Despite claims of an insect decline worldwide, our understanding of extinction risk in insects is incomplete. Using bionomic data of all odonate (603 dragonflies and damselflies) North American species, we assessed: a) regional extinction risk and whether this is related to local extirpation; b) whether these two patterns are similar altitudinally and latitudinally; and, c) areas of conservation concern. We used geographic range size as a predictor of regional extinction risk and body size, thermal limits and habitat association as predictors of local extirpation. We found that: a) greater regional extinction risk is related to narrow thermal limits, lotic habitat use and large body size (this in damselflies but not dragonflies); b) southern species are more climate-tolerant but with limited geographic range size than northern species; and, c) two priority areas for odonate conservation are the cold-temperate to sub-boreal Northeast USA and the Transversal Neo-Volcanic System. Our approach can be used to estimate insect extinction risk as it compensates for the lack of abundance data. 

odonata_NA-Rocha.csv

Odonata thorax size and related thermal properties. Data on adult thorax size were mainly extracted for each species from the Encyclopedia Of Life. These were complemented with other sources such as http://natuurtijdschriften.nl/natuur and www.odonatephenotypicdatabase.org. Climatic tolerance was evaluated using a proxy of thermal tolerance, the average isothermality values (BIO3) across each species’ extent of occurrencel. The values of isothermality (BIO3) were taken from bioclimatic variables [49]. Habitat specialization was categorized by breeding habitat: lentic, lotic or no preference. 

Phylo_Odonata.nex

A super-tree was generated from Odonata mega-tree (Waller & Svensson, 2017) using the software Phylomatic Version 3 (Webb & Donoghue, 2005).Families were dated in Phylocom (Webb et al. 2005) using the bladj algorithm and taking into account the dating dates proposed by Davis et al. ( 2011). For each continuous trait (body size, climatic tolerance) we calculated Pagel’s lambda to quantify the strength of phylogenetic signal from zero (no signal) to one (Revell, 2012). We controlled for significant signal in subsequent modelling.

Waller JTJ., Svensson EI. 2017 Body size evolution in an old insect order: No evidence for Cope’s Rule in spite of fitness benefits of large size. Evolution (N. Y). 71, 2178–2193. (doi:10.1111/evo.13302) 

Webb C, Donoghue MJ. 2005 Phylomatic: tree assembly for applied phylogenetics. Mol. Ecol. Notes 5, 181–183. (doi:10.1111/j.1471-8286.2004.00829.x) 

Webb C., Ackerly D, Kembe S. 2008 Phylocom: software for the analysis of phylogenetic community structure and trait evolution. Bioinformatics 24, 2098–2100. 

Davis RB, Nicholson DBD., Saunders ELR, Mayhew P. PJ. 2011 Fossil gaps inferred from phylogenies alter the apparent nature of diversification in dragonflies and their relatives. BMC Evol. Biol. 11, 252. (doi:10.1186/1471-2148-11-252) 

Revell L. 2012 Phytools: an R package for phylogenetic comparative biology (and other things). Methods Ecol. Evol. 3, 217–223. 

coordenate_odonata-Rocha

Data were obtained from OdonataCentral, a storage and distribution hub for adult odonate records throughout North America and from CONABIO a storage site for, mainly, Mexican diversity.