Agromyza rudbeckiana, Lonsdale, 2018

Lonsdale, Owen, 2018, A survey of Agromyzidae (Diptera) reared from leafmines on Long Island, New York; host associations, distribution data, and the description and host association of a new species, Zootaxa 4450 (1), pp. 77-90 : 82-89

Agromyza rudbeckiana spec. nov.

Description. Wing length 2.8–2.9mm (♂), 2.9–3.4mm (♀). Length of ultimate section of vein CuA1 divided by penultimate section: 0.6–0.7. Eye height divided by gena height: 6.8–9.0. Apex of first flagellomere with slightly longer hairs that are broadly distributed apically to more discretely arranged in large ovate patch; segment slightly longer than high. Orbital plate less than 1/5 width of frons, inner margin ill-defined, slightly better sclerotized than frontal vitta. Ocellar triangle not much larger than tubercle, subtriangular with corners rounded; anterior ocellus slightly displaced anteriorly. Parafacial and cheek narrow. Buccal cavity essentially straight, with slight curve; ventromedial portion of face with more weakly sclerotized triangular section sometimes faded or depigmented to form shallow epistoma.

Chaetotaxy: Two ors, three ori. Ocellar and postvertical setae subequal to fronto-orbitals. Four dorsocentral setae, strongly decreasing in length anteriorly, with third seta less than half length of second seta and fourth seta up to twice length of notal setulae. Acrostichal seta subequal to second dorsocentral. Acrostichal setulae in 8 scattered rows, reaching level of acrostichal seta, absent from dorsocentral row behind first dorsocentral. Mid tibia with 2–3 medial setae.

Coloration: Setae light to dark brown. Head base color brownish-orange; antenna yellowish-orange, sometimes with dark brown ill-defined infuscation on distal half or predominantly brown to dark brown with basal margin orange; frons sometimes brown to dark brown on posterior half, becoming darker posteriorly, with inner margin of orbital plate paler; posterolateral corner of frons, ocellar tubercle, face, venter of gena, palpus, clypeus and back of head dark brown; remainder of gena yellowish; lunule beige. Thorax and abdomen dark brown, subshining. Wing veins light brown to whitish, becoming paler to base. Calypter and halter white. Legs dark brown; apices of femora, and bases and sometimes apices of tibiae light yellow to yellowish, but yellow pigment sometimes very reduced, especially on mid and hind legs; tibiae and tarsi usually paler than femora, brownishyellow, anterior tibia paler, posterior tibia darker.

Genitalia: (Fig. 5) Epandrium broadly rounded, fused to surstylus, which is short, rounded with apex subtriangular and with cluster of small, slightly pointed tubercle-like setae medially to basally. Cercus large, widest past midpoint. Hypandrium gracile, large, with elongate apical apodeme; inner lobe weakly sclerotized with patch of setae along curved sclerotized band. Postgonite lobate with row of minute dorsomedial setae and long basal tail. Phallophorus shorter ventrally, slightly asymmetrical where it meets basiphallus. Basiphallus with two subparallel plates that fuse distally to one pair of sharply squared rectangular paraphalli that are more heavily sclerotized ventrally; left plate of basiphallus basally lobate, better sclerotized along dorsomedial margin; right plate abbreviated at base, shape irregular to bent but mostly linear. Hypophallus membranous, lobate. Mesophallus fused to elongate distiphallus, forming irregular supporting structure with basal bulb and heavily sclerotized laterodorsal complex surrounding distiphallus base. Distiphallus as long as basiphallus, with slight ventral curve on distal 3/5, sclerotized, narrow, tubular and only partially split at very apex, where each half has one short, narrow, posteriorly directed process. Ejaculatory apodeme not observed.

PLATE 4. a: Phytomyza aquilegiana on Aquilegia sp.; b: Phytomyza aquilegivora on Aquilegia sp.; c: Phytomyza crassiseta on Veronica ; d: Phytomyza erigerophila on Erigeron; e: Phytomyza glabricola on Ilex glabra ; f: Phytomyza ilicicola on Ilex opaca ; g: Phytomyza opacae on Ilex opaca ; h: Phytomyza plantaginis on Plantago lanceolata .

Variation: Vermont specimens with head dark brown; frontal vitta sometimes with orange patches or orange anteromedially; antenna brownish-orange with distal margin darker; gena brown.

PLATE 5. Agromyza rudbeckiana spec. nov., male genitalia; a: external components, Ventral; b: same, posterior; c: postgonite, lateral; d: hypandrium, Ventral; e: phallus, Ventral; f: same, left lateral.

Species Plant Host (Family) Larvae Notes Geographic Distribution New to Present NY

Agromyzinae

Agromyza ambrosivora Spencer Ambrosia artemisiifolia , A. trifida August Leafmine is typically a large white blotch on Canada; USA: CA, NY, MD Yes [GB: EF104649 ] ( Asteraceae ) A. trifida (Fig. 1a). On A. artemisiifolia the

mine is black, and the mined tissue may

immediately dry and crumble even while the

larva is still present (Fig. 1b). Pupation is

external.

Agromyzas deserta (Patton) * Celtis laevigata (Cannabaceae) April, May This species forms conspicuous petiole and USA: CN, NY, WV Yes twig galls (Fig. 1g). Larvae exit the mine to

pupate shortly after the initial appearance of

spring leaves, so the larvae are easily missed.

Agromyza masculina Sehgal Rosa sp. ( Rosaceae ) June Leafmine occurs along leaf edge, gradually Canada; USA: NY, UT Yes widening (Fig. 1c). Pupation is external.

Agromyza proxima Spencer Dichanthelium sp. ( Poaceae ) June, July Blotch mine (Fig. 1d) proceeds from leaf tip Canada; USA: FL, NY no with multiple larvae feeding together. Pupation is external. Agromyza rudbeckiana n. sp. Rudbeckia sp., June Leafmine is a conspicuous blotch starting at USA: NY Yes [GB: EF104653 ] yellow-flowered garden composite the tips of the leaves. As the larvae feed ( Asteraceae ) towards the base of the leaf, the mined tip portion of the leaf often dries out and begins to crumble (Figure 1e). Pupation is external.

Ophiomyia carolinensis Spencer possibly Symphyotrichum sp. June, July The leafmine starts as a long thin linear mine, USA: NC, NY Yes ( Asteraceae ) but then becomes a poorly defined blotch mine

running along both sides of the leaf midrib

Fig. 1h). The blotch portion of the mine is

often reddish in color. Pupation is internal.

……continued on the next page Amauromyza flavifrons (Meigen) Saponaria officinalis , Silene latifolia , S. June – Leafmine is a conspicuous linear-blotch on Canada: US; DE, MI, MN, NY, Yes [GB: EF104670 ] stellata, Dianthus barbatus November upper, lower, or both leaf surfaces (Fig. 2a). OH, OR, PA, VT, WA, WI. ( Caryophyllaceae ) When lit from below, eggs within the leaves Western Europe to the Kyrghyz

can be readily seen under a dissecting Republic ( Spencer, 1976).

microscope. Pupation is external. Calycomyza solidaginis (Kaltenbach) Solidago spp. ( Asteraceae ) May, Leafmine is an extended blotch along the leaf Canada; Europe; USA: no [GB: EF104682 ] August edge in the basal half of the leaf (Fig. 2f). widespread

Pupation is internal with the pupa located on a

pile of frass.

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Species Plant Host (Family) Larvae Notes Geographic Distribution New to Present NY Cerodontha (C.) dorsalis (Loew) grass ( Poaceae ) August Not recorded. Widespread in Americas; no [GB: EF104686 ] Mongolia; East Siberia; Middle Asia Cerodontha (Poemyza) incisa grass ( Poaceae ) July Not recorded. Canada; Europe; USA: no (Meigen) widespread in northern states; [GB: EF104689 ] Pakistan; Japan Cerodontha (Poemyza) pygmaea grass ( Poaceae ) June Not recorded. Canada; Europe; Russia; USA: no (Meigen) AK, NY Liriomyza arctii Spencer Arctium lappa (Asteraceae) June Leafmine is a linear mine that follows along Canada; USA: MN, NY, WI Yes leaf veins (Fig. 2g). Pupation is external. Liriomyza asclepiadis Spencer Asclepias syriaca (Apocynaceae) June, July Leafmine is a compact blotch (Fig. 2h). USA: ID, MA, MN, NH, NY no [GB: KR671136.1] Pupation is external. Liriomyza brassicae (Riley) Alliaria petiolata (Brassicaceae) , August Leafmine is linear, often twisting (Fig. 2i). Widespread in Americas and no [GB: EF104700 ] Tropaeolum sp. ( Tropaeolaceae ) Pupation is external. elsewhere Liriomyza eupatorii (Kaltenbach) Aster sp., Solidago spp. ( Asteraceae ) May, June Leafmine is linear, generally with a Canada; Europe; USA: CA, DE, Yes [GB: LT795097 ] conspicuous spiral at start (Fig. 3a). Pupation GA, MA, MI, MS, MT, NC, NY, is external. PA, SC, TN, WA, WV Liriomyza fricki Spencer Trifolium , Pisum (Fabaceae) June Leafmine is a linear-blotch (Fig. 3b). Pupation Canada; USA: CA, MA, MD, MI, Yes [GB: EF104702 ] is external. MN, NY, WA, WI, WY Liriomyza philadelphivora Spencer Philadelphus sp. ( Hydrangeaceae ) May Leafmine is a linear-blotch. Canada; USA: DC, NY no [GB: EF104704 ] Liriomyza taraxaci Hering Taraxacum officinale , Lactuca sp. June Leafmine is a blotch. Pupation is external (Fig Canada; Europe; USA: AK, IL, Yes ( Asteraceae ) 3c). NY, WI, WN Liriomyza trifoliearum Spencer Cleome (Cleomaceae) , Medicago , May, June, Leafmine is linear (Fig. 3d). Pupation occurs Canada; USA: AZ, CA, DE, FL, no [GB: EF104705 ] Pisum (Fabaceae) July within the mine. MA, MD, NM, NY, OH, OR, PA, UT, WA, WI, WV

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Phytomyza plantaginis Robineau- Plantago lanceolata (Plantaginaceae) June Leafmine is primarily linear (Fig. 4i). Australia; China. New Zealand.; no Desvoidy Pupation takes place at the end of the mine. Canada; Europe; Japan; USA:

[GB: EF104729 ] widespread throughout

Phytomyza sp. Lactuca sp. ( Asteraceae ) June, July Mine is located in the leaf midrib. Pupation --- ---takes place within the midrib.

Host: This species was reared from ornamental Rudbeckia ( Asteraceae : black-eyed Susan) in Stony Brook, NY. It has also been reared from undetermined yellow-flowered composite in a garden in Rutland, VT. The mine is a conspicuous blotch starting at the leaf apex. As the larvae feed towards the base of the leaf, the mined apical portion of the leaf often dries out and begins to crumble and fall from the plant (Figure 1e), often while the larvae continue to mine the fresh leaf tissue.

Distribution: USA: NY, VT.

Etymology: This species is named after one of its hosts, Rudbeckia .

Holotype: USA. NY: Suffolk Co., SUNY, Stony Brook, larva coll. 17.vi.1993, S.J. Scheffer, 93-183, miner on Rudbeckia , overwintered in lab, eclosed 16.ii.1994 (1♂, USNM) .

Paratypes USA. NY: Suffolk Co., SUNY, Stony Brook, larva coll. 17.vi.1993, S.J. Scheffer, 93-183, miner on Rudbeckia , overwintered in lab, eclosed 10.vii.1994 (1♀, USNM), VT: Rutland Co. , Rutland , Town Line Rd. , 14.vii.2002, S.J. Scheffer, ex. Yellow-flowered Asteraceae in a planted garden 02-06 (4 ♂, 1 ♀, USNM).

Comments: External and genitalic morphology strongly support this new species as a relative of Agromyza ambrosivora and A. virginiensis , most obviously in chaetotaxy, color and structure of the distiphallus. It can be differentiated from A. ambrosivora by having two ors rather than one, three ori rather than four, and the paired tubules of the distiphallus are fused until just prior to the apex and only slightly curved (not curved in a semicircle). This species can be differentiated from A. virginiensis by having a slightly shorter distiphallus that is fused throughout its length until the apex, not split to the midpoint.