These experiments are part of a larger study designed to investigate the influence of husbandry parameters on the life history of the apple snail, Marisa cornuarietis. The overall objective of the program is to identify suitable husbandry conditions for maintaining multi-generation populations of this species in the laboratory for use in ecotoxicological testing. In this article, we focus on the effects of photoperiod, temperature, and population density on adult fecundity and juvenile growth. Increasing photoperiod from 12 to 16 h of light per day had no effect on adult fecundity or egg hatching and relatively minor effects on juvenile growth and development. Rearing snails at temperatures between 22°C and 28°C did not influence the rates of egg production or egg clutch size. However, the rates of growth and development (of eggs and juveniles) increased with increasing temperature in this range, and when temperatures were reduced to 22°C egg-hatching success was impaired. Juvenile growth and development were more sensitive to rearing density than adult fecundity traits. On the basis of the present results, we conclude that rearing individuals of M. cornuarietis at a temperature of 25°C, a photoperiod of 12L:12D, and a density of <0.8 snails L−1 (with lower densities for juvenile snails) should provide favorable husbandry conditions for maintaining multi-generation populations of this species.

中文翻译：

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饲养参数对苹果蜗牛生活史特征的影响：温度、光周期和种群密度的影响

这些实验是一项更大的研究的一部分，该研究旨在调查饲养参数对苹果蜗牛 Marisacornuarietis 生活史的影响。该计划的总体目标是确定合适的饲养条件，以在实验室中维持该物种的多代种群，以用于生态毒理学测试。在本文中，我们关注光周期、温度和种群密度对成虫繁殖力和幼虫生长的影响。将光周期从每天 12 小时增加到 16 小时对成虫繁殖力或卵孵化没有影响，对幼虫生长发育的影响相对较小。在 22°C 至 28°C 的温度下饲养蜗牛不会影响产蛋率或产蛋量。然而，在这个范围内，随着温度的升高，（鸡蛋和幼鱼的）生长和发育速度增加，当温度降低到 22°C 时，孵化成功率会受到影响。与成年繁殖力性状相比，幼年生长发育对饲养密度更敏感。根据目前的结果，我们得出结论，在 25°C 的温度、12L:12D 的光周期和 <0.8 只蜗牛 L-1 的密度下饲养 M.cornuarietis 个体（幼蜗牛的密度较低）应为维持该物种的多代种群提供有利的饲养条件。