University of Oulu

Gábor Horváth, Ádám Egri, V. Benno Meyer-Rochow & György Kriska (2019) How did amber get its aquatic insects? Water-seeking polarotactic insects trapped by tree resin, Historical Biology, DOI: 10.1080/08912963.2019.1663843

How did amber get its aquatic insects? : water-seeking polarotactic insects trapped by tree resin

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Author: Horváth, Gábor1; Egri, Ádám2,3; Meyer-Rochow, V. Benno4;
Organizations: 1Environmental Optics Laboratory, Department of Biological Physics, ELTE Eötvös Loránd, University, Budapest, Hungary
2MTA Centre for Ecological Research, Evolutionary Systems Research Group, Tihany, Hungary
3MTA Centre for Ecological Research, Danube Research Institute, Budapest, Hungary
4Department of Ecology and Genetics, University of Oulu, Oulu, Finland and Department of Plant Medicals, Andong National University, Andong, Republic of Korea
5Group for Methodology in Biology Teaching, Biological Institute, ELTE Eötvös Loránd University, Budapest, Hungary
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.3 MB)
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Language: English
Published: Informa, 2019
Publish Date: 2021-05-03


Amber contains numerous well-preserved adult aquatic insects (e.g., aquatic beetles — Coleoptera, water bugs — Heteroptera, dragonflies — Odonata, caddisflies — Trichoptera, mayflies — Ephemeroptera, stone flies — Plecoptera). Since amber is fossilised resin of terrestrial conifer trees, it is an enigma how aquatic insects have ended up in the resin. Based on field studies in a Hungarian forest along a freshwater creek we suggest that tree resin traps water-seeking flying polarotactic aquatic insects because of its property to polarise reflected light. The sticky tree resin was modelled by a water-proof, transparent, colourless insect-monitoring glue laid on vertical and horizontal fallen tree trunks next to the creek. Adults of various polarotactic aquatic insect species were trapped only by the horizontal sticky trunk. In earlier field experiments we showed that these insects find water by means of the horizontal polarisation of water-reflected light, and therefore are attracted to and land on all surfaces which reflect horizontally polarised light. Using imaging polarimetry, we revealed the criterion of polarisation-based trapping by resiny tree trunks. According to our observations, flying aquatic insects can be trapped by sticky (resiny) regions of fallen tree trunks that reflect horizontally polarised light and thus attract polarotactic species. The resin continues to flow out of the trees even when fallen over or fractured in a storm. Our findings support and complement an earlier hypothesis, according to which amber-preserved adult aquatic insects have been trapped by resiny bark when they dispersed over land.

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Series: Historical biology
ISSN: 0891-2963
ISSN-E: 1029-2381
ISSN-L: 0891-2963
Issue: Epub ahead of print
DOI: 10.1080/08912963.2019.1663843
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: Ádám Egri was supported by the Economic Development and Innovation Operational Programme [GINOP-2.3.2-15-2016-00057] and the János Bolyai Research Scholarship of the Hungarian Academy of Sciences. V. Benno Meyer-Rochow was supported through a grant to Prof. Chuleui Jung of Andong National University’s Insect Industry R&D centre via the Basic Science Research Programme and the National Research Foundation of Korea (NRF) funded by the Ministry of Education [NRF-2018R1A6A1A03024862].
Copyright information: © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.