Hudina Sandra, Hock Karlo
Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia.
Behav Processes. 2012 Sep;91(1):77-81. doi: 10.1016/j.beproc.2012.05.011. Epub 2012 Jun 9.
Ecosystems today increasingly suffer invasions by multiple invasive species, some of which may share similar advantageous life history traits and ecological niche. In such cases, direct competition can influence invasion success of both species, and provide insights into competition without co-evolution in species equally novel to the environment. We used two widespread crayfish invaders of freshwater ecosystems of Europe, signal crayfish (Pacifastacus leniusculus) and spiny cheek crayfish (Orconectes limosus), to investigate how behavioural decisions in agonistic encounters contribute to competitive advantages in the absence of adaptation to either opponents or an environment. In direct competition against novel but comparable opponents, the key factor for establishing clear dominance of P. leniusculus in interspecific bouts was its greater tendency towards continued engagement in high-intensity fights. With O. limosus individuals consistently retreating from staged bouts as fights became more intense, P. leniusculus individuals did not need to adapt their strategy to be successful, suggesting that their agonistic behaviour intrinsically predisposed them to win. While both species are detrimental to invaded ecosystems, our results indicate that aggressive behaviour of P. leniusculus against unfamiliar opponents could allow it to more easily outcompete other comparable species and consequently present a potentially greater threat for native ecosystems.
如今，生态系统越来越多地遭受多种入侵物种的侵害，其中一些物种可能具有相似的有利生活史特征和生态位。在这种情况下，直接竞争会影响两个物种的入侵成功率，并为在没有共同进化的情况下研究物种间竞争提供见解，这些物种对环境同样陌生。我们利用欧洲淡水生态系统中两种广泛分布的小龙虾入侵者，即信号小龙虾（Pacifastacus leniusculus）和刺颊小龙虾（Orconectes limosus），来研究在没有适应对手或环境的情况下，争斗遭遇中的行为决策如何促成竞争优势。在与陌生但相当的对手的直接竞争中，在种间较量中确立信号小龙虾明显优势的关键因素是其更倾向于持续参与高强度战斗。随着刺颊小龙虾个体在模拟争斗中随着战斗强度增加而不断退缩，信号小龙虾个体无需调整策略就能获胜，这表明它们的争斗行为本质上使它们易于取胜。虽然这两个物种对入侵生态系统都有危害，但我们的结果表明，信号小龙虾对陌生对手的攻击性行为可能使其更容易在竞争中战胜其他相当的物种，从而对本地生态系统构成潜在更大的威胁。
