Sabine Nooten: Ant body size mediates functional performance and species interactions in carrion decomposer communities

In this blog post, Sabine Nooten, postdoctoral researcher at the University of Würzburg, Germany, presents her latest work ‘Ant body size mediates functional performance and species interactions in carrion decomposer communities‘. She highlights the importance of linking species traits to function in the community and ecological process, and discusses the power of field-based experiments in functional ecology.

About the paper

Ecological processes are driven by the organisms that make up a community; however, not every organism plays the same role. The different actors belong to different taxonomic and ecological groups, and are characterised by different sets of morphological traits. Body size is a key trait that is linked to multiple life history features and influences vital ecological functions, such as pollination, seed dispersal, and decomposition. With large species often among the first to disappear following disturbance, it is essential to understand their relative contribution to ecosystem functions. Subsequently, this vital knowledge will help us to evaluate long-term consequences for ecosystems.

Setting up a cage on the forest floor for the decomposition experiment (Credit: Taylor Bogar)

About the research

In our study, we investigated the decomposition process of dead animal matter and the importance of several decomposers in function of their body sizes. In Hong Kong forests, small mammal carcasses (a short-lived protein-rich food source) are quickly discovered by ants and flies. The ants actively eat the carcass, while the flies lay their eggs into the cavities of the carcass. We noticed that some ants performed a second role through the predation of hatching fly maggots; therefore, an ideal opportunity presented itself to study these interactions in more detail. The ant community was quite diverse, presenting a wide range of body sizes. To understand the role of these different species in situ, we had to be creative and needed a setup that could ‘filter’ the access of ants to a decomposing carcass in function of their body size. The final design was a cage where a dead mouse is tied on a raised platform at the centre. Ant access to the mouse is filtered by body size, through adjustments of the platform heights, hole diameter sizes, and Tanglefoot application.

A cage with a dead mouse tied on a raised platform at the centre to filter ant access by body size. This was left out in the field for 48 hours (Credit: Sabine Nooten)

Through this setup, we discovered that larger ants indeed provide the strongest contribution—they show a double action by increasing decomposition rate (by one third) and predating on maggots (by removing 3 times more). Small ants, however, are rather inefficient decomposers and did not act as predators on other decomposers. As a result, the loss of large members in a community might have disproportional impacts on key ecological processes.

About the author

I am an insect ecologist and I am passionate about finding out why organisms live where they live and how they are connected to their environment. Growing up with plenty of access to nature, I quickly became interested in the plants and animals around me. My interest led me to study biology – the science of life – in Germany and I continued my studies through a PhD in Australia.

Specifically, I investigate how species traits are linked to the environment and which traits are needed to persist under rapid environmental change, and, which traits are needed to survive more stressful conditions in the future. I have pursued this line of work across four different continents (Australia, North America, Asia, and now Europe) in a variety of habitats, ranging from dry to wet forests, and from native to managed ecosystems.

Currently, I am a postdoc at the University of Würzburg, Germany, where I received a research grant from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) to expand my work on functional traits to include chemical traits and investigate how they are linked to environmental features.

Sabine Nooten (Credit: Sabine Nooten)

Enjoyed the blog? Read the research here.

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