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

Area of Science:

• * Evolutionary Biology
• * Molecular Ecology
• * Insect Physiology

Background:

• * Natural populations must balance resource allocation for survival and reproduction amidst seasonal changes.
• * A known trade-off exists between migration and reproduction in insects, but regulatory pathways remain unclear.
• * Understanding these pathways is crucial for explaining insect migratory behavior and adaptation.

Purpose of the Study:

• * To investigate how environmental cues related to resource availability influence gene transcription during development in the long-distance migrant butterfly, Vanessa cardui.
• * To identify the molecular mechanisms underlying the trade-off between migration and reproduction.
• * To connect environmental context to the molecular basis of migratory behavior across developmental stages.

Main Methods:

• * A multi-cue, developmental stage-specific experimental design was employed.
• * Adult Vanessa cardui females were exposed to host plant presence or absence.
• * Larvae experienced controlled conditions of food limitation or crowding.

Main Results:

• * Adult exposure to host plants altered expression in ecdysteroid and juvenile-hormone pathways, indicating endocrine regulation of reproduction and flight.
• * Larval resource limitation impacted developmental and metabolic pathways, suggesting carry-over effects on adult traits.
• * Metabolism emerged as a key molecular pathway linking transcriptional responses across different life stages.

Conclusions:

• * Resource-driven environmental cues induce stage-specific and general transcriptional changes in Vanessa cardui.
• * These transcriptional signatures connect environmental conditions to the molecular underpinnings of migratory behavior.
• * The findings provide insights into the endocrine and metabolic regulation of the oogenesis-flight syndrome in migratory insects.