Pariaconus ohiacola (Crawford, 1918) Crawford, 1918

Percy, Diana M., 2017, Making the most of your host: the Metrosideros-feeding psyllids (Hemiptera, Psylloidea) of the Hawaiian Islands, ZooKeys 649, pp. 1-163 : 70-73

Pariaconus ohiacola (Crawford, 1918) comb. n. Figures 34, 35, 50E, G–H, M–R

Trioza ohiacola Crawford, 1918: 442

Adult colour.

General body colour red-brown to orange-brown. Females often appear to have a dark abdomen due to darkly pigmented egg load. Fore wing membrane clear or fuscous.

Adult structure.

Fore wing apex acute to bluntly acute; spinules distributed in all cells; short to medium-short setae on margins and veins (Fig. 34 A–D). Antennae medium-long (av. length 1.02; ratio AL:HW av. 1.76); genal processes medium-long to long (ratio VL:GP av. 1.66), and acute; medium-long setae on vertex and thorax; distal proboscis segment short (av. length 0.08); hind tibia slightly shorter than head width (ratio HW:HT av. 1.05) (Fig. 34 E–J). Male terminalia (Fig. 35 A–G): paramere longer than proctiger (ratio MP:PL av. 0.87), slender, broader at base and tapering evenly to apex with anteriorly directed hook; distal aedeagus segment shorter or subequal to paramere (ratio PL:AEL av. 1.15) with base rounded and slightly inflated, and a shallow hooked apex (ratio AEL:AELH av. 2.35). Female terminalia (Fig. 35 H–K, M–O): proctiger long, dorsal surface convex, apex acute to bluntly rounded, anal ring short (ratio FP:RL av. 4.83); subgenital plate with slight to moderate medial bulge ventrally, acute to bluntly acute apically; ovipositor apex lacking serrations, valvulae dorsalis not strongly convex dorsally. Egg short, broad, pigmented dark brown (except tip of pedicel and tail), surface with dense microsculpturing, extremely long to moderately short pedicel with no or slightly inflated tip, tail medium-long to short (Fig. 35L, P).

Immature.

Colour and structure: 2nd-5th instars: Orange or orange-red with cream wing buds. Elongate ovoid in outline, wing buds protruding with moderate humeral lobes (Fig. 50R). Tarsi with large claws. Circumanal ring small (CPW:RW av. 21.78), u-shaped with a single row of often interrupted cells (Fig. 50E). 1st instar (Fig. 50Q): yellow-brown with scaly dorsal surface. Chaetotaxy: 2nd-5th instars: Head, thorax and abdomen with scattered long to medium-long simple setae. 1st instar (Fig. 50 G–H): Margin with broad fan-shaped setae (anterior of head with 5-6 pairs, a single pair post ocular, a single pair on the apices of each wing bud, and 7-8 pairs on the abdomen).

Host plant notes.

Mostly associated with glabrous morphotypes.

Island.

Oahu.

Distribution notes.

A widespread taxon and probably the most commonly encountered on Oahu, but as with Pariaconus oahuensis appears to be undergoing incipient divergence. Forms ohiacola and obtusipterus are the most widespread, found in the Waianae, Aiea, and Koolau mountain regions; form waianaiensis is currently only known from the central Waianae Mnts; form angustipterus is most common in the southern Waianae Mnts, but also occurs in the southern Koolau region.

Biology.

Makes flat leaf galls. 1st instars are found in very shallow pits (Fig. 50Q), usually on the lower surface of young leaves that are often still in bud, the leaf tissue around the instar often becomes red or brown. By the 2nd instar there is complete enclosure, generating a flat leaf gall type, often with a slight central depression on the lower surface where the original 1st instar pit was located (Fig. 50O); the 1st instar exuviae are often found with 2nd instars in the gall chamber. The scaly sclerotization on the dorsal surface of 1st instars of the ohialoha group (Fig. 50F) may prevent dehydration during the period when the 1st instar is on the leaf surface before gall enclosure.

Comments.

Four forms are recognized (Figs 34-35): form ohiacola (based on the type has fore wing with apex acute, medium long genae, long paramere, long female terminalia that is apically acute, eggs ovoid with long pedicel), form angustipterus (fore wing more narrow with apex acute), form obtusipterus (largest form, with fore wing apex rounded, shorter genae, long female terminalia), and form waianaiensis (smallest form, with fore wing apex bluntly acute, notably long thin genae, paramere slender, short female terminalia, eggs almost round with short pedicel). In some cases these forms correspond to distinct clusters in the DNA analysis (Fig. 3) and may be good candidates for species recognition with further study of specimens and biology. However, there is substantial variation in fore wing shape, genal process length, and female and male terminalia that are intermediate between these forms, with different combinations found within and between populations making the overall observed pattern complex.

Type material.

Holotype, male (dry mounted, BPBM). See Table 2 for details of type and other material examined for this study.