Preliminary study of wing interference patterns (WIPs) in some species of soft scale (Hemiptera, Sternorrhyncha, Coccoidea, Coccidae)

Abstract

The fore wings of scale insect males possess reduced venation compared with other insects and the homologies of remaining veins are controversial. The hind wings are reduced to hamulohalterae. When adult males are prepared using the standard methods adopted to females and nymphs, i.e. using KOH to clear the specimens, the wings become damaged or deformed, an so these structures are not usually described or illustrated in publications. The present study used dry males belonging to seven species of the family Coccidae to check the presence of stable, structural colour patterns of the wings. The visibility of the wing interference patterns (WIP), discovered in Hymenoptera and Diptera species, is affected by the way the insects display their wings against various backgrounds with different light properties. This frequently occurring taxonomically specific pattern is caused by uneven membrane thickness and hair placement, and also is stabilized and reinforced by microstructures of the wing, such as membrane corrugations and the shape of cells. The semitransparent scale insect's fore wings possess WIPs and they are taxonomically specific. It is very possible that WIPs will be an additional and helpful trait for the identification of species, which in case of males specimens is quite difficult, because recent coccidology is based almost entirely on the morphology of adult females.

Keywords: Coccidae; Scale insects; WIP; interference colour patterns; males; wings.

Figures 1–5.

1 General scheme of the fore wing (after Koteja 2008) acp-alar cupolae, afx-anterior flexing patch, alf-alar fold, alp-alar lobe, asfd-anterior subcostal field, ast-alar setae, clfd-claval (anal) field, cofd-costal field or thickening, cufd-cubital field, cur-cubital ridge, mat-macrotrichia, mit-microtrichia, pfx-posterior flexing patch, psfd-posterior subcostal field, ptst-pterostigma, rs-“radial sector”, scr-subcostal ridge 2, 3 Pulvinaria vitis (Linnaeus): scanning electron microphotographs of the wing, showing its microsculpture 4, 5 Male of Pulvinaria vitis (Linnaeus) on white background, with invisible WIPs, and 2 on a black background, showing WIPs.

Figures 6–13.

Males with “horizontally striped patterns” of WIPs, subfamilies Eulacaninae and Coccinae: 6–7 WIP of Sphaerolecanium prunastri (Boyer de Fonscolombe) 8–9 WIP of Eulecanium tiliae (Linnaeus) 10, 11 WIP of Pulvinaria vitis 12–13 WIP of Parthenolecanium corni (Bouché).

Figures 14–19.

Males with “eliptical” patterns of WIPs, subfamily Eriopeltinae: 14, 15 WIP of Luzulaspis frontalis Green 16–17 WIP of Luzulaspis nemorosa Koteja. 18–19 WIP of Eriopeltis lichtensteini Signoret.