Differential adaptations between cold-stenothermal environments in the bivalve Lissarca cf. miliaris (Philobryidae) from the Scotia Sea islands and Antarctic Peninsula

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• 作者：Adam J. Reed^a ; ^{ajr104@soton.ac.uk" class="auth_mail} ; Katrin Linse^b ; Sven Thatje^a
• 关键词：Southern Ocean ; Plasticity ; Bivalve ; Speciation ; Reproduction ; Morphology
• 刊名：Journal of Sea Research
• 出版年：April, 2014
• 年：2014
• 卷：88
• 期：Complete
• 页码：11-20
• 全文大小：1420 K

文摘

The cold stenothermal nature of the Southern Ocean, and highly adapted fauna living within, raises the question of how much intra-specific variation there is among invertebrate populations, and how variation may have a role in speciation processes through ecological divergence, natural selection, and reproductive isolation. Despite decades of collecting biological material, this question remains largely unanswered, and many studies compare 鈥榩opulations鈥?of pooled material from wide geographic ranges to compensate for sampling constraints. In this study, variations in ecophysiological traits are explored by measuring growth, reproduction, and shell morphology among six populations of the small bivalve m>Lissarcam> cf. m>miliarism> (Philippi, 1845) from the Southern Ocean, which experience subtle differences in temperature, disturbance, and food availability. There are significant differences in shell morphology and growth among different populations and slower growth rates at higher latitude populations. Prodissoconch sizes show an inverse 鈥楿鈥?shaped relationship with latitude, and are correlated with egg size at South Georgia and King George Island's Potter Cove. Higher brood sizes at the South Georgia population represent a trade-off with lower egg size, and correlate with shell morphology by offering lower internal capacity to brood young. Lower investment into offspring and morphological variations in m>L.m> cf. m>miliarism> highlight the importance of local scale environmental variations on species' ecology. These variations in physical traits appear to be underestimated in the Southern Ocean, but may be important drivers of ecological divergence and speciation, which should be considered in future genetic investigations on different invertebrate populations.