Agromyza deserta (Patton)

Agromyza deserta (Patton) View in CoL View at ENA

Material examined. OKLAHOMA: Payne Co., Mehan , 36.014339, −96.996744, 7.v.2018, em. 14.iii.2019, M.W. Palmer, ex Celtis occidentalis , # CSE5276 , GoogleMaps CNC1754040–1 View Materials ( 1♂ 1♀) .

Photographed galls. ARKANSAS: Faulkner Co., Conway, 35.099612, −92.462252, 21.iv.2023, M. Hammond, vacated gall on Celtis laevigata (iNat 155976415); ILLINOIS: Cook Co., Chicago, Che-Che-Pin-Qua Woods, 25.v.2023, N. Furlan, galls on Celtis occidentalis (iNat 164583788); IOWA: Linn Co., Mt. Vernon, 41.918651, −91.414019, 24.v.2022, I. Winkler, galls on Celtis occidentalis (iNat 118853139); KANSAS: Brown Co., 39.667924, −95.512706, 20.v.2023, ksgardener1, vacated gall on Celtis occidentalis (iNat 162778208); KENTUCKY: Woodford Co., 38.051322, −84.764075, 29.v.2022, T.Frey, galls on Celtis (iNat 119342208); MINNESOTA: Rice Co., Carleton College, 44.45948, −93.149527, 22.v.2022, M. Zappa, gall on Celtis occidentalis (iNat 118396136); MISSOURI: McDonald Co., 23.v.2023, ozarkpoppy, vacated gall on Celtis (iNat 163645329); NORTH CAROLINA: Wake Co., Raleigh, 2.v.2024, T.S. Feldman, gall on Celtis laevigata (iNat 213021481); OHIO: Hamilton Co., Cincinnati, 39.122319, −84.518886, 24.iv.2023, Y. Kemper, gall on Celtis (iNat 156486330); PENNSYLVANIA: Centre Co., Blacksburg, 40.780793, −77.793965, 24.v.2023, C. Smith, larva in opened hackberry gall (iNat 171281233); SOUTH CAROLINA: Greenwood Co., Ninety Six National Historic Site, 34.145547, −82.010597, 15.iv.2023, T. Frey, vacated galls on Celtis laevigata (iNat 155086415); TEXAS: Wilson Co., Stockdale, 29.216008, −98.012039, 18.iii.2023, birdingtexan, vacated gall on Celtis (iNat 151553189); VIRGINIA: Fairfax Co., Elklick Preserve, 38.876663, −77.499183, 29.iv.2023, I. Farr, galls on Celtis (iNat 160136318).

Hosts. Cannabaceae : [ Celtis laevigata Willd. ], C. occidentalis L.

Larval biology. ( Scheffer & Lonsdale 2018: Fig. 1g View FIGURES 1–8 ) The larva develops in an elongate swelling at the base of a new twig, which remains green while the leaves beyond it wither, die, and drop off. After boring its way through the length of this gall, beginning at the apex, the larva exits through a circular hole near the base ( Gagné 1983).

Puparium. Brown; posterior spiracles each with an almost complete circle of 23–28 pores ( Spencer 1988); formed outside the gall.

Phenology and voltinism. Over most of this species’ range, larvae are present in April and May; in southern Texas, vacated galls have been found as early as 18 March. Pupae overwinter and adults emerge the following spring.

Distribution. USA: [AR, CT ( Patton 1897), IA, IL, KS, KY, MD ( Spencer 1988), MN, MO, NC, NY ( Scheffer & Lonsdale 2018), OH], *OK, [PA, SC, TX, VA], WV (von Tschirnhaus 2017). Although Connecticut is the type locality, this species was described from the gall alone, and the only known adult specimens are the West Virginia one described by von Tschirnhaus (2017) and the Oklahoma ones listed here.

Comments. The new male specimen and the first known female examined here present some variation not previously noted. The female wing length is 3.7 mm and the basal ⅓ of each tibia is pale (not just the base). Regarding differences observed in both sexes, there are five fronto-orbitals that are not readily differentiated into ori and ors; there appear to be five dorsocentrals, with the anterior seta often barely distinguishable from the surrounding setulae; the first flagellomere has an anterodorsal angle that is rounded and barely evident to slightly more pronounced; the first flagellomere is either entirely brown (female), or brown on the outer-basal half (male); the side of the frons at and behind the posterior fronto-orbital is more thinly darkened; the paler parts of the body are not yellowish-white, but pale orange with a yellowish tint; the matt gray pruinosity covers all darker parts of the body except for the antenna, is sparser on the legs past the coxae with the fore femur still having the pruinosity relatively pronounced, and it is nearly absent on the tibiae and tarsi. A correction to Lonsdale (2021) is also provided here, as a couplet in the species key infers that the calypter of this species is white, when it actually brown on the hairs and along the margin.

With the named Celtis -feeding Agromyza species now numbering seven, a new key is provided here to better differentiate them:

1. Calypter margin and hairs white. Legs light yellow. Parafacial and orbital plate mostly visible laterally, particularly anteriorly on orbit. Eye 1.6–2.7 times height of gena....................................................... 2

- Calypter margin and hairs brown. Legs predominantly brown. Parafacial and orbital plate not or narrowly visible laterally. Eye at least 3.5 times height of gena.................................................................... 3

2. Setae black. Ocellar seta as long, or nearly as long as postocellar.............................. A. aristata Malloch View in CoL

- Setae yellow ( Fig. 7 View FIGURES 1–8 ). Ocellar seta half length of postocellar................................ A. pallidiseta Malloch View in CoL

3. Larger species, wing length usually 2.6–3.4 mm, but can be as small as 2.2 mm. Parafacial and orbital plate evident when viewed laterally. Epistoma present, distinct. Length of ultimate section of vein M 4 divided by penultimate section not more than 0.7. Dark parts of body (less so on legs) with dense ash-colored pruinosity. Apical portion of distiphallus short, dark and not obviously haired............................................................................. 4

- Smaller species, wing length 1.6–2.3 mm. Parafacial and orbital plate usually only partially visible when viewed laterally, if at all. Epistoma negligible in size. Length of ultimate section of vein M 4 divided by penultimate section 0.9–1.0. Body usually subshining (slightly heavier on thorax), with pruinosity darker and much sparser, revealing underlying sclerites. Distiphallus larger, heavily haired..................................................................... 5

4. Wing length 3.4 mm. Epistoma higher than first flagellomere, margin curved. Notum ash-gray; dark portions of frons and abdomen similarly pruinose. Length of ultimate section of vein M 4 divided by penultimate section 0.4. Apex of hind femur yellow for distance equal to width of femur apex; inner-distal margin of femur produced as a shallow lobe covering inner base of tibia. Male cercus evenly narrowed to a gradual point that is similar at dorsal and ventral apices; many pointed tubercle-like setae along inner surface on distal half. Branches of basiphallus slightly curved, but essentially still linear; smooth, shape not unusual as below. Mesophallus dark, narrow, ventrally curved, not articulating with short, dark distiphallus (see von Tschirnhaus (2017: Figs. 1–5 View FIGURES 1–8 ))........................................ A. deserta (Patton) View in CoL

- Wing length 2.2–2.6 mm. Epistoma slightly shallower than height of first flagellomere, deeper at middle. Notum grayish-blue in color ( Fig. 16 View FIGURES 9–16 ); dark portions of frons and abdomen with faint pruinescence revealing sclerites. Length of ultimate section of vein M 4 divided by penultimate section 0.7. Apex of hind femur very narrowly yellow; inner apex of femur not produced. Male cercus abruptly narrowed at apex only; few pointed tubercle-like setae apically only ( Figs. 249, 250 View FIGURES 249–255 ). Branches of basiphallus strongly twisting ventrally, with left branch pointed and minutely spinulose, and right branch ribbon-like with line of weakness along midline. Mesophallus broad, pale, not much longer than wide, broadly articulating with ventrobasal extensions of broader, pale distiphallus ( Figs. 254, 255 View FIGURES 249–255 )................... Agromyza torta View in CoL sp. nov.

5. Wing length 1.6 mm. Base color of head dark orange ( Fig. 3 View FIGURES 1–8 ); face brown in antennal grooves. Third dorsocentral not much longer than setulae. Acrostichal seta thin, almost setula-like, shorter than scutellum. Distiphallus (viewed laterally) high, with base dark and slightly longer, curving under apex of mesophallus ( Fig. 231 View FIGURES 225–231 ). Phallophorus with dark ring-like swelling around base...................................................................... A. celtitexana View in CoL sp. nov.

- Wing length 1.7–2.3 mm. Base color of head white to yellow and bright orange; face entirely white to yellow. Third dorsocentral long and strong. Acrostichal seta strong, longer than scutellum. Distiphallus relatively slender, with base neither darkened nor extended under mesophallus. Phallophorus without basal ring-like swelling................... 6

6. Tibiae dark brown with only base of fore tibia yellowish. Male: cercus broad and V-shaped; hypandrial apodeme not much longer than wide; mesophallus comparable in length to distiphallus.................. A. fission Eiseman & Lonsdale View in CoL

– Mid and hind tibiae dark brown with base yellow, and fore tibia yellow with center brownish. Male (unknown for Agromyza sp. 1 View in CoL ): cercus thin along length; hypandrial apodeme much longer than wide; mesophallus much shorter than distiphallus, not much longer than high........................................................................... 7

7. Dark portions of frons subshining; ocellar triangle paler outside ocellar tubercle, yellowish at edges anteriorly. Acrostichal seta shorter than scutellum; abdomen nearly as pruinose as thorax................................ Agromyza sp. 1 View in CoL

- Dark portions of frons mostly shining; ocellar triangle entirely dark brown.Acrostichal seta as long or longer than scutellum. Abdomen shining to faintly pruinose................................................. A. varifrons Coquillett View in CoL

A key to the immature stages and larval habits of the North American Celtis View in CoL -feeding agromyzids, including an additional undetermined species for which adults are unknown, is presented below.

1. Larva developing in a shoot gall or a tightly rolled leaf; posterior spiracles of puparium each with 15+ bulbs/pores..... 2

- Larva a leafminer, not typically in a rolled leaf; posterior spiracles of puparium each with 3–10 bulbs/pores (not observed for all species)..................................................................................... 3

2. Larva developing in a shoot gall; posterior spiracles with>20 pores............................ A. deserta (Patton) View in CoL

- Larva mining in a rolled leaf ( Figs. 103, 104 View FIGURES 93–105 ); posterior spiracles with ~16 pores............. Agromyza torta View in CoL sp. nov.

3. Mine linear or a linear-blotch......................................................................... 4

- Mine a primary blotch, elongate or compact ( Figs. 101, 102 View FIGURES 93–105 )........................ Agromyza pallidiseta Malloch View in CoL

4. Larva present only in spring; egg inserted at the midrib; mine beginning with a long, narrow linear portion, then widening irregularly as it begins to follow the leaf margin ( Fig. 105 View FIGURES 93–105 )...................................... Agromyza sp. 2 View in CoL

- Larva present in spring or later; egg placement variable; mine shorter and/or wider, not consistently following the leaf margin........................................................................................... 5

5. Mine on the upper or lower surface, essentially linear throughout; larvae present from March to May; posterior spiracles with 8–10 bulbs..................................................................... A. aristata Malloch View in CoL

- Mine on the upper surface (the very beginning may be interparenchymal or lower-surface), linear or linear-blotch; larvae may be present from March to September; posterior spiracles with 3 bulbs/pores (not confirmed in one species known only from Texas)....................................................................................... 6

6. Mine entirely linear; Texas........................................................................... 7

- Mine widening to a blotch; widespread................................................................. 8

7. Egg inserted along a vein, away from the leaf margin; beginning of mine (usually?) appearing pale green from above (interparenchymal or perhaps lower-surface) ( Figs. 95, 96 View FIGURES 93–105 )................................. A. celtitexana View in CoL sp. nov.

- Egg inserted at the leaf margin; beginning of mine suffused with brown (upper-surface like the rest of the mine)............................................................................................ Agromyza sp. 1 View in CoL

8. Mine gradually widening throughout its length, most often following the leaf margin. Puparium yellowish-orange; spiracles about as long as tubercles; tubercles more ventrally positioned and more widely spaced than spiracles.............................................................................................. A. varifrons Coquillett View in CoL

- Mine with an extended, though often contorted, linear portion; position on the leaf variable. Puparium brownish-red; posterior spiracles longer than paired tubercles ventral to them; spiracles and tubercles forming the points of a square........................................................................... A. fission Eiseman & Lonsdale View in CoL