African Grass Blue

EASY GARDEN BUTTERFLIES

African Grass BlueZizeeria knysna knysna

African Grass Blues are tiny (wingspan 18-24 mm), low-flying butterflies in the Lycaenidae (Gossamer-winged Butterflies), subfamily Polyommatinae (Blues, Bronzes, Hairstreaks etc.). Blues are tiny to small butterflies, many of which have brilliant blue uppersides (although some are dull grey or brown).

The sexes differ slightly on their upper sides. Male African Grass Blues are shiny violet-blue above with a well-defined grey wing margin. They differ from their females which are charcoal grey with the bases of the wings being sky blue with ill-defined margins. The underside of both sexes has patterns of grey-brown spots and arrow-marks on a whitish grey ground.

African Grass Blues fly very low and spend most of their time in the grass – hence their common name. They feed on low-growing flowers and like to sit on damp earth and mud, sucking up dissolved minerals. The sexes fly together and engage in courtship when they encounter one another.

Distribution

African Grass Blues are found all over South Africa except for the central Nama Karoo and the highest altitude grasslands. They are common all over Africa, Madagascar, and the Indian Ocean islands. The Asian Grass Blue subspecies Zizeeria knysna karsandra is found in North Africa, southern Europe, the Middle East and across tropical Asia to Australia.

Egg

Female African Grass Blues lay tiny, pale blue-green eggs singly on buds or flower stalks of the host plant. They turn white as they mature. They are flattened disks 0.5mm in diameter by 0.25mm high. They have double rows of whorled white ribs that are joined by horizontal ribs on the side to create a pattern of triangles with a tiny mole where they meet. There is a prominent dark mark at the centre of the top. The egg stage lasts about five days.

Caterpillar

African Grass Blue caterpillars are tiny. They are slug-shaped, as are most caterpillars of the Lycaenidae. Fully-grown caterpillars vary in colour from pale green to dull mid-green, with pale whitish diagonal side markings and a pale stripe along the back. The skin is covered in tiny bristles and appears velvety. Young larvae eat slots into the leaves of the plant and conceal themselves in those. Older larvae wrap themselves around a leaf and consume it – they are very hard to see when they do this. They grow from 0.8mm to 10-11mm long in three moults over two to three weeks. They have a ‘honey gland’ on their rear segments like many other Lycaenidae, which attracts the attentions of ants.

Pupa/Chrysalis

African Grass Blue pupae are covered with tiny bristles. They vary in colour from pale yellow-green to darker green with a varying amount of grey speckling. The caterpillars pupate in debris below their host plant. They are attached by tiny hooks on their tail to a silken pad spun by the larva and by a silken girdle around their ‘waist’. They are about 7-8mm long, and of a typical rounded Lycaenid shape. The adult normally emerges in about one to three weeks although it can be longer in cold or dry conditions.

Host plants

African Grass Blue caterpillars feed on a variety of plants from various families. One of the best-known is the Creeping woodsorrel, Oxalis corniculata – a common lawn weed found all over Africa. Few gardens will not have these little Blues flying around their lawn. Not all gardeners are fond of this plant and even fewer like one of its other host plants, Devil-thorn Tribulus terrestris! It also uses plants in the Pea family, Fabaceae, like Lucerne, Medicago sativa.

How to attract them

It’s very difficult to prevent this little species from appearing in a garden because a main host plant is a widespread lawn weed! This is one of the best arguments for avoiding weed killers and insecticides, accepting biodiversity into the lawn environment. Think of Creeping woodsorrel as an attractive ground cover with benefits!