Global scale of dragonfly migration revealed - University of Exeter

Migration flights by dragonflies and damselflies criss-cross much of our planet, new research reveals.

Scientists from the universities of Exeter and Lund reviewed global evidence and found 100 dragonfly and damselfly species that migrate, and a further 85 possible migratory species.

This means that only 1.5% of all dragonfly and damselfly species migrate (or 2.9% including possible migrants) – but the migrations can include millions of individuals, and some travel thousands of kilometres.

Most of these species are listed as “Least Concern” on the IUCN Red List of Threatened Species, suggesting migratory habits may make them resilient to rapid environmental changes caused by human activity.

“Dragonflies and damselflies are not usually thought of as migratory insects,” said Dr Johanna Hedlund, from Lund University and Exeter’s Centre for Ecology and Conservation. “However, our review found evidence of migration in four dragonfly families and two damselfly families, and analysis suggests migration has evolved independently multiple times. Given the distances covered and the number of individuals involved, these migrations are likely to have considerable impacts on ecosystems, including moving biomass and nutrients, and controlling pests.”

Migratory dragonflies and damselflies typically live longer in their flying adult stage than non-migrants, some for several months, whereas species that do not fly long distances spend more of their lifetime as nymphs in freshwater.

Migration in dragonflies is likely driven by their habitats being unsuitable for breeding at certain times of year, often due to cold or extreme heat or drought.

Unlike birds and mammals, most insect migrants do not complete a round-trip journey within their lifetime. It is subsequent generations, the offspring of the parent dragonflies that once left, that return to the original breeding location.