The Relationship Between the Presence of Satellite Males and Nest‐Holders' Mating Success in the Azorean Rock‐Pool BlennyParablennius sanguinolentus parvicornis

Abstract

In the Azorean rock‐pool blenny, sexually active males may adopt alternative reproductive tactics. In the present paper the relationship between the presence of satellite males and the reproductive success of nest‐holders was investigated by comparing nests with and without an associated satellite male. Males with an associated satellite male suffered more conspecific intrusions but they did not display a higher frequency of attacks towards conspecifics. Nest‐holder males were more aggressive towards other conspecifics than towards satellites and the tolerance of nest‐holders towards satellites was inversely correlated with the time spent by the satellites in the breeding territory, which suggests control by the nest‐holder male of the satellite investment in shared territorial defence. Nest‐holders with an associated satellite male had higher condition factors and received more female visits and more spawnings. These results bear two possible interpretations. (1) Nest‐holders benefit from the presence of a satellite male by increased attractiveness of their nests to females; satellite males are mutualists helping to defend the nest‐owner's territory and to attract females, which is why they are tolerated. (2) Satellite males associate preferentially with more successful nest‐holder males which have higher condition factors, and by doing so have more opportunities to achieve parasitic fertilizations. Only experiments will allow these two hypotheses to be distinguished.