Ferrisia malvastra (McDaniel)

Kaydan, M. B. & Gullan, P. J., 2012, 3543, Zootaxa 3543, pp. 1-65 : 32

Ferrisia malvastra (McDaniel)

( Fig. 12)

Heliococcus malvastrus McDaniel, 1962: 323 .

Heliococcus malvastrus ; McKenzie, 1967: 181. Incorrect synonymy with D. virgatus .

Ferrisia consobrina Williams & Watson, 1988: 77 . Synonymy by Williams, 1996: 5.

Ferrisia malvastra ; Williams, 1996: 5. Revived status and change of combination.

Type material examined. Holotype: adult ♀, 2 labels: “ Holotype ♀ / UC Davis Type # 1502 / Heliococcus / malvastrus / B. M c DANiel / BrowNsville Texas / JuNe 16, 1961 / Ex. Malvastrum / sp. / M.F. Schuster coll. / B. M c DANiel Det.” and “ U.C. Davis / TYPE / 1502” ( BME) . Paratype: adult ♀, labels: “ Heliococcus / malvastrus / M c DANiel / Paratype ♀ ” [the word “ Paratype ” is in red ink] and “BROWNSViLLe Tex. / JUNe 16, 1961 / Ex. Malvastrum / sp. M.F. Schuster coll. / B. M c DANiel Det” ( USNM) [the handwriting on the labels is an odd mix of upper and lower case letters] .

This widespread and polyphagous species was first described from Malvastrum (Malvaceae) from Texas, U.S.A., but was confused with F. virgata for many years. Nur (1977) recognised that specimens of this species were distinct from F. virgata , although at that time this species was referred to as the parthenogenetic form of F. virgata . Subsequently Williams (1985a) described this species as the “uniparental strain” of F. virgata , based partly on Nur’s research, and later named it F. consobrina based on specimens from Queensland, Australia ( Williams & Watson 1988). Subsequently, Williams (1996) discovered the synonymy of F. consobrina and H. malvastrus , revived the latter from synonymy with Dactylopius virgatus and transferred it to Ferrisia as F. malvastra . There is a good illustration of the adult female in Williams (1985 a, 2004), Williams & Watson (1988) and Williams & Granara de Willink (1992), which has been redrawn and modified here ( Fig. 12).

We examined the two type specimens (listed above) as well as numerous specimens (from ANIC, AUCC, BME, CSCA, FSCA and USNM) of F. malvastra from many countries and several states of the USA (Arizona, California, Florida and Texas), and from a diversity of host plants. The species appears to be found most often on succulent and herbaceous plants, including shrubs, often in the families Asteraceae , Cactaceae , Euphorbiaceae , Malvaceae , Solanaceae and Verbenaceae . Ben-Dov (2005) recorded F. malvastra from 18 plant families in Israel, where it is considered to be an introduced species. It has been distributed widely and is found in all biogeographic regions ( Ben-Dov 2012). Williams & Granara de Willink (1992) predicted that F. malvastra may be found more widely in Central and South America. In addition to the Neotropical countries listed by Williams & Granara de Willink (1992), F. malvastra has been recorded from Brazil on the roots of a weedy asteraceous plant, Bidens pilosa ( Culik et al. 2006) . It is sometimes called the malvastrum mealybug (e.g., Ben-Dov 2005).

The adult female of F. malvastra has a broadly oval body shape, both pairs of ostioles well developed, multilocular pores only immediately anterior and posterior to the vulva, and the dorsal enlarged tubular ducts often have their associated setae situated on the edge of the small sclerotised area surrounding each duct. Most importantly, the dorsal enlarged tubular ducts on adult females of this species are noticeably more slender than in other species (except for F. terani ), especially the ducts on the head which are ≤4.5 µm in diameter at mid length in F. malvastra , whereas these ducts in other species are typically ≥5.0 µm in diameter at mid-length. However if adult females of F. malvastra are over-cleared in KOH, the ducts collapse and increase in apparent width. Also the size of the sclerotised area around the opening of these enlarged tubular ducts varies depending on the maturity of the specimen, being larger in old females. This species is compared with the closely related F. terani under the entry for the latter species.