Abstract
Numerous reports were devoted to the variation of sperm length in relation to sperm competition amongst species. However, studies on intraspecific variations of sperm size are very scarce and the number of sperm measured, very limited. This paper investigates within-individual, between-individual and between-population variation of sperm length in the two cosmopolitan species, D. simulans and D. melanogaster. Sperm length distributions are completely discriminated against with these two species, with the mean values equal to 1.121 ± 0.002 and 1.989 ± 0.008 mm, respectively. Results of intraspecific variation show a contrasting pattern between the two species. The mode of sperm length distributions is much less variable in D. simulans than in D. melanogaster. The sperm size divergence is unaffected whenever the two species are in sympatry (tested at 'Evolution Canyon', Mount Carmel, Israel) or in allopatry, but the two species react differentially to abiotic local factors. D. melanogaster, in contrast to D. simulans, shows a clinal pattern in sperm size associated with drought. We discussed this pattern in relation to the potential role of sperm length in the ongoing process of non-random mating and incipient sympatric speciation observed in this locality in D. melanogaster.
Original language | English |
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Pages (from-to) | 233-244 |
Number of pages | 12 |
Journal | Genetica |
Volume | 120 |
Issue number | 1-3 |
DOIs | |
State | Published - Mar 2004 |
Bibliographical note
Funding Information:E. Nevo and A. Korol thank the Israeli Ministry of Science for grants nos. 1426 and 4147; the Israel Science Foundation (grants nos. 9048/99, 9030/96 and 02198) and the Ancell-Teicher Research Foundation for Genetics and Molecular Evolution. We would like to thank Dr Tomas Pavlicek and Dr Eugenia Rashkovetsky for assistance in field and laboratory work in Israel, Dr Roland Allemand for collecting the French 2001 strains (grants GDR-CNRS 2153 ‘Evolution des systèmes hôtes-parasitoïdes’), and Bruno Le Rü (UR IRD 072) for collecting the Kenyan 2001 lines. We thank Béatrice Dejonghe for rearing the flies and for cysts and nuclei measurements, Patricia Gibert and Olivier Langella for their statistical advices and Robin Permut for editing. Insightful comments from Pierre Capy, Catherine Montchamp-Moreau, Daniel Lachaise and two referees were greatly appreciated.
Keywords
- D. melanogaster
- D. simulans
- Environment
- Geographic variation
- Polymorphism
- Sexual selection
- Sperm length distribution
ASJC Scopus subject areas
- Animal Science and Zoology
- Genetics
- Plant Science
- Insect Science