Arytaina vittata, Percy Csiro, 2003

Percy Csiro, Diana M., 2003, Legume-feeding psyllids (Hemiptera, Psylloidea) of the Canary Islands and Madeira, Journal of Natural History 37, pp. 397-461 : 445-448

Arytaina vittata sp. n.

(figures 2D, F, 15, 16A, 22C, 23A)

Adult

Colour. Males generally darker than females, head and thorax brown or paler chesnut, thorax with grey bands, genal cones pale grey or blue-grey, legs grey to yellow-grey, abdomen bright green to yellow-green with distinctive dark brown to black dorsal stripe, male abdomens sometimes darker grey or chestnut. Apical forewing cells with brown patches, but these are less extensive than in A. nubivaga , forewing veins uniform mid- or dark brown; hindwing costal and claval margins darkly pigmented.

Structure. Forewing with margins more or less parallel, apex somewhat acute; costal break and pterostigma absent; the middle, but not the apex, of vein Rs is curved towards the costal wing margin; surface forewing spinules absent from cells c+sc and r, but usually present, though often reduced, in other cells, sparse: less 1

than 40 per 0.1 mm 2; apical spines in wing cells cu, m, m, and few in cell r; 1 1 2 2 hindwing costal margin markedly concave. Antennae long, with 10 segments; head not, or only weakly deflexed downwards with genal cones in approximately the same plane as the vertex; genal cones long, terminal setae typically shorter than the vertex. Distal proboscis segment short. Tibia shorter than the femur, tarsi long; metatarsal spur one. Male genitalia as in figure 15F–I; paramere with an internal medial ridge that, in posterior view, is almost contiguous when the parameres are closed (figure 16A); proctiger with a pronounced posterior extension apically; aedeagus distal segment with a well-developed, curved hook, tip of aedeagus hook acute. Female genitalia as in figure 15E; proctiger dorsal profile with a slight post-anal depression; eggs with a stout lateral pedicel.

Adult measurements and ratios. (5 W, 5 X) Total length: W 3.32 –3.88, X 3.68–4.33; WL: W 2.7 –2.88, X 3–3.2; HW: W 1.01 –1.03, X 1.08–1.13; AL: 2.15–2.41; GC: 0.15–0.2; PB: 0.13–0.14. GCVL: 0.57–0.71; VLW: 0.45–0.5; WLW: 2.68–2.91; CUR: 1.65–2.03; MR: 0.41–0.52; TLFL: 0.84–0.91. Adult genitalia W: MP: 0.46–0.49; PL: 0.34–0.36; AEL: 0.33–0.37; MSLH: 1.25–1.4; AHS: 0.23–0.26; PLSH: 0.94–1.03. X: FP: 0.91–1.04; FSP: 0.6–0.7; RL: 0.25–0.29; OV: 0.2–0.22; EL: 0.25–0.33.

Nymph

Colour. First to second instars cream and orange or black, 3rd–5th instars cream and orange, pale yellow or blue-green, with black tergites. Sclerites, wing pads, legs and terminal antennal segments darker brown.

Fifth instar measurements. (Specimens 5) BL: 1.83–2.3; BW: 1.15–1.35; WL: 0.65–0.77; CPL: 0.57–0.65; CPW: 0.76–0.87; RW: 0.22–0.24; HW: 0.79–0.9; AL: 1.18–1.28.

Fifth instar chaetotaxy. Head and antennal setae simple; ocular seta simple, inconspicuous; primary post-ocular seta simple or narrowly capitate; secondary postocular seta absent or simple. Dorsal thoracic setae short simple. Forewing pad with one apical macroseta, distinctly or narrowly capitate (occasionally reduced to small simple); hindwing pad with two apical macrosetae, distinctly capitate; proximal setae absent; simple microsetae scattered on the wing pad surfaces. Dorsal abdominal pre-caudal macrosetae present on anterior tergites, short simple (or very slightly capitate), caudal plate macrosetae two, narrowly capitate; sectasetae one pair in the third position (apical pair in the fourth position are small simple or rod setae); marginal abdominal setae (other than sectasetae) four pairs, distinctly capitate (fourth pair sometimes simple); pleurite setae paired simple. Foreleg without capitate setae; middle and hind leg capitate setae on femora and tibiae, on tibiae one (distal).

Host plant. Spartocytisus filipes , S. supranubius .

Distribution. Canary Islands: La Gomera, La Palma and El Hierro.

Notes. Occurs on the three most westerly islands. It is found throughout the host plant range, from dry lowland to sabinar and laurisilva habitat. On La Palma, it is sympatric with Arytainilla serpentina in the laurisilva habitat, where it is less common than the latter species.

Biology. Eggs, on Spartocytisus filipes , are laid in rows around the inside rim of the calyx, and in small clusters on the inner surfaces of corolla segments (figure 23A). Of 46 flowers examined, 35 were found to have from five to more than 30 eggs per flower, the majority laid on the inner surface of the calyx which is persistent during development of the young fruit. In mid-May, small nymphs (1st–2nd instars) were observed in flowers on the corolla and calyx.

Etymology. Named for the dorsal, longitudinal stripe or ‘vittae’, particularly distinct in females, which makes this species easily recognizable in the field and distinguishes it from the closely related species, A. nubivaga .

Comment. A. vittata is very similar to A. nubivaga , and appears to represent a recent speciation event involving a host switch from the upland to the lowland Spartocytisus species. At present these two species do not occur on the same island. On La Palma Spartocytisus supranubius (the upland host) is rare and when sampled a few adults and nymphs of A. vittata were found. The lowland host, Spartocytisus filipes , is present but extremely rare on Tenerife, where no individuals were located for sampling. It is not apparent, therefore, whether the host switch occurred on one island, or was coupled with colonization of a new island. A. vittata can be distinguished from A. nubivaga by the more slender paramere with an extended internal ridge which is shallow in A. nubivaga , also by adult coloration (i.e. dorsal vittae) and the 5th instar nymph which has a single pair of sectasetae in A. vittata .

Type material. Holotype W (slide mounted), Canary Islands, La Palma: Barranco de las Angustias, 28°40∞30◊N, 17°55∞W, ca 300 m, 18 May 1998 ( BMNH) . Paratypes 5 W, 53 X, 1 nymph, as for holotype ( BMNH) . 1 W, 1 X, as for holotype ( DZUL) . 1 X, as for holotype ( NHMB) . 1 X, SE rd Santa Cruz to La Caldera, 28°45∞N, 17°49∞30◊W, 1950 m, ex Spartocytisus supranubius , 16 July 1997 ( BMNH) . La Gomera: 2 W, 2 X, S of Hermigua , 28°08∞30◊N, 17°12∞W, 500–600 m, 25 May 1998 ( BMNH) . 3 W, 1 X, as for previous (NHMB). El Hierro: 5 nymphs, between Frontera and Sabinosa , 27°45∞N, 18°04∞W, 300 m, 22 May 1998 ( BMNH) .

Other material examined. (ex Spartocytisus filipes unless otherwise stated) La Gomera: 8 W, 10 X, above El Retamal, Valle Gran Rey , 28°7∞N, 17°18∞30◊W, 550 m, 13 July 1997 ( DP 66 ) . 17 W, 16 X, 7 nymphs, rd Arure to Las Hayas , 28°7∞30◊N, 17°18∞30◊W, 900 m, 13 July 1997 ( DP 69 ) . 21 W, 14 X, S of Hermigua , 28°08∞30◊N, 17°12∞W, 500–600 m, 25 May 1998 ( DP 220 ) . 2 W, 8 X, below Roque Cano, 28°11∞N, 17°15∞30◊W, 300–400 m, 26 May 1998 ( DP 222 ) . La Palma: 1 X, SE rd Santa Cruz to La Caldera, 28°45∞N, 17°49∞30◊, 1950 m, ex Spartocytisus supranubius , 16 July 1997 ( DP 80.1 ) . 6 W, 23 X, Barranco de las Angustias, above Los Llanos 28°41∞N, 17°53∞30◊W, 420 m, 17 July 1997 ( DP 83 ) . 3 nymphs, La Caldera, 28°46∞N, 17°5∞30◊W, 2280 m, ex Spartocytisus supranubius , 17 July 1997 ( DP 85 ) . 1 X, nr Los Galguitos, Barranco de la Fuente, 28°46∞N, 17°46∞W, 350 m, 17 May 1998 ( DP 191 ) . 17 W, 15 X, Barranco de Jurado , S of Tijarafe, 28°42∞15◊N, 17°56∞45◊W, ca 600 m, 18 May 1998 ( DP 197 ) . 1 W, 15 X, between Barlovento and Roque Faro, 200–500 m, 19 May 1998 ( DP 198 ) . El Hierro: 12 W, 11 X, ca 5 km W of Frontera , 27°45∞N, 18°03∞30◊W, 230 m, 10 July 1997 ( DP 58 ) . 27 W, 13 X, 13 nymphs, between Frontera and Sabinosa , 27°45∞N, 18°04∞W, 300 m, 22 May 1998 ( DP 213 ) .