Odonata origins, biogeography, and diversification in an Eastern North American hotspot: multiple pathways to high temperate forest insect diversity

Abstract

Abstract. 1. We assessed the origins and historical biogeography of a rich regional odonate fauna in New York State (NYS), Northeastern United States.2. We computed North American (NA) range centres and NYS range margins and reviewed the taxonomic literature to provide a useful phylogenetic framework for the fauna. We analysed results from a newly completed Odonata atlas using generalised linear ANOVA models to assess the effects of species' origins and zoogeographic affinities on relative frequency and extinction risk metrics.3. Phylogenetic reconstruction based on taxonomic nomenclature revealed different patterns of diversification. Zygoptera in NYS is mainly of neotropical origin~60 Ma displaying a pattern of tropical conservatism, but with a burst recent of Plio-Pleistocene speciation in certain groups. Alternatively, Anisoptera contains crown group endemic taxa and other very old lineages from the Mesozoic era before the breakup of Pangaea, highlighting the evolutionary significance of the Appalachian Mountains as an important global centre of temperate forest freshwater diversity.4. These high regional levels of odonate diversity have been brought about by at least three different mechanisms: dependence on forests, predominance of non-ecological speciation mechanisms, and niche conservatism across hundreds of millions of generations.5. NYS lies at a crossroads of both ancient and more recent Odonata evolution comprising separate boreal, temperate, and tropical faunas. Those species encountered less frequently and having higher overall extinction risk metrics generally tended to be the boreal species on the rear edge of their range, a widespread phenomenon for the insects of many regions generally attributed to ongoing climate change.

Effects of experimental warming on survival, phenology, and morphology of an aquatic insect (Odonata)

“…It may be that the temperatures we reached in this experiment fall below those at which growth is maximised. A similar result was found in studies of European damselflies occurring across a broad range of latitude (Nilsson‐Örtman et al ., ) and may reflect the neotropical origins of P. longipennis (Corser et al ., ). Alternatively, if small or slow‐growing dragonflies are differentially vulnerable to the increased mortality observed with warming, selection through mortality could play a part in this pattern, but we do not currently know the traits associated with the dead individuals.…”

Why do bugs perish? Range size and local vulnerability traits as surrogates of Odonata extinction risk

“…Of course, insect relations with climate are more complex. Actually, the evolutionary patterns of odonate thermoregulation are driven by interactions with biogeographic origin, body size, surface colour and behaviour, at both local and broad scale, across temperate and tropical regions [60,63,64]. Still, a general pattern is that larger odonate species tend to be endothermic or heliothermic, whereas smaller species tend to be more ectothermic [60].…”

Opportunistic data reveal widespread species turnover in Enallagma damselflies at biogeographical scales

“…Notably, however, we found random species assemblages over a much smaller extent within the region, supporting our spatial scale prediction. The Mid Atlantic also appears to be at a crossroad, with Enallagma and other odonates following complex evolutionary and colonization pathways (Turgeon et al , Corser et al ). This region also includes several Enallagma species confined to the Atlantic coastal plain, potentially creating turnover between coastal and non‐coastal localities.…”