Ecology and Evolution of Cooperative Fungiculture in Beetles

合作在自然界中无处不在，它的进化对几代进化生物学家提出了挑战。今天，社会进化的许多原则被广泛接受，但主要问题仍然没有解决。例如，进化生物学中最强大的方法，即特征的实验进化，还没有在动物的社会行为中完成。同样地，虽然选择种内社会性的生态因素相对来说是众所周知的，但还不清楚是否有特定的因素始终促进种间互惠的进化。树皮甲虫和豚草甲虫是解决这些问题的极好模型。原因是这些物种中的许多种都种植真菌作为食物-这一特性在这个群体中独立进化了至少十次。最有趣的是，这种真菌栽培的进化总是伴随着更复杂的社会组织的进化。因此，许多农业物种正处于从亚社会生活方式向真社会生活方式的过渡，这在动物中非常罕见。我已经开发了一种人工饲养和观察技术，适用于许多树皮甲虫和豚草甲虫物种，现在可以直接测试某些生态条件如何影响社会行为的进化以及与真菌的互利共生。此外，我们可以学到很多关于动物养殖的机制，这在许多方面与人类农业相媲美。在这个埃米诺特项目中，我将解决社会进化和互利共生中未解决的主要问题，使用仙甲虫作为模型。我的主要目标是（i）通过选择甲虫传播的时间和操纵病原体压力来进行越来越多的社会甲虫菌株的实验进化，（ii）测试共同选择的真菌群落对社会行为的影响，并研究社会行为，繁殖和传播之间的权衡，（iii）调查社会多态性以及它们如何受到栖息地特征和共生体群落的影响，（iv）确定甲虫的劳动分工是否受化学调节，（v）检查甲虫是否能够积极控制真菌群落，确定巢防御病原体的机制和通过互利细菌诱导真菌结果实的机制，以及（vi）在从事农业昆虫工作的研究人员和农学家之间建立对话，从进化的角度比较农业实践，并激发新的研究。为了实现所有这些目标，我的团队将采用跨学科的方法，将选择实验，实验测定和培养方法与最先进的分子（例如qPCR，下一代测序）和生物化学（例如GC-MS）技术相结合。维尔茨堡是这个项目的首选地点，因为这个环境结合了社会昆虫行为，进化和化学生态学（包括真菌养殖蚂蚁）的巨大专业知识，提供了良好的合作。

Cooperation is ubiquitous in nature and its evolution has challenged generations of evolutionary biologists. Today many principles of social evolution are widely accepted, but major issues remain unsolved. For example, the strongest approach in evolutionary biology, namely experimental evolution of a trait, has not been accomplished for social behaviour in animals. Likewise, while the ecological factors that select for intraspecific sociality are relatively well known, it is unclear if there are specific factors that consistently facilitate the evolution of interspecific mutualisms. Bark- and ambrosia beetle species are excellent models to address these questions. The reason is that many of these species grow fungi for food - a trait which has independently evolved at least ten times in this group. Most interestingly, the evolution of this fungiculture was always accompanied by the evolution of more complex social organization. Thus, many farming species are at the transition from a sub-social to a eusocial lifestyle, which is quite rare in animals. I have developed an artificial rearing and observation technique, suitable for many bark- and ambrosia beetle species, which now allows me to directly test how certain ecological conditions affect the evolution of social behaviours and the mutualism with fungi. Additionally, we can learn a lot on the mechanisms of animal farming, which is comparable to human agriculture in many ways.In this Emmy Noether project, I will tackle major unsolved issues in social evolution and mutualism, using ambrosia beetles as a model. My main objectives are to (i) conduct experimental evolution of less and more social beetle strains by selecting on timing of beetle dispersal and manipulating pathogen pressure, (ii) test the effects of the co-selected fungal community on social behaviour and study trade-offs between social behaviour, reproduction, and dispersal, (iii) investigate social polymorphisms and how they are affected by habitat characteristics and symbiont communities, (iv) determine if division of labour in beetles is chemically regulated, (v) examine if beetles can actively control fungus communities, identify the mechanisms of nest defence against pathogens and of induction of the fruiting of the fungi by means of mutualistic bacteria, and (vi) establish a dialogue between researchers working with farming insects and agronomists to compare farming practices from an evolutionary perspective, and stimulate novel research. To achieve all these objectives, my group will apply an interdisciplinary approach, combining selection experiments, experimental assays, and culturing methods with state-of-the-art molecular (e.g. qPCR, next-gen-sequencing) and biochemical (e.g. GC-MS) techniques. Würzburg is the preferred place for this project as this environment unifies tremendous expertise on social insect behaviour, evolution and chemical ecology (including fungus-farming ants), offering excellent collaborations.