McKillup Stephen C, Butler Alan J
Department of Zoology, University of Adelaide, GPO Box 498, 5001, Adelaide, S.A., Australia.
Oecologia. 1983 Jan;56(1):16-22. doi: 10.1007/BF00378212.
It is often difficult to estimate the amount of food available to an animal population, especially for species having unspecialised diets. The intertidal snail Nassarius pauperatus is omnivorous, feeding on both algae and animal carrion. Sampling the standing crops of carrion and algae was not thought to be a valid measure of the amount of food available to N. pauperatus. Instead, food availability was estimated indirectly, by measuring how hungry snails were.The percentage of snails feeding within 15 min of having been offered a meal of the bivalve Katelysia scalarina (Lamarck) was found to be a realiable and comparative estimate of food availability, and was measured in the field at 17 locations. The mean length of adult Nassarius pauperatus was negatively correlated with hunger, and at locations having high indices of hunger there was evidence of intraspecific competition for space to feed around items of carrion.These results are discussed and it is proposed that Nassarius pauperatus are surrounded by algal food of poor quality, with carrion being an important part of their diet for survival, growth and reproduction.
通常很难估算动物种群可获得的食物量，尤其是对于食性不特殊的物种。潮间带蜗牛贫 Nassarius pauperatus 是杂食性的，以藻类和动物腐肉为食。对腐肉和藻类的现存生物量进行采样被认为不是衡量贫 Nassarius pauperatus 可获得食物量的有效方法。相反，通过测量蜗牛的饥饿程度来间接估算食物可获得性。发现喂食双壳贝类卡特利亚 scalarina（拉马克）一餐15分钟内进食的蜗牛百分比是食物可获得性的可靠且可比的估计值，并在17个地点的野外进行了测量。成年贫 Nassarius pauperatus 的平均长度与饥饿程度呈负相关，在饥饿指数高的地点，有证据表明存在种内竞争，争夺围绕腐肉觅食的空间。对这些结果进行了讨论，并提出贫 Nassarius pauperatus 周围是质量较差的藻类食物，腐肉是它们生存、生长和繁殖饮食的重要组成部分。
