Oxidation and allocation of nectar amino acids during butterfly flight

Flying animals face extreme energetic demands, relying mainly on carbohydrates and lipids, with occasional contributions from proteins and amino acids. In nectar-feeding species such as butterflies and hummingbirds, sugars are the primary fuel, yet the extent to which nectar-derived amino acids support flight versus other functions remains unclear. Using 13C-labelled nectar, we tracked the metabolic fate of sugars and amino acids during flight in Pieris rapae butterflies. We found that proline and glycine, two abundant nectar amino acids, were oxidized alongside sugars. We also compared females subjected to low- versus high-intensity flight. High flight intensity females incorporated less glycine into tissues, implying greater diversion toward energy use during flight. In contrast, they deposited more threonine – an essential amino acid – into their abdomens, prioritizing reproduction and storage. These findings reveal the role of nectar-derived nutrients in supporting locomotion and re..., , # Oxidation and allocation of nectar amino acids during butterfly flight

Data for Tigreros et al. (2026). Article DOI: [https://doi.org/10.1242/jeb.251674](https://doi.org/10.1242/jeb.251674)

## Description of data

This repository contains data from two experiments examining the use and allocation of nectar-derived carbon to flight and reproduction in the cabbage white butterfly (Pieris rapae), using stable carbon isotope techniques.

### Data files

**breathFlight.csv** — Experiment 1: Carbon isotope composition of CO2 exhaled during flight.

Variables:
* ID: Butterfly identifier
* Nectar: Adult nectar treatment
* CO2: CO2 production during flight
* Delta: δ13C (‰) of exhaled CO2

Used to test whether nectar-derived carbon fuels flight.

**Delta_flight2025.csv** — Experiment 2: Carbon isotope composition of butterfly tissues following nectar and flight treatments.

Variables:
* Block: Experimental block
* ID: Butterfly identifier
* Nectar: Adult nectar treatment
* Flight: F...,