Social-trap or mimicry? An empirical evaluation of the Hypoplectrus unicolor–Chaetodon capistratus association in Bocas del Toro, Panama
Article
Puebla, O, Picq, S, Lesser, JS et al. (2018). Social-trap or mimicry? An empirical evaluation of the Hypoplectrus unicolor–Chaetodon capistratus association in Bocas del Toro, Panama
. CORAL REEFS, 37(4), 1127-1137. 10.1007/s00338-018-01741-0
Puebla, O, Picq, S, Lesser, JS et al. (2018). Social-trap or mimicry? An empirical evaluation of the Hypoplectrus unicolor–Chaetodon capistratus association in Bocas del Toro, Panama
. CORAL REEFS, 37(4), 1127-1137. 10.1007/s00338-018-01741-0
Associations between resembling species have been noted long ago by naturalists and have been traditionally interpreted in terms of mimicry, whereby a mimetic species is naturally selected to resemble a model (Batesian and aggressive mimicry) or a co-mimic (Müllerian mimicry). Recently, it has been proposed that resemblances among reef fishes might be coincidental and that associations between them may result from social-traps, i.e., out-of-normal-context responses toward similar-looking individuals. The social-trap hypothesis is stimulating and calls for an in-depth reassessment of putative cases of mimicry in reef fishes. Nevertheless, an explicit field-based evaluation of these two hypotheses has yet to be conducted. Here, we test five specific predictions derived from the two hypotheses in the association between the butter hamlet (Hypoplectrus unicolor, Serranidae) and the foureye butterflyfish (Chaetodon capistratus, Chaetodontidae), which was one of the associations considered to develop the social-trap hypothesis. We present the results from 117 h of behavioral observation, 21 transect surveys covering 8400 m2 of reef, stomach content analysis of 107 fish, morphometric analysis of 165 fish and size measurements of 386 fish from Bocas del Toro, Panama. These data indicate that (i) C. capistratus is 14 times more abundant than H. unicolor at our study site, (ii) the association with C. capistratus represents only 4% of H. unicolor’s time, (iii) the association targets Coryphopterus gobies in particular and deceives this prey, (iv) H. unicolor departs from sympatric hamlets not only in terms of color pattern but also behavior, diet, size and body shape, and (v) H. unicolor spends only 0.66% of its time with conspecifics out of mating contexts. We conclude that the association between H. unicolor and C. capistratus in Bocas del Toro is a true mimetic relationship, but do not rule out the possibility that a social-trap might have contributed to its evolution.
