Cotesia anthelae (Wilkinson, 1928) (Hymenoptera: Braconidae) a natural parasitoid of Cirrochroa thais (Fabricius, 1787) (Lepidoptera: Nymphalidae), first report from the Oriental region

Field surveys conducted during 2020–2021 in Nedumpura, Cheruthuruthy, Thrissur district of Kerala yielded Cotesia anthelae (Wilkinson) (Hymenoptera: Braconidae) as a gregarious larval parasitoid of a nymphalid butterfly Cirrochroa thais (Fabricius) (Tamil Yeoman) along with its hyperparasitoid Mesochorus sp. (Hymenoptera: Ichneumonidae). This is the first report of C. anthelae parasitizing a nymphalid butterfly, earlier reports were from a host belonging to Anthelidae (Lepidoptera: Bomycoidea). Also, this is the first report of C. anthelae from the Oriental region, earlier reports are confined to Australia. The present study provides morphological identification of C. anthelae and biological details of its host. 


Material and Methods
Caterpillars of Cirrochroa thais (Fabricius) (Lepidoptera: Nymphalidae) were collected feeding on

Diagnosis of C. anthelae (Image 1)
Female: Body length 2.5−2.6 mm; general body colour black; legs except coxae, tegulae (light brown), basal ventrites yellowish-brown; apices of hind femora and apical one third of hind tibiae dark brown to black. Hind tibial spurs, palpi and lateral margins of first tergite pale yellow. Pterostigma and wing veins brown. First and second tergites black, rest of metasoma pale at anterior end, darkening towards hypopygium.
Metasoma: Metasoma with first tergite strongly and coarsely punctate in apical third, mostly parallel sided, curving inwards at apical corners; sclerotized portion of second tergite rough and ovoid shaped, strongly and distinctly crenulate at posterior margin and lateral edges. Ovipositor sheaths exserted, subequal to length of longer hind tibial spur. Third tergite onwards smooth.
Cocoons: Gregarious in nature; all the cocoons observed were white in colour and mostly arranged vertically on the host dorsal surface (Image 3).
Host: The butterfly Cirrochroa thais (Fabricius) (Lepidoptera: Nymphalidae), commonly known as Tamil Yeoman, is known to be distributed in India and Sri Lanka.
Distribution: Australia (Victoria (type) and New South Wales) and Oriental region -Kerala, India (present study).

Discussion
Wilkinson (1928) included C. anthelae in the 'Indo-Australian species of genus Apanteles' hence likelihood of its presence in India is not surprising. However, the more interesting aspect is the discovery of its new butterfly host − C. thais as the earlier and the only valid host record was from a species of moth -A. ocellata (Anthelidae). According to Fagan-Jeffries & Austin (2020), the other host -Opodiphthera eucalypti (Scott) (Lepidoptera: Saturniidae) remains 'doubtful' owing to absence of corresponding specimens. Wilkinson (1928) also mentioned that the cocoons were 'apparently' solitary however as per our observations based on multiple rearings it is confirmed that C. anthelae is indeed gregarious in nature.

Conclusion
Our studies substantiate the fact that C. anthelae is not a host specific parasitoid species as it is capable to parasitize a butterfly species in addition to moth and with its new distribution record in India the species is no more considered to be endemic to Australia.

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