Ametrodiplosis adetos Elsayed, Yukawa & Tokuda, 2021

Elsayed, Ayman Khamis, Yukawa, Junichi, Mochizuki, Ko, Tokuda, Makoto & Kawakita, Atsushi, 2021, Three new species of Ametrodiplosis (Diptera: Cecidomyiidae) from Japan, with a key to the Japanese species and a molecular phylogenetic analysis, Zootaxa 4942 (2), pp. 151-172 : 155-159

Ametrodiplosis adetos Elsayed, Yukawa & Tokuda , n. sp.

[ Figures 4–5 & 10–26 ]

Adult. Head. Eyes connate; facets round, 7–8 facets long at vertex. Occiput with short dorsal protuberance ( Fig. 10 ). Antenna: flagellomere XII with microtrichose, narrow apical prolongation ( Figs 12–13 ); female flagellomeres cylindrical, with bare necks, node about twice as long as neck ( Figs 12, 14 ); male flagellomeres with bare internode, evanescing after flagellomere VII ( Figs 13, 15 ). Frons with 8–12 setae (n = 4). Mouthparts ( Figs 10, 11 ): labrum pointed, without microtrichia, with 6–8 short setae (n = 4); hypopharynx elongate, pointed, with long microtrichia on margins; labellum elongate, narrow in frontal view, with 5–7 strong setae (n = 4); palpus 4-segmented, with noticeable palpiger, segments usually consecutively longer, but in one specimen palpal segment II as long as III.

Thorax. Wing ( Figs 4, 5 ) 1.5 mm long in females (n = 2), 1.3–1.4 mm long in males (n = 3); R 1 joining C before wing mid-length; R 5 strongly curved distally, joining C posteriad of wing apex; C broken after conjunction with R 5. Acromere ( Fig. 16 ): claws untoothed, bent and slightly widened after midlength; empodia slightly shorter than claws; pulvilli ca. 0.3 times shorter than claws. Scutum with 4 longitudinal rows of setae; scutellum laterally with 6–7 setae (n = 4). Anepimeron with 4–5 setae (n = 4); anepisternum with 1–3 scales (n = 4); katepisternum bare.

Female abdomen ( Fig. 17 ). Tergites I–VII with anterior pair of trichoid sensilla; tergites I–VI rectangular, with few lateral setae, sparse scattered scales and 1 row of posterior setae; tergite VII with few lateral setae and 2 rows of posterior setae; tergite VIII membranous, differentiated from remainder of tergum only by anterior pair of trichoid sensilla and a few setae posteriorly. Sternites II–VI with scattered setae and setiform scales near midlength, and 1 row of posterior setae; sternites III–VII with anteromedial pair of trichoid sensilla located intersegmentally; sternite VII with scattered setae and few scales near midlength and 2 rows of posterior setae; sternite VIII differentiated from remainder of sternum only by anterior pair of lateral trichoid sensilla. Ovipositor ( Fig. 18 ): protrusible portion bare dorsally, mostly covered with short and few long setae ventrally; cerci ovoid, ca. 2.3 times longer than wide, with short setae and 2 apicoventral setae slightly thicker and longer than surrounding setae; hypoproct with 2 apical setae.

Male abdomen ( Fig. 19 ). Tergites I–VI as in female but with fewer scales; tergite VII with anterior pair of trichoid sensilla, 2 setae each placed posterolaterally, without scales; tergite 8 differentiated from remainder of tergum only by anterior pair of trichoid sensilla. Sternites II–VII as in female; sternite VIII short, about 0.5 as wide as sternite VII, with anterior pair of trichoid sensilla placed intersegmentally, and posterior and midlength groups of setae coalesced. Terminalia ( Figs 20, 21 ): gonocoxite narrowly cylindrical except for prominent mediobasal lobe slightly before midlength; gonostylus microtrichose basally, carinate and setose distally, with cluster of setae on base ventrally; each lobe of cerci trapezoid, microtrichose, with few setae along posterior margin; hypoproct longer than cerci, with microtrichia on distal half, bilobed, each lobe with 1 dorsal and 1 ventral subapical seta; aedeagus longer than hypoproct, slightly tapered to narrow and rounded apex, with lateral sensoria on posterior half; basal portion of aedeagus not extending anteriorly beyond base line of gonocoxite.

Pupal exuviae. Antennal base with tiny, pointed anteroventral umbo-like sclerotized prolongation, antennal papillae invisible. Vertex with 2 cephalic papillae on each side, outermost papillae with long seta. Face with 2 setose and 2 asetose median papillae, and triplet lateral papillae on each side, 2 asetose and 1 setose ( Fig. 22 ). Prothoracic spiracles ( Fig. 23 ) pigmented, elongate, 24–27 μm long (n = 4), curved, with trachea extending to tip, ca. 4.5 times longer than cephalic seta. Segments II–VI with rudimentary abdominal spiracles. Terga I–VIII with pair of trichoid sensilla anteriorly and short spicules on anterior third; terga II–VIII with 2–3 horizontal rows of spine-like spicules on anteromedian third; terga I–VII with 2 asetose and 4 setose dorsal papillae; tergum VIII with 2 setose dorsal papillae.

Larva. Third instar. In life creamy white, body cylindrical. Spatula with rounded lobes ( Fig. 24 ). Ventral and dorsal papillar pattern basic for Cecidomyiidi ( Möhn 1955). Terminal segment: ventrally ( Fig. 25 ) with smooth median perineal pads each bearing 1 asetose anal papilla, 2 posterolateral smooth plaques each bearing 2 asetose anal papillae, surface anterior and lateral to anus covered with pointed and raised cuticular warts; anal opening surrounded by microtrichia; dorsally ( Fig. 26 ) covered with tiny pointed verrucae and with 2 long setose papillae and 6 large corniform papillae, most anterior 2 corniform papillae thinner than others, innermost 2 shorter than others.

Etymology. The species name is derived from the Greek word “adetos”, meaning free, for the fact that the larvae live freely in the flowers of Tylophora aristolochioides without gall-induction.

Holotype. 1♂ ( ELKU): Reared by A. K. Elsayed and emerged on 5.viii.2019 from a flower of Tylophora aristolochioides collected by A. K. Elsayed & K. Mochizuki in Shiramine Village, Hakusan City, Ishikawa Prefecture, Japan on 16.vii.2019.

Paratypes. All collected from flowers of Tylophora aristolochioides in Japan; 5 larvae: collected on 8.ix.2019 by K. Mochizuki & S. Nemoto in Shirakawa City, Fukushima, Japan. The remaining paratypes were collected at the type locality by A. K. Elsayed & K. Mochizuki and reared by A. K. Elsayed: 3 pupal exuviae & 2 ♀♀: emerged on 1.viii.2019 ; 1 pupal exuviae & 1♂: emerged on 5.viii.2019; 2 pupal exuviae: emerged on 2.viii.2019; 1 pupal exuviae & 1♀: emerged on 30.vii.2019; 2 ♀♀: emerged on 14.vii.2019; 3 ♀♀: emerged on 2.viii.2019; 4 larvae: collected on 16.vii.2019.

Distribution. Japan, Honshu: Ishikawa and Fukushima Prefectures.

Life history and biological notes. Larvae of A. adetos are ectophagous on the flowers of Tylophora aristolochioides (Apocynaceae) and do not induce galls ( Fig. 1 ). Pupation takes place in the soil. In the laboratory, the adults emerged 2–3 weeks after larvae were transferred to rearing cups. Ametrodiplosis adetos has several overlapping generations in summer due to the long flowering season of T. aristolochioides that extends from July to September.

Remarks. Ametrodiplosis adetos is most similar to A. mamajevi Kovalev, 1972 , sharing with it the curved R 5 distally, narrow gonocoxites, mediobasal lobes placed on the basal half of gonocoxites and trapezoid lobes of cerci. They can be distinguished as follows: aedeagal base ends before gonocoxal bases in A. adetos but exceeds the gonocoxal bases in A. mamajevi ; mediobasal lobes are more pronounced in A. adetos ; and the male flagellomere XII ends with a narrow apical prolongation in A. adetos but lacks the apical prolongation in A. mamajevi ( Kovalev 1972) .

Figures

FIGURES 4–9. Female and male wings of Japanese Ametrodiplosis species. 4–5. Female and male wings of A. adetos n. sp., respectively. 6–7. Female and male wings of A. aeroradicis n. sp., respectively. 8–9. Female and male wings of A. stellariae n. sp., respectively. Scale bars = 50 µm.

FIGURES 10–16. Ametrodiplosis adetos n. sp. 10. Head. 11. Ventral view of mouthparts. 12. Female antennal flagellomeres. 13. Male antennal flagellomeres. 14. Ventral view of female flagellomere V. 15. Ventral view of male flagellomere V. 16. Tarsomere V and acromere. Scale bars = 50 µm.

FIGURES 17–18. Female of Ametrodiplosis adetos n. sp. 17. Terminal part of abdomen. 18. Ovipositor. Scale bars = 50 µm.

FIGURES 19–21. Male of Ametrodiplosis adetos n. sp. 19. Terminal part of abdomen. 20. Ventral view of gonostylus. 21. Male terminalia. Scale bars = 50 µm.

FIGURES 22–23. Pupa of Ametrodiplosis adetos n. sp. 22. Ventral view of head. 23. Prothoracic spiracle. Scale bars = 50 µm.

FIGURES 24–26. Larva (third instar) of Ametrodiplosis adetos n. sp. 24. Spatula. 25. Ventral view of terminal abdominal segments. 26. Dorsal view of terminal abdominal segments. Scale bars = 50 µm.

FIGURES 1–3. Ametrodiplosis species on their hosts in Japan. 1. Larvae of A. adetos n. sp. on a flower of Tylophora aristolochioides (Apocynaceae). 2. Aerial root galls (arrows) of A. aeroradicis n. sp. on Trachelospermum asiaticum (Apocynaceae). 3. Leaf bud gall of A. stellariae n. sp. on Stellaria uliginosa (Caryophyllaceae).