Observations on a gynochromatic (?) male of the dragonfly, Rhodothemis rufa (Rambur, 1842) (Odonata: Libellulidae)

Abstract

The dragonfly Rhodothemis rufa exhibits a conspicuous sexual dimorphism in its body colour. The mature male is characterized by the homogenous striking brilliant red body while the mature female is dull brown with a prominent mid-dorsal light yellow streak running from the top of the head through the thorax and down to the fifth segment of the abdomen. The sexes can easily be identified from quite a long distance. On 7 November 2012, we observed the unusual sight of a female Rhodothemis rufa chasing another female and forming a tandem link which was followed by copulation. This peculiar reproductive behavior instigated us to net the specimen. On inspection we found that although it appeared a female, it had well developed external male genitalia in the form of the secondary copulatory apparatus on the venter of the second and third abdomen, a pair of coxites on the ninth abdominal tergum and an additional infra anal appendage at the terminal tip of the abdomen. The testes contained a large number of lobules filled with mature spermatozoa, and the vasa differentia also contained mature sperms. The sperm sac was filled with sperms embedded in seminal fluid. Observations indicate that this could be a rare case of a gynochromatic male of Rhodothemis rufa which has retained the colour patterning of the female even after sexual maturity and concomitantly exhibiting active sexual behaviour, although the case of it being a subadult male which has yet to attain its typical red coloration cannot be ruled out. Keywords: