2019 by Amanda Whispell

CURRENT RESEARCH

I am currently studying the mating-associated color change exhibited by Argia apicalis  (Odonata: Coenagrionidae) males, and the adaptive advantage it may offer to them. In Odonata (dragonflies and damselflies), the gradual development of adult coloration during their post-eclosion, teneral period is a well-known phenomenon, and these morphological color changes occur slowly and irreversibly.  

Argia apicalis - male

© Amanda Whispell

Argia apicalis - Immature male

© Amanda Whispell

Argia apicalis - Mature male

© Amanda Whispell

Physiological color change, in contrast, is always rapid and reversible, and has only been studied in a few insect species. While the change exhibited by most species is primarily temperature sensitive – changing to dark-phase (DP) coloration when below a certain temperature threshold, and then returning to their bright-phase (BP) when the temperature rises above it – this is not always the case. 

A. apicalis - Male after 20 minutes in a cooler

© Amanda Whispell

A. apicalis - Male kept at an ambient temperature of  27°C 

© Amanda Whispell

 

Since many Odonata males are brightly colored, they may be trading reduced survival for increased mating success. Rather than make this compromise, the ability to change color allows A. apicalis males to retain their BP coloration for inter-/intraspecific interactions, and adopt DP coloration to protect themselves from predation while copulating and ovipositing. 

 

A. apicalis males possess the unique ability to change color, from BP to DP, in response to copulation, and given the past research into the selective advantage of physiological color change, the ability to change color in direct response to copulation could provide them with a significant adaptive advantage. 

A. apicalis - Pair captured in tandem

© Amanda Whispell

A. apicalis - Solitary in BP

© Amanda Whispell

A. apicalis - Mating pair in DP

© Amanda Whispell

Argia apicalis - Mating pair

© Amanda Whispell