Investment in testes, sperm-duct glands and lipid reserves differs between male morphs but not between early and late breeding season in Pomatoschistus minutus

Authors / Editors

Manson, Wilbur

Research Areas

No matching items found.

Publication Details

Output type: Journal article

Author list: Kvarnemo C, Svensson O, Manson W

Publisher: Wiley

Publication year: 2010

Journal: Journal of Fish Biology (0022-1112)

Volume number: 76

Issue number: 7

Start page: 1609

End page: 1625

Number of pages: 17

ISSN: 0022-1112

eISSN: 1095-8649

Languages: English-Great Britain (EN-GB)

Unpaywall Data

Open access status: closed

Abstract

This study of the sand goby Pomatoschistus minutus, a nest-holding fish with paternal care, focused on gonadal investment among males of different sizes collected early and late in the breeding season. All males caught at the nest had breeding colour, whereas trawl-caught fish consisted of males both with and without colour. The absence or presence of breeding colour was a good predictor of testes investment. Compared to males with breeding colour, males without colour were smaller in body size but had extraordinarily large testes. In absolute terms, testes mass of males without breeding colour was on average 3.4 times greater than those of males with breeding colour. Since small colourless males are known to reproduce as sneaker males, this heavy investment in testes probably reflects that they are forced to spawn under sperm competition. Contrary to testes size, sperm-duct glands were largest among males with breeding colour. These glands produce mucins used for making sperm-containing mucous trails that males place in the nest before and during spawning. Since both sneakers and nest-holders potentially could benefit from having large glands, this result is intriguing. Yet, high mucus production may be more important for nest-holders, because it also protects developing embryos from infections. There was no significant effect of season on body size, testes or sperm-duct glands size, but colourless males tended to be less common late in the season. Possibly this may indicate that individual small colourless males develop into their more colourful counterparts within the breeding season. (C) 2010 The Authors Journal compilation (C) 2010 The Fisheries Society of the British Isles

Keywords

accessory glands, Gobiidae, gonado-somatic index, parasitic spawning, seminal vesicles

Documents