Banca de DEFESA: THIAGO DE FREITAS CORDEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : THIAGO DE FREITAS CORDEIRO
DATE: 08/08/2025
TIME: 09:00
LOCAL: Videoconferência
TITLE:

ADAPTIVE ROLE OF COLOR POLYMORPHISM IN FEMALE Cardisoma guanhumi Latreille 1828 (BRACHYURA: GECARCINIDAE)

KEY WORDS:

Decapoda; Color patterns; Camouflage; Anti-harassment; Reproductive signaling.

PAGES: 83
BIG AREA: Ciências Humanas
AREA: Psicologia
SUMMARY:

Coloration plays diverse adaptive roles in animal visual communication, including camouflage, sexual attraction, and harassment avoidance signaling. In crustaceans, research on coloration has primarily focused on males, leaving gaps in our understanding of the functional roles of coloration in females. Female land crabs Cardisoma guanhumi exhibit four distinct color morphs, one of which (color pattern IV) is characteristic of the reproductive period. In this study, we investigated whether this color pattern functions as a camouflage strategy, a nuptial signal, or a harassment avoidance signal. To this end, we combined physiological, morphological, and behavioral analyses. We measured reflectance from four body regions in females exhibiting different color patterns and performed visual modeling based on the visual systems of conspecifics and potential predators. In parallel, we conducted male choice behavioral assays to assess visual preference for different female color morphs. Our results indicate that, from the perspective of predator vision, pattern IV exhibits lower luminance on the dorsal carapace, suggesting enhanced camouflage in this vital region. In contrast, under conspecific vision, this pattern is more conspicuous in signaling regions. However, behavioral assays did not reveal any male preference for specific color patterns. This may indicate an absence of visual sexual selection or reliance on alternative cues, such as chemical or tactile signals. Additionally, females displaying pattern IV showed a higher frequency of ovaries in resting or recovery stages and a greater proportion of turgid seminal receptacles, suggesting that this coloration may signal low reproductive receptivity, potentially functioning as a harassment avoidance mechanism. We conclude that pattern IV does not appear to function as a nuptial signal but presents partial evidence for adaptive roles related to both camouflage and harassment avoidance. This study highlights the importance of integrating multidisciplinary approaches to investigate visual ecology and suggests the need for further validation in natural environments.

COMMITTEE MEMBERS:
Presidente - 1476621 - DANIEL MARQUES DE ALMEIDA PESSOA
Externo ao Programa - 1545394 - FULVIO AURELIO DE MORAIS FREIRE - UFRNExterna à Instituição - RENATA AKEMI SHINOZAKI MENDES - UFRPE