Ishigakidiplosis karamae Elsayed, 2024

Elsayed, Ayman Khamis, 2024, Integrative taxonomy reveals a new gall midge genus and species (Diptera: Cecidomyiidae) developing in the flower buds of Pongamia pinnata (Fabaceae) in Japan, Zoological Journal of the Linnean Society 202, pp. 1-13 : 10-12

Ishigakidiplosis karamae Elsayed , sp. nov.

LSID: urn:lsid:zoobank.org:act:8DD46135-EE4A-44F1-A26E-B492F4C671D7

Description and diagnosis

Adult ( Fig. 1E * F) & head: Facets round* eye bridge eight to nine facets long at vertex ( Fig. 2A * B). Antenna: scape with one seta ventrally and bare dorsally; pedicel with a few short setae lateral on inner side; flagellomere XII with microtrichose* narrow apical prolongation in both sexes ( Fig. 2D * F); female flagellomeres with mostly bare necks ( Fig. 2C ); male flagellomeres with bare internodes and necks* nodes slightly shorter than necks* distal flagellomeres successively with longer internodes and more constricted distal nodes* basal node with one set of looped circumfila* distal node with two sets* mostly equal in length ( Fig. 2E )* basal circumfila reach base of distal node* median circumfila reaches base of flagellomeral neck* distal circumfila slightly exceed distal end of neck. Clypeus with few setae and no scales. Mouthparts ( Fig. 2A * G* H): labrum without microtrichia; hypopharynx slightly elongate* with dense and remarkable long microtrichia; labellum slightly elongate* with stout setae ventrolaterally; palpus with noticeable palpiger* segments with setae and no scales* segment I shortest* segments II–IV almost equal in length.

Adult& thorax: Scutum pigmented* with four longitudinal lines of setae and no scales* not reaching scutellum posteriorly; median lines with one to three rows of setae; lateral lines with sparse setae near midlength of scutum; scutellum pigmented* with setae laterally. Acromere ( Fig. 3A ): empodia shorter than claws* slightly longer than basal tooth; pulvilli not discernable. Wing ( Figs 1E * F* 3B) unmarked* 2.6–2.9 mm long in females (N = 5) and 2.3–2.5 mm long in males (N = 5).

Female abdomen ( Figs 3C * 4): In life* light brown ( Fig. 1E ). Tergites I–VII rectangular* with anterior pair of trichoid sensilla* lateral setae* scattered setiform scales and a few scattered setae along midlength* and one or two posterior rows of setae; tergite VIII membranous* differentiated from remainder of tergum only by anterior pair of trichoid sensilla and scattered setae posteriorly. Sternites II–VII rectangular* with one or two posterior rows of setae; sternite II without anterior pair of sensilla* with few setae on anterior half; sternites III–VII with anteromedial pair of trichoid sensilla and scattered setae and setiform scales; sternite VIII differentiated from remainder of sternum only by anterolateral pair of trichoid sensilla and scattered setae posteriorly ( Fig. 4A * B). Ovipositor ( Fig. 4 ): protrusible portion about as long as tergite VII and sternite VII; cercus ovoid* about three times longer than wide* with fewer setae dorsally than ventrally.

Male abdomen ( Fig. 5 ): Colour in life ( Fig. 1F ) and tergites I–V as in female. Tergites VI–VIII with anterior pair of trichoid sensilla; tergite VI with lateral setae* scattered setiform scales at midlength and one posterior row of setae; tergite VII with lateral setae* no or few scales at midlength* and few posterolateral setae; tergite VIII unpigmented medially* bare ( Fig. 5A ). Sternites II– VII as in female; sternite VIII with anterolateral pair of trichoid sensilla and posterior and midlength groups of setae coalesced on posterior half ( Fig. 5B ). Terminalia ( Fig. 5C–G ): cercus microtrichose with few setae; hypoproct longer than cerci; aedeagus longer than gonocoxites* with lateral sensoria on posterior half; gonocoxite length about two times as long as width; gonostylus elongate* slightly shorter than gonocoxite* curved at midlength* microtrichose and mostly asetose on basal third* carinate and setose distally.

Pupal exuviae ( Fig. 6A ): Each antennal base with tiny* pointed anteroventral umbo-like sclerotized prolongation; antennal papillae absent. Vertex with two cephalic papillae on each side* outermost papillae each with long seta. Face with two setose and two asetose median papillae* and two or three lateral papillae on each side* one or two asetose and one setose ( Fig. 6B ). Prothoracic spiracle ( Fig. 6C ) about 5.2 times longer than cephalic seta. Terga II–VIII with small fields of 6–20 simple dorsal spines ( Fig. 6D ); terga I–VII with ten dorsal papillae: six setose and four asetose; tergum VIII with two setose dorsal papillae.

Larva& third instar: In life* light orange* body cylindrical ( Fig. 1D ). Terminal segment: ventrally ( Fig. 7B ) with smooth median perianal pads each bearing one asetose anal papilla* two posterolateral smooth plaques each bearing two asetose anal papillae; surface anterior* lateral to anus covered with pointed and raised cuticular warts; surface posterior to anus covered with tiny crescentic verrucae; dorsally ( Fig. 7C ) covered with tiny pointed verrucae anteriorly* gradually becoming larger and crescentic posteriorly; caudally with two long setose papillae and six corniform papillae: outermost two thinner and shorter than others* innermost four papillae mostly equal in size.

Etymology

The species is named to honour Dr. Hedaya Hamza Karam* Emeritus Professor of Economic Entomology at Alexandria University* Egypt * in recognition of her remarkable contributions in advancing the understanding of the Egyptian fauna of mealybugs and scale insects* her passionate dedication to teaching insect morphology and taxonomy* and her attentive guidance of A. K. Elsayed during his MSc studies.

Life history and remarks

Larva of I. karamae develops in flower buds of P. pinnata . The infested buds remain closed* compact* and slightly swollen owing to thickened petals ( Fig. 1B ). Some infested buds remain attached to the inflorescence* whereas others drop to the ground before larval emergence. Each gall contains a single larva or a few larvae. Third instar larvae are initially white but become orange when mature. The adults emerged in late October to early November from reared larvae collected in the middle of October. Considering the quick emergence of adults and the availability of host flower buds (oviposition sites) during the extended flowering season from May to November ( Ohashi 2016)* this species probably completes multiple generations per year.

Mature larvae of I. karamae jump actively by springing away after tightly arching the body to allow the terminal abdominal segments to catch the posteroventral part of the thorax ( Farley et al. 2019 * 2022). This behaviour is widespread in gall midge species of which the larvae pupate into soil ( Gagné 1994)* and is thought to be an adaptive trait for finding a suitable pupation site or escaping from potential natural enemies ( Tokuhisa et al. 1979 * Farley et al. 2022).

Distribution

Japan * Okinawa Prefecture * Ishigaki Island.

Type material

Holotype: ♂ * JAPAN: Okinawa Prefecture * Ishigaki Island * near Nagura (24°24 ʹ 52.913″N * 124°08 ʹ 25.522″E)* coll. 14–15 October 2022 (Elsayed)* flower bud gall on Pongamia pinnata ( Fabaceae ) * em. 29 October–1 November 2022 ( ELKU) .

Paratypes: JAPAN: Same type locality* six mature larvae * six pupal exuviae * five ♂ * eight ♀ * coll. 14–15 October 2022 (Elsayed)* flower bud galls on Pongamia pinnata ( Fabaceae )* em. 25 October –1 November 2022 ( ELKU) .

Molecular phylogenetic analysis

The obtained sequences of I. karamae were identical in the three analyzed specimens* with pairwise intraspecific similarity of 100%. The monophyly of Cecidomyiidi and the clades of the analysed tribes were strongly supported* with a bootstrap value of 100%. Ishigakidiplosis karamae was not grouped with any of the main tribes of Cecidomyiidi * but was closest to Acodiplosis inulae (Loew) * which is also not assigned to a tribe presently ( Fig. 8 ). Ishigakidiplosis karamae differs from A. inulae by 12.9%* 16%* and 2.5% in the sequences of COI * 16S * and 28S genes* respectively.

Figures

Figure 1. Ishigakidiplosis karamae and its host plant.A* Pongamia pinnata (Fabaceae) growing behind mangroves on Ishigaki Island* Japan. B* flower buds of P.pinnata infested with I.karamae (red arrows). C* immature larvae in a flower bud that has been cut open. D* mature larva in a flower bud that has been cut open. E* freshly emerged female.F* freshly emerged male (terminal tarsal segments are lost).

Figure 2. Adult head of Ishigakidiplosis karamae. A* head. B* occiput with dorsal protuberance bearing two setal bases.C* ventral view of female antennal flagellomere V. D* female antennal flagellomeres.E* dorsal view of male flagellomere III. F* male antennal flagellomeres.G* dorsolateral view of mouthparts. H* lateral view of mouthparts. Scale bars:50 µm.

Figure 3. Ishigakidiplosis karamae. A* tarsomere I and acromere.B* wing.C* female terminal abdominal segments. Scale bars: 50 µm.

Figure 4. Female abdomen of Ishigakidiplosis karamae. A* terminal abdominal segments. B* lateral view of abdominal segment VIII and protrusible part of ovipositor.C* lateral view of cercus. Scale bars:50 µm.

Figure 5. Male abdomen of Ishigakidiplosis karamae. A* tergites VI–VIII. B* sternites VI–VIII. C* ventral view of hypoproct. D* dorsal view of hypoproct. E. ventral view of gonostylus. F* dorsal view of terminalia (hypoproctal setae not shown). G* dorsal view of aedeagus. Scale bar: 50 µm.

Figure 6. Pupal exuviae of Ishigakidiplosis karamae. A* exuviae of freshly emerged adults in soil. B* ventral view of head. C* prothoracic spiracle. D* dorsal view of abdomen.Scale bars: 50 µm.

Figure 7. Third instar larva of Ishigakidiplosis karamae. A* spatula.B* abdominal segment VIII and terminal segment Ventrally.C* abdominal segment VIII and terminal segment dorsally.Scale bars:50 µm.

Figure 8. A maximum likelihood phylogenetic tree based on the alignment of partial sequences of COI* 16S* ITS* CAD* and 28S genes (4654 bp including gaps). Support of less than 50% bootstrap value is not shown.