Morphological divergence and evidence for reproductive isolation in Littorina saxatilis (Olivi) in northeast England

Hull, Sue; Hull, SL; Grahame, J; Mill, PJ

Abstract

Current work at Old Peak (Ravenscar) on the northeast coast of England indicates that boulder-dwelling Lutonna saxatilis (Olvi) comprise at least two distinct forms, inhabiting high- and mid-shore boulders Using multivariate morphometrics we show that these forms are significantly different in shape. Rare intermediates between these two distinct forms were occasionally found, usually with the low shore animals The two forms show different reproductive strategies. High shore females (L. saxatilis H) mature at a smaller size and produce a smaller number of large eggs giving rise to large crawlaways The mid-shore form (L. saxatilis M) matures at a larger size and produces a large number of small eggs which give rise to small crawlaways. A novel observation is that intermediate females (L. saxatilis I) contain eggs of both sizes, giving rise to a bimodal distribution of egg sizes within the brood pouch. The usual incidence of abortion (observed in H and M forms) is Very low (

Citation

Hull, S., Grahame, J., & Mill, P. (1996). Morphological divergence and evidence for reproductive isolation in Littorina saxatilis (Olivi) in northeast England. Journal of Molluscan Studies, 62(1), 89-99. https://doi.org/10.1093/mollus/62.1.89

• Journal Article Type: Article
• Acceptance Date: Sep 15, 1995
• Online Publication Date: Feb 15, 1996
• Publication Date: 1996-02
• Journal: Journal of Molluscan Studies
• Print ISSN: 0260-1230
• Electronic ISSN: 1464-3766
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 62
• Issue: 1
• Pages: 89-99
• DOI: https://doi.org/10.1093/mollus/62.1.89
• Keywords: Animal Science and Zoology; Aquatic Science
• Public URL: https://hull-repository.worktribe.com/output/409467