Argia vivida

Blue-morph on pitcher plant in California

Female dimorphism occurs in two populations of Argia vivida from British Columbia, Canada. They are described as varying from a blue color morph and red color morph. Physiological color changes occur in males and both female morphs as a result of changing temperatures throughout the day. The two phases of color changes are denoted as the "bright phase" and "dark phase." Individuals transition to the bright phase as shade temperatures rise over 25°C; males and blue-morph females transition to a lighter shade of blue with pale blue or blue-grey markings, while red-morph females transition to a red-brown or brown with tan or grey-tan markings. At lower temperatures around 18°C, the dark phase occurs; males and blue-morph females transition to a darker blue shade, while red-morph females transition to a grey-brown to brown shade.[9]

Mates are encountered in two ways, morning matings or afternoon matings.[9] In the morning, the males bask at sunspots and attempt to gain the attention of females by darting out at them. Successful males and females will then engage in copulation, tandem flight, and finally oviposition. In the afternoon, unmated males move towards the water and wait for an available female released from a previous mating pair. These new pairs begin the mating cycle once again but throughout a more brief time period than the morning matings.[10]

Upon mating, females lay their eggs on sources of vegetation just below the surface of the water.[6] Egg development requires cold temperatures of at least 11°C but can fluctuate from 0-33°C.[6][13] In thermal springs, the life cycle takes approximately 1 year to complete, but may extend for up to 2 to 3 years in cooler springs.[6][13] Argia vivida finally emerge as adults anytime between April through October depending on the current temperature.[6]

Argia vivida exhibit thermoregulation by living in habitats that allow for different thermal regimes throughout the day. At night, individuals typically settle in forest trees to maintain their body temperatures and slow the radiant loss of heat. During the day, they move away from the trees into sunspots available in thinned forest for thermal basking.[7] Therefore, an ideal habitat for the species consists of a forest containing dense trees in addition to cleared patches or thinned forest to best suit their thermoregulation requirements.[7]

In fuel-modified forests, Argia vivida still roost in trees at night but prefer cleared fuel treatment sections of the forest compared to thinned forest for the purposes of basking and foraging.[14]

• Kalkman, V. J. (2013). Studies on phylogeny and biogeography of damselflies (Odonata) with emphasis on the Argiolestidae (PhD). Leiden University. hdl:1887/22953.