Molecular-Assisted Pollen Grain Analysis Reveals Spatiotemporal Origin of Long-Distance Migrants of a Noctuid Moth.

Hong Chang,Xiaowei Fu,Youming Hou,Yongqiang Liu,Kris Wyckhuys,Jianglong Guo,Kongming Wu

doi:10.3390/ijms19020567

Abstract

Pollen grains are regularly used as markers to determine an insect’s movement patterns or host (plant) feeding behavior, yet conventional morphology-based pollen grain analysis (or palynology) encounters a number of important limitations. In the present study, we combine conventional analytical approaches with DNA meta-barcoding to identify pollen grains attached to migrating adults of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae) in Northeast China. More specifically, pollen grains were dislodged from 2566 A. segetum long-distance migrants captured on Beihuang Island (Bohai Sea) and identified to many (plant) species level. Pollen belonged to 26 families of plants, including Fagaceae, Oleaceae, Leguminosae, Asteraceae, Pinaceae and Rosaceae, including common species such as Citrus sinensis, Olea europaea, Ligustrum lucidum, Robinia pseudoacacia, Castanopsis echinocarpa, Melia azedarach and Castanea henryi. As the above plants are indigenous to southern climes, we deduce that A. segetum forage on plants in those locales prior to engaging in northward spring migration. Our work validates the use of DNA-assisted approaches in lepidopteran pollination ecology research and provides unique and valuable information on the adult feeding range and geographical origin of A. segetum. Our findings also enable targeted (area-wide) pest management interventions or guide the future isolation of volatile attractants.

Highlights

Plant-pollinator interactions can reveal co-evolutionary processes in both animal and plant communities [1]
Sci. 2018, 19, 567 and pollen morphology, 12 of the 40 samples were identified to species level: Castanea mollissima Blume, Pterocarya rhoifolia Siebold et Zucc., Olea europaea L., Amorpha fruticosa Linn., Ligustrum lucidum Ait., Robinia pseudoacacia L., Castanopsis echinocarpa Miq., Citrus sinensis Blanco, Melia azedarach L., Elaeagnus umbellata Thunb., Chenopodium album L. and Adenophora trachelioides Maxim (Table 1, Figure 1, Supplementary Text S1) and 16 of the samples to the genus level, including Pinus L., Heliotropium L., Corylus L., Betula L., Ailanthus Desf., Brassica L., Cercidium L., Artemisia L., Pilea Lindl., nom. conserv., Gnaphalium L., Polygala L., Galium L., Gaura L., Fendlera L., Chrysanthemum L. and Helianthus L
We employed conventional morphology-based pollen identification, DNA meta-barcoding and published information on the geographical distribution of plants to reveal the host plant foraging range of Chinese populations of Pollen grains have been commonly used as a natural marker to reveal foraging patterns or host plant associations for different types of pollinators [3,4,24]

Summary

Introduction

Plant-pollinator interactions can reveal co-evolutionary processes in both animal and plant communities [1]. There are a variety of pollination modes in nature and entomophily has been one of the determinants of the ecological and evolutionary success of angiosperms and the associated coevolution with multiple orders of insects over the past 100 million years [2]. Pollen-grain analysis (or palynology) is one approach that is regularly used to study the role of insects in pollination [5,6,7,8,9]. Aside from revealing plant-pollinator linkages, pollen can serve as a natural marking material to determine an insect’s host plant range and its related geographical origin or movement patterns in time or space [5,9]. Pollen identification is useful to study insect migration for four reasons: (a) entomophily-dependent plant species have evolved pollen that adheres readily to the insect body [5]; (b) the rigid exterior (or exine) of pollen grains is composed of sporopollenin, one of the most enduring natural polymers [10]; (c) pollen grains are distinctive and can be used to identify genus of originating plants [11]; (d) the distribution and flowering periods of most plants are well known, which helps to establish both temporal as spatial facets related to origin of captured insects [5]

Methods

Results

Discussion

Conclusion