Elevational gradients are frequently linked to dramatic biodiversity shifts, but the drivers and dynamics of alpine adaptation often remain unclear. A Batesian mimicry polymorphism in Aotearoa New Zealand stoneflies provides an ideal system for assessing the role of elevational gradients in selecting for melanic (dark) versus non-melanic (light) colour phenotypes. Although previous studies have proposed that melanism should be favoured in alpine ecosystems, we find the opposite pattern, with consistently reduced frequencies of dark phenotypes detected in upland versus lowland habitats. Specifically, parallel alpine reductions in frequencies of melanic (mimic) Zelandoperla (approx. 1500 specimens genotyped across 7 independent stream populations) are linked to reduced abundance of the noxious model Austroperla above the alpine treeline. Our findings highlight that shifting ecological interactions across environmental gradients can drive rapid evolutionary change over fine spatial scales.
- 9926883785701891
- Alpine adaptation drives rapid colour evolution in a Batesian mimic
- Kahu HemaGraham A McCullochJonathan M Waters
- Zoology
- Biology letters, Vol.22(6), 20260052
- The Royal Society
- 24/06/2026
- Adapting to NZ's deforested ecosystems: testing for human-driven shifts in insect colour, MFP-UOO2213, Royal Society Te Apārangi (New Zealand, Wellington)Anthropogenic evolution of New Zealand's endemic insects: rapid evolution in a fast-changing world, MTN-UOO2401, Royal Society Te Apārangi (New Zealand, Wellington)
- Copyright © The Author(s) 2026. This work was first published in Biology Letters (The Royal Society). This is an open access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://www.creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing, adaptation, distribution and reproduction in any medium or format, provided that the original work is properly attributed to the creator(s) and the source, a link to the Creative Commons license is provided, and any changes made are indicated.
- English
- Journal article