Thread by @MarkKLWong

*New paper* in #ProcB @RSocPublishing!
Can #plant🌱 trait approaches explain how competition drives #ant 🐜 invasions and structures ant communities? A 🧵on the final paper from my DPhil @UniofOxford... royalsocietypublishing.org/doi/10.1098/rs…

One recurring theme I encountered while reviewing animal trait studies: the implicit assumption that species’ trait differences reflect niche differences. This often underlies inferences on the importance of Environmental Filtering vs. Competition in structuring communities...

But modern coexistence theory & many plant 🌱 studies suggest that species’ trait differences can also reflect differences in their competitive abilities for the same resources. May such trait-mediated hierarchical competition likewise structure animal communities?...

In a field study of a fire #ant🐜invasion, I investigated whether trait differences between the invader & resident ant species reflected the effects of Environmental Filtering, Limiting Similarity-Competition, or Hierarchical Competition in structuring the invaded communities...

With help from @chimanleong & @Rogerholee, I measured a suite of morphological, dietary, physiological & behavioural traits for the 17 ant species collected in the field (lots of fun, lots of work!) Then used species' trait differences to model invasion success...

Interestingly, invasion success was attributed to the effects of Limiting Similarity-Competition in some traits (e.g. Body Size), but also Hierarchical Competition in others (e.g., Head Width, Trophic Position, Interference Ability); differences in CTmax were a bit of both...

Clearly, body size-differences aren't the be all & end all of competitive interactions. E.g., smaller fire ants have stronger interference ability (ability to usurp & defend resources) than larger native ants. Such hierarchical competition likely structures invaded communities...

Moreover, the two different competition mechanisms led to distinct trait patterns in the invaded communities. Limiting-Similarity Competition drove overdispersion in some traits, while Hierarchical Competition drove clustering in others...

Importantly, this suggests that inferences on the importance of competition (& the specific mechanism at play) cannot not simply be drawn from patterns in the multidimensional trait structure of the communities (as is commonly done in observational studies)...

& thus, we call for observational studies of animal communities to consider a more nuanced view of the role of trait differences & competition in shaping community assembly & responses...

For more, the full paper is available Open Access: royalsocietypublishing.org/doi/10.1098/rs… Big thanks to my amazing collaborators @chimanleong @Rogerholee, supervisors @OwenTLewis & Benoit Guénard,@MyrmecoFrank for ant photos, & funding from @InsideNatGeo, @UniofOxford, @ForrestResearch 🐜 !

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