Different ontogenetic trajectories of body colour, pattern and crypsis in two sympatric intertidal crab species

Author(s)

Duarte, Rafael C. ^{[1, 2]} ; Dias, Gustavo M. ^[1] ; Flores, V, Augusto A. ; Stevens, Martin ^[3]

Affiliation

^[1] Univ Fed ABC UFABC, Ctr Ciencias Nat & Humanas, Sao Bernardo Do Campo - Brazil

^[2] V, Univ Sao Paulo, Ctr Biol Marinha, Sao Sebastiao - Brazil

^[3] Univ Exeter, Ctr Ecol & Conservat, Penryn Campus, Exeter, Devon - England

• Document type: Journal article
• Source: Biological Journal of the Linnean Society; v. 132, n. 1, p. 17-31, JAN 2021.
• Web of Science Citations: 0

Abstract

Animals frequently exhibit great variation in appearance, especially in heterogeneous habitats where individuals can be concealed differentially against backgrounds. Although background matching is a common anti-predator strategy, gaps exist in our understanding of within- and among-species variation. Specifically, the drivers of changes in appearance associated with habitat use and occurring through ontogeny are poorly understood. Using image analysis, we tested how individual appearance and camouflage in two intertidal crab species, the mud crab Panopeus americanus and the mottled crab Pachygrapsus transversus, relate to ontogeny and habitat use. We predicted that both species would change appearance with ontogeny, but that resident mud crabs would exhibit higher background similarity than generalist mottled crabs. Both species showed ontogenetic changes; the mud crabs became darker, whereas mottled crabs became more green. Small mud crabs were highly variable in colour and pattern, probably stemming from the use of camouflage in heterogeneous habitats during the most vulnerable life stage. Being habitat specialists, mud crabs were better concealed against all backgrounds than mottled crabs. Mottled crabs are motile and generalist, occupying macroalgae-covered rocks when adults, which explains why they are greener and why matches to specific habitats are less valuable. Differential habitat use in crabs can be associated with different coloration and camouflage strategies to avoid predation. (AU)

• FAPESP's process: 19/01934-3 - Colour change and camouflage in coastal benthic crustaceans: occurrence, selective pressures and ecological function
• Grantee: Rafael Campos Duarte
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 15/22258-5 - Strengthening of the scientific collaboration between the Centre for Ecology and Conservation, University of Exeter, UK, and the Centre for Marine Biology, University of São Paulo
• Grantee: Augusto Alberto Valero Flores
• Support type: Research Grants - Visiting Researcher Grant - International
• FAPESP's process: 19/15628-1 - Effect of light pollution, habitat complexity and proximity to coastal infrastructures on the dynamics and diversity of marine benthic communities
• Grantee: Gustavo Muniz Dias
• Support type: Regular Research Grants