# Metabolic adaptations underlie life-history evolution in a range expanding arthropod

## TL;DR

This study shows how metabolic changes in spider mites support their life-history evolution during range expansion.

## Contribution

The first demonstration of metabolic adaptations underlying life-history evolution during species range expansion.

## Key findings

- Metabolic differentiation was observed along a latitudinal gradient during range expansion.
- Northern populations with higher dispersal had lower amino acid concentrations, suggesting metabolic pathway downregulation.
- Metabolic changes covaried with previously documented life-history traits in expanding mite populations.

## Abstract

During range expansions or range shifts, species’ life histories evolve due to changing selection pressures or spatial sorting. Despite an increasing number of studies documenting such life-history evolution, we lack a mechanistic understanding of the underlying physiological processes.
We used a powerful metabolomics approach to study physiological changes associated with the recent range expansion of a model arthropod, the two-spotted spider mite Tetranychus urticae.
Mite populations were sampled in the field along a latitudinal gradient from range core to range edge, and reared under common garden conditions for two generations. Thereafter, we obtained metabolic population profiles using Gas Chromatography-Mass Spectrophotometry (GC-MS).
We found gradual metabolic differentiation along the latitudinal gradient, indicating rapid evolution of the metabolome in association with range expansion. In addition, we observed that some of this differentiation covaried with the life-history evolution previously found to be associated with the mite’s range expansion.
Particularly, more northern populations, which evolved a higher dispersal tendency, showed lowered concentrations of several essential and non-essential amino acids, suggesting a downregulation of certain metabolic pathways and a potential dispersal-foraging trade-off.
This study is the first to demonstrate how metabolic adaptations might underlie life-history evolution during range expansion.

During range expansions or range shifts, species’ life histories evolve due to changing selection pressures or spatial sorting. Despite an increasing number of studies documenting such life-history evolution, we lack a mechanistic understanding of the underlying physiological processes.

We used a powerful metabolomics approach to study physiological changes associated with the recent range expansion of a model arthropod, the two-spotted spider mite Tetranychus urticae.

Mite populations were sampled in the field along a latitudinal gradient from range core to range edge, and reared under common garden conditions for two generations. Thereafter, we obtained metabolic population profiles using Gas Chromatography-Mass Spectrophotometry (GC-MS).

We found gradual metabolic differentiation along the latitudinal gradient, indicating rapid evolution of the metabolome in association with range expansion. In addition, we observed that some of this differentiation covaried with the life-history evolution previously found to be associated with the mite’s range expansion.

Particularly, more northern populations, which evolved a higher dispersal tendency, showed lowered concentrations of several essential and non-essential amino acids, suggesting a downregulation of certain metabolic pathways and a potential dispersal-foraging trade-off.

This study is the first to demonstrate how metabolic adaptations might underlie life-history evolution during range expansion.