Structural cutaneous adaptations for defense in toad (Rhinella icterica) parotoid macroglands

Author(s)

Regis-Alves, Eduardo ; Jared, Simone G. S. ; Mauricio, Beatriz ; Mailho-Fontana, Pedro L. ; Antoniazzi, Marta M. ; Fleury-Curado, Maria Cecilia ; Brodie, Jr., Edmund D. ; Jared, Carlos

• Document type: Journal article
• Source: Toxicon; v. 137, p. 128-134, OCT 2017.
• Web of Science Citations: 6

Abstract

Toads have a pair of glandular accumulations on each side of the dorsal region of the head known as parotoid macroglands. These macroglands consist of secretory units (granular glands), each one capped with an epithelial plug. When threatened, toads point one of the parotoids toward the aggressor, and if the aggressor squeezes the parotoid with its teeth, jets of poison will come out of the secretory units and hit the predator's oral mucosa, thereby causing poisoning. Our study focused on the mechanism of parotoid function by comparing parotoids from toads naturally attacked by dogs with those manually compressed. We verified that the process of glandular emptying in response to dog bites is very similar to that following manual compression. We observed that the structure of the plug plays an essential role in the release of the poison jets. Our results suggest that the parotoids may act as ``bulletproof vests,{''} reducing the impact of the force exerted by predator attacks, and thus may function as a passive anti predator mechanism. (C) 2017 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 14/15334-4 - The skin and the defense of toads (Bufonidae) against predators and desiccation
• Grantee: Pedro Luiz Mailho Fontana
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/00999-3 - Comparative morphology of integument and cutaneous glands of species of toads and salamanders from South America and North America
• Grantee: Pedro Luiz Mailho Fontana
• Support type: Scholarships abroad - Research Internship - Doctorate