Aclerdidae

Common name

Flat grass scales or aclerdids

Field characters

Body flattened, generally reddish-brown or pink, with apex of abdomen heavily sclerotized and dark brown. Usually with small amount of white wax ventrally and on head. Occurring in leaf sheaths or in crown of plant near soil surface. Species of Rhodesaclerda and Kwazulaclerda produce abundant wax dorsally similar to species of wax scales in the genus Ceroplastes.

Validation characters

Margin of posterior abdomen crenulate; single anal plate; ventral groove beneath anal complex; anal tube apodemes present. Additional characters that are not unique to flat grass scales or are present in most but not all aclerdids are as follows. Legs absent or represented by small sclerotized areas; antennae 1-segmented; spiracles with pores in atrium; body margin with conical setae; anal cleft present but short.

Notes

There are some exceptions to the characters listed above. Lecanaclerda macropoda Hodgson & Millar (South Africa on leaf bases and roots of grasses) has an anal plate that is almost completely divided, well-developed antennae and legs, and lacks marginal conical setae. Rhodesaclerda species (South Africa and Zimbabwe on stems of Combretum) have crenulations on the sclerotized cone at the apex of the abdomen, lack pores directly in the spiracular atrium but have clusters near the spiracle, and lack marginal conical setae. Kwazulaclerda loranthi Hodgson & Millar (South Africa on Loranthus) lacks crenulations on the abdomen, lacks pores directly in the spiracular atrium but has clusters near the spiracle, and lacks marginal conical setae. Aclerdidae Cockerell was first used as a family by Ferris (1937).

Distribution

Flat grass scales occur in all zoogeographical regions of the world. Find a list of species from the Australasian region, Afrotropical region, Nearctic region, Neotropical region, Oriental region, and Palaearctic region. They are most speciose in the Nearctic region. 

Hosts

Flat grass scales are primarily found on grasses, generally in grass sheaths or in the crown near the soil surface. Rhodesaclerda species occur on Combretum in the Combretaceae, Aclerda tillandsiae Howell occurs on Tillandsia in the Bromeliaceae, and Kwazulaclerda loranthi occurs on Loranthus in the Loranthaceae.

Life history

Aclerdids apparently have 4 instars in the female and 5 in the male. Little is known about the biology of these cryptic species but most apparently have a single generation each year and the second-instar male forms a delicate test similar to the ones constructed by soft scales.

Important references

Borchsenius 1960d; Gill 1993; Hodgson and Millar 2002; Howell 1973; La Face 1916, McConnell 1954.

Diversity

Click here for a check list of all aclerdid genera and species.