Olfactory-mediated host tracking and rapid local adaptation in a seed-feeding wasp
- 1University of Edinburgh
Abstract
Understanding how specialized herbivores track divergence among their hosts is central to evolutionary biology. Congruent genetic structure between hosts and herbivores is often interpreted as evidence of long-term codivergence, but similar patterns may also arise when herbivores rapidly adapt to pre-existing host differentiation. Here, we integrate population genomics, host volatile profiling, and behavioral assays to examine host-associated divergence in the obligate seed-feeding wasp Megastigmus daduheensis and its conifer host Cupressus chengiana across three river valleys on the eastern Qinghai-Tibet Plateau. Despite strong phylogeographic congruence between each of the three wasp and host lineages, calibrated demographic analyses indicate that wasp divergence occurred during the early Holocene, substantially later than the Pliocene-Pleistocene divergence of host lineages. This temporal mismatch is inconsistent with strict long-term codivergence and instead supports rapid host tracking in a topographic complex region. Host lineages differed in volatile organic compound profiles, and behavioral assays showed that wasps were preferentially attracted to volatiles from their local host lineages. These results identify olfactory-mediated host recognition as a plausible mechanism promoting host fidelity and reinforcing host-associated genomic and behavioral differentiation. Our findings show that apparently concordant host-herbivore divergence can emerge over compressed evolutionary timescales through rapid local adaptation, highlighting how ecological differentiation can accumulate within species through host tracking.
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BibTeX
@misc{chen2026olfactorymediated,
title = {{Olfactory-mediated host tracking and rapid local adaptation in a seed-feeding wasp}},
author = {X. Chen and Y. M. Zhang and J. Kuang and Y. Wang and J. Li and W. Hu and S. Yang and W. Wang and H. Lv and T. Li and G. N. Stone and K. Mao},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.01.755887},
url = {https://www.biorxiv.org/content/10.64898/2026.10.01.755887v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Olfactory-mediated host tracking and rapid local adaptation in a seed-feeding wasp
AU - X. Chen
AU - Y. M. Zhang
AU - J. Kuang
AU - Y. Wang
AU - J. Li
AU - W. Hu
AU - S. Yang
AU - W. Wang
AU - H. Lv
AU - T. Li
AU - G. N. Stone
AU - K. Mao
PY - 2026
DA - 2026/10/01
PB - bioRxiv
DO - 10.64898/2026.10.01.755887
UR - https://www.biorxiv.org/content/10.64898/2026.10.01.755887v1
AB - Understanding how specialized herbivores track divergence among their hosts is central to evolutionary biology. Congruent genetic structure between hosts and herbivores is often interpreted as evidence of long-term codivergence, but similar patterns may also arise when herbivores rapidly adapt to pre-existing host differentiation. Here, we integrate population genomics, host volatile profiling, and behavioral assays to examine host-associated divergence in the obligate seed-feeding wasp Megastigmus daduheensis and its conifer host Cupressus chengiana across three river valleys on the eastern Qinghai-Tibet Plateau. Despite strong phylogeographic congruence between each of the three wasp and host lineages, calibrated demographic analyses indicate that wasp divergence occurred during the early Holocene, substantially later than the Pliocene-Pleistocene divergence of host lineages. This temporal mismatch is inconsistent with strict long-term codivergence and instead supports rapid host tracking in a topographic complex region. Host lineages differed in volatile organic compound profiles, and behavioral assays showed that wasps were preferentially attracted to volatiles from their local host lineages. These results identify olfactory-mediated host recognition as a plausible mechanism promoting host fidelity and reinforcing host-associated genomic and behavioral differentiation. Our findings show that apparently concordant host-herbivore divergence can emerge over compressed evolutionary timescales through rapid local adaptation, highlighting how ecological differentiation can accumulate within species through host tracking.
ER -