Visual recognition of allopatric predator by the Nile Tilapia (Oreochromis niloticus)

• Grant number: 14/10385-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2014
• End date: June 30, 2015
• Field of knowledge: Biological Sciences - Zoology - Animal Behavior
• Principal Investigator: Tânia Marcia Costa
• Grantee: Edison de Freitas Cossignani Ferreira dos Santos
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

The visual communication plays crucial roles in the survival of the majority of animals, and the early recognition of predators and prey is essential. Specifically for the nile tilapia (Oreochromis niloticus), the vision is of great importance. This species can visually recognize an allopatric predator innately. Based on this information, the hypothesis that such recognition occurs due to morphological similarities between sympatric and allopatric predators was created. With the objective to test this hypothesis, two experiments will be carried. Firstly, tridimensional simulacra and photography of the allopatric predator, spotted sorubim (Pseudoplatystoma corruscans), will be used to verify the better method to induce defensive responses by tilapia to a model. After that the model that induce the better response will be altered morphologically. The behavioral responses, or their absence, will be tested using the quantification of the movement and the ventilatory frequency. The animals will be acclimated to the laboratory environment aiming to reduce the influence of external effects. The tilapia is an important product of the national and global aquaculture. Using a model of a predator in farms can induce defensive responses, reducing the agonistics behaviors of this cichlid, contributing to raise the biomass in production. (AU)