Scarlet Skimmer (Crocothemis servilia) 

#GS3 #Environment 

A peculiar dragonfly, the Scarlet Skimmer (Crocothemis servilia), was spotted in the Puzhakkal area of the Kole wetlands in Thrissur last year 

  • Male dragonflies typically have a prominent blood-red colouration in almost all the body parts, including the head, thorax, abdomen and legs, and the female is pale yellow in colour with a dark brown thorax and legs. 
  • But another one that spotted on July 14 as part of the Kole Odonata Survey 2019, conducted by the Society for Odonate Studies and Kole Birders in association with Kerala Agricultural University and the Kerala Forest and Wildlife Department, was “part red and part yellow”. 
  • Later, while compiling data, it was discovered as  ‘gynandromorphism’ — a very rare biological phenomenon.  

Genetic aberration 

  • Gynandromorphs are chimeric individuals having both male and female tissues and it is viewed by the scientific community as a genetic aberration. Even though common in some arthropod taxa such as Crustacea and Arachnida, the paper says it is very rare in odonates and only 30 individuals from seven families have been reported with the condition worldwide. 
  • The spotted individual showed bilateral gynandromorphism of only the thorax, half of which showed blood red colouration as in males and the other half pale yellow characteristic of females. The base of the wing of the red half was marked with rich amber, in contrast with the other wing base which was paler. The head, legs and abdomen showed typical female morphology. 
  • It had mixtures of male and female external characters ranging from almost entirely female to about equally divided. They were symmetrical in development with normally dimorphic structures mostly having characters intermediate between the typical male and female conditions. 
  • Further research has to be undertaken to investigate the influence of environmental factors on this phenomenon. 

The Society for Odonate Studies has been conducting surveys at Kole wetlands since 2018 and 37 species of dragonflies and damselflies have been reported from the wetlands so far.

 

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