# Resource Availability Modulates Gene Expression Across Life Stages in a Migratory Butterfly

## TL;DR

This study shows how resource availability affects gene expression in different life stages of a migratory butterfly, linking environmental cues to migratory behavior.

## Contribution

The study reveals how resource-related cues influence gene expression across life stages in a migratory butterfly, uncovering molecular mechanisms behind migration-reproduction trade-offs.

## Key findings

- Adult exposure to host plants affects ecdysteroid and juvenile-hormone pathways, influencing reproductive readiness.
- Larval resource limitation alters developmental and metabolic pathways, potentially affecting adult traits.
- Metabolism is a shared axis linking gene expression responses across life stages.

## Abstract

Natural populations are in constant need of balancing resource allocation to compensate for seasonal environmental variation. In many insects, a well‐established trade‐off between migration and reproduction exists. While this trade‐off has been characterised phenotypically for decades, the underlying regulatory pathways are poorly understood. Here, we examined how resource‐related environmental cues shape transcription across development in the long‐distance migrant butterfly
Vanessa cardui
. In a multi‐cue, developmental stage‐specific design, adult females were exposed to host‐plant presence or absence, while larvae experienced food limitation or crowding. Adult exposure to host plants was associated with differential expression in ecdysteroid and juvenile‐hormone pathways, consistent with endocrine regulation of reproductive readiness and predictions of the oogenesis–flight syndrome. Larval resource limitation altered developmental and metabolic pathways, suggesting molecular predispositions and potential carry‐over effects to adult traits. Across all contrasts, metabolism emerged as a shared axis linking responses across life stages. Together, our results show that resource‐driven cues leave both stage‐specific and general transcriptional signatures that connect environmental context with the molecular basis of migratory behaviour.