Biology subjects

Jäger, F.

Publications and source records attributed to Jäger, F..

3 recordsLinked to original sources

bioRxiv2026

Eco-evolutionary dynamics create extinction avalanches in mutualistic-antagonistic networks

Evolution has given rise to the diversity of life on Earth, but it can also cause species extinctions. While major extinction events are usually associated with external drivers, in this study, we show mechanistically how evolution can trigger abrupt extinction avalanches in ecological networks without any environmental change. In particular, we investigate an eco-evolutionary simulation model of a tripartite mutualistic-antagonistic network, such as a plant-pollinator-herbivore network, with additional intraguild competition. The prevalence of self-organised extinction avalanches depends on a subtle balance of the different interaction types, where antagonism and similarity-based competition are needed for initial diversification while mutualism and trait-independent competition foster evolutionarily driven extinction events. Extinction avalanches are triggered by a mutualist evolving to interact with plants that are not subject to sufficient antagonistic control. Subsequently, the mutualist, its plant partners and their main antagonist potentially outcompete the rest of the community. Our findings point out that evolutionary murder may claim many victims simultaneously and highlight the need to take different interaction types into account to gain a comprehensive understanding of the links between evolution and biodiversity in ecological communities.

evolutionary biology↗

bioRxiv2026

Between Friends and Foes: Evolutionary Diversification in Mutualistic-Antagonistic Networks

Biotic interactions can drive evolutionary diversification, but the underlying mechanisms differ depending on the type of interaction. For instance, Ehrlich and Ravens escape-and-radiate coevolution provides a pathway of diversification in antagonistic interactions, whereas in mutualistic networks, coevolution is hypothesized to result in trait convergence rather than diversification. The combined effect of mutualism and antagonism on diversification remains unclear, even though organisms naturally engage in multiple types of interactions simultaneously. Using an eco-evolutionary simulation model, we investigate diversification in tripartite ecological networks such as plant-pollinator-herbivore networks. We find that diversification patterns vary according to the way mutualism and antagonism are connected on the trait level. If the two interactions are governed by uncorrelated plant traits, we observe little diversification in the mutualistic and substantial diversification in the antagonistic subnetwork. By contrast, if the same plant trait mediates both mutualism and antagonism (an example of ecological pleiotropy), diversification rates in all guilds become interdependent. In this case, even the mutualistic guild diversifies considerably when antagonism is strong, while strong mutualism restricts diversification also in the antagonistic guild. Our study underlines that the inclusion of multiple interaction types is necessary to advance our understanding of evolutionary dynamics in ecological networks.

evolutionary biology↗

bioRxiv2024

From friend to foe and back - Coevolutionary transitions in the mutualism-antagonism continuum

Interspecific interactions evolve along a continuum ranging from mutualism to antagonism. Evolutionary theory so far focused mostly on parts of this continuum, notably on mechanisms that enable and stabilise mutualism. These mechanisms often involve partner discrimination ensuring that interaction intensity is higher with more cooperative partners. However, the gradual trajectory of coevolutionary transitions between mutualism and antagonism remains unclear. Here, we model how discrimination ability in one partner coevolves with mutualistic service provided by the other and analyse the resulting evolutionary trajectories in the mutualism-antagonism continuum. We show that strong ecological change, such as a radical host shift or colonisation of a new environment, can trigger transitions in both directions including back-and-forth transitions between antagonism and mutualism. Moreover, we find an evolutionary tipping point: a stable mutualism may break down to antagonism if the cost of either mutualistic service or discrimination ability gradually increases above a threshold beyond which this transition cannot be reversed by reducing costs again. Our study provides a new perspective on the evolution of biotic interactions and hence on the dynamic structure of ecological networks.

evolutionary biology↗