Lestodiplosis syringopais (Hering)

Kolesik, Peter & Gagné, Raymond J., 2020, A review of the gall midges (Diptera: Cecidomyiidae) of Indonesia: taxonomy, biology and adult key to genera, Zootaxa 4847 (1), pp. 1-82 : 44

Lestodiplosis syringopais (Hering)

[ Figs 23 a–q]

Coprodiplosis syringopais Hering 1931: 59 .

Lestodiplosis syringopais (Hering): Gagné 1973: 504 , new combination.

Type series. Hering (1931) described the male, female, pupa and larva from a population co-occurring with a population of the mining moth Phyllocnistis nepenthae Hering feeding on the pitcher plant Nepenthes tobaica Danser , collected along a road between Balige and Siborong-Borong, Lake Toba, Sumatra, 17-iv-1929. The types are not present in the Museum für Naturkunde, Humboldt-Universität, Berlin ( ZMHB, Jenny Pohl, pers. comm. 11-v-2017) and might be lost.

Description (based on description and illustrations in Hering (1931)). Adult. Flagellomeres 12. Palpus 3-segmented, first segment half-length of second, third slightly longer than second [ Fig. 23b ]. Wing with R 5 evenly bowed, reaching beyond wing apex; R 1 about half wing length; M 4 and Cu 1 forming fork; R S positioned less than halfway between arculus and end of R 1 [ Fig. 23a ]. Tarsal claws thin, simple, empodia nearly as long as claws [ Figs 23d, e ].

Male. Size 1.2 mm. Flagellomeres with spheroid proximal and ovoid distal node; proximal node with single whorl of looped circumfila, distal with two, proximal loops reaching mid length of internode, middle loops barely reaching bases of distal loops, distal loops reaching end of neck [ Figs 23 f–h]. Terminalia [ Figs 23 i–k]: gonocoxite narrow, mesobasal lobe long, acutely pointed; gonostylus narrow, tapering; cerci and hypoproct blunt apically; aedeagus evenly cylindrical, sinuous in lateral view.

Female. Flagellomeres constricted at mid length, with two whorls of short-looped, bowed, longitudinally linked circumfila [ Figs 23l, m ]. Cerci ovoid, hypoproct about one-third cercal length [ Fig. 23k ].

Pupa. Little in a diagnostic way is described or drawn of this stage in Hering (1931) except that the abdominal spiracles of the fourth through seventh segment appear long and tube-like.

Larva. Little is diagnostic for the larva, also, although the drawing of the head appears remarkably more accurate than any other part of the body. [ Fig. 23n ]. Other than that, characters that may be diagnostic are: outer pair of dorsal thoracic papillae have long setae and two middle pairs much shorter [ Figs 23o, p ]. The terminal segment shows 6 or 8 papillae but without the usual setae, which could have broken off [ Fig. 23q ].

Remarks. See comparison among adults of congeners occurring in Indonesia under L. lactifera and between this species and L. oomeni under the latter species.

Biology. The life cycle of this species as the predator of a mining moth needs to be confirmed. Larvae of the type population were found on pitcher plants Nepenthes tobaica (Nepenthaceae) with a dense, superficial network of mines on their pitchers caused by caterpillars of the mining moth Phyllocnistis nepenthae ( Lepidoptera : Gracillariidae : Phyllocnistinae ) at Lake Toba, Sumatra ( Hering 1931). Gall midge larvae pupated in a silky cocoon on the pitcher. The assumption that L. syringopais is a predator of P. nepenthae was based on a large abundance of both species, the gall midge and the mining moth (Thienemann pers. comm. in Hering (1931)), rather than an observation of predation. On the other hand, Beaver (1979) found in Penang, Malaysia, several larvae that he identified as L. syringopais in pitchers of N. albomarginata and N. gracilis that had no association with any leaf miner. The larvae were seen to attack and feed on small larvae of Endonepenthia schuitemakeri ( Diptera : Phoridae ) in the liquid at the bottom of the pitchers. When mature, the larvae of the gall midge were seen to crawl up the side of the pitcher and construct silken cocoon-like coverings in which they pupated. We have not seen Beaver’s specimens.

Geographical distribution. The confirmed occurrence of this species is currently confined to its type locality at Lake Toba , Sumatra, 17-iv-1929 .

Figures

FIGURES 23a–q (from Hering (1931)). Lestodiplosis syringopais: a–c, adult: a, wing; b, palpus; c, tarsus of midleg; d–j, male: d, last tarsal segment (lateral); e, last tarsal segment (ventral); f scape, pedicel and first flagellomere; g, flagellomere (with neck of previous member); h, last flagellomere; i, terminalia (lateral); j, terminalia (dorsal); k–m, female: k, postabdomen (lateral); l, flagellomere; m, scape to first flagellomere; n–q, larva: n, head; o, second thoracic segment; p, third thoracic segment; q, larval terminal segment.