Life history of Hypolycaena othona - Orchid Tit

Life history of Hypolycaena othona - Orchid Tit

- Nitin Kawthankar (2024)

Life history of Orchid Tit ©️Nitin Kawthankar

Butterfly Biodata:

Butterfly: Orchid Tit
Species: Hypolycaena othona Hewitson, [1865]
Subspecies: H. othona othona Hewitson, [1865]
Classification: Lycaenidae: Theclinae: Hypolycaenini
Wingspan: 24-27 mm

Distribution: Oriental (India to Indonesia)
Larval host plants: Epiphytic orchids (Orchidaceae)

Introduction:

     The genus Hypolycaena is represented by two species in the Western Ghats: H. nilgirica and H. othona, with the former being endemic to the southern Western Ghats and Sri Lanka. In contrast, the Orchid Tit (H. othona) exhibits a broader distribution, ranging from India (Western Ghats, East India, Himalayas, Northeast India & Andaman & Nicobar Islands) to Indonesia (Fiedler, 1992; Butterflies of India, 2024; iNaturalist, 2024; Sethumadhavan et al. 2024). This species typically inhabits moist forested areas where its host plant, orchids, are present.

     The taxonomic placement of the Orchid Tit within Hypolycaena has been questioned, with some authors supporting its old classification as Chliaria (Fiedler, 1992; Sawant et al., 2016; Bhakare & Ogale, 2018). The life history of the Orchid Tit has been well-documented in previous studies (Davidson et al., 1896; Bell, 1915; Fiedler, 1992; Sawant et al., 2016; Bhakare & Ogale, 2018; Butterflies of India, 2024).

Larval Host Plants:

1. Acampe praemorsa (Orchidaceae) - Brittle Tiger Orchid, वाघरी

2. Aerides crispa (=A. crispum) (Orchidaceae) - Curled Aerides, पानशिंग

3. Aerides maculosa (Orchidaceae) - Fox Brush Orchid, ठिपके इरीड आमरी

4. Cottonia peduncularis (Orchidaceae) - Bee Orchid, भ्रमरी

5. Rhynchostylis retusa (Orchidaceae) - Foxtail Orchid, सीतेची वेणी

     Orchid Tit is an oligophagous species, feeding exclusively on floral parts of epiphytic orchids from the family Orchidaceae (Nicéville, 1900; Bell, 1915; Wynter-Blyth, 1957; Sawant et al., 2016; Nitin et al., 2018; Butterflies of India, 2024).

     Additionally, Veenakumari et al. (1997) recorded Papilionanthe subulata (=Thrixspermum filiforme)(Orchidaceae) from the Andaman & Nicobar Islands. Fiedler (1992) reported a ground orchid, Spathoglottis plicata (Orchidaceae), as the first non-epiphytic host plant from Malaysia.

     Orchidaceae, the second-largest plant family, is surprisingly utilized as a host plant by a single butterfly genus, Hypolycaena, in India.

Early Stages:

Eggs: Although direct observation of oviposition was not made, the egg-laying pattern could be inferred from the egg distribution. Eggs were typically laid singly on either floral buds (inflorescence buds) or seed pods. Notably, no more than two eggs were found on a single plant (n=8). Eggs were small, white and hemispherical in shape, resembling a half-cut golf ball.

1st Instar: The egg hatched after 4-5 days (n = 2). A tiny, yellowish egg-larva emerged from the egg by consuming just enough of the egg shell to emerge, leaving the remaining egg shell intact. It began feeding by boring into the floral bud or seed pod, creating a small tunnel that fitted its body exactly. Notably, a chain of frass pellets was visible around the feeding tunnel. This instar lasted 2 days, during which the larva reached a length of 3 mm (n=2).

2nd Instar: In this instar, the caterpillar acquired the colour of the plant part it fed on, i.e. green or reddish-green, and a mid-dorsal pink-red band developed, passing through all segments. The feeding behaviour was consistent with the previous instar. This instar lasted 3 days, during which the larva reached a length of 5 mm. Most caterpillars left their feeding tunnels and moulted externally on the seed pod or stem (n=2).

3rd Instar: A distinct change in this instar was the presence of two tail-like projections on the last abdominal segments ("tail-points" of Bell, 1915), which were clearly visible, projecting from the feeding tunnel. Another obvious change was that the tunnel openings were cleaner than in previous instars, with no frass remains. This instar reached a length of 9 mm and lasted 3 days (n=2).

4th Instar: The fourth and final instar caterpillars resembled the previous instar but were relatively large and prominently marked compared to previous instars. They fed voraciously, digging completely inside the pod or floral buds and nearly hollowing them out. This instar lasted 4-5 days and reached a maximum length of 16 mm (n=2).

Prepupa: On the last day of the final instar, the caterpillar underwent complete decolorisation, including the loss of its distinctive mid-dorsal pink-red band, and found a secure place for pupation on a seed pod or stem, where it rested for 1 day before pupation (n=4).

Pupa: The pupa was green in color, featuring a distinctive wavy mark near the wing pad. It was attached to the substrate in a head-down position, secured by a silk girdle and silk pad. After 1 day of pupation, the colour became slightly greyish. After 7-8 days, the wing pad area became whitish. One day prior to eclosion, the pupa became dark, with the upper wings visible through the wing pad (n=4). 

Imago: It took 10-12 days to eclose from the pupa. Adults emerged between 07:45 to 12:00 hours in the morning (n=4).

     The complete life cycle lasted approx. 26-30 days: egg (4-5 days), larva (12-15 days), and pupa (10-12 days).

Mymecophily: 

     The Orchid Tit caterpillars exhibit facultative mymecophily, as previously documented by several authors (Bell, 1915; Wynter-Blyth, 1957; Fiedler, 1992). Although various ant species (Formicidae) frequently visited the floral nectaries of the host plant, they occasionally tended to the caterpillars, indicating a non-obligate association. Caterpillars possess a functional dorsal nectary organs (DNOs) from the 3rd instar but lack a tentacular organs (TOs) (Fiedler, 1992).

Discussion:

     The above observations largely confirm previous records, with some notable differences. Notably, caterpillars possess two tail-like projections, known as tail-points, on the last abdominal segment, which become prominently visible from the 3rd instar.

     Caterpillars exhibit variability in colour, ranging from green to purple, most likely influenced by the colour of the plant part they feed on. Interestingly, they exhibit a partially endophytic feeding behavior, tunneling into host plant parts like floral buds and seed pods, while avoiding leaves, which aligns with previous studies. However, we did not observe the caterpillars feeding on open flowers or flower petals (Bell, 1915; Sawant et al., 2016; Bhakare & Ogale, 2018; Butterflies of India, 2024), stems (Fiedler, 1992), or aerial root tips (Bhakare & Ogale, 2018).

     Our observations indicate that the caterpillars have four larval instars, which agrees with Fiedler (1992) but disagrees with Sawant et al.'s (2016) record of five, and further research is needed to clarify this difference.

     The Orchid Tit shows a sharp peak in activity between November to February. In contrast, most of its recorded host plant Orchids, flower and fruit typically during the monsoon, from May to September. Further study is needed to understand how the butterfly synchronizes with its host plant phenology.

     Notably, Acampe, a single recorded host plant species, reproduces multiple times a year, with year-round flowering coinciding with the butterfly's activity peaks. This can be inferred as Acampe being the likely preferred larval host plant of the Orchid Tit in the Western Ghats.

References:

- Butterflies of India (2024): Hypolycaena othona Hewitson, [1865] - Orchid Tit. Acc. 12/12/2024.

- iNaturalist (2024): Orchid Tit (Hypolycaena othona). Acc. 12/12/2024.

- Bell (1915). The common butterflies of the plains of India, Part 17. JBNHS, 23: 481-497.

- Davidson, Bell & Aitken (1896). The butterflies of the North Kanara district of the Bombay presidency, Part II. JBNHS, 10: 372-393.

- Fiedler (1992). Notes on the biology of Hypolycaena othona (Lepidoptera: Lycaenidae) in West Malaysia. Nachr. Entomol. Vereins Apollo, 13(2): 65-92.

- Sawant, Sarang, Mhatre & More (2016). Northernmost breeding record of Orchid Tit Chliaria othona (Hewitson 1865) from the Western Ghats, at Sanjay Gandhi National Park, Thane, India. JBNHS, 113: 37-39.

- Bhakare & Ogale (2018). A Guide to the Butterflies of Western Ghats (India).

- Nicéville (1900). The food-plants of the butterflies of the Kanara district of the Bombay presidency, with a revision of the species of butterflies there occurring. J. Asiat. Soc. Beng., 69(2): 187-278.

- Nitin, Balakrishnan, Churi, Kalesh, Prakash & Kunte (2018). Larval host plants of the butterflies of the Western Ghats, India. JoTT, 10(4): 11495-11550. DOI: 10.11609/jott.3104.10.4.11495-11550.

- Sethumadhavan, Dev, Sriramulu & Jeevith (2024). Notes on the immature stages and larval host plant of the Nilgiri Tit (Hypolycaena nilgirica Moore,[1884]) in the Western Ghats, India. Trop. Lepid. Res., 34(2): 88-92.

- Veenakumari, Mohanraj & Sreekumar (1997). Host plant utilization by butterfly larvae in the Andaman and Nicobar Islands (Indian Ocean). Journal of Insect Conservation, 1: 235-246.

- Wynter-Blyth (1957). Butterflies of the Indian Region.

Observations & text by Nitin Kawthankar.