1. In many animal species, individuals engage in fights with conspecifics over access to limited resources (e.g. mates, food, or shelter). Most theory about these intraspecific fights assumes that damage has an important role in determining the contest winner. Thus, defensive structures that reduce the amount of damage an individual accrues during intraspecific competition should provide a fighting advantage.
2. Examples of such damage‐reducing structures include the dermal shields of goats, the dorsal osteoderms of crocodiles, and the armoured telsons of mantis shrimps. Although numerous studies have identified these defensive structures, no study has investigated whether they influence the outcomes of intraspecific fights.
3. Here we investigated whether inhibiting damage by enhancing an individual's armour influenced fighting behaviour and success in the giant mesquite bug, Thasus neocalifornicus (Insecta: Hemiptera: Coreidae).
4. We found that experimentally manipulated individuals (i.e. those provided with additional armour) were 1.6 times more likely to win a fight when compared to the control. These results demonstrate that damage, and damage‐reducing structures, can influence fighting success.
5. The implications of these results are twofold. First, our results experimentally support a fundamental assumption of most theoretical fighting models: that damage is a fighting cost that can influence contest outcomes. Second, these results highlight the importance of an individual's defensive capacity, and why defence should not be ignored.

中文翻译：

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防御结构会影响战斗结果

1. 在许多动物物种中，个体为了获得有限的资源（例如伴侣，食物或庇护所）而与物种争斗。关于种内斗争的大多数理论都认为，损害在确定比赛获胜者中起着重要作用。因此，减少个体在种内竞争过程中遭受的伤害的数量的防御结构应该提供战斗优势。
2. 这种减少损害的结构的例子包括山羊的皮盾，鳄鱼的背骨皮以及螳螂虾的装甲telsons。尽管许多研究已经确定了这些防御结构，但没有研究调查它们是否影响种内战斗的结果。
3. 在这里，我们研究了通过增强个体的装甲来抑制伤害是否影响了巨大的豆科灌木臭虫Thasus neocalifornicus（Insecta：Hemiptera：Coreidae）的战斗行为和成功。
4. 我们发现，与对照组相比，经实验操纵的人（即提供额外装甲的人）赢得战斗的可能性高1.6倍。这些结果表明，损害和减少损害的结构会影响战斗的成功。
5. 这些结果的含义是双重的。首先，我们的结果在实验上支持了大多数理论战斗模型的基本假设：损害是可以影响比赛结果的战斗费用。其次，这些结果突出了个人防御能力的重要性，以及为何不应忽视防御的原因。