Ichneumonopsis burmensis, Hardy, 1973

Kovac, Damir, Freidberg, Amnon & Steck, Gary J., 2013, Biology And Description Of The Third Instar Larva And Puparium Of Ichneumonopsis Burmensis Hardy (Diptera: Tephritidae: Dacinae: Gastrozonini), A Bamboo-Breeding Fruit Fly From The Oriental Region, Raffles Bulletin of Zoology 61 (1), pp. 117-132 : 127-130

Comparison of I. burmensis larvae with other Gastrozonini

and Tephritidae . — So far, larvae of four Gastrozonini species have been described ( Elson-Harris, 1992): Chaetellipsis atrata Hardy, 1973 (= Chaetellipsis paradoxa, Bezzi ), Chaetellipsis sp. (= C. maculosa Hancock & Drew ; D. Hancock, pers. com.), Gastrozona fasciventris (Macquart) and Taeniostola limbata Hendel (= Cyrtostola limbata , see Hancock & Drew 1999). The main characters of the Gastrozonini larvae described by Elson-Harris (1992) and of I. burmensis are compared in Table 1. Elson-Harris explicitly described the stomal organ, facial mask, anterior spiracle, and anal lobes of each species. The data entries in Table 1 for labial lobes, antenna, maxillary organ, pad organ, oral lobe, and paired sensilla are based on our interpretation of her SEM figures.

The facial mask of I. burmensis broadly flanks the mouth laterally and extends to the antennal and maxillary sensory organs. It mainly consists of accessory plates. Oral ridges are reduced, non-dentate and cover just a narrow area along the preoral cavity. In Gastrozonini larvae described by Elson- Harris (1992), the facial mask is more or less triangular, confined to the lateral mouth area and consists mainly of dentate oral ridges. In some species a few accessory plates are present at the apices of the oral ridges.

The labial lobe of I. burmensis is covered with strong spines and bears a paired labial organ. Both of these features are unusual, and perhaps unique, among tephritid larvae described to date. The Gastrozononi studied by Elson-Harris (1992) possess a bare labial lobe.

The antenna of I. burmensis is two-segmented, the antennae of Gastrozonini described by Elson-Harris (1992) are 3- segmented. The maxillary sense organ of I. burmensis and other Gastrozonini is similar. It consists of two sensilla groups: a group with two papilla sensilla (one of them larger) and a group with three papilla sensilla and a peg or peg-like sensillum. The stomal organ of I. burmensis and other Gastrozonini is also similar, containing at least one pit sensillum and several peg-like sensilla.

There are 2 pairs of pad organs in I. burmensis (one posterior to the cephalic lobes, one at posteroventral corner of the oral ridge region). Pad organs are also present in other Gastrozonini (not studied in detail) and seem to be widely distributed in Tephritidae . In Anastrepha ludens there are 5 pairs of pad organs (Carroll & Wharton, 1989), and in Ceratitis rosa , 6 pairs ( Carroll, 1998), all arranged in similar positions.

A laterally flattened oral lobe, which is perhaps homologous with the oral lobe of Headrick & Goeden (1990), protrudes between the mouth hooks in I. burmensis . In other Gastrozonini an oral lobe or paired oral lobes are also present (Elson-Harris, 1999).

The most striking morphological character of I. burmensis larvae is the large and strongly ramified anterior spiracle ( Figs. 28 , 34, 35 ), with some 100 comparatively flat papillae. Tephritids (and other Acalyptratae) usually possess tube-like papillae (tubules) arranged in a fan-like row. In Tephritidae the anterior spiracles possess in general 2–20 tubules; in relatively large bodied species there may be more, for example, in some Rhagoletis , Anastrepha and also in Strauzia ( Phillips, 1946; Steck et al., 1990). Frías et al. (2006) observed up to 27 tubules in Toxotr y pana. In the Gastrozonini studied so far (Elson-Harrison, 1992) the anterior spiracles are fan-like and possess 13–36 tubules arranged in 1–3 rows ( Table 1).

A conspicuous character of I. burmensis larvae is the paired sensilla located on the prothorax ( Figs. 34, 36, 37 , pts 1–10). They consist of a pit sensillum and a papilla sensillum (or maybe a peg sensillum with an obscured peg). In other Gastrozonini from our collection we have only found single sensilla on the prothorax. Paired sensilla similar to those found in I. burmensis also occur on the labial lobe of Anastrepha ludens (Carroll & Wharton, 1989, Fig. 42 ).

Other differences between I. burmensis and other Gastrozonini studied by Elson-Harris (1992) include the shape of the spinules of the creeping welt (apex of spinules truncated in I. burmensis , pointed in other Gastrozonini ), the anal lobes (absent in I. burmensis , present in other Gastrozonini ). Additionally, we have noted that a caudal ridge is absent in I. burmensis , but present in most other Gastrozonini in our possession.

Figures

Figs. 28–33. Cephalopharyngeal skeleton, anterior/ posterior spiracles and larval habitus of I. burmensis (light microscopy). 28, Anterior spiracle. 29, Detail of anterior spiracle showing the papillae. 30, Posterior spiracle. 31. Spiracular hairs. 32, Cephalopharyngeal skeleton. 33, Larval habitus. A1–A7 = abdominal segments; as = anterior spiracle; cs = caudal segment; cw = creeping welt; da = dorsal apodeme; db = dorsal bridge; dc = dorsal cornu; ec = ecdysial scar; hb = hypopharyngeal bridge; hs = hypopharyngeal sclerite; ls = labial sclerite; mh = mouth hook; p ceph = pseudocephalon; pb = parastomal bar; pt = praeapical tooth; sh = spiracular hairs; T1–T3 = thoracic segments; win = window; va = ventral apodeme; vb = ventral bridge; vc = ventral cornu; vs = ventral sclerite.

Figs. 34–41. Thoracic and abdominal segments of the I. burmensis larva. 34, Pseudocephalon and prothorax, dorsal view. 35, Prothoracic paired sensilla and anterior spiracle (lateral view). 36, Prothoracic paired sensilla (dorsal view). 37, Enlarged paired prothoracic sensilla (pts5). 38, Detail of anterior spiracle showing the papillae. 39, Detail of a creeping welt showing the spinules. 40, Caudal segment showing the posterior spiracle, anus and the locations of some sensilla. 41, Posterior spiracles. T1 = prothorax; an = anus; as = anterior spiracle; es = ecdysial scar; I1, I2 = intermediate sensilla; p ceph = pseudocephalon; pts 1–10 = prothoracic sensilla; ps = posterior spiracle; sh = spiracular hairs.

Figs. 42–46. Puparium of I. burmensis (SEM photographs). 42, Apical end of the puparium showing the anterior spiracles. 43, Detail of invaginated frontal part of prothorax showing the locations of the paired sensilla. 44, Detail of the anterior spiracle showing three papillae. 45, Caudal end of the puparium. 46, Posterior spiracles. an = anus; as = anterior spiracle; pts 2–9 = prothoracic sensillae.