Mirror tests have been used to test aggressiveness because they reduce the variability of the real opponent and allows for repeated measurements. Regular mirrors have also several disadvantages due to the inability to display a head-to-tail position during lateralization. Recently, a method using a non-reversing mirror was developed, which eliminated this disadvantage, but was tested in a single species only. The present study reflects the need for validating the non-reversing mirror test in other species, represented by chub (Squalius cephalus L.) in the present study, due to species-specific manifestations of aggressiveness. The prediction that a non-reversing mirror would lead to more aggressive interactions than a regular mirror in chub was confirmed. The durations of aggressive interactions were longer in fish exposed to the regular mirror test with specific significance in case of the frontal and the lateral displays. The individuals maintained the same level of aggressiveness throughout both tests, suggesting that both tests are valid for testing the aggressiveness. Nevertheless, due to higher number of interactions performed, a non-reversing mirror may offer a stronger stimulus and could represent a real contest better than the regular mirror. Therefore, the non-reversing mirror test should be recommended for use in future studies.

中文翻译：

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在侵略性测试中，鲤科鱼在非反转镜与常规镜中的表现

镜像测试已被用于测试攻击性，因为它们减少了真实对手的可变性并允许重复测量。由于在侧化过程中无法显示头对尾的位置，常规镜子也有几个缺点。最近，开发了一种使用非反转镜的方法，它消除了这一缺点，但仅在单一物种中进行了测试。由于攻击性的物种特异性表现，本研究反映了在本研究中以 chub (Squalius cephalus L.) 为代表的其他物种中验证非反转镜测试的必要性。与普通镜子相比，非倒车镜会导致更具侵略性的相互作用的预测得到证实。在暴露于常规镜子测试的鱼中，攻击性相互作用的持续时间更长，在正面和侧面展示的情况下具有特殊意义。个体在两次测试中都保持相同水平的攻击性，这表明两种测试对于测试攻击性都是有效的。然而，由于执行的交互次数较多，非倒车镜可能会提供更强的刺激，并且比常规镜更能代表真正的比赛。因此，应推荐在未来的研究中使用非倒车镜测试。由于执行的交互次数较多，非倒车镜可能会提供更强的刺激，并且比普通镜子更能代表真正的比赛。因此，应推荐在未来的研究中使用非倒车镜测试。由于执行的交互次数较多，非倒车镜可能会提供更强的刺激，并且比普通镜子更能代表真正的比赛。因此，应推荐在未来的研究中使用非倒车镜测试。