Family

AGROMYZIDAE

Subfamily

AGROMYZINAE

Genus

MELANAGROMYZA

Species

Melanagromyza astragali Spencer, 1976

Mine

N/A. An internal stem-borer. Feeding within the stems. Pupariation internal.

Host Plants

Confusion Species

N/A.

Recording Grade

5

National Status

pRDB 1.

Puparium

Unknown. No puparia are present with holotype or paratypes in the MZLU or NHMUK collections, respectively. Spencer (1976) did not discuss larval/puparial details when describing the species.

Adult

Head: Frons 1.5-1.6x as wide as eye, orbits slightly projecting above eye in profile, with 2 strong ors, 2 strong ori. Orbital setulae relatively sparse, in a single row, all reclinate. Eye bare in both sexes. Gena slightly deeper in centre below eye, 0.14-0.20x as high as eye. Cheek barely forming a ring below eye. Orbits relatively narrow; lunule semi-circular, sometimes with a distinct central furrow. Ocellar triangle reaching to level of lower ors, sometimes to upper ori. Third antennal segment small, rounded with short pubescence, not longer than the basal section of the arista.
Mesonotum: 2 strong dc; acr in 8-10 rows, reducing to 4-5 at level of first dc. Prescutellar acrostichal setae, shorter than dc, frequently present (including in holotype and paratypes, not detected by Spencer); 5 out of 7 specimens examined by the author possess distinct prsc. Material examined by Owen Lonsdale (pers. comm.) also possess prsc; out of 4 specimens, 3♂ with prsc (asymmetrical in 1), 1 without prsc. Frequently, 1-6 lateral to dorsolateral scutellar setulae close to lateral scutellar setae (including in holotype, not detected by Spencer) are present.
Wing: Hyaline, ultimate section of vein M4 0.80 to about equal that of the penultimate. Costal sections (2-4) with an average ratio of 100:29:24. Length 2.1-2.2 mm in male, 2.5 mm in female.
Colour: Frons matt, deep black. Orbits slightly shining, ocellar triangle weakly shining. Lunule slightly paler than frons. Gena brownish-black, palpi black. Mesonotum and abdomen black, shining, with no coppery tinge. Calypter greyish, margin dark, black to dark brown, fringe paler, light brown. Legs with 2 (rarely 3) posterolateral setae on mid tibia. In smaller specimens, the posterolateral setae are frequently absent.
Male genitalia: Surstylus possessing a group of long setae and several spines on inner surface; basiphallus ring-like, very close to mesophallus; basal bladder of mesophallus with slight upward curvature; distiphallus with weak areas of spiculae when viewed from above; distal tubule upcurved and rather weak.
Female genitalia: Egg guide acute apically, 4.5x as long as maximum width, medial membrane with numerous sensilla centrally between inner and outer margins.

Additional information

Taken from Warrington 2024:

This species was added to the British list by Bland (2001), based on material reared from puparia in the dead stems of Astragalus glycyphyllos in South Essex.  In total, Keith Bland reared three females (pers. comm.), two of which were kindly loaned to me for the purpose of this revision.  Upon examination, both specimens are not conspecific with the type description of astragali by Spencer (1976); both females possess distinctly proclinate orbital setulae, which are in two rows (astragali is stated to possess entirely reclinate orbital setulae in a single row) and a pale margin to the calypter (dark in astragali).

High resolution images of the holotype (held in Biological Museum, Lund University, Sweden) were kindly sent to me; upon examination, Spencer’s original description is accurate, the only omissions being that the holotype possesses four erect orbital setulae and one slightly proclinate setula, prsc are present, with the scutellum possessing one small scutellar setula close to each lateral scutellar seta.

The orbital setulae in the dissected male specimens discussed by Warrington and Perry (2023) are reclinate, with the calypter margin being dark, brownish, agreeing with the description by Spencer.  Material (2♂) in the von Tschirnhaus collection also possess reclinate orbital setulae and agree with the description by Spencer (Michael von Tschirnhaus pers. comm.).  Considering the significant differences between the female material reared by Keith Bland, the type specimen of astragali and the dissected material mentioned above, it seems only prudent that the record by Keith Bland is hereby excluded, with the first formal British records being those published by Warrington and Perry.

The Bland specimens were reared from puparia possessing dark, very closely-spaced posterior spiracles, each with 14-16 bulbs.  Of the known British species, only M. angeliciphaga, M. galegae and M. moatesi agree in terms of posterior spiracular detail and entirely proclinate orbital setulae.  The pale calypter margin of the Bland material differs from galegae and moatesi, whilst angeliciphaga is a much larger species (even allowing for natural variation).  It seems probable that the material reared by Keith relates to another possibly undescribed species. In Great Britain, only M. pubescens is similar to astragali, owing to the dark calypter margin/fringe and reclinate orbital setulae but that species is larger in size, possesses a darker calypter fringe and strikingly different male genitalia.

Distribution

Adult

Head and squama

Genitalia