Polyandry in the medfly - shifts in paternity mediated by sperm stratification and mixing

BMC Genetics

Research

Paolo Gabrieli¹  Francesca Scolari¹  Ludvik M Gomulski¹  Anna R Malacrida¹  Giuliano Gasperi¹  Ernst A Wimmer²  Boaz Yuval³  Federico Bassetti⁴  Marc F Schetelig⁵ 

[1] Department of Biology and Biotechnology, University of Pavia, Pavia, Italy;Department of Developmental Biology, Johann-Friedrich-Blumenbach Institute of Zoology and Anthropology, GZMB, Georg-August-Universität Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany;Department of Entomology, The Hebrew University of Jerusalem, 76100, Rehovot, Israel;Department of Mathematics, University of Pavia, Pavia, Italy;Institute of Phytopathology and Applied Zoology, Justus-Liebig-University Gießen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany;

关键词: Medfly;    polyandry;    sperm stratification;    transgenic sperm;    fertilization chamber;   

DOI  :  10.1186/1471-2156-15-S2-S10

来源: Springer

【 摘 要 】

BackgroundIn the Mediterranean fruit fly (medfly), Ceratitis capitata, a highly invasive agricultural pest species, polyandry, associated with sperm precedence, is a recurrent behaviour in the wild. The absence of tools for the unambiguous discrimination between competing sperm from different males in the complex female reproductive tract has strongly limited the understanding of mechanisms controlling sperm dynamics and use.ResultsHere we use transgenic medfly lines expressing green or red fluorescent proteins in the spermatozoa, which can be easily observed and unambiguously differentiated within the female fertilization chamber. In twice-mated females, one day after the second mating, sperm from the first male appeared to be homogenously distributed all over the distal portion of each alveolus within the fertilization chamber, whereas sperm from the second male were clearly concentrated in the central portion of each alveolus. This distinct stratified sperm distribution was not maintained over time, as green and red sperm appeared homogeneously mixed seven days after the second mating. This dynamic sperm storage pattern is mirrored by the paternal contribution in the progeny of twice-mated females.ConclusionsPolyandrous medfly females, unlike Drosophila, conserve sperm from two different mates to fertilize their eggs. From an evolutionary point of view, the storage of sperm in a stratified pattern by medfly females may initially favour the fresher ejaculate from the second male. However, as the second male's sperm gradually becomes depleted, the sperm from the first male becomes increasingly available for fertilization. The accumulation of sperm from different males will increase the overall genetic variability of the offspring and will ultimately affect the effective population size. From an applicative point of view, the dynamics of sperm storage and their temporal use by a polyandrous female may have an impact on the Sterile Insect Technique (SIT). Indeed, even if the female's last mate is sterile, an increasing proportion of sperm from a previous mating with a fertile male may contribute to sire viable progeny.

【 授权许可】

Unknown   
© Scolari et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.