Evidence for widespread gene flow and migration in the Globe Skimmer dragonfly Pantala flavescens

Abstract

The global population structure and dispersal patterns of Pantala flavescens (Fabricius, 1798) are evaluated using a geographically extensive mitochondrial DNA dataset, a more limited samples of nuclear markers, wing isotopic (δ²H) data and a literature review. No spatial or temporal haplotype structure was recovered between the samples. Isotope data suggest that most samples were immigrants at the collection locations. A literature review of migration events for the species confirms regular inter-and intra-continental migrations occur (the majority reported from Asia, Africa and Australasia), with individuals and swarms dispersing thousands of kilometers over land and oceans. Migrations coincide with prevailing winds and seasonal rains, which points to a mechanism we name the “pantropical Pantala conveyor belt”, suggesting widespread gene flow is possible for an aquatic insect with excellent flying ability linked to rapid larval development.

Exploring chromosome evolution in 250 million year old groups of dragonflies and damselflies (Insecta:Odonata)

“…These species are extremely variable in their natural histories. P. pennipes and I. elegans are highly territorial odonates with relatively limited vagility, while P. flavescens is considered the global wanderer, given their globally panmictic population, with individuals potentially crossing oceans (Ware et al, 2022). Further, these 3 species are all relatively young lineages from species rich families (Kohli et al, 2021;Suvorov et al, 2021).…”

Newly Sequenced Genomes Reveal Patterns of Gene Family Expansion in select Dragonflies (Odonata: Anisoptera)

“…It makes long transcontinental and trans-oceanic migrations [23,24], and is frequently found in warmer regions, particularly in the tropics, but is found in temperate regions in the summer [25]. Though it is nNot surprisingly-given the migratory nature of the species-evidence suggests widespread gene flow between populations across the globe, and it may be appropriate to refer to many, if not all, of the migratory sub-populations as panmictic [24]. An smc++ [26] analysis, using individuals from Guangdong Province, China found that the effective population size of P. flavescens has varied between 1 million and 10 million individuals over the last million years, with declines associated with the onset of the agricultural and industrial period [27].…”

“…Hypothesis 7: migratory dragonflies can more efficiently process carbohydrates. In P. flavescens, the expansion of gene families related to the carbohydrate metabolic process are a plausible mechanism for allowing this species to undertake trans-oceanic and trans-continental migrations in a single generation [24]. It is likely that an especially efficient process for obtaining energy from carbohydrates would be selected for on such long migrations.…”

Diversity of Nearctic Dragonflies and Damselflies (Odonata)

“…Pantala flavescens is probably the only species capable of consistent transoceanic dispersions without the aid of humans. Its amazing gliding abilities, together with a very fast larval cycle [77] and its adaptation to become dormant enabling it to survive drought conditions [78], make it the most widespread Odonata species in the world [79].…”