The marine gastropod Crepidula plana has an extensive latitudinal range along the eastern coast of the United States. It is usually found living within gastropod shells occupied by hermit crabs, although individuals can sometimes also be found living on rocks and on the exposed surfaces of shells. Our study sought to determine the extent to which residing inside periwinkle (Littorina littorea) shells occupied by the hermit crab Pagurus longicarpus at a study site in coastal Massachusetts compromises the fecundity of C. plana, through size limitation. The egg masses of symbiotic and free‐living females of C. plana included comparable numbers of egg capsules and embryos per female despite the smaller sizes of the symbionts; symbiotic females compensated for their smaller size by producing significantly more embryos per milligram of female body tissue than their free‐living counterparts. These data raise interesting questions about why—unlike its congener C. fornicata—C. plana has not yet become a successful invasive species.

中文翻译：

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研究共生生活方式对海洋腹足纲Crepidula Plana繁殖力的影响

海洋腹足纲Crepidula Plana在美国东海岸的纬度范围很广。它通常被发现生活在寄居蟹占据的腹足动物的壳内，尽管有时也可以发现一些人生活在岩石和壳的裸露表面上。我们的研究试图确定居​​住在马萨诸塞州沿海一个研究地点的寄居蟹Pagurus longicarpus占据的长春花壳（Littorina littorea）壳内通过大小限制损害平面藻繁殖力的程度。平面C.共生和自由生活雌性的卵重尽管共生体的大小较小，但每个女性的卵囊和胚胎的数量相当；共生雌性通过补偿其较小的大小，通过每毫克雌性人体组织产生的胚芽比自由活动的雌性组织多得多。这些数据提高对为什么，不像它的同类有趣的问题C. fornicata - C.扁平疣还没有成为一个成功的入侵物种。