Disentangling the interrelations of body mass, egg deposition site, climate and microhabitat use in frogs and salamanders
Data files
Oct 27, 2025 version files 808.42 KB
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Data_sources_Cejp_Griebeler.txt
22.76 KB
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Dataset_Cejp_Griebeler.csv
340.97 KB
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Dataset_Cejp_Griebeler.xlsx
413.96 KB
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RCode_Cejp_Griebeler.txt
27.76 KB
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README.md
2.96 KB
Abstract
Amphibians exhibit a large diversity in reproductive and developmental strategies, which in turn are linked to their body size, life history and habitat. Here, we explore why terrestrial egg-laying frogs are on average smaller than aquatic egg-laying ones and whether this pattern exists in salamanders, too. We hypothesized that egg deposition site and body mass are not linked directly across species, but that terrestrial egg layers occur in climates and use microhabitats that favor small masses. To test this, we compiled a dataset on egg deposition site (terrestrial or aquatic), development mode (biphasic with larvae or direct development without larvae), body mass, microhabitat use (water-dependent, ground-dwelling or arboreal) and climate within their distribution area (temperature, precipitation and seasonality in both) of 3091 frog and 244 salamander species. We analyzed the interrelations between these traits and environmental factors by using a cross-species approach and phylogenetic generalized least squares analysis. Body masses increased along a gradient from warm, humid and unseasonal climates to cold, dry and seasonal climates in frogs and salamanders. Terrestrial egg deposition was constrained to warm, humid and unseasonal climates only in frogs. Terrestrial eggs and an arboreal microhabitat use were linked in frogs and salamanders, and arboreal frogs were smaller than non-arboreal ones. We confirmed that frogs with terrestrial eggs had smaller average body masses than those with aquatic eggs, irrespective of their development mode, but this difference disappeared when we corrected body masses for the effects of climate and microhabitat use. In salamanders, however, egg deposition site and development mode were neither directly related to body mass, nor indirectly via the effects of climate and microhabitat use. Our results suggest that thermal and hydric environmental conditions determine the geographical distribution of body mass and reproductive strategies in amphibians and set the framework for their evolution.
Dataset DOI: 10.5061/dryad.9cnp5hqz0
Description of the data and file structure
The data in "Dataset_Cejp_Griebeler.xlsx" and "Dataset_Cejp_Griebeler.csv" were collected from the literature sources listed in "Data_sources_Cejp_Griebeler.txt". The data were used in the analyses for which the code is provided in RCode_Cejp_Griebeler.txt.
In the study, we compared body mass differences between frog and salamander species of different reproductive modes. We explored whether these differences could be a consequence of 1) thermal and hydric needs of adult individuals constraining body mass differently in different climates and microhabitats, and of 2) thermal and hydric needs of eggs constraining terrestrially egg laying species to those climates and microhabitats in which species are constrained to small adult body masses. For more detail, refer to the published article.
Files and variables
File: Dataset_Cejp_Griebeler.xlsx
Description: Dataset_Cejp_Griebeler.xlsx contains the data used in the study. There are 3091 frog species and 244 salamander species in the dataset. For each of them, the dataset contains information on the variables listed below. For more details and a description of the analyses, refer to the methods section in the published article.
Variables
- Order (Anura or Caudata)
- Family (following Frost 2024)
- Species_Tree (Species names using the nomenclature of the phylogenetic tree of Jetz & Pyron 2018),
- mean body mass (grams)
- microhabitat use (water-dependent, ground-dwelling, or arboreal)
- reproductive mode (Aq-L: aquatic eggs and biphasic, larval development; Ter-L: terrestrial eggs and biphasic, larval development; Ter-D: terrestrial eggs and direct development without a larval stage)
- PC1 and PC2 values calculated from the mean values across the species distribution area of:
- BIO1 (mean annual temperature, °C)
- BIO7 (annual temperature range, °C)
- BIO 12 (total annual precipitation, mm)
- BIO15 (precipitation seasonality, coefficient of variation)
File: Dataset_Cejp_Griebeler.csv
Description: Dataset_Cejp_Griebeler.csv contains the same data table as Dataset_Cejp_Griebeler.xlsx but is in a tab-delimited csv format.
File: Data_sources_Cejp_Griebeler.txt
Description: Data_sources_Cejp_Griebeler.txt contains a list of the literature surveyed to gather the data.
File: RCode_Cejp_Griebeler.txt
Description: RCode_Cejp_Griebeler.txt contains the R-code to conduct the analyses.
Code/software
All analyses were done in R version 4.4.0. All required packages are listed in the methods section of the published article and in the RCode_Cejp_Griebeler.txt.
Access information
Data was derived from the following sources:
- see Data_sources_Cejp_Griebeler.txt