Dragonfly (Odonata: Corduliidae, macromiidae, gomphidae, aeshnidae) and damselfly (odonata: Calopterygidae) exuviae observed at record heights in pinus strobus and picea abies canopies

Abstract

Most odonate species do not typically climb higher than 50 cm when choosing an emergence support. We observed multiple species of odonate nymphs using trees as emergence supports at heights greater than 50 cm and up to 4, 6.9, and 14.6 m for Calopteryx maculata (de Beauvois) (Ebony Jewelwing, Odonata: Calopterygidae), Somatochlora minor (Calvert) (Ocellated Emerald, Odonata: Corduliidae), and Didymops transversa (Say) (Stream Cruiser, Odonata: Corduliidae), respectively. These heights represent the greatest heights ever documented for odonate nymph emergence supports. Our research suggests that some species (S. minor; D. transversa) appear to have a greater affinity for climbing to great heights during emergence than others (Dromogomphus spinosus Selys (Black-Shouldered Spinyleg, Odonata: Gomphidae); Basiaeschna janata (Say) (Springtime Darner, Odonata: Aeshnidae); Macromia illinoiensis Walsh (Swift River Cruiser, Odonata: Corduliidae)). Odonate nymphs appeared to have a strong preference for emergence sites at the underside or base of branches. Researchers have hypothesized that competition for emergence sites drives climbing to such great heights. We propose three alternative hypotheses that could potentially explain these unique behaviors.