Challenges of a novel range: Water balance, stress, and immunity in an invasive toad

Author(s)

Giorgi Barsotti, Adriana Maria ^{[1, 2]} ; Madelaire, Carla Bonetti ^{[1, 2]} ; Wagener, Carla ^[2] ; Titon Jr, Braz ; Measey, John ^[2] ; Gomes, Fernando Ribeiro ^[3]

Affiliation

^[1] Univ Sao Paulo, Dept Fisiol, Inst Biociencias, Rua Matao, Trav 14 321, Cidade Univ, BR-05508090 Sao Paulo, SP - Brazil

^[2] Stellenbosch Univ, Dept Bot & Zool, Ctr Invas Biol, Stellenbosch - South Africa

^[3] Titon Jr, Jr., Braz, Univ Sao Paulo, Dept Fisiol, Inst Biociencias, Rua Matao, Trav 14 321, Cidade Univ, BR-05508090 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 253, MAR 2021.
• Web of Science Citations: 0

Abstract

Species introduced by human activities can alter the normal functioning of ecosystems promoting negative impacts on native biodiversity, as they can rapidly expand their population size, demonstrating phenotypic plasticity and possible adaptive capacity to novel environments. Twenty years ago, the guttural toad, Sclerophrys gutturalis, was introduced to a peri-urban area of Cape Town, with cooler and drier climatic characteristics than its native source population, Durban, South Africa. Our goal was to understand the phenotypic changes, in terms of physiology and immunity, of populations in native and novel environments. We evaluated body index (BI), field hydration level, plasma corticosterone levels (CORT), proportion of neutrophils: lymphocytes (N: L), plasma bacterial killing ability (BKA), and hematocrit (HTC) in the field, and after standardized stressors (dehydration and movement restriction) in males from the native and invasive populations. Toads from the invasive population presented lower BI and tended to show a lower field hydration state, which is consistent with living in the drier environmental conditions of Cape Town. Additionally, invasive toads also showed higher BKA and N:L ratio under field conditions. After exposure to stressors, invasive animals presented higher BKA than the natives. Individuals from both populations showed increased CORT after dehydration, an intense stressor for these animals. The highest BKA and N:L ratio in the field and after submission to stressors in the laboratory shows that the invasive population has a phenotype that might increase their fitness, leading to adaptive responses in the novel environment and, thus, favoring successful dispersion and population increase. (AU)

• FAPESP's process: 18/00406-0 - SEASONAL RELATIONSHIP BETWEEN IMMUNOCOMPETENCE, STERIODS AND STRESS RESPONSE IN ECTOTERMS
• Grantee: Carla Bonetti Madelaire
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/16320-7 - Impacts of climate/environmental change on the fauna: an integrative approach
• Grantee: Carlos Arturo Navas Iannini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 18/23661-6 - Challenges of invasion front: Water balance, stress and immunity in Sclerophrys gutturalis
• Grantee: Adriana Maria Giorgi Barsotti
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate