Evolution of Body Mass in Bats: Insights from a Large Supermatrix Phylogeny

Abstract

Bats are atypical small mammals. Size is crucial for bats because it affects most aerodynamic variables and several key echolocation parameters. In turn, scaling relationships of both flight and echolocation have been suggested to constrain bat body size evolution. Previous studies have found a large phylogenetic effect and the inclusion of early Eocene fossil bats contributed to recover idiosyncratic body size change patterns in bats. Here, we test these previous hypotheses of bat body size evolution using a large, comprehensive supermatrix phylogeny (+800 taxa) to optimize body size and examine changes reconstructed along branches. Our analysis provides evidence of rapid stem phyletic nanism, an ancestral value stabilized at 12 g for crown-clade Chiroptera followed by backbone stasis, low-magnitude changes inside established families, and massive body size increase at accelerated rate in pteropodid subclades. Total variation amount explained by pteropodid subclades was 86.3%, with most changes reconstructed as phyletic increases but also apomorphic decreases. We evaluate these macroevolutionary patterns in light of the constraints hypothesis, and in terms of both neutral and adaptive evolutionary models. The reconstructed macroevolution of bat body size led us to propose that echolocation and flight work as successive, nested constraints limiting bat evolution along the body size scale.

Dietary and body mass reconstruction of the Miocene neotropical batNotonycteris magdalenensis(Phyllostomidae) from La Venta, Colombia

“…In agreement with our DTA, this could indicate that N. magdalenensis was not a specialised carnivore and could have instead had an insectivorous or omnivorous diet, similar to other omnivorous, large-bodied Miocene noctilionoid species (Hand et al 2015b. Other studies have estimated phyllostomid BM ancestral state range as between 11-12 g, close to the ancestral state for Noctilionoidea (9-12 g) and modern Chiroptera (12-14 g) (Arévalo 2020, Giannini et al 2012, 2020, Moyers Arévalo et al 2018. This suggests relative evolutionary stasis in body size during the early evolution of modern bat families, most of which had evolved and/or had appeared in the fossil record before the early Oligocene (~35 Mya) (Arévalo 2020, Giannini et al 2012, Moyers Arévalo et al 2018.…”

“…Other studies have estimated phyllostomid BM ancestral state range as between 11-12 g, close to the ancestral state for Noctilionoidea (9-12 g) and modern Chiroptera (12-14 g) (Arévalo 2020, Giannini et al 2012, 2020, Moyers Arévalo et al 2018. This suggests relative evolutionary stasis in body size during the early evolution of modern bat families, most of which had evolved and/or had appeared in the fossil record before the early Oligocene (~35 Mya) (Arévalo 2020, Giannini et al 2012, Moyers Arévalo et al 2018. Within Phyllostominae, a significant shift to increased size to more than 50 g has been recovered for the clade including C. auritus and V. spectrum (divergence dated at around 16 Mya), highlighting a rapid gain of > 30 g in the first 10 My following the origin of Phyllostomidae (Arévalo 2020).…”

“…With the exception of Trachops cirrhosus (~35 g), all carnivorous phyllostomids have average body masses higher than 70 g, well above the average for any other diet (Moyers Arévalo et al 2018, Norberg and Fenton 1988, Santana and Cheung 2016. V. spectrum, thought to be the closest living relative of N. magdalenensis, is the largest bat in the New World (BM ~170 g), and regarded to be an example of the coevolution of increased body size and carnivory in Phyllostomidae (Arévalo 2020, Moyers Arévalo et al 2018. Our estimate of BM for N. magdalenensis (~53 g) based on m1 area indicates that this species was smaller than most phyllostomid carnivores, larger than most insectivores, and within the range of omnivorous phyllostomids.…”

Detection of Tioman Virus in Pteropus vampyrus Near Flores, Indonesia

“…Flying foxes in the genera Pteropus and Acerodon include the world's largest bats (forearm size >89 mm and body mass up to 1600 g) and with 70 species, they constitute over a third of all species in the family Pteropodidae [16,17]. Indonesia is home to about a third of all flying fox species (21 Pteropus spp.…”

Inferring coevolution in a plant–pollinator network

“…a phylogenetic tree). Although generally assumed to require slow evolutionary rate to report reasonable results (Omland ), recent research shows that very high evolutionary rates of character change is as faithfully captured by parsimony reconstruction as small, even erratic changes (Moyers Arévalo et al ). In addition, parsimony does not require specification of branch length and can successfully reconstruct evolutionary changes that allowed us to incorporate a wide diversity of taxa for which there was no published phylogeny with branch lengths available.…”