Carapace color change in Uca pugilator as a response to temperature

Nyssa Silbiger, Pablo Munguia

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


Brachyurid species have various coloration patterns that fluctuate among individuals due to behavioral interactions or a changing environment. In the fiddler crab Uca pugilator, the historical notion is that color change is regulated by circadian rhythms. In this study, color patterns of U. pugilator were affected by changes in temperature; crab carapaces become light in warm temperatures and dark in colder temperatures. The response to temperature occurred within 15 min (often within 5 min of exposure to the treatment), suggesting that temperature may play a key role in color change, and it is activated not through a hormonal pathway, but rather a direct response of the chromatophores. Color change occurred differently between day and night for each sex, which implies that endogenous rhythms are not the sole mechanism for color change in U. pugilator. Both sexes became darker in the cold treatment, however there were differences between the sexes with high temperatures. Females did not show significant coloration changes, while males became significantly lighter and more speckled. Results from this study suggest sex-specific constraints in response to temperature that could be associated to morphological body mass to surface area ratios, as males have large cheliped, which may be involved in thermoregulation. Constraints could also be associated to different diel activities that each sex performs or visual cues associated with mating behaviors.

Original languageEnglish
Pages (from-to)41-46
Number of pages6
JournalJournal of Experimental Marine Biology and Ecology
Issue number1
Publication statusPublished - 8 Feb 2008
Externally publishedYes


  • Color change
  • Diel activity
  • Fiddler crabs
  • Physiological constraint
  • Temperature


Dive into the research topics of 'Carapace color change in Uca pugilator as a response to temperature'. Together they form a unique fingerprint.

Cite this