Warren’s Blue’s last stand

Over 90 species of butterflies have been recorded at Verloren Valei—and it is the only place the rare Warren’s Blue occurs. More proof, if any were needed, of the pivotal role this small reserve plays in preserving South Africa’s biodiversity.

While Verloren Valei Nature Reserve may be better known for its wonderful plant life, it is also home to a number of butterflies specially adapted to high altitudes. In total, over 90 species have been recorded at the reserve—30 more than the approximately 60 species present in the entire United Kingdom!

Of these high-altitude butterflies, Orachrysops warreni, Warren’s blue or Donkerblou Bloutjie, deserves to be singled out. It is extremely rare, being known only from Verloren Valei Nature Reserve.

Unique to Verloren Valei - Warrens Blue (Photograph byJustin Bode)
Unique to Verloren Valei – Warrens Blue (Photograph byJustin Bode)

The genus Orachrysops contains11 species, including the well-known Orachrysops niobe, the Brenton Blue or Brenton Bloutjie, which was saved from extinction in the late 1990s by a highly publicised campaign led by the Lepidopterists’ Society of Africa.

The flight period of Warren’s Blue lasts from November to January, with a peak in December. The rest of the year is spent in the pupal and larval stages. The larvae of the genus Orachrysops feed on leaves and young shoots of the Indigofera (forest indigo) species in the early stages, and one species in the genus is known to feed on the woody rootstock in the later larval stages.

An interesting characteristic of these butterflies, in common with other species, is that they are myrmecophilous; that is, associated with ants. This association is mainly a survival strategy, and its exact nature varies from species to species. At one extreme, the ants offer some sort of protection to the butterflies; at the other, the butterfly larvae actually feed on the ant-brood or are fed regurgitated food by the ants. In the case of Warren’s Blue, the association is thought to be at the protection end of the spectrum in that the subterranean ant nests provide safety not only from predators but also from the harsh winters and veld fires. More study on the Warren’s Blue is needed to deepen our understanding of its life cycle and place in the ecology of the reserve.

The Brenton Blue was driven to the point of extinction by the loss of habitat, and has only been saved by the proclamation of a reserve to protect the last remaining colony at Brenton-on-Sea, near Knysna. Even though it is so rare, occurring only at Verloren Valei, the Warren’s Blue is classified in the South African Red List for butterflies as Least Concern because its habitat is in an existing reserve. Protecting Verloren Valei is thus critical to the survival of this butterfly.

The public is encouraged to submit photographic records of butterflies to LepiMap, The Atlas of African Lepidoptera.

Find out more about our butterflies and moths.

Sources

S Mecenero, JB Ball, DA Edge, Ml Hamer, GA Henning, M Krüger, EL Pringle, RF Terblanche, and MC Williams (eds), Conservation assessment of butterflies of South Africa, Lesotho and Swaziland: Red List and atlas. Saftronics (Pty) Ltd: Johannesburg & Animal Demography Unit, Cape Town, 2013.

MC Williams, Afrotropical Butterflies, www.metamorphosis.org.za, 2016.

CK Willis and DA Edge. (2015). “Oviposition and mating behaviour in Orachrysops warren”, Metamorphosis 26: 1–3.

S Woodhall, Field Guide to Butterflies of South Africa. Struik, Cape Town, 2005.

Leave a Reply

Your email address will not be published. Required fields are marked *