What explains vast differences in jumping power within a clade? Diversity, ecology and evolution of anuran jumping power

Abstract

1. Anuran (frog and toad) jumping power varies greatly across species, yet muscle power does not. Given that the jumping power of some species is up to five times higher than typical muscle power, power amplification by elastic elements is suggested to explain this discrepancy. However, the ecological reasons for this variation in jumping power remain unclear. One hypothesis is that small jumpers are limited by the time available to accelerate their body during take-off, leading to small species needing greater power production than larger species to achieve similar jumping performance. Another (non-mutually exclusive) hypothesis is that the microhabitat species inhabit may drive variation through trade-offs with performance in microhabitat-specific, non-jumping behaviours.2. We compared jumping power across 68 anuran species that were diverse in evolutionary relationships, microhabitat use and body mass. We used phylogenetic comparative methods to compare the role of microhabitat and body mass in explaining variation in jumping power across species.3. We found the strongest support for a model that included two factors and their interaction. First, as body mass increased, jumping power decreased. Second, species that burrowed showed lower jumping power than species that did not burrow.Third, the interaction between body mass and burrowing behaviour showed that jumping power declines more rapidly with body mass in burrowing species than non-burrowing species.4. The effect of body mass suggests that interspecific variation in jumping power might be partly explained by scaling relationships. Anurans with small body mass may be able to achieve similar locomotor performance (e.g. takeoff velocity) as those with larger body mass, by more effectively amplifying muscle power.Additionally, the effect of burrowing behaviour suggests that species that use hindlimbs to burrow may experience a reduction in their ability to generate jumping power. This may indicate a functional trade-off between jumping and burrowing performance. K E Y W O R D S body mass, burrowing, comparative biology, frogs, microhabitat, power amplification, trade-offs S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section.

A Morphological Method to Approximate Jumping Performance in Anurans for Macroevolutionary Studies

“…leg muscle mass) and species with more than one individual. Additionally, we did not include Astley's (2016) data on Heterixalus alboguttatus because these values showed unusually low performance for this genus; power values were more than an order of magnitude lower than our (DSM's) unpublished data on two other congeners and are inconsistent with all other published data on arboreal frogs of the same body size (Mendoza et al 2020). Overall, our dataset comprised morphological measures and jumping performance from a total of 256 adult anurans from 51 species, which spanned a wide body-size range and were found in a variety of microhabitats.…”

“…However, since back muscles make up <0.5% of body mass (Emerson and DeJongh 1980), their contribution to jumping is small compared to leg muscle mass, which makes up 5-30% of body mass in anurans (Mendoza et al 2020). Furthermore, Clemente and Richards (2013) found that plantaris muscle force scaled with body mass to the 0.94 power in Xenopus laevis, and not 2/3 as predicted above by geometric isometry.…”

“…The preserved length measurements included length of the femur, tibiofibula, tarsus, and foot. We obtained estimates of wet muscle mass for these individuals from Mendoza et al (2020), who estimated wet muscle mass for the Moen et al (2013) taxa as the product of live body mass and the live muscle-mass-to-body-mass ratio from a subset of taxa for which both types of data were available. These wet muscle mass estimates from Mendoza et al (2020) came from the same individuals for which linear measurements were obtained (Moen et al 2013).…”

Comparative osteology of the fossorial frogs of the genus Synapturanus (Anura, Microhylidae) with the description of three new species from the Eastern Guiana Shield

“…Notably, in the fossorial Hemisus (Engelkes et al, 2020) and in the semifossorial Hamptophryne (de Sá & Trueb, 1991) and may provide a strong, fixed arch against which the muscles of the shoulder and arm brace to enable digging. These characteristics are seemingly accompanied by a reduction of the size of phalanges, more developed fringes on the fingers, smaller eyes and an increase in body size, altogether suggesting an overall increase of the fossorial habits of these species (Emerson, 1976;Mendoza et al, 2020;Thomas et al, 2020). In contrast, the differences in the posterior part of the body are subtle among all Synapturanus species.…”

“…This fusion may thus confer the Synapturanus of the western clade strong jumping abilities related to their leaf-litter habitat (Fabrezi et al, 2017). Mendoza et al (2020) found that jumping power declines more rapidly with body mass in burrowing species of frogs than non-burrowing species and suggested the existence of a functional trade-off between jumping and burrowing performance. Therefore, the smaller size of these species compared to the ones of the eastern clade also strengthens the idea that they are more epigean.…”