Tierney A J, Andrews K, Happer K R, White M K M
Neuroscience Program, Department of Psychology, Colgate University, Hamilton, NY 13346, USA.
Behav Processes. 2013 Oct;99:47-51. doi: 10.1016/j.beproc.2013.06.001. Epub 2013 Jun 13.
Our experiment examined the ability of crayfish (Procambarus clarkii) to discriminate between familiar and unfamiliar conspecifics of equivalent social status, and investigated whether this species displays dear enemy or nasty neighbor effects. Pairs of size and sex matched crayfish fought to establish social status and the resulting dominant and subordinate crayfish then participated in a choice phase in which they interacted with two conspecifics tethered in an arena. Both choice conspecifics had the same social status and sex, but one was familiar (the focal animal's previous opponent) and the other was novel. We found that subordinate focal animals of both sexes spent significantly more time in proximity to the unfamiliar choice animal, behavior inconsistent with the dear enemy and nasty neighbor hypotheses. In contrast, male and female dominant focals differed significantly: females spent more time close to and fighting with the familiar choice animal while male dominants responded equivalently to the two choice animals. Thus the response of crayfish toward familiar and unfamiliar conspecifics was complex and not explained by a single hypothesis. We suggest that, in addition to familiarity and unfamiliarity, the perceived threat-level of opponents influences the behavior of crayfish toward conspecifics.
我们的实验研究了小龙虾（克氏原螯虾）区分同等社会地位的熟悉和不熟悉同种个体的能力，并调查了该物种是否表现出“亲爱的敌人”效应或“讨厌的邻居”效应。将大小和性别匹配的小龙虾配对进行争斗以确立社会地位，然后让产生的优势和从属小龙虾参与一个选择阶段，在此阶段它们与两只拴在竞技场中的同种个体进行互动。两个选择同种个体具有相同的社会地位和性别，但一个是熟悉的（焦点动物之前的对手），另一个是陌生的。我们发现，两性的从属焦点动物在陌生选择动物附近花费的时间显著更多，这种行为与“亲爱的敌人”和“讨厌的邻居”假说不一致。相比之下，优势焦点的雄性和雌性有显著差异：雌性在靠近熟悉选择动物并与之争斗上花费更多时间，而优势雄性对两个选择动物的反应相同。因此，小龙虾对熟悉和不熟悉同种个体的反应是复杂的，不能用单一假说解释。我们认为，除了熟悉和不熟悉之外，对手的感知威胁水平会影响小龙虾对同种个体的行为。
