Yurkovic Alexandra, Wang Oulu, Basu Alo C, Kravitz Edward A
Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17519-24. doi: 10.1073/pnas.0608211103. Epub 2006 Nov 6.
Male Drosophila melanogaster (Canton-S strain) exhibit aggression in competition for resources, to defend territory, and for access to mates. In the study reported here, we asked: (i) how long flies fight; (ii) whether flies adopt distinct winning and losing strategies as hierarchical relationships are established; (iii) whether flies exhibit experience-dependent changes in fighting strategies in later fights; and (iv) whether flies fight differently in second fights against familiar or unfamiliar opponents. The results showed that flies fought for up to 5 h. As hierarchical relationships were established, behavioral strategies changed: winners progressively lunged more and retreated less, whereas losers progressively lunged less and retreated more. Encounters between flies were frequent during the first 10 min of pairing and then dropped significantly. To ask whether flies remembered previous fights, they were re-paired with familiar or unfamiliar opponents after 30 min of separation. In familiar pairings, there were fewer encounters during the first 10 min of fighting than in unfamiliar pairings, and former losers fought differently against familiar winners than unfamiliar winners. Former losers lost or no decision was reached in all second fights in pairings with familiar or unfamiliar winners or with naive flies. Winner/winner, loser/loser, and naive/naive pairings revealed that losers used low-intensity strategies in later fights and were unlikely to form new hierarchical relationships, compared with winners or socially naive flies. These results strongly support the idea that learning and memory accompany the changes in social status that result from fruit fly fights.
雄性黑腹果蝇（Canton-S品系）在争夺资源、保卫领地以及争夺配偶时会表现出攻击性。在本文所报道的研究中，我们提出了以下问题：（i）果蝇争斗多长时间；（ii）随着等级关系的建立，果蝇是否会采取不同的胜负策略；（iii）果蝇在后续争斗中是否会表现出依赖经验的争斗策略变化；（iv）果蝇在与熟悉或不熟悉的对手进行第二次争斗时表现是否不同。结果表明，果蝇争斗长达5小时。随着等级关系的建立，行为策略发生了变化：胜者逐渐增加扑击次数并减少撤退次数，而败者逐渐减少扑击次数并增加撤退次数。配对后的前10分钟内，果蝇之间的相遇频繁，随后显著减少。为了探究果蝇是否记得之前的争斗，在分开30分钟后，将它们与熟悉或不熟悉的对手重新配对。在熟悉的配对中，争斗开始的前10分钟内的相遇次数比不熟悉的配对少，而且前败者与熟悉的胜者争斗时的表现与和不熟悉的胜者争斗时不同。在与熟悉或不熟悉的胜者或未经历过争斗的果蝇进行的所有第二次争斗中，前败者要么失败，要么未分出胜负。胜者/胜者、败者/败者以及未经历过争斗的果蝇/未经历过争斗的果蝇的配对结果显示，与胜者或未经历过社交互动的果蝇相比，败者在后续争斗中采用低强度策略，并且不太可能形成新的等级关系。这些结果有力地支持了这样一种观点，即学习和记忆伴随着果蝇争斗所导致的社会地位变化。
