Liriomyza pusilla (Meigen)

Guglya, Yuliia, 2021, Rearing mining flies (Diptera: Agromyzidae) from host plants as an instrument for associating females with males, with the description of seven new species, Zootaxa 5014 (1), pp. 1-158 : 54-57

Liriomyza pusilla (Meigen)

( Figs. 150–154 , 499–506 , 537 )

Material examined: Ukraine: Kyiv Region: Kyiv , location “Lysa Hora”, 50°23’N, 30°32’E, 6, 18.viii.2019, Yu. Guglya, ex Centaurea jacea (2♂ 1♀) ; near Obukhiv, Tarasivka , 50°09’N, 30°35’E, 22.v.2019, Yu. Guglya (2♂) ;

Kharkiv Region: Kharkiv: City Centre, 50°00’N, 36°14’E, 20–22.vii.2011, Yu. Guglya, ex Arctium tomentosum (3♂) ; Velyka Danylivka , 50°01’N, 36°18’E, 3.viii.2015, I. Moskalets, ex Symphyotrichum novi-belgii (2♂ 2♀) ; same locality, 17–19.vii.2014, I. Moskalets, ex Galeopsis bifida (1♂ 2♀) ; Piatуkhatky , 50°05’N, 36°14’E, 6.vi.2012, 13, 19.vii.2012, Yu. Guglya, ex Centhaurea jacea (2♂ 4♀) ; near Petrivske , 49°10’N, 36°58’E, 9–14.vii.2020, Yu. Guglya, ex Centaurea jacea (3♂ 5♀) ; near Rubizhne , 50°07’N, 36°46’E, 30–31.vii.2020, Yu. Guglya, ex Galeopsis bifida (3♂ 1♀) ; same locality, 21.v.2017, Yu. Guglya (3♂ 1♀) ; same locality, 18.v.2019, Yu. Guglya (3♂ 3♀) ; same locality, 17.viii.2014, Yu. Guglya (1♂) ; Haidary , 49°37’N, 36°19’E, 12–13.viii.2020, Yu. Guglya, ex Centaurea jacea (2♂ 1♀) .

Hosts. Lamiaceae : Galeopsis L., Asteraceae : Aster L., Eupatorium L., Lapsana L., Solidago L. ( Benavent-Corai et al. 2005), Helianthus L. ( Warrington 2021), 12 species from Baccharis L., Symphyotrichum Nees , Xanthium L., Callistephus Cass. (Asteraceae) and Asclepias L. ( Apocynaceae ) ( Eiseman & Lonsdale 2018; Eiseman et al. 2021)—as host plants for L. eupatorii . Aster L., Bellis L., Bidens L., Callistephus Cass. , Crassocephalum Moench. , Epaltes Cass. , Solidago L., Synedrella Gaertn. , Tithonia Desf. ex Juss. , Vernonia Schreb. and Xanthium L. ( Benavent-Corai et al. 2005), Arctium L., Artemisia L., Erigeron L., Hypochaeris L. and Verbesina L. ( Warrington 2021) are recorded as host plants for L. pusilla . Centaurea jacea L. firstly recorded host plant.

Mine. ( Fig. 150, 151 ) The larva forms a narrow, initially spiral, later serpentine upper surface leaf mine. Pupation takes place outside the mine.

Puparium. ( Figs. 152–154 ) Orange, glossy, 2.0 mm long, with deep segmentation; surface quite smooth except for narrow spine bands and two last abdominal segments finely wrinkled. Posterior spiracles set on bulbous protuberances that are entirely separate; brown, with three hook-like sessile bulbs set in a circular configuration at right angles to each other. Anal plate brown, not protruding above the surface of the puparium viewed from the side and directed ventrally.

Cephalopharyngeal skeleton. ( Fig. 499 ) Right mouthhook larger than the left, each with sharp abducted portion directed ventro-anteriorly and bearing two narrow accessory teeth. Intermediate sclerite massive, 1.17× as long as maximum height of left mouthhook. Straight parastomal bar exist. The mouthhook and the intermediate sclerite centrally and ventrally are strongly sclerotized, the intermediate sclerite dorsally and the pharyngeal sclerite much less so. Sclerotization of the ventral cornu is much weaker than in dorsal one. The dorsal cornu bears an elongated “open” window posteriorly and the ventral cornu bears a “closed” window in the posterior half. Indentation index 86.

Female head. ( Figs. 500, 501 , 537 ) Yellow, with only arista, oc tr and postgena posteriorly black, pedicel and pped sometimes orange; orbit not projecting above eye in profile, 2 orb s, 2 fr s, lunule low, narrow, flat posteriorly, reaching the level of the anterior fr s; pped large, rounded; gena medially 0.21× as high as maximum height of eye.

Thorax viewed from the side. ( Fig. 502 a, b ) Mostly bright yellow. Coloration of anepist, kepst, anatg, mr, kepmand cx 1, cx 2 and cx 3 may vary from darker ( Fig. 502 a ) to lighter ( Fig. 502 b ). Generally kepst in ventral two-thirds and mr black; coloration of anatg vary from black to grey; anepist ventro-anteriorly vary from black to blackish. Calypter vary from grey to black, with black margin and grey fringe. Cx 1, cx 2 and cx 3 more or less darkened. Thorax and head (dorsal view) see in Lonsdale (2017: Fig. 26 ).

Female genitalia. ( Figs. 503, 504 ) Capsule of spermatheca relatively large, 0.42× as high as height of anterior part of oviscape. Spermathecae equal in size, dark brown, spherical, slightly acute and less sclerotized basally. Neck of spermatheca distinctly narrower than spermathecal base. Spermathecal duct weakly sclerotized.

Distribution. Widespread in Europe, also recorded from China, Egypt, Iran, Japan, South Korea ( Papp & Černý 2017), USA, Canada ( Eiseman & Lonsdale 2018). Ukraine (first record).

Comments. Liriomyza pusilla was synonymised with Liriomyza eupatorii (Kaltenbach) by Papp & Černý in 2017. This conclusion was based on similarity of external characters and male genitalia though Spencer’s figures of ventral views for L. pusilla (1990) and L. eupatorii (1976) are not conspecific with the analogous figure for L. pusilla in Papp & Černý (2017). Further, Eiseman et al. (2021) considered their synonymy unreasonable, though “no speciments of L. pusilla were available to” them, so they could not compare morphology of preimaginal stages, female terminalia, mine pattern in the same hosts and in the same territory.

Males and females were reared from four host plants collected on seven locations in Ukraine (see Table 2). All mines were of the same type: linear, with more or less conspiculous spiral initial portion. In all cases females were reared with males together, so the association males with females is reliable .

The comparison of all reared specimens revealed that the lateral coloration of the thorax in the Ukrainian reared material showed great variation amongst both males and females. Figs. 497 a, b show two extreme types of thorax coloring; there are several variants between them. Also, one captured male with additional row of orb s ( Fig. 537 ) and two strong subapical setae on the surstyli was detected. The shape of the subepandrial sclerite and phallus viewed from below appears to be of two types though other features were similar. One type is identical to L. eupatorii sensu Spencer (1976) (hereafter “ f. eupatorii ”) ( Fig. 506 ) and another is identical to L. pusilla sensu Papp & Černý (2017) (hereafter “ f. pusilla ”) ( Fig. 505 ). When viewed laterally, size and shape of the phallus of both forms are completely identical. When comparing all reared specimens, all other features agreed, including mines pattern, preimaginal stages (shape of puparia and posterior spiracles, cephalopharyngeal skeleton), and relative size and shape of female terminalia.

Earlier, only Aster and Solidago were known as mutual hosts for L. pusilla and L. eupatorii . My data revealed Centaurea (Asteraceae) and Galeopsis (Lamiaceae) as mutual hosts for both.

Taking into account all of the above, Liriomyza pusilla “ f. pusilla ” and Liriomyza pusilla “ f. eupatorii ” seem to belong to the same species, though they show great variability in some features. It should be noted that the term “form” (i.e., “f.”) is used conventionally here, in order to easily explain data obtained. However, further investigation including molecular data may change their species status.

Figures

FIGURES 150–158. Figures 150–154: L. pusilla (Meigen); 150–151: mines; 150: “f. eupatorii” in Centaurea jacea leaf; 151: “f. pusilla” in Galeopsis bifida leaf. 152–153: posterior segments of puparium; 152: lateral view; 153: posterior view. 154: posterior spiracles (posterior view). Figures 155–158: Liriomyza heringi Nowakowski; 155: mine in Euphorbia esula leaf; 156–157: posterior segments of puparium; 156: lateral view; 157: posterior view. 158: posterior spiracles (posterior view).

FIGURES 499–504. Liriomyza pusilla (Meigen); 499: cephalopharyngeal skeleton; 500: frontal view of head; 501: head viewed from the side; 502 a–b: thorax viewed from the side; 503: oviscape and spermathecae proportionally; 504: spermatheca.

FIGURES 505–506. Liriomyza pusilla (Meigen), a: phallus viewed from below; b: subepandrial sclerite; 505: L. pusilla f. pusilla; 506: L. pusilla f. eupatorii.

FIGURES 537–544. Figure 537: Liriomyza pusilla (Meigen), head with additional orb s. Figures 538–541: Nemorimyza posticata (Meigen); 538: cephalopharyngeal skeleton; 539: frontal view of head; 540: head viewed from the side; 541: spermatheca. 542–544: Phytoliriomyza melampyga (Loew); 542: cephalopharyngeal skeleton; 543: oviscape and spermathecae proportionally; 544: spermathecae.

FIGURES 19–28. Figures 19–22: Melanagromyza achilleacaulis spec. nov.; 19: puparium (indicated by arrow) in Achillea millefolium stem; 20–21: posterior segments of puparium; 20: lateral view; 21: posterior view; 22: posterior spiracles (posterior view). Figures 23–25: M. aenea (Meigen); 23–24: posterior segments of puparium; 23: lateral view; 24: posterior view. 25: posterior spiracles (posterior view). Figures 26–28: M. angeliciphaga Spencer; 26–27: posterior segments of puparium; 26: lateral view; 27: posterior view. 28: posterior spiracles (posterior view).

FIGURES 493–498. Liriomyza hieracii (Kaltenbach); 493: cephalopharyngeal skeleton; 494: frontal view of head; 495: head viewed from the side; 496: thorax viewed from the side; 497: oviscape and spermathecae proportionally; 498: spermatheca.