Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens)
Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius) was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found al...
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| Format: | Online |
| Language: | English |
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Public Library of Science
2015
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674270/ |
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pubmed-46742702015-12-23 Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens) Utne-Palm, A. C. Eduard, K. Jensen, K. H. Mayer, I. Jakobsen, P. J. Research Article Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius) was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found along the rocky shores of the North East Atlantic. The two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. According to the literature the males are on average larger than the females. Here we report for the first time a population showing a reversal of this trend, with males on average being smaller than females, a difference likely caused by a large proportion of small males. Early in the breeding season these small males have typical sneaker characters, with relatively large testes and small seminal duct glands compared to the larger dominant territorial males. The presence of these two alternative male reproductive tactics is confirmed by histological studies, which shows the presence of sperm in the sperm duct glands (SDG) of smaller males, but not in the SDG of intermediate and larger males. To our knowledge, males with typical sneaker characters have not been reported in earlier studied populations of two-spotted goby. Interestingly we found that testes investment declined significantly over the course of the breeding season, and that this reduction was significantly more pronounced in small compared to the large males. Further, a significant increase in seminal duct gland (SDG) mass was observed for the smaller males over the breeding season. We propose that this indicates a possible shift in mating tactic by smaller males from a parasitic to a nest-holding tactic over the course of the breeding season. Thus, the observed size dependent plasticity in investment in SDG over time suggests that the reproductive tactic of G. flavescens is conditional, and possibly influenced by mate availability and male—male competition. Public Library of Science 2015-12-07 /pmc/articles/PMC4674270/ /pubmed/26642324 http://dx.doi.org/10.1371/journal.pone.0143487 Text en © 2015 Utne-Palm et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
| repository_type |
Open Access Journal |
| institution_category |
Foreign Institution |
| institution |
US National Center for Biotechnology Information |
| building |
NCBI PubMed |
| collection |
Online Access |
| language |
English |
| format |
Online |
| author |
Utne-Palm, A. C. Eduard, K. Jensen, K. H. Mayer, I. Jakobsen, P. J. |
| spellingShingle |
Utne-Palm, A. C. Eduard, K. Jensen, K. H. Mayer, I. Jakobsen, P. J. Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens) |
| author_facet |
Utne-Palm, A. C. Eduard, K. Jensen, K. H. Mayer, I. Jakobsen, P. J. |
| author_sort |
Utne-Palm, A. C. |
| title |
Size Dependent Male Reproductive Tactic in the Two-Spotted Goby
(Gobiusculus flavescens) |
| title_short |
Size Dependent Male Reproductive Tactic in the Two-Spotted Goby
(Gobiusculus flavescens) |
| title_full |
Size Dependent Male Reproductive Tactic in the Two-Spotted Goby
(Gobiusculus flavescens) |
| title_fullStr |
Size Dependent Male Reproductive Tactic in the Two-Spotted Goby
(Gobiusculus flavescens) |
| title_full_unstemmed |
Size Dependent Male Reproductive Tactic in the Two-Spotted Goby
(Gobiusculus flavescens) |
| title_sort |
size dependent male reproductive tactic in the two-spotted goby
(gobiusculus flavescens) |
| description |
Male investment in testes and sperm duct gland in the polygamous nest breeding
two-spotted goby Gobiusculus flavescens (Fabricius) was
investigated in relation to time in reproductive season and individual physical
parameters. This small teleost fish is most likely the most abundant species
found along the rocky shores of the North East Atlantic. The two-spotted goby
has a single reproductive season, during which nest-caring males can raise
several clutches of offspring. According to the literature the males are on
average larger than the females. Here we report for the first time a population
showing a reversal of this trend, with males on average being smaller than
females, a difference likely caused by a large proportion of small males. Early
in the breeding season these small males have typical sneaker characters, with
relatively large testes and small seminal duct glands compared to the larger
dominant territorial males. The presence of these two alternative male
reproductive tactics is confirmed by histological studies, which shows the
presence of sperm in the sperm duct glands (SDG) of smaller males, but not in
the SDG of intermediate and larger males. To our knowledge, males with typical
sneaker characters have not been reported in earlier studied populations of
two-spotted goby. Interestingly we found that testes investment declined
significantly over the course of the breeding season, and that this reduction
was significantly more pronounced in small compared to the large males. Further,
a significant increase in seminal duct gland (SDG) mass was observed for the
smaller males over the breeding season. We propose that this indicates a
possible shift in mating tactic by smaller males from a parasitic to a
nest-holding tactic over the course of the breeding season. Thus, the observed
size dependent plasticity in investment in SDG over time suggests that the
reproductive tactic of G. flavescens is
conditional, and possibly influenced by mate availability and male—male
competition. |
| publisher |
Public Library of Science |
| publishDate |
2015 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674270/ |
| _version_ |
1613511355329937408 |