A record of gynandromorphism in the libellulid dragonfly Crocothemis servilia (Insecta: Odonata) from India

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Gynandromorphs are genetically and phenotypically chimeric specimens and differ from intersexes which are genetically uniform (Narita et al. 2010). Gynandromorphism can be bilateral, appearing to divide down the middle into male and female sides, or they may be a mosaic, with patches characteristic of one sex appearing in a body part characteristic of the other sex. Gynandromorphism is a rare phenomenon in nature and is usually detected in species that show distinct sexual dimorphism. It is known to occur in different arthropod taxa such as Crustacea (Farmer 2004) Hollander et al. 1956). Gynandromorphs occasionally afford a powerful tool in genetic, developmental, and behavioural analyses. In Drosophila melanogaster, for instance, gynandromorphs were used to provide evidence that male courtship behaviour originates in the brain (Hotta & Benzer 1972).
They have normal female reproductive organs and are fertile (Robertson 1985;Andrew 2013). Immature male imagoes of many Anisoptera resemble females in colouration, but can be distinguished by the male reproductive structures. Gynandromorphism, on the contrary, is believed to be a genetic aberration caused by abnormal mitosis in the embryo leading to unequal distribution of sex chromosomes (May 1988). Crocothemis servilia, is a common dragonfly associated with marshes, ponds, rivers and tanks. It is widely distributed in the Oriental and Australian region (Subramanian 2009). The male has prominent blood red colouration in almost all body parts including the head, thorax, abdomen and legs. The wings are transparent with the base marked with rich amber (Image 2). The female is pale yellow with dark brown thorax and legs (Image 3).
At Puzhakkal region of the Kole wetlands (10.540 0 N & 76.172 0 E), an individual of Crocothemis servilia that looked part male and part female was photographed during the survey. The specimen could not be collected Image 1. Survey location from where Crocothemis servilia gynandromorph was recorded.
as it started raining and the individual moved into the deep marshes. Subsequent efforts to collect the specimen failed because of heavy rains that continued for the next few days, submerging the location. The species was initially identified using the field guide by Kiran & Raju (2013) and confirmed by referring to Fraser (1936).
The photographed 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. Status of the anal appendages could not be asserted from the photograph (Image 4). Since the female characters dominated, this cannot be considered a "balanced" gynandromorphy. The individual exhibited a genetic mosaic condition only in the thoracic region. May (1988) reported gynandromorphism in two species of family Corduliidae, namely Somatochlora filosa and Somatochlora provocans from the United States of America. The specimens he examined 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 from Bangladesh (Shome et al. 2019), in which the specimen's head and thorax, including wings were bilaterally gynandromorphic.
The abdomen was androchromic but had female appendages at the tip. In India, gynandromorphism was reported in Neurothemis tullia (Family: Libellulidae) and Heliocypha bisignata (Family: Chlorocyphidae) (Emiliyamma 2009), but photographs or illustrations were unavailable for confirmation or comparison. According to Siva-Jothy (1987), gynandromorphs have been reported to fail in mating because of aberrant sex organs but in the present individual the abdomen is typically female and since the internal and external female reproductive organs/ genitalia are abdominal, this individual could be a fertile