Barrientos Zaidett
Rev Biol Trop. 2016 Mar;64(1):55-68.
Very little is known about the ecology and biology of Drymaeus tripictus, an extremely rare and endemic land snail species from Costa Rican highlands. I studied the ecology and reproductive biology of D. tripictus from April 2009 through June 2010 in an old forest, a young forest and a Cupressus lusitanica plantation in central Costa Rica. Every three months I visited each habitat and collected specimens in 20 random sampling plots (3x3 m2 each). I observed the snail’s activity and microhabitat preference in the field, and in the laboratory I recorded high definition videos of its mating behavior and analyzed reproductive morphology with light microscopy. The snail is more abundant in the old forest (0.017 ind./m(2)) and prefers leaves with little epiphyllous cover (0-25 % cover, chi-square test, p <0.0001). During the dry season the snails become active between 20:00 pm and 8:00 am (chi-square = 22.65, df=3, p < 0.0001); they are inactive mainly during the afternoon (11:00 am to 16:59 pm). I found active individuals mostly on the upper side of leaves, where they feed (Chi-square =6.76, df=1, p = 0.0093). Mating is unilateral, by shell mounting, with cryptic phallus intromission and without role switching or multiple mating. Its reproductive system is morphologically similar to that of Drymaeus costaricensis. Mating behavior is as expected for snails with high-spired shells, except for the lack of role switching. The density of D. tripictus is low even when compared with other endangered bulimulids.
关于三色干玛蜗牛（Drymaeus tripictus）的生态和生物学特性，人们知之甚少。这是一种极为罕见的地方性陆地蜗牛物种，来自哥斯达黎加高地。2009年4月至2010年6月，我在哥斯达黎加中部的一片老林、一片幼林和一片葡萄牙柏木种植园中研究了三色干玛蜗牛的生态和繁殖生物学。每隔三个月，我会走访每个栖息地，并在20个随机抽样地块（每个地块3×3平方米）收集标本。我在野外观察了蜗牛的活动和微生境偏好，在实验室里，我记录了其交配行为的高清视频，并通过光学显微镜分析了其生殖形态。这种蜗牛在老林中更为常见（0.017只/平方米），并且更喜欢叶面上附生植物覆盖较少的叶子（覆盖度为0 - 25%，卡方检验，p < 0.0001）。在旱季，蜗牛在晚上8点至上午8点之间变得活跃（卡方值 = 22.65，自由度 = 3，p < 0.0001）；它们主要在下午（上午11点至下午4点59分）不活动。我发现活动的个体大多在叶子的上表面，它们在那里觅食（卡方值 = 6.76，自由度 = 1，p = 0.0093）。交配是单边的，通过壳上挂载进行，阴茎隐性插入，没有角色转换或多次交配。其生殖系统在形态上与哥斯达黎加干玛蜗牛（Drymaeus costaricensis）相似。除了缺乏角色转换外，交配行为与具有高螺旋壳的蜗牛预期的一样。即使与其他濒危的 Bulimulidae 科蜗牛相比，三色干玛蜗牛的密度也很低。
