Ontogenic colour change, survival, and mating in the damselfly Agriocnemis pygmaea Rambur (Insecta: Odonata)

Abstract

1. Damselflies often show intra‐specific colour variation, which may represent genetic polymorphism or age‐related (ontogenic) colour changes. 2. Such variation has distinct implications for the species' ecology and evolution. Colour variation in females of the damselfly Agriocnemis pygmaea was studied, which range from blue male‐like individuals (andromorphs) to those with a distinct red colour (heteromorphs). From preliminary observations, it was hypothesised that this species exhibits ontogenic colour change from heteromorph to andromorph coloration. 3. Mark–recapture experiments and egg counts of dissected females suggested that immature females are heteromorphic and gradually begin to resemble males as they attain sexual maturity. 4. Reflectance spectra of field‐caught individuals indicated that, although males are indistinguishable from andromorphs, they could be easily differentiated from heteromorphs. 5. Finally, field observations and mate choice experiments showed that males rarely attempt to mate with heteromorphic females and prefer andromorphs. Together, this study's results suggest that the observed colour variation in A. pygmaea females is ontogenic and is associated with sexual maturity.

Heterospecific pairing between male Agriocnemis kalinga Nair & Subramanian, 2014, and female A. pygmaea Rambur, 1842 (Odonata: Coenagrionidae)

“…Nair & Subramanian 2014). The female was identified as a heteromorphic form of A. pygmaea by its salmon pink ground colour, two postocular spots, greater number of antenodals, and terminal segments with black dorsal markings (‘intermediate’ sensu Joshi & Agashe 2020; cf. Huang & Reinhard 2012).…”

First record of androchrome females of Anax nigrofasciatus (Odonata: Aeshnidae) from Bhutan and notes on its occurrence in Asia

“…Joshi & Agashe (2020) showed that colour variation could be related to genetic polymorphism and ontogenic change where an immature Agriocnemis pygmaea (Rambur, 1842) was observed to be heteromorphic but acquired andromorphic colours on reaching sexual maturity. In European Zygoptera, andromorphs have been reported in 54 % of genera ( Cordero & AndrÉs 1996) but they are rare in Anisoptera, and most occur in libellulid genera such as Crocothemis, Neurothemis, Sympetrum, and Urothemis ( Kumar 1988; Kotarac 1996; Corbet 1999; Payra 2019a, 2019b; Willink et al 2019; Joshi et al 2020; Prasad et al 2000; Andrew 2013). Additionally, among aeshnids, four studies of androchrome females from the Palaearctic region have been made on Aeshna grandis (Linnaeus, 1758) , Anax guttatus (Burmeister, 1839) , A. immaculifrons Rambur, 1842, and A. imperator Leach in Brewster, 1815 ( Fincke et al 2005) .…”