The Effect of Hypoxia and Hyperoxia on Dragonfly Development A Link Between Paleozoic Oxygen Levels and Insect Gigantism


Meeting Abstract

P1.83  Tuesday, Jan. 4  The Effect of Hypoxia and Hyperoxia on Dragonfly Development: A Link Between Paleozoic Oxygen Levels and Insect Gigantism WEED, M.D.*; MUNOZ, E.E.; HARRISON, J.F.; VANDENBROOKS, J.M.; Arizona State University; Arizona State University; Arizona State University; Arizona State University mdweed@asu.edu

During the Paleozoic Era (~300 mya), it is hypothesized that an increase in atmospheric oxygen levels to approximately 31% allowed for the evolution of giant insects. Some of the most well-known Paleozoic insect giants were dragonflies belonging to the order Protodonata. To date, there is no evidence as to whether varied oxygen levels impact modern dragonfly body sizes or development. Here we report the first successful rearing of dragonflies from larvae to adult in the lab under varying oxygen conditions. Two hundred dragonflies were reared in three different oxygen levels (12, 21, and 31%) at 24°C mimicking the range of modeled oxygen variation over the past 300 million years. Each dragonfly larva was placed in a separate container with aquarium rocks and synthetic vegetation in an oxygen-regulated Lexan chamber. The dragonflies were fed an excess of California blackworms (Lumbriculus variegatus) daily and had their pH controlled (7.2-7.8) water changed daily. Each week, body mass and head width were measured, and molts were recorded daily. The results are that body mass and head width increased in hyperoxia and decreased in hypoxia, while the timing of molting was also affected. These data support a role of atmospheric oxygen level in determining dragonfly body size and an oxygen effect on developmental events. It also lends support to the hypothesis that atmospheric oxygen influenced dragonfly size over evolutionary time. This research was supported by NSF EAR 07463522 to JFH.

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