Repeated dietary shifts in elapid snakes (Squamata: Elapidae) revealed by ancestral state reconstruction

Abstract

Identifying the traits of ancestral organisms can reveal patterns and drivers of organismal diversification. Unfortunately, reconstructing complex multistate traits (such as diet) remains challenging. Adopting a ‘reconstruct, then aggregate’ approach in a maximum likelihood framework, we reconstructed ancestral diets for 298 species of elapid snakes. We tested whether different prey types were correlated with one another, tested for one-way contingency between prey type pairs, and examined the relationship between snake body size and dietary composition. We demonstrate that the evolution of diet was characterized by niche conservation punctuated by repeated dietary shifts. The ancestor of elapids most likely fed on reptiles and possibly amphibians, with deviations from this ancestral diet occurring repeatedly due to shifts into marine environments and changes in body size. Moreover, we demonstrate important patterns of prey use, including one-way dependency—most obviously the inclusion of eggs being dependent on a diet that already included the producers of those eggs. Despite imperfect dietary data, our approach produced a robust overview of dietary evolution. Given the paucity of natural history information for many organisms, our approach has the potential to increase the number of lineages to which ancestral state reconstructions of multistate traits can be robustly applied.

Body size predicts prey preference but not diet breadth in pythons

“…Regardless of phylogenetic relatedness, we found that large‐bodied python species showed an increased preference to consume endotherms, whereas smaller species more frequently use ectotherms. Similar relationships between snake size and endotherm prey utilization have been observed in some species of elapids (Maritz et al., 2021) and in New World lampropeltines (Pyron & Burbrink, 2009). Importantly, all of the larger‐most species of pythons (i.e.…”

“…Several factors other than body size can influence the evolution of differential prey use by snakes. Notably, ecological opportunity afforded by geographic colonization of novel habitats is among the most influential drivers of the evolution of diet in snakes (Barends & Maritz, 2022a; Greene, 1997; Grundler & Rabosky, 2021; Maritz et al., 2021; Naik et al., 2021). The most recent common ancestor of the pythons likely originated in Asia during the Oligocene before subsequently dispersing through Africa and Oceania respectively (Esquerré et al., 2020).…”

“…Accordingly, all else being equal, large‐bodied snakes with wide gapes should theoretically be able to consume a broader variety of prey compared to small‐bodied snakes with narrow gapes (King, 2002; Rodríguez‐Robles et al., 1999). In reality, increases in snake body size typically correlate with disproportionate increases in the proportional use of endothermic prey types within their diets (Maritz et al., 2021; Naik et al., 2021; Pyron & Burbrink, 2009). As a result, larger species often have broader dietary niche breadths compared to smaller species (Barends & Maritz, 2022a).…”

High-throughput proteomics and in vitro functional characterization of the 26 medically most important elapids and vipers from sub-Saharan Africa

“…As an exception, D. polylepis is often (but not always) more ground-dwelling than its congeners, being commonly found in open savannas and rocky hills [ 44 , 45 ]. Overall, mambas mainly prey on birds and small mammals such as rodents and bats [ 42 , 46 ], although their diet and ecology are poorly known.…”

When can we reconstruct the ancestral state? Beyond Brownian motion

“…The main task of the ancestral state reconstruction problem is to estimate the trait value of the most recent common ancestor of a group of species from their observed trait values. This problem has many applications in ecology and evolution, such as reconstructing ancestral diets (Maritz et al, 2021), studying female song in songbirds (Odom et al, 2014), and inferring the origin of infectious disease epidemics (Faria et al, 2014;Gill et al, 2017). Moreover, ancestral state reconstruction methods have been applied to reconstruct the place of origin of a language family (Bouckaert et al, 2012;Neureiter et al, 2021).…”