Am J Bot. 1998 Jan;85(1):88.
Pitcher plants (Sarracenia purpurea L.) attract insects to pitchers and then capture them in fluid-filled, pitfall traps, but how efficient are pitcher plants at capturing prey in their natural environment? We monitored insect activity by videotaping pitchers and analyzing videotapes for several variables including identity of each visitor and outcome of each visit (e.g., departure or capture). Efficiency of capture (i.e., number of captures per number of visits) was low. Overall efficiency of capture was 0.83-0.93%, depending on whether potential prey were broadly or narrowly defined. Ants constituted 74% of the potential prey. Efficiency of capture of ants was even lower at 0.37%. Potential prey were more likely to visit pitchers with greater red venation and less water in the pitcher. There was no correlation between number of potential prey visiting a pitcher and pitcher age, length, or mouth width. Also, number of potential prey visits did not correlate with plant size, air temperature, time of day or date of videotaping. While the overall efficiency of prey capture was very low, pitcher plants may still benefit from the additional nutrients. However, the relationship between ants and S. purpurea remains an enigma, since it is unclear whether the plants capture enough ants to compensate for nectar lost to ants.
猪笼草（Sarracenia purpurea L.）通过吸引昆虫进入瓶状陷阱，并利用充满液体的陷阱来捕获它们，那么猪笼草在自然环境中捕获猎物的效率如何呢？我们通过对猪笼草进行录像，并分析录像带中的几个变量，包括每个访客的身份和每次访问的结果（例如离开或捕获），来监测昆虫的活动。捕获的效率（即捕获次数与访问次数的比率）很低。总的捕获效率取决于潜在猎物的广义或狭义定义，在 0.83%-0.93%之间。蚂蚁占潜在猎物的 74%。蚂蚁的捕获效率甚至更低，为 0.37%。潜在猎物更有可能访问具有更多红色叶脉和较少瓶内水的猪笼草。潜在猎物访问猪笼草的数量与猪笼草的年龄、长度或瓶口宽度之间没有相关性。此外，潜在猎物的访问次数与植物大小、空气温度、一天中的时间或录像带拍摄日期之间也没有相关性。虽然猎物的总体捕获效率非常低，但猪笼草可能仍然受益于额外的营养物质。然而，蚂蚁和 S. purpurea 之间的关系仍然是一个谜，因为不清楚植物是否捕获了足够的蚂蚁来弥补因蚂蚁而损失的花蜜。
