What are the consequences of being left-clawed in a predominantly right-clawed fiddler crab?
Male fiddler crabs (genus Uca) have an enlarged major claw that is used during fights. In most species, 50% of males have a major claw on the left and 50% on the right. In Uca vocans vomeris, however, less than 1.4% of males are left-clawed. Fights between opponents with claws on the same or opposite side result in different physical alignment of claws, which affects fighting tactics. Left-clawed males mainly fight opposite-clawed opponents, so we predicted that they would be better fighters due to their relatively greater experience in fighting opposite-clawed opponents. We found, however, that (i) a left-clawed male retains a burrow for a significantly shorter period than a size-matched right-clawed male, (ii) when experimentally displaced from their burrow, there is no difference in the tactics used by left- and right-clawed males to obtain a new burrow; however, right-clawed males are significantly more likely to initiate fights with resident males, and (iii) right-clawed residents engage in significantly more fights than left-clawed residents. It appears that left-clawed males are actually less likely to fight, and when they do fight they are less likely to win, than right-clawed males. The low-level persistence of left-clawed males is therefore unlikely to involve a frequency-dependent advantage associated with fighting experience.
Backwell
P R Y
PR
School of Botany and Zoology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia. pat.backwell@anu.edu.au
Matsumasa
M
M
Double
M
M
Roberts
A
A
Murai
M
M
Keogh
J S
JS
Jennions
M D
MD
D000374:Aggression; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003386:Brachyura / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D008297:Male; D012098:Reproduction; D012930:Social Dominance
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