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Function and variability of male sex traits in a blenniid fish, Parablennius tentacularis
Author(s) -
Giacomello E.
Publication year - 2003
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2003.216bd.x
Subject(s) - biology , sexual dimorphism , zoology , sexual selection , seasonal breeder , intraspecific competition , context (archaeology) , paternal care , hermaphrodite , ecology , mating , pregnancy , paleontology , genetics , offspring
The theory of sexual selection aims to explain the occurrence of secondary sex traits and sexual dimorphism. In this context, fish represent an excellent model, as they show a wide array of reproductive modalities and a high variability of their sex traits, both at intra‐ and inter‐specific level. This study is focused on the function and development of male sex traits in Parablennius tentacularis , a species releasing demersal eggs and with male parental care. This blenny is sexually dimorphic: males exhibit both external and internal dimorphic characters. Indeed, males show large orbital tentacles and bulb glands on the spiny anal finrays, called anal glands, and their reproductive apparatus is provided with accessories structures as the testicular glands and the blind pouches. Field data were collected in a rocky area in shallow waters of the Northern Adriatic sea. During the breeding season, males of P. tentacularis are found inside empty shells, which they adopt as nests, and where they care for eggs. Differently sized nesting males were collected; their external sex traits were measured and gonado‐somatic index calculated. Size and type of nest were recorded and the total egg number was estimated to obtain an evaluation of male mating success. Intraspecific variability of male sexual traits is discussed in relation to individual mating success and the possible presence of sperm competition.