-finding behavior might facilitates survival of an invasive anuran in a xeric habitat. Additionally, we suggest a link between elevated CORT levels and water finding success. Our results lend support to the importance of adaptive behavior in successful invasions and the modulation of water-finding behavior by CORT.

Rapid Local Adaptations in an Invasive Frog (Xenopus laevis) the Importance of Functional Trait Measurements to Predict Future Invasions

S9-6  Monday, Jan. 6 10:30 – 11:00  Rapid Local Adaptations in an Invasive Frog (Xenopus laevis): the Importance of Functional Trait Measurements to Predict Future Invasions. HERREL, A*; ARASPIN, L; PADILLA, P; COURANT, J; SERRA MARTINEZ, A; REBELO, R; IHLOW, F; BACKELJAU, T; MOKHATLA, M; GINAL, P; RöDDER, D; MEASEY, J; CNRS/MNHN, Paris, France; CNRS/MNHN, Paris, France; CNRS/MNHN, Paris, France; CNRS/MNHN, Paris, France; CNRS/MNHN, Paris, France; Uuniversity of Lisbon, Portugal; ZFMK, Bonn, Germany; RBINS, Brussels, Belgium; Stellenbosch University, South Africa; ZFMK, Bonn, Germany; ZFMK, Bonn, Germany; Stellenbosch University, South Africa

The control and eradication of invasive species is an ever-increasing problem for wildlife management and conservation practitioners. Understanding the potential future spread of invasive species is critical to inform management decisions. One often used tool to predict future species distributions is species distribution modelling (SDM) under alternative scenarios of climate change. Although extremely relevant and insightful, most of these models suffer from two drawbacks: 1) the lack of physiological data describing the dependence of organisms on changes in temperature and hydric state; 2) they ignore any potential for adaptive differentiation of invasive populations. To test what the effect could be of these two parameters we focused on invasive populations of the invasive amphibian, Xenopus laevis. We collected data on anatomy and physiology (temperature dependence of performance traits) for animals from the source population as well as invasive populations. These data were then used to inform SDMs that predict future spread under different climate change scenarios and to test for the potential adaptive divergence of invasive populations relative to the native population in morphology and physiology. Our results show that incorporating physiological data in SDMs does provide different predictions on future distribution ranges with a much higher invasion potential than previously estimated. Furthermore, our results show rapid (less than 30 years) changes in morphology and physiology in different populations suggesting local adaptation. These results stress the importance of using biologically informed data to inform conservation practices.

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