Biofluorescência do cavalo-marinho Hippocampus reidi Ginsburg, 1933: uma abordagem geográfica, metodológica e comportamental

Abstract

This thesis addresses biofluorescence in different contexts, using the species Hippocampus reidi as a model. The research was divided into three main chapters. The first chapter aims to evaluate, through a bibliographic review, the relationship between the distribution of bony fish species and their biofluorescent hues, with an emphasis on the order Syngnathiformes. The results indicated the distribution of biofluorescent patterns, particularly the predominance of these patterns in the Pacific Ocean and along the latitudinal gradient, with a concentration of biofluorescent species in the tropical zone. In the second chapter, we evaluated three techniques as tools for biofluorescence image analysis, aiming to propose a method for standardizing biofluorescence image analyses for seahorses and other animal groups. In the results, we presented the advantages and disadvantages of each software tested, considering the analysis objectives, the study subject, and the environment in which the images were captured. Additionally, we proposed a new script in Python for biofluorescence analysis. In the third chapter, we utilized the methodod suggested in the previous chapter to experimentally investigate whether the biofluorescence exhibited by the seahorse H. reidi serves as a response to two contexts with different levels of threat: the introduction of a novel object related to varying personalities and predation. Our results did not find a relationship between the biofluorescence patterns and the different personalities of seahorses, nor in relation to behavior towards the novel object. However, our findings indicate that individuals of the seahorse species H. reidi utilize biofluorescence as a response to stress during predation, with the red hue covering a larger area of the animal's body. The data obtained from this thesis allowed us to compile existing literature on biofluorescence, identifying gaps and suggesting that the evolution of biofluorescence may be directly linked to species evolution. We identified the need for standardization of analytical methods and proposed methods for future studies. Furthermore, experimental data revealed that biofluorescence may function as a response to stress levels in seahorses, and our findings can serve as a reference material for new experimental studies, not only with seahorses but also with other taxonomic groups.