Molecular, behavioural and morphological comparisons of sperm adaptations in a fish with alternative reproductive tacticsShow others and affiliations
2023 (English)In: Evolutionary Applications, E-ISSN 1752-4571, Vol. 16, no 2, p. 338-353Article in journal (Refereed) Published
Abstract [en]
In species with alternative reproductive tactics, there is much empirical support that parasitically spawning males have larger testes and greater sperm numbers as an evolved response to a higher degree of sperm competition, but support for higher sperm performance (motility, longevity and speed) by such males is inconsistent. We used the sand goby (Pomatoschistus minutus) to test whether sperm performance differed between breeding-coloured males (small testes, large mucus-filled sperm-duct glands; build nests lined with sperm-containing mucus, provide care) and parasitic sneaker-morph males (no breeding colouration, large testes, rudimentary sperm-duct glands; no nest, no care). We compared motility (per cent motile sperm), velocity, longevity of sperm, gene expression of testes and sperm morphometrics between the two morphs. We also tested if sperm-duct gland contents affected sperm performance. We found a clear difference in gene expression of testes between the male morphs with 109 transcripts differentially expressed between the morphs. Notably, several mucin genes were upregulated in breeding-coloured males and two ATP-related genes were upregulated in sneaker-morph males. There was a partial evidence of higher sperm velocity in sneaker-morph males, but no difference in sperm motility. Presence of sperm-duct gland contents significantly increased sperm velocity, and nonsignificantly tended to increase sperm motility, but equally so for the two morphs. The sand goby has remarkably long-lived sperm, with only small or no decline in motility and velocity over time (5 min vs. 22 h), but again, this was equally true for both morphs. Sperm length (head, flagella, total and flagella-to-head ratio) did not differ between morphs and did not correlate with sperm velocity for either morph. Thus, other than a clear difference in testes gene expression, we found only modest differences between the two male morphs, confirming previous findings that increased sperm performance as an adaptation to sperm competition is not a primary target of evolution.
Place, publisher, year, edition, pages
John Wiley & Sons, 2023. Vol. 16, no 2, p. 338-353
Keywords [en]
accessory glands, gene expression, Gobiidae, mucins, sexual selection, sperm competition, sperm performance, spermatozoa
National Category
Evolutionary Biology
Research subject
Teacher Education and Education Work
Identifiers
URN: urn:nbn:se:hb:diva-28358DOI: 10.1111/eva.13438ISI: 000819875000001Scopus ID: 2-s2.0-85133159862OAI: oai:DiVA.org:hb-28358DiVA, id: diva2:1686935
Funder
Academy of Finland, 136464Swedish Research Council Formas, 217-2008-1719Swedish Research Council, 2016-03343Swedish Research Council, 621-2011-4004
Note
This study was performed within the Centre for Marine Evolutionary Biology, CeMEB, at the University of Gothenburg (https://www. gu.se/en/cemeb -marin e-evolu tiona ry-biology), supported by a Linnaeus-grant from the Swedish Research Councils VR and Formas (grant nr 217-2008- 1719). The resources created by the Infrastructure for MArine Genetic model Organisms, IMAGO (https://www.gu.se/ en/cemeb-marine-evolu tionary-biology/imago) were especially important. Additional funding was given by the Swedish Research Council VR (CK, 2016-03343 and 621-2011- 4004), the Academy of Finland (EL, grant nr 136464) and the ASSEMBLE programme (KL and EL).
2022-08-122022-08-122024-02-01Bibliographically approved