Diversification and functional evolution of reef fish feeding guilds

Abstract

A core eco‐evolutionary aim is to better understand the factors driving the diversification of functions in ecosystems. Using phylogenetic, trophic, and functional information, we tested whether trophic habits (i.e. feeding guilds) affect lineage and functional diversification in two major radiations of reef fishes. Our results from wrasses (Labridae) and damselfishes (Pomacentridae) do not fully support the ‘dead‐end’ hypothesis that specialisation leads to reduce speciation rates because the tempo of lineage diversification did not substantially vary among guilds in both fish families. Our findings also demonstrate a tight relationship between trophic habits and functional roles held by fish in reef ecosystems, which is not associated with a variation in the tempo of functional diversification among guilds. By illustrating the pivotal importance of the generalist feeding strategy during the evolutionary history of reef fishes, our study emphasises the role of this feeding guild as a reservoir for future diversity.

Trophic innovations fuel reef fish diversification

“…Using near-complete phylogenies, coupled with a comprehensive ecological and geographical dataset, we identified species trophic guild and body size as major drivers of diversification in reefassociated fishes. Although the role of different types of resource use has been previously suggested as a driver of evolutionary rates in some reef fish groups [25][26][27][28]31,33 , we reveal its full potential across the complete reef fish tree of life. Through an intricate relationship with body size, the trophic identity of species was more important in predicting the pace of reef fish evolution than any other ecological or geographical factor examined.…”

“…In the latter group, extinction rates were estimated to be even higher than speciation, leading the authors to flag omnivory as a macroevolutionary sink. Although this was not the case for reef fishes in both small 31 and large taxonomic scales, low historical rates of diversification in omnivorous lineages seem to be a common pattern in vertebrate evolution.…”

“…Although recent studies have independently explored these potential ecological mechanisms or geographical factors underlying reef fish diversification patterns (e.g., refs. 16,25,[29][30][31][32] ), they are yet to be examined in a comparative analytical framework capable of quantifying relative support.…”

The macroecology of reef fish agonistic behaviour

“…This speciose group is an example of convergent and iterative radiation in the ocean (Frédérich et al ) with surprisingly low trophic diversification compared to other reef fish lineages (e.g. Labridae; Gajdzik et al ). Several factors might have contributed to this repeated pattern of adaptive radiation among damselfishes, such as the presence of many potential competitors (e.g.…”

Phylogenetic measures reveal eco‐evolutionary drivers of biodiversity along a depth gradient

“…1bii, biii, cii). Second, if long-term stability decreases extinction, and increases the opportunity for speciation through specialization (Jansson and Dynesius 2002, Kozak and Wiens 2012, Salisbury et al 2012, Rolland and Salamin 2016, Gajdzik et al 2019, we expect PD and MPD to increase with depth toward more stable environments, while VPD and MNTD should decrease with depth ( Fig. 1bii, iv, d).…”