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Content archived on 2024-05-29

Sperm competition in the grey short-tailed opossum (Monodelphis domestica) and the post-copulatory role of sperm storage

Objective

The grey short-tailed opossum (Monodelphis domestica) is a small American marsupial of the family Didelphidae. Didelphids are the only mammals known to have both specialized sperm storage crypts in the oviducts and paired sperm. Paired sperm have a distinct motility advantage over single sperm and are efficiently transported in the female reproductive tract. In captivity females will mate with more than one male during oestrus. Evidence of mixed paternity litters is yet to be established and the presence of paired sperm and sperm storage crypts may represent a novel adaptation in mammals to post-copulatory competition that warrants further investigation. The aim of this study is to investigate the mating system of M. domestica and the role of the storage cry pts in sperm competition and cryptic female choice.

Females will be naturally mated with two males in sequence to test for the effect of:
(i) male size,
(ii) mating order,
(iii) time of mating relative to ovulation, on paternity success of the offspring. In addition, females will be artificially inseminated with different ratios of mixed sperm from two males and paternity success determined.

Sperm will be deposited (i) vaginally and (ii) directly into the uteri, to determine if the lower tract plays a selective role in sperm migration. Finally, the time and pattern of sperm colonization and the heterospermic composition of the storage crypts will be examined by histology, and a combination of laser capture micro-dissection and DNA microsatellite genotyping of encrypted sperm. This study will give an insight into the mating system of Monodelphis domestica. New tools will be developed in this species including electroejaculation and heterospermic artificial insemination (as a bioassay for reduced fertility). This project will advance the independent career of the applicant, establish new collaborations, and further the competitiveness of Europe through research into this increasingly important comparative model.

Fields of science (EuroSciVoc)

Topic(s)

Call for proposal

FP6-2002-MOBILITY-7
See other projects for this call

Funding Scheme

IIF - Marie Curie actions-Incoming International Fellowships

Coordinator

UNIVERSITY OF GLASGOW
EU contribution
No data
Total cost
No data