Asphondylia rosulata, Dorchin & Joy & Hilke & Wise & Abrahamson, 2015

Dorchin, Netta, Joy, Jeffrey B., Hilke, Lukas K., Wise, Michael J. & Abrahamson, Warren G., 2015, Taxonomy and phylogeny of the Asphondylia species (Diptera: Cecidomyiidae) of North American goldenrods: challenging morphology, complex host associations, and cryptic speciation, Zoological Journal of the Linnean Society 174 (2), pp. 265-304 : 285-286

ASPHONDYLIA ROSULATA DORCHIN SP. NOV.

Host plants

Solidago rugosa , S. gigantea .

Gall and biology

This species has several generations a year and forms snap and bud galls ( Figs 11, 12, 14 ), similar to the situation in A. solidaginis . Snap galls join two or more leaves together, are formed in spring and early summer, and are usually found on leaves very close to the apical bud, rather than on more mature leaves farther down the shoot. In this respect, the galls of A. rosulata sp. nov. constitute intermediate steps between snap and rosette galls, and the distinction between these two types is not as clear as in A. solidaginis ( Figs 7, 8, 13 ). As in A. solidaginis , this species appears to use S. gigantea as a complementary host, as indicated by our molecular analysis, but the bud galls are found only on the primary host: S. rugosa . The small rosette galls develop only in apical buds and can be locally very common. These galls are composed of several shortened leaves that surround a single central, rigid chamber made of closely attached leaves ( Fig. 14 ), and are lined by white mycelium on the inside. Adults emerge from these galls from late June to late August.

Adult

Characters as in A. monacha , except for the following. Head: Flagellomere 1/flagellomere 5 ratio = 1.11–1.18 in male (N = 5), 1.38–1.48 in female (N = 5).

Thorax: Wing length 2.62–2.85 mm in males (N = 6), 2.61–2.78 mm in females (N = 6).

Female abdomen: Sclerotized part of ovipositor 2.31– 2.56 as long as sternite 7 (N = 5).

Male terminalia: Aedeagus cylindrical, same width throughout length, tapered at apex.

Larva (third instar)

Orange; integument covered by round, flat bumps. Length 2.18–3.46 mm (N = 3). Antennae about as long as wide; cephalic apodeme slightly longer than head capsule. Spatula ( Figs 40, 41 ) with lateral teeth longer than median teeth, and gap between median teeth much deeper than between lateral and median teeth.

Pupa ( Figs 68, 69 )

Characters as in A. monacha , except for the following: antennal horns long and slender, almost straight, apices tapered and finely serrated along median margins in frontal view.

Diagnosis

Asphondylia rosulata sp. nov. can be distinguished from other Asphondylia spp. on goldenrods by its host plant and gall structure. The bud gall resembles that of A. solidaginis on S. altissima , and is flatter than that of A. pseudorosa sp. nov. Pupae are morphologically similar to those of A. solidaginis , A. pseudorosa sp. nov., and A. silva sp. nov., all having antennal horns that are more slender than those of A. monacha .

Etymology

The species is named after its gall, which forms a small rosette in apical buds.

Notes

We did not find morphological differences among adults from the two types of galls induced by this species, and our molecular analysis indicated that they belong to the same species. The small rosette galls of this species may be mistaken for the superficially similar galls of Rhopalomyia solidaginis on S. rugosa but differ from them in being flatter rather than spherical, composed of a smaller number of leaves, and containing a central, rigid larval chamber that is lined by white mycelium, similar to the rosette galls of A. solidaginis .

Type material

Holotype: ♂, USA, PA, Lewisburg , 26 June 2007, G. Lee and D. Ryan, from Solidago rugosa leaf snap gall ( TAUI) . Paratypes: 1 exuviae, USA, MD , Silver Spring , unspecified date, R . J. Gagné ( USNM) ; 1 larva, USA, PA , Pittsburgh , Weible Road, 15 August 1991, J. Plakidas ( USNM) ; 1♀, USA, PA , Lairdsville , 9 August 2006, N. Dorchin; 4 exuviae , 4♂, 4♀, USA, PA , Black Moshannon State Forest , 8 July 2007, N. Dorchin and M.J. Wise (1♂, 1♀ USNM, others TAUI) , 2 larvae, USA, PA , Lairdsville , 19 July 2007. N. Dorchin & D. Ryan .

Other material examined

1♂, 1♀, 1 exuviae, USA, PA, Fox Chapel, Squaw Run Road, 25 June 2010, J. Plakidas (Plakidas, private collection) .

Figures

Figures 7–14. Galls: 7, 8, Asphondylia solidaginis snap galls on Solidago altissima; 9, Asphondylia solidaginis snap galls on Solidago gigantea; 10, Asphondylia solidaginis pupa in snap gall on Solidago altissima – gall was cut open to show pupa in fungus-lined chamber; 11, 12, Asphondylia rosulata sp. nov. snap galls on Solidago rugosa; 13, Asphondylia solidaginis rosette gall on Solidago altissima; 14, Asphondylia rosulata sp. nov. rosette gall on Solidago rugosa.

Figures 38–44. Asphondylia larval spatulae: 38, 39, Asphondylia solidaginis; 40, 41, Asphondylia rosulata sp. nov.; 42–44, spatulae of larvae taken from Solidago gigantea snap galls. Scale bars: 0.1 mm.

Figures 62–69. Pupal heads: 62, 63, Asphondylia monacha, spring generation; 64, 65, Asphondylia monacha, summer generation; 66, 67, Asphondylia solidaginis; 68, 69, Asphondylia rosulata sp. nov. Scale bars: 200 μm.