Inbreeding depression is defined as a fitness decline in progeny resulting from mating between related individuals, the severity of which may vary across environmental conditions. Such inbreeding‐by‐environment interactions might reflect that inbred individuals have a lower capacity for adjusting their phenotype to match different environmental conditions better, as shown in prior studies on developmental plasticity. Behavioural plasticity is more flexible than developmental plasticity because it is reversible and relatively quick, but little is known about its sensitivity to inbreeding. Here, we investigate effects of inbreeding on behavioural plasticity in the context of parent–offspring interactions in the burying beetle Nicrophorus vespilloides. Larvae increase begging with the level of hunger, and parents increase their level of care when brood sizes increase. Here, we find that inbreeding increased behavioural plasticity in larvae: inbred larvae reduced their time spent associating with a parent in response to the length of food deprivation more than outbred larvae. However, inbreeding had no effect on the behavioural plasticity of offspring begging or any parental behaviour. Overall, our results show that inbreeding can increase behavioural plasticity. We suggest that inbreeding‐by‐environment interactions might arise when inbreeding is associated with too little or too much plasticity in response to changing environmental conditions.

中文翻译：

---

近亲繁殖对埋葬甲虫亲代互动行为可塑性的影响

近交衰退被定义为由于相关个体之间的交配导致后代的健康下降，其严重程度可能因环境条件而异。这种近交与环境的相互作用可能反映了近交个体调整其表型以更好地匹配不同环境条件的能力较低，如先前关于发育可塑性的研究所示。行为可塑性比发育可塑性更灵活，因为它是可逆的且相对较快，但对其近亲繁殖的敏感性知之甚少。在这里，我们研究了近亲繁殖对埋葬甲虫 Nicrophorus vespilloides 亲代相互作用背景下行为可塑性的影响。幼虫随着饥饿程度的增加乞讨，当育雏大小增加时，父母会提高他们的照顾水平。在这里，我们发现近交增加了幼虫的行为可塑性：近交幼虫比远交幼虫减少了与父母交往的时间，以应对食物剥夺的时间长度。然而，近亲繁殖对后代乞讨或任何父母行为的行为可塑性没有影响。总的来说，我们的结果表明近亲繁殖可以增加行为的可塑性。我们认为，当近亲繁殖与响应不断变化的环境条件的可塑性太少或太多相关时，近亲繁殖与环境的相互作用可能会出现。与远交幼虫相比，近交幼虫减少了与父母交往的时间，以应对食物剥夺的时间长度。然而，近亲繁殖对后代乞讨或任何父母行为的行为可塑性没有影响。总的来说，我们的结果表明近亲繁殖可以增加行为的可塑性。我们认为，当近亲繁殖与响应不断变化的环境条件的可塑性太少或太多相关时，近亲繁殖与环境的相互作用可能会出现。与远交幼虫相比，近交幼虫减少了与父母交往的时间，以应对食物剥夺的时间长度。然而，近亲繁殖对后代乞讨或任何父母行为的行为可塑性没有影响。总的来说，我们的结果表明近亲繁殖可以增加行为的可塑性。我们认为，当近亲繁殖与响应不断变化的环境条件的可塑性太少或太多相关时，近亲繁殖与环境的相互作用可能会出现。