COS 211-2 - Conservatism in Ecological and Competitive Traits: Phylogenetic Patterns to Inform Assembly of Novel Communities in Damselflies (Odonata: Zygoptera)

Abstract: Range shifting, a common response to climate change, can lead to novel interactions between range shifting species and local endemics, the outcomes of which can be potentially damaging for local biodiversity. Understanding the process of species community assembly, which dictates whether newly introduced species can coexist alongside established species, is therefore paramount to understanding the impacts of range shifting. Phylogenetic patterns of trait conservation have often been used to inform community assembly under competition, with conservatism of niche traits thought to lead to phylogenetic overdispersion of communities shaped by stabilizing forces, whereas conservatism of competitive traits predicts underdispersion of communities shaped by equalizing forces. Here we investigate the conservatism of competitive vs. niche traits in the damselfly superfamily Coenagrionoidea (Odonata: Zygoptera), to determine the likely community assembly process of novel competition in response to range shifting in this group. Odonates are among the most rapidly range shifting of all insect clades, and previous research indicates that competitive exclusion in impacted communities may be mediated by competitive rather than niche traits. Damselfly morphological and behavioural traits were split into two groups, those pertaining to niche use and those contributing to competitive ability, and were modelled for both phylogenetic signal and more widespread trait conservatism. We found that competitive traits display strong phylogenetic signal, showing high values of Pagel’s lambda and greater proportions of nodes evolving at BM (Variable Rates model). Niche traits exhibited stronger stabilising tendencies, displaying strong selective forces towards phylogeny-wide trait optima, returning high alpha-values from OU models. These results suggest that while distantly related species will have similar ecological requirements, competition will be better balanced between closely related species, predicting a phylogenetic clustering pattern to competitive outcomes following range shifting.