McKillup Stephen C
Department of Zoology, University of Adelaide, GPO Box 498, 5001, Adelaide, S.A., Australia.
Oecologia. 1983 Jan;56(1):58-66. doi: 10.1007/BF00378217.
The snail Nassarius pauperatus (Lamarck) is common on intertidal sandflats in southern Australia. A behaviour described and defined as being a "Twister" was observed in some individuals. Upon contacting a member of their own species, Twisters gave a very specific response, rotating their shell from side to side in a way similar to the escape responses displayed by many gastropods to predators. However, some individuals, defined as "Non Twisters", never gave this response after contacting another N. pauperatus. Breeding experiments suggested that being a Twister was heritable. The frequency of Twisters varied between populations of N. pauperatus, and was negatively correlated with food availability (as estimated by measuring hunger) and positively correlated with the population density of juvenile N. pauperatus.It was found in the laboratory that Twisters were better than Non Twisters at competing for space to feed, when food was in short supply and distributed as discrete patches. There was also evidence that competition for space to feed occurred when food was in short supply in the field and it was postulated that Twisters thus had a selective advantage compared to Non Twisters in such situations.These results are discussed in terms of whether the behavioural differences between populations can be attributed to either selection or stochastic factors.
贫蚶 Nassarius pauperatus（拉马克）在澳大利亚南部的潮间带沙滩很常见。在一些个体中观察到一种被描述和定义为“扭转者”的行为。当接触到同种个体时，扭转者会给出一种非常特殊的反应，将它们的壳左右旋转，其方式类似于许多腹足类动物对捕食者表现出的逃避反应。然而，一些被定义为“非扭转者”的个体在接触另一只贫蚶后从未给出这种反应。繁殖实验表明，成为扭转者是可遗传的。扭转者在贫蚶种群中的频率各不相同，并且与食物可获得性（通过测量饥饿程度估算）呈负相关，与幼年贫蚶的种群密度呈正相关。在实验室中发现，当食物短缺且以离散斑块形式分布时，扭转者在争夺进食空间方面比非扭转者更具优势。也有证据表明，在野外食物短缺时会发生争夺进食空间的情况，据此推测在这种情况下，扭转者相对于非扭转者具有选择优势。本文根据种群之间的行为差异是可归因于选择因素还是随机因素来讨论这些结果。
