Data from: Desert lizards modulate their nutritional responses to match seasonal biological needs
Data files
Nov 26, 2025 version files 70.65 KB
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datasets_seasonal_nutritional_responses_in_desert_lizards.xlsx
64.32 KB
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README.md
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Abstract
Animals in extreme environments, such as deserts, experience severe seasonal fluctuations in abiotic conditions and resources. Under these conditions, they must obtain macronutrients in optimal amounts and ratios to meet their nutritional requirements, which themselves vary with seasonal changes in physiological and life-history processes. To understand whether nutritional intakes and retention align with key life-history events across seasons, we examined the nutritional ecology of the desert-dwelling lizard Saara hardwickii. We first measured seasonal variation in the quantity and quality of plants available for these herbivorous lizards. By combining field observations of foraging behaviour with elemental analysis, we determined carbon (C) and nitrogen (N) levels in dietary intakes and faecal matter across seasons. Intake C: N was lowest and faecal C: N highest in June, reflecting greater proportional consumption and retention of N, likely meeting increased protein demands during breeding. Conversely, dietary C: N and faecal %N were highest in October, indicating greater consumption and retention of C prior to hibernation. Surprisingly, these putative herbivores consumed insects only around the breeding season, despite their year-round availability. Overall, we show that S. hardwickii employs both behavioural diet choice and post-ingestive physiology to match seasonal nutritional needs by differentially consuming and retaining nutrients in an extreme environment.
Dataset DOI: 10.5061/dryad.sn02v6xjz
Description of the data and file structure
Research permission and ethical approval: Saara hardwickii is protected under Indian Wildlife Protection Act (1972), so we acquired the Rajasthan Forest Department permit to work in Jorbeer Gadhwala Conservation Reserve and collect plant and faecal samples. Since all our data on this species was observational, we did not need any ethical approval for this study.
Files and variables
File: datasets_seasonal_nutritional_responses_in_desert_lizards.xlsx
Description of data and file structure (Sheet1): This datasheet contains raw measurements of %C, %N, and C:N of all the components in S.hardwickii diets across seasons.
Variables
- season: four sampling seasons - April, June, August, and October
- Diet component: all the plant species available for the lizards to eat in their habitat, and the insects they consumed across the four seasons
- C: N: carbon to nitrogen ratios for each dietary component
- %C: proportion of elemental carbon in the dietary component
- %N: proportion of elemental nitrogen in the dietary component
Description of data and file structure (Sheet2): This datasheet contains data on wet biomass, species composition, and relative abundance of all the plant species consumed by S. hardwickii across seasons.
Variables
- seasons: four sampling seasons -April, June, August, and October
- biomass (g/sqm): total mass of all the grasses and herbs present in 1a square meter area under the quadrat
- total biomass (g/400sqm): calculated biomass for the entire sampling plot of 20 x 20 meters
- dact: mean percentage area of the quadrat covered by Dactyloctenium sp.
- euph: mean percentage area of the quadrat covered by Euphorbia sp.
- helio: mean percentage area of the quadrat covered by Heliotropium sp.
- aerva: mean percentage area of the quadrat covered by Aerva sp.
- sum: total percentage area covered by all the plants
- %d: proportion of the total biomass constituted by Dactyloctenium sp.
- %e: proportion of the total biomass constituted by Euphorbia sp.
- %h: proportion of the total biomass constituted by Heliotropium sp.
- %a: proportion of the total biomass constituted by Aerva sp.
- d: absolute biomass of Dactyloctenium sp. in the plot
- e: absolute biomass of Euphorbia sp. in the plot
- h: absolute biomass of Heliotropium sp. in the plot
- a: absolute biomass of Aerva sp. in the plot
Description of data and file structure (Sheet3): This datasheet contains raw data for bite counts of all food items consumed by S. hardwickii across seasons.
Variables
- plot: plot IDs for all the plots marked for sampling across seasons
- season: four sampling seasons - April, June, August, and October
- dact_bc: absolute number of bite counts of Dactyloctenium per day
- euph_bc: absolute number of bite counts of Euphorbia per day
- helio_bc: absolute number of bite counts of Heliotropium per day
- aerva_bc: absolute number of bite counts of Aerva per day
- insects_bc: absolute number of bite counts of insects per day
Description of data and file structure (Sheet 4): This datasheet contains data on diet composition and the contribution of each food item to the diet of S. hardwickii across seasons.
Variables
- plot: plot IDs for all the plots marked for sampling across seasons
- season: four sampling seasons -April, June, August, and October
- dact_g: amount of Dactyloctenium consumed per day in grams
- euph_g: amount of Euphorbia consumed per day in grams
- helio_g: amount of Heliotropium consumed per day in grams
- aerva_g: amount of Aerva consumed per day in grams
- insects_g: amount of insects consumed per day in grams
- total (g): total biomass consumed per day in grams
- dact_%m: proportion of the total biomass constituted by Dactyloctenium
- euph_%m: proportion of the total biomass constituted by Euphorbia
- helio_%m: proportion of the total biomass constituted by Heliotropium
- aerva_%m: proportion of the total biomass constituted by Aerva
- insects_%m: proportion of the total biomass constituted by insects
- dact_%c: proportion of the total consumed carbon constituted by Dactyloctenium
- euph_%c: proportion of the total consumed carbon constituted by Euphorbia
- helio_%c: proportion of the total consumed carbon constituted by Heliotropium
- aerva_%c: proportion of the total consumed carbon constituted by Aerva
- insects_%c: proportion of the total consumed carbon constituted by insects
- dact_%n: proportion of the total consumed nitrogen constituted by Dactyloctenium
- euph_%n: proportion of the total consumed nitrogen constituted by Euphorbia
- helio_%n: proportion of the total consumed nitrogen constituted by Heliotropium
- aerva_%n: proportion of the total consumed nitrogen constituted by Aerva
- insects_%n: proportion of the total consumed nitrogen constituted by insects
Description of data and file structure (Sheet5): This datasheet contains data on the elemental composition of S. hardwickii diets across seasons.
Variables
- plot: plot IDs for all the plots marked for sampling across seasons
- season: four sampling seasons - April, June, August, and October
- intake_cn: C: N ratio of total daily dietary intake
- total_c: total daily consumption of carbon in grams
- total_n: total daily consumption of nitrogen in grams
- total_mass: total biomass consumed per day in grams
- prop_c: proportion of the dietary mass constituted by carbon
- prop_n: proportion of the dietary mass constituted by nitrogen
Description of data and file structure (Sheet6): This datasheet contains data on the elemental composition of S. hardwickii faecal matter across seasons.
Variables
- plot: plot IDs for all the plots marked for sampling across seasons
- season: four sampling seasons - April, June, August, and October
- faecal_cn: C: N ratio of the faecal matter collected from each plot
- faecal_c%: proportion of the faecal matter constituted by carbon
- faecal_n%: proportion of the faecal matter constituted by nitrogen
We sampled S. hardwickii from April to October 2022 in Jorbeer-Gadhwala Conservation Reserve, Rajasthan, India. All measurements were repeated in the same 20 plots of 20x20m across four seasons - April, June, August, and October. Since these desert lizards are known to be herbivorous, we estimated the plant species composition and wet biomass by setting up 20 smaller quadrats of 1x1m in each of the larger sampling plots. We carried out behavioural focal observations in a separate sampling plot each day and recorded all the items and their amounts consumed by these lizards throughout the day. At the end of focal observations, we collected samples of all the consumed food items from the same plot to measure the nutritional composition of each dietary component. We also collected fresh faecal pellets from each plot to estimate their elemental composition and infer about retained nutrients. Elemental composition was measured for all the dietary components and faecal matter, and this information was combined with behavioural data to estimate the nutritional composition of diets across seasons (N = 20/season).