Evolution of Parent-Offspring Communication: Who Controls Resource Allocation and Is Signalling Costly?

亲子交流在父母在孵化或出生后反复为后代提供资源的物种中很常见。亲子沟通最近引起了许多理论和实证的兴趣，因为它提供了对父母和他们依赖的子女之间潜在的利益冲突的表型表现的关键见解。当父母为子女提供资源时，预计会发生亲子冲突，因为父母提供照料会产生成本，而且父母与子女之间的关系不对称。由于亲子冲突，子女对父母的要求应该比父母准备提供的资源更多。然而，如果后代这样做，父母应该被选择忽略后代乞讨的表现，在这种情况下，父母和后代的沟通将在进化上不稳定。因此，行为生态学的一个关键目标是理解在父母和子女具有不同但重叠的进化利益的情况下，亲子沟通如何在进化上保持稳定。最近的解决模型基于对父母和子女所扮演的策略的明确假设，对父母-子女冲突的表型结果进行了可检验的预测。这些模型表明，亲子沟通在解决亲子冲突中可以发挥关键作用。目前这种解决模式主要有三类：诚实信号、争抢竞争和免费乞讨模式。诚实的信号模型表明，父母从监控昂贵的后代乞讨节目中受益，因为这种节目提供了关于子女营养需求的诚实和可靠的信息，这反过来又允许父母控制资源的分配。相比之下，争抢竞争模型表明，昂贵的后代乞讨是兄弟姐妹之间争抢竞争的一种形式，资源分配受到后代的控制，而不是父母的控制。最后，零成本模型表明，即使乞讨不会给后代带来成本，后代乞讨和亲子沟通在进化上也可以是稳定的。区分这三种类型的模型仍然是行为生态学中一个重要的悬而未决的问题。这些模型对后代信号和父母的反应做出了非常相似的预测，但基于关于谁控制资源分配以及乞讨是否代价高昂的不同假设。这个项目试图通过使用埋葬甲虫作为研究系统来测试替代模型所依赖的关键假设，从而区分这些模型。这个项目的第一个目标是确定资源分配是由父母控制的，如诚实的信号和免费乞讨模式所假设的那样，还是由后代控制的，如争抢竞争的乞讨模式所假设的那样。第二个目标是测试乞讨是否会像诚实的信号和争抢乞讨的竞争模式所假设的那样给后代带来成本，或者乞讨是否像零成本乞讨模式假设的那样是免费的。然后，关于谁控制资源分配以及乞讨是否昂贵的信息将被用来区分现有的亲子沟通进化模式。这个项目将通过提供关于谁控制资源分配以及乞讨是否昂贵的单一研究系统的关键假设的信息，有助于我们理解亲子沟通的演变和亲子冲突的解决。

Parent-offspring communication is common in species where parents provide their offspring repeatedly with resources after hatching or birth. Parent-offspring communication has recently attracted much theoretical and empirical interest because it provides key insights into the phenotypic manifestation of underlying conflicts of interest between parents and their dependent offspring. Parent-offspring conflict is expected when parents provide their offspring with resources because parents incur costs from providing care and because there are asymmetries in relatedness between parents and offspring. Due to parent-offspring conflict, offspring should demand more resources from their parents than parents are prepared to provide. However, if offspring do so, parents should be selected to ignore offspring begging displays, in which case parent-offspring communication would be evolutionarily unstable. Thus, a key aim in behavioural ecology is to understand how parent-offspring communication can be evolutionary stable in situations where parents and offspring have diverging but overlapping evolutionary interests. Recent resolution models make testable predictions about the phenotypic outcome of parent-offspring conflict based on explicit assumptions about the strategies played by parents and offspring. Such models suggest that parent-offspring communication can play a key role in resolving parent-offspring conflict. There are currently three main classes of such resolution models: honest signalling, scramble competition and cost-free models of begging. Honest signalling models suggest that parents benefit from monitoring costly offspring begging displays because such displays provide honest and reliable information on the offspring's nutritional needs, which in turn allow the parents to control the allocation of resources. By contrast, scramble competition models, suggest that costly offspring begging is a form of scramble competition among siblings, and that resource allocation is under offspring rather than parental control. Finally, cost-free models suggest that offspring begging and parent-offspring communication can be evolutionarily stable even if begging does not incur costs to the offspring. Distinguishing between these three types of models remains an important unresolved problem in behavioural ecology. The models make very similar predictions concerning offspring signalling and parental responsiveness, but are based on different assumptions concerning who controls resource allocation and whether begging is costly or not. This project seeks to distinguish between these models by testing the critical assumptions upon which the alternative models rests using the burying beetle Nicrophorus vespilloides as study system. The first aim of this project is to establish whether resource allocation is controlled by parents, as assumed by honest signalling and cost-free models of begging, or controlled by offspring as assumed by scramble competition models of begging. The second aim is to test whether begging incurs costs to the offspring as assumed by honest signalling and scramble competition models of begging or whether begging is cost-free as assumed by cost-free models of begging. The information on who controls resource allocation and whether begging is costly or not will then be used to distinguish between existing models for the evolution of parent-offspring communication. This project will contribute to our understanding of the evolution of parent-offspring communication and the resolution of parent-offspring conflict by providing information on the critical assumptions of who controls resource allocation and whether begging is costly or not from a single study system.