Ametrodiplosis aeroradicis 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 : 161-165

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

[ Figures 6, 7 & 27–45 ]

This species is morphologically similar to A. adetos except for the following characters:

Adult. Head ( Figs 27–32 ). Frons with 5–9 setae (n = 7). Male flagellomeres with bare internode evanescing after flagellomere X but slight constriction remaining in flagellomeres XI–XII ( Fig. 30 ). Mouthparts: labrum with 6–8 short setae (n = 7); labellum with 8–10 strong setae (n = 9).

Thorax. Wing ( Figs 6, 7 ) 2.2–2.6 mm long in females (n = 5), 1.8–1.9 mm long in males (n = 3); R 5 slightly curved distally. Scutellum laterally with 5–11 setae (n = 7). Anepimeron with 4–7 setae (n = 8); anepisternum with 2–5 scales (n = 5).

Female abdomen ( Figs 34, 35 ). Tergite VII with scales only on posterior third. Sternites VI with 2 rows of posterior setae; sternite VII with 3 rows of posterior setae. Ovipositor: protrusible portion with 2 lateral setae postero-dorsally; cerci ca. 2.6 longer than wide.

Male abdomen ( Figs 36–38 ). Tergite VI with few scales, no lateral setae and 1 row of posterior setae. Terminalia: gonostylus with microtrichia from base to before midlength dorsally and from base to midlength ventrally; hypoproct with deep triangular notch.

Pupal exuviae ( Figs 39, 40 ). Antennal base with elongate, pigmented, serrate protuberance, nearly as long as cephalic seta. Prothoracic spiracles 26–27 μm long (n = 2), ca. 3.3 times longer than cephalic seta. Terga II–VIII with 3–4 horizontal rows of spine-like spicules on anteromedian third of segment.

Larva. Third instar ( Figs 41–43 ). Orange in life. Spatula with pointed lobes. Anus surrounded by median perineal pads covered with pointed and raised cuticular warts. Most anterior pair of corniform terminal papillae thinner than others; median pair wider than others.

Larva. Second instar ( Figs 44, 45 ). Light orange in life, body cylindrical. Spatula absent. Integument ventrally with anteromedian field of tiny pointed cuticular warts on anterior half of thoracic segments and abdominal segments I–VIII, dorsally and laterally covered pointed verrucae on anterior two thirds and rounded verrucae on distal third. One group of two setose and one asetose lateral papillae present on each thoracic segment. Ventral papillae invisible. Two sternal papillae on each thoracic segment and four sternal papillae on abdominal segments I– VIII, all without setae. Two pairs of setose pleural papillae present on thoracic and abdominal segments I–VIII. Terminal segment: ventrally with median perineal pads each bearing 1 asetose anal papilla and few rows of pointed cuticular warts surrounding anal opening, 2 posterolateral smooth plaques each bearing 2 asetose anal papillae, surface anterior and lateral to anus covered with tiny, pointed cuticular warts; dorsally covered with pointed verrucae and with 2 long setose papillae and 6 large corniform papillae, most anterior 2 corniform papillae thinner than others, median 2 wider than others, innermost 2 shorter than others.

Etymology. The species name, aeroradicis , is based on the two Latin words “aer” for air and “radices” for root to indicate that galls of this species are formed on the aerial roots.

Holotype. 1♂ ( ELKU): emerged on 23–24.vi.2011 from gall on aerial root on Trachelospermum asiaticum collected by S. Sato on 19.vi. 2011 in Kanou , Kiyotake, Miyazaki City, Miyazaki Prefecture, Japan.

Paratypes. All from aerial root galls on Trachelospermum spp. in Japan; 4 second instars: collected by K. Ogata on 18.ix.2019 from galls on T. gracilipes var. liukiuense in Tanegashima, Nishinoomote City, Kagoshima Prefecture and dissected on 2.x.2019 by A. K. Elsayed ; 1♂: same as the holotype; 2♀♀ & 2 pupal exuviae: collected by S. Sato on 19.vi.2011 from galls on T. asiaticum at the type locality, emerged on 22.vi.2011; The following specimens were reared or obtained from the aerial root galls on T. asiaticum that were collected by H. Ikenaga from Shiroyama, Kagoshima City , Kagoshima Prefecture: 3♀♀ emerged on 22.vi.1977 ; 1♂, 1♀ on 15.iv.1978; 1♀ on 26.vi.1977; 1♀ on 28.vi.1977; 1♀ & 1 pupal exuviae on 22.vi.1977; 1♂ & 1 pupal exuviae on 29.vi.1977; 1♀ on 26.vi.1977; 1♀ on 29.vi.1977; 2 third instars obtained on 4.iii.1978. In addition, J. Yukawa reared or obtained the following specimens from the root galls on T. asiaticum in Shiroyama : 1♂, reared on 15.iv.1978 ; 1♀, on 23.iv.1978; 2 third instar larvae obtained on 27.v.1972.

Distribution. Widespread in Japan: Honshu (Fukushima, Chiba, Tokyo, The Izu Islands, Shizuoka, and Wakayama Prefectures), Kyushu (Fukuoka, Oita, Miyazaki, and Kagoshima Prefectures), and Okinawa Prefecture.

Life history and biological notes. Ametrodiplosis aeroradicis induces irregular, brown, spherical galls of 2.3– 7.0 mm in diameter on the aerial roots of Trachelospermum asiaticum and T. gracilipes var. liukiuense (Apocynaceae) ( Fig. 2 ). The galls are sometimes fused and each harbors one to four larvae in separate chambers. Larvae can be found in the galls in all seasons of the year and pupation takes place in the gall.

Remarks. Two species of Ametrodiplosis are known to induce irregular spherical galls on the roots of their host plants: A. recondita Gagné on Pycnanthemum tenuifolium Schard. (Lamiaceae) in North America ( Gagné 2018a) and A. auripes (Löw) on Galium mollugo (Rubiaceae) in Europe ( Löw 1888). Although the life history and the gall shape of these two species resemble those of A. aeroradicis , they are associated with distant hosts and are very different morphologically ( Gagné 2018a; Möhn 1955).

Ametrodiplosis aeroradicis is most similar to A. adetos with which it shares mediobasal lobes that are closer to base than to distal part of gonocoxites, narrower gonostylus from base to apex, and aedeagal base not exceeding the gonocoxal base. They can be distinguished easily as follows: male flagellomeres VIII–XII are slightly constricted in A. aeroradicis , but cylindrical in A. adetos ; R 5 is less curved distally in A. aeroradicis ; mediobasal lobes are less protruding from gonocoxites in A. aeroradicis ; pupal antennal bases of A. aeroradicis possess long serrate apical protuberances but tiny, acute apical protuberances in A. adetos ; and anterior lobes of larval spatula are pointed and narrower in A. aeroradicis but rounded and wider in A. adetos .

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 27–33. Ametrodiplosis aeroradicis n. sp. 27. Head (left palpus is incomplete). 28. Ventral view of mouthparts. 29. Female antennal flagellomeres. 30. Male antennal flagellomeres. 31. Ventral view of female flagellomere V. 32. Dorsal view of male flagellomere V. 33. Tarsomere V and acromere. Scale bars = 50 µm.

FIGURES 34–38. Ametrodiplosis aeroradicis n. sp. 34. Female tergites VI–VII (left to right). 35. Segment VIII to Ovipositor. 36. Male tergites V–VII (left to right). 37. Ventral view of gonostylus. 38. Male terminalia. Scale bars = 50 µm.

FIGURES 39–40. Pupa of Ametrodiplosis aeroradicis n. sp. 39. Ventral view of head. 40. Prothoracic spiracle. Scale bars = 50 µm.

FIGURES 41–45. Larva of Ametrodiplosis aeroradicis n. sp. 41. Spatula in third instar. 42. Ventral view of terminal abdominal segments of third instar. 43. Dorsal view of terminal abdominal segments of third instar. 44. Ventral view of terminal abdominal segments of second instar. 45. Dorsal view of terminal abdominal segments of second instar. 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).