Chaetotaxy of first instar caterpillar of the Common Pierrot Castalius rosimon (Fabricius) (Papilionoidea: Lycaenidae: Polyommatinae)

 

 

Manbeer Kaur 1, Avtar Kaur Sidhu 2 & H.S. Rose 3

 

 

1 BAM Khalsa College, Garhshanker, Disrict, Hoshiarpur, Punjab 144527, India

2 High Altitude Regional Centre, Zoological Survey of India, Saproon, Solan, Himachal Pradesh 173211, India

3 SUS College of Research & Technology, Mohali, Punjab 140306, India

1 kaur.manbeer@rediffmail.com (corresponding author), 2 avtarkaur2000@gmail.com, 3 profhsrose@gmail.com

 

 

 

doi: http://dx.doi.org/10.11609/JoTT.o3798.7839-42

 

Editor: R.M. Sharma, Retired, Zoological Survey of India, Pune, India. Date of publication: 26 September 2015 (online & print)

 

Manuscript details: Ms # o3798 | Received 03 October 2013 | Final received 14 August 2015 | Finally accepted 21 August 2015

 

Citation: Kaur, M., A.K. Sidhu & H.S. Rose (2015). Chaetotaxy of first instar caterpillar of the Common Pierrot Castalius rosimon (Fabricius) (Papilionoidea: Lycaenidae: Polyommatinae). Journal of Threatened Taxa 7(11): 7839–7842; http://dx.doi.org/10.11609/JoTT.o3798.7839-42

 

Copyright: © Kaur et al. 2015. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: Indian Council of Agriculture Research and Zoological Survey of India.

 

Conflict of Interest: The authors declare no competing interests.

 

Acknowledgements The authors are thankful to ICAR for funding the project titled, “Monitoring the status of butterfly diversity” for financial assistance. The second author is thankful to Director, Zoological Survey of India for providing necessary facilities.

 

 

According to Bridges (1988), the genus Castalius Hübner comprises three species, viz.: austini Heron, 1894, sostris Fruhstorfer, 1916, and rosimon Fabricius, 1775. Castalius rosimon commonly called Common Pierrot occurs in South-east Asia. The life history and immature biology of Castalius rosimon is studied in detail by Sidhu et al. (2009) but no details on the chaetotaxy of the larva is given. Chaetotaxy not only plays a key role in the identification of different insect species during their larval stages, but is also significantly important in understanding phylogenetic relationships amongst different taxa of varying ranks. Ballmer & Pratt (1988) have stated chaetotaxy to be the most reliable and primary tool for identifying the larvae of Lepidoptera. In view of this, the chaetotaxy of the first instar larva of C. rosimon is attempted for the first time. Since it is the type species of the genus, it will also help in improving the diagnosis of the genus

Material and Methods: In order to examine the chaetotaxy, the first larvae reared on the leaves of its natural host plant, Zizipus oenoplia Mill. (Rhamnaceae) in Himachal Pradesh in the laboratory culture, were first killed by dipping in boiling hot water before preserving them in nine part 75% ethyl alcohol and one part glycerine (Stehr 1987). For examination of the larval chaetotaxy, the larvae were degraded and brought down to water. The head of each larva was detached from the body under a zoom stereo-binocular. In order to make skin preparation, the body of the larva was given a midventral longitudinal cut with a sharp blade. Both the body and the head of the larva were put in 10% KOH solution for a period of about 6-8 hours (first instar) at room temperature for maceration and proper clarity. The traces of KOH were removed by placing the material in 1% glacial acetic acid. After dehydration, the chaetotaxy of head was examined by putting the same in glycerine in a cavity slide. The skin preparation of the body of each larva was stained in eosine solution, followed by dehydration and clearing in xylene before mounting it permanently on the slide in canada balsam. The tactile setae on the head and the body of first instar have been drawn with the help of a graph eye piece fixed in a stereoscopic microscope binocular. The proprioceptors or micro setae have been located quite carefully with stereoscopic microscope (at 40x20x or 100x20x). Except the head capsule and A10, the setal maps showing relative position and size of the setae, and other structures between dorsal and ventral meson from left side have been for all the remaining segments, i.e., T1, T2 (T3 is similar to T2), A1 (A2, A7, A8 are similar to A1), A3 (A4 to A6 are similar to A3) and A9 (Hinton 1946; Stehr 1987). The chaetotaxy of the head capsule and A10 have been drawn similar to their shape. For naming different setae and pores, the nomenclature proposed by Heinrich (1916), Hinton (1946) Clark & Dickson (1956), Stehr (1987), Ballmer & Pratt (1989, 1992), and Ballmer & Wright (2008) has been followed in the present study.

Observations: First Instar Larva (Fig. 1): Cephalic chaetotaxy (Figs. 1 and 2): Cranium longer than broad, less sclerotized; epicranial notch extremely deep, giving the head somewhat bilobed appearance, frontoclypeus as long as wide; lateral adfrontal suture very long, more than double the length of epicranial suture; ecdysial line obscure; stemmatal area bears six stemmata; 1 to 5 placed equidistantly, arranged in a semicircle. Stemma 6 caudad to stemma 3, widely spaced from stemma 5. Head capsule characterized by 15 setae and 2 pores.

Frons graced with seta F1 and pore Fa; F1 slightly posterad and mesad to C1, slightly longer than the latter; Fa prominent, posterad and mesad to F1; single seta C1 makes up clypeus group, present near epicondyle. Adfrontal group trisetose, represented by setae AF1, AF2 and AF3; AF2 beset near middle of lateral adfrontal suture; AF1 anterad to AF2 infront of stemma 3; AF3 mesad to A1, cephalad to AF2; all adfrontal setae nearly equal in length.

Anterodorsal area furnished with three setae. A1, A2, A3 and pore Aa; A1 anteromesad to stemma 4; A3 lies infront of stemma 4; A1 mesad to stemma 1; Aa situated close to A3, infront of stemma 2. Posteriodorsal group composed of single seta P2, lies laterad to epicranial notch, as long as A1. Stemmatal group represented by setae S1, S2 and S3 on stemmatal area; S1 beset within the stemmatal semicircle, caudoventrad to stemma 3; S2 caudad to stemma 1; S3 present behind stemma 6. Substemmatal area furnished with setae SS1, SS2 and SS3; SS1 lies at base of mandible; SS2 behind stemma 5; SS3 ventrad to SS2; SS2> SS3 = SS1 lengthwise.

Thoracic chaetotaxy: Tactile setae mounted on cone-like chalazae; V1 seta of ventral group and proprioceptors raised on pinacula.

 

 

 

 

T1 (Fig. 3): Prothoracic shield elongated with anterior margin curved, posterior straighter; each half graced with four setae and one lenticle. XD group composed of XD1 and XD2 setae; XD1 situated on the shield at its middle, towards middorsum; XD2 posterolaterad to XD1, near posterior margin of the shield, as long as XD1. Dorsal group formed of setae D1 and D2 besides lenticle DL; seta D1 lies at anterior margin of the shield, cephalad to XD1; D2 lies below XD2, less than 1/4 of the length of XD2, as long as D1. Two fringe setae (FS) situated at membranous area, anterolaterad to the shield. Subdorsal group bisetose, with seta SD1 ventral to D2, below posterior margin of the shield, slightly shorter than XD2; SD2 anterodorsad to SD1, equal to half of the length of the latter. Lateral group exhibited by setae L1 and L2 along with lenticle SPSL, beset above spiracle; L1 ventrad to SD2; L2 posterolaterad to L1, anterodorsad to SPSL, equal to 1/2 of the length of L1; SPSL located cephalodorsad to spiracle, below SD1. Subventral group constituted by setae SV1 and SV2, lying below spiracle; SV1 ventrad to L2; SV2 anterodorsad to SV1, shorter than the latter. Ventral group consisted of single seta V1 graced at postcoxal position, near median ventral line. Proprioceptor seta MXD1 lies posterodorsad to XD2; microsetae MV2 and MV3 situated before coxa of the leg; MV3 ventrad to MV2.

T2 and T3 (Figs. 4 and 5): Dorsal group composed of setae D1, D2 and lenticle DL; D1 very long, lies toward dorsal mesal line; D2 posterolaterad to D1, 2/3 of the length of the latter; DL present anterolaterad to D2. Subdorsal group exhibited by setae SD1, SD2, SD3, and SD4; SD1 located very close and laterocaudad to DL, as long as D1, SD3 dorsad to DL and cephalad to D2, 2/3 of the length of SD1; SD2 anterolaterad to SD1, very short, less than 1/5 of the length of SD1; SD4 caudoventrad to SD2, as long as the latter. Setae L1, L2, L3, L4, L5 and L6 represent lateral group; L4, L1, L2 and L3 lie in a horizontal line respectively in lateral area, L1 longest, remaining three setae nearly equal in length; L5 situated anterolaterad but close to L4, equal to less than 1/2 of the length of L2; L6 ventrad to L5, as long as the latter; on T3, setae L5 and L6 absent. Subventral group trisetose, formed of setae SV1, SV2 and SV3 lying above coxa of the leg; SV2 anterad to SV1, SV3 ventrad to SV2, nearly equal to 1/2 of the length of the latter; in T3 seta SV3 wanting. V1 seta of ventral group beset near median ventral line. Microscopic seta MD1 situated cephalad to DL; MSD1 and MSD2 in front of seta SD4, MSD2 ventrad to MSD1; before coxa of the leg, lies proprioceptors MV1, MV2 and MV3, MV1 cephalad to SV2, MV2 posterolaterad to MV2, lies equidistantly between MV1 and MV3, the latter ventrad to MV1.

Abdominal chaetotaxy: Tactile setae beset on cone-like chalazae; microsetae and V1 seta of ventral group lie on pinacula.

A1 and A2 (Figs. 8 and 9): Setae D1 and D2 besides lenticle DL make up dorsal group: D1 lies closer to dorsal meson; D2 located below D1, slightly shorter than the latter; DL laterad to D2. Subdorsal group comprised of seta SD3 and a pore SDP; SD3 anterodorsad to DL, very short in size; SDP posterolaterad to DL, lies above spiracle; on A2, SDP larger in size, in subdorsal group also present a lenticle SPSL, lying immediately dorsad to spiracle. Lateral group possesses setae L1, Lz, L3 and lenticle SBSL; the latter lie very close and anteroventrad to spiracle, SBSL absent in A2; L1, Lz and L3 beset below but widely apart from SBSL, L1 directly ventrad to SBSL, L2 anteroventrad to L1, L3 posterodorsad to L1; L1> L2> L3 lengthwise. Subventral group unisetose, with seta SV1 lying well below L1, very short in size. Ventral group consists of seta V1, located towards midventral line. Microscopic seta MD1 situated cephalad to DL; MSDz anterad to spiracle; MV3 anteroventrad to SV1.

A3 and A6 (Figs. 7 and 10): D1 seta lies dorsad to D2, near middorsal line, longer than D2; lenticle DL situated anterad to D2. Subdorsal group composed of seta SD3 and pore SDP; SD3 anterodorsad to DL, very short in size; SDP posterolaterad to DL. Lateral group setae L1, L2 and L3 present below spiracle, closely approximated, beset in a horizontal line, L2 taking the anterior most position, L1, in the middle and L3 the most caudad seta of the group; L1> L2> L3 lengthwise. Subventral group represented by setae SV1, SV2, SV3 and SV4; SV3 and SV4 liecaudoventrad to lateral group; SV3 caudad to SV4, slightly longer than the latter; setae SV1 and SV2 situated on dorsal area of proleg. V1 seta of ventral group present near median ventral line. Microseta MD1 lies anterad to DL; MSD 2 cephalad to spiracle; MV3 precoxal in position. Proleg graced with uniserial, uniordial crochets; fleshy spatulate lobe present in centre, enflanked by one crochet on either side.

A7 (Fig. 11): Dorsal group exhibited by one seta D1 and two lenticles, DL1 and DL2; D1 longest seta of the segment, lies close to dorsal meson; DL1 caudolaterad to D1; DL2 ventrad to DL1. Lateral group trisetose, represented by setae L1, L2 and L3; L3 beset below spiracle; L2 anteroventrad to L3; L2 cephalad to L1; L1 longest seta of the group, somewhat shorter than D1; L2 and L3 equal in length, 2/3 of the length of L1, SV1, seta of subventral group situated well below L1 on subventral area, very short in size. Ventral group composed of seta V1, situated ventrad to SV1, towards ventral mesal line. Proprioceptor seta MD1 lies cephalad to DL, MSD2 anterad to spiracle; MV3 anteroventrad to SV1.

A8 (Fig. 12): Seta D1 and lenticle DL make up dorsal group; D1 very long, present near median dorsal line; DL laterad to D1. Lateral group represented by setae L1, L2 and L3 lying below spiracle; L2 directly ventrad to spiracle; L1 caudad to L2; L3 posterodorsad to L1; L1 as long as D1, L2 nearly 1/2 the length of L1, L3 shorter than L2. Microseta MD1 present anterad to DL; MSD2 lies infront of spiracle; MV3 cephaloventrad to SV1.

A9 (Fig. 13): Lateral group trisetose, composed of setae L1, L2 and L3, arranged closely on lateral area; L2 the most anterior seta of the group; L1 caudad to L2; L3 dorsad to L1; L1> L2> L3 lengthwise.

A10 (Fig. 13): Anal shield ill-defined, caudal margin rounded furnished with closely placed four setae; D1 dorsal most seta on shield; D2 anterodorsad to D1; SD2 ventrad to D2, as long as D2; SD1 caudad to SD2, equal to 1/2 the length of the latter. Lateral group setae L1 and L2 placed contiguous with lateral group setae of 9th segment; L1, much longer and dorsad to L2. Anal leg beset with setae SV1 and SV2 of sub ventral group. Seta V1 of ventral group situated below the proleg, closer to ventral mesal line.

Discussion and significance of the present study: Hinton (1946) has recognized two functional types of setae, i.e., microscopic or proprioceptor setae which are relatively much smaller and located near the anterior margins of the body segments and the posterior dorsal area of the head, where different body parts make contact, and the tactile setae which are quite long and widely distributed on the body of the caterpillars. The tactile setae have earlier been differentiated as primary, subprimary and secondary (Fracker 1914). The former i.e., primary setae represent an archetypal lepidopteran setal pattern, whose number and position is constant in the first instar larvae. The subprimary setae mostly appearing in the second instar also occur at fixed locations (Stehr 1987), except the family Lycaenidae, in which they may occur in the first instar as well (Hinton, 1946; Ballmer & Pratt 1988). In butterflies, it is a prerequisite to examine the first instar caterpillar of any species for authentic identification. Lawrence & Downey (1966) reported MD group setae (they termed it as V group) on the head capsule and three lateral setae on T2 and T3 segments of Everes comynta Godart of subfamily Polyommatinae. Sidhu & Rose (2004) observed MD group of setae on head capsule, four lateral group setae on T2 and three lateral group setae on T3 in the species Freyria putli (Kollar) of subfamily Polyommatinae. Duarte et al. (2005) recorded MD group of setae on the head capsule of Calycopis caulonia (Hewitson) of subfamily Theclinae and three lateral setae on T2 and T3 segments of the said species. Ballmer & Wright (2008) observed MD setae on head capsule and three lateral setae on T2 and T3 segments of Ahmetia achaja (Fruhstorfer) of subfamily Theclinae. Durate & Robbins (2009) reported MD group of setae (they termed it as CD group) on head capsule and three lateral setae on second and third thoracic segments in species Calycopis bellera (Hewitson) and C. janeirica (Felder) of subfamily Theclinae. The absence of CD group on head capsule, presence of five lateral setae on T2 and presence of four lateral setae on T3 in the presently studied species appears to constitute the diagnostic characters of Castatlius rosimon. The present study will help in field identification of species at larval stage and in better understanding of taxonomic classification of the group.

 

 

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