miércoles, 6 de diciembre de 2017

DNA metabarcoding data unveils invisible pollination networks      

André Pornon, Christophe Andalo, Monique Burrus & Nathalie Escaravage

Animal pollination, essential for both ecological services and ecosystem functioning, is threatened by ongoing global changes. New methodologies to decipher their effects on pollinator composition to ecosystem health are urgently required. We compare the main structural parameters of pollination networks based on DNA metabarcoding data with networks based on direct observations of insect visits to plants at three resolution levels. By detecting numerous additional hidden interactions, metabarcoding data largely alters the properties of the pollination networks compared to visit surveys. Molecular data shows that pollinators are much more generalist than expected from visit surveys. However, pollinator species were composed of relatively specialized individuals and formed functional groups highly specialized upon floral morphs. We discuss pros and cons of metabarcoding data relative to data obtained from traditional methods and their potential contribution to both current and future research. This molecular method seems a very promising avenue to address many outstanding scientific issues at a resolution level which remains unattained to date; especially for those studies requiring pollinator and plant community investigations over macro-ecological scales.

Bipartite pollination networks built from visit surveys (Nobs, right panels) and metabarcoding (Nseq, left panels) data. (a,b) Plant-pollinator groups; (c,d) plant-pollinator species; (e,f) individual pollinator-plant species (Empis leptempis pandellei as an example of pollinator species). Line thickness highlights the proportion of interactions. Apis: Apis mellifera; Bomb.: Bombus sp.; W.bee: wild bees; O.Hym.: other Hymenoptera; O.Dipt.: Other Diptera; Emp.: Empididae; Syrph.: Syrphidae; Col.: Coleoptera; Lep.: Lepidoptera; Musc.: Muscidae.


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