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Psyche
Volume 2016 (2016), Article ID 9028105, 8 pages
http://dx.doi.org/10.1155/2016/9028105
Research Article

Perch Selection by Three Cooccurring Species of Celithemis (Odonata: Libellulidae): Testing for a Competitive Hierarchy among Similar Species

Biology Department, Furman University, Greenville, SC 29613, USA

Received 25 April 2016; Revised 12 August 2016; Accepted 28 August 2016

Academic Editor: G. B. Dunphy

Copyright © 2016 Wade B. Worthen and Parker H. Morrow. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In many communities of perching dragonflies (Odonata: Libellulidae), a size-dependent competitive hierarchy creates a positive relationship between male body size and perch height. We tested for this pattern among three similar-sized species: Celithemis elisa, C. fasciata, and C. ornata. Males were caught and photographed from May to July 2015 at Ashmore Heritage Preserve, Greenville County, SC, USA, and perch heights and perch distance to open water were measured. Five indices of body size were measured with ImageJ software: abdomen length, forewing length, hindwing length, area of forewing, and area of hindwing. Celithemis fasciata was significantly larger than the other two species for all five anatomical characters and used perches that were significantly taller and closer to open water than the other species, though these differences changed over the summer. Aggressive interactions between and within species were tallied and compared to expected distributions based on mean relative abundances derived from hourly abundance counts. Patterns of interspecific aggression were also consistent with a size-dependent hierarchy: the large C. fasciata was attacked less frequently, and the small C. ornata more frequently, than predicted by their relative abundances. We conclude that even small differences in body size may contribute to niche partitioning in perch selection.