Date of Award
The traits of an opponent can influence how an individual uses aggressive displays to dissuade the opponent from physical conflict. Whereas one previous study found that conspecific aggression was less intense between differently-colored Siamese fighting fish (Betta splendens), we felt that more evidence was needed to corroborate or dispute their findings. We hypothesized that B. splendens act less aggressively towards similarly- colored fish than to differently-colored fish, based on the notion that males would avoid conflict with a phenotypically similar opponent due to the costs of displaying. To test for differences in aggression due to coloration, we paired 10 fish in view of one another, as well as in view of a mirror reflection, and measured duration of gill flaring and the number of tail beats. We found that the duration of gill flaring and the number of tail beats were significantly lower between differently-colored pairs of fish compared to the other groups. While contrary to our predictions, our data corroborate previous studies on color bias in aggressive displays. Our findings indicate that, as with other species, coloration in B. splendens may influence interactions due to underlying phenotypic influences.
Bones, Julian and Johnson, Thomas, "Aggressive Displays in Male Betta splendens Based on Color Patterns" (2017). Thinking Matters. 83.