Dickson's Strandveld Copper

INTRODUCTION
Dickson’s Strandveld Copper, Chrysoritis dicksoni, (Top L, female ovipositing; Top R; male underside - photos © R F Terblanche) was originally discovered by Charles Dickson near Melkboschstrand and described by Gabriel as Phasis dicksoni (Gabriel 1947). It has always been a scarce butterfly, and has a history of disappearing from its known habitats and then being rediscovered.

IUCN RED-LIST STATUS

Originally Red-Listed as VULNERABLE by Henning & Henning (1989). Changed to CRITICALLY ENDANGERED in the new Red List (Henning Terblanche & Ball, 2009).

SCIENTIFIC KNOWLEDGE

Type locality:    near Melkboschstrand (Gabriel 1946).

Distribution:    Historically found on the Cape west coast between Melkboschstrand and Mamre. Its last known colony was near the Pella Research Site, where eight sub colonies were located over an area of 60ha (Heath & Brinkman 1995). It disappeared from these habitats in the mid nineties, for reasons unknown. A population found in 1979 at Witsand over 200km from the type locality also disappeared, but fortunately further populations were discovered between Witsand and Vermaaklikheid in the southern Cape (Pringle 1990).

Habitat:    The colony near Pella was on Atlantis Sand Fynbos, consisting of moderately undulating to flat sand plains with a dense, moderately tall ericoid shrubland and an open, short restioid stratum (Mucina & Rutherford 2006 FFd4). The colonies near Witsand occur on Canca Limestone Fynbos (Mucina & Rutherford 2006 FFl3), on fairly level ground where limestone pavements outcrop. The vegetation is predominantly restioid with a sparse low shrub layer and patches of bare rock and sand. There is light grazing by cattle and game.

Early stages:    Eggs are laid on a variety of substrates responding to cues from the host ant Crematogaster peringueyi Emery and the usual presence of scale insect infestations on nearby shrubs. The 1st, 2nd and final instar larvae are fed by the host ant by trophallaxis, and the host ants in turn appear to feed on scale insect secretions (Heath & Brinkman, 1995a; Heath, 1998). Final instar larvae and pupae have been found both inside the carton nests and also at the base of plants.

Eggs of Chrysoritis dicksoni © S E Woodhall

CONSERVATION

Current threats are from possible changes in agricultural practices or the encroachment of alien vegetation. This may have caused the extinction of the species on the west coast.

This butterfly was placed on the protected wild animal list of the Cape Province in 1976 (Ordinance 19 of 1974, modified in 1976). This had no practical results in terms of preserving the remaining habitat near Pella.

Close co-operation with the landowners where the remaining colonies are found is essential, in order to conduct research on the ecology of the butterfly and to establish a suitable management regime.

REFERENCES

CLARK, G.C. & DICKSON, C.G.C. 1980. Life histories of the South African lycaenid butterflies.
Purnell, Cape Town. 272 pp.

COTTRELL, C.B. 1984. Aphytophagy in butterflies: its relationship to myrmecophily. Zoological Journal of the Linnaean Society 79: 1-57.

GABRIEL, A.G. 1946. A new species of Phasis (Lepid. Lycaenidae) from South Africa. The Entomologist 80: 60-1.

HEATH, A. 1997a. A review of African genera of the tribe Aphnaeini (Lepidoptera: Lycaenidae). Metamorphosis Occasional Supplement 2: 60 pp.

HEATH, A. 1997b. Myrmecophily and the male genitalia of African Lycaenidae: a preliminary discussion. Metamorphosis Occasional Supplement 3: 89-97.

HEATH, A. 1998. Further aspects on the life history of the myrmecophilous species Chrysoritis dicksoni (Gabriel) (Lepidoptera: Lycaenidae). Metamorphosis 9(4): 160-172.

HEATH, A. 2001. New synonymies and taxonomic notes on the genus Chrysoritis Butler (Lepidoptera: Lycaenidae). Metamorphosis 12(3): 85-98.

HEATH, A. & BRINKMAN, A.J. 1995. Aspects of the life history, distribution and population fluctuations of Oxychaeta dicksoni (Gabriel) (Lepidoptera: Lycaenidae). Metamorphosis 6(3): 117-127.

HEATH, A. & CLAASSENS, A.J.M. 2000. New observations of ant associations and life history adaptations (Lepidoptera: Lycaenidae) in south Africa. Metamorphosis 11(1): 3-19.

HEATH, A. & CLAASSENS, A.J.M. 2003. Ant-association among southern African Lycaenidae. Journal of the Lepidopterists’ Society 57: 1-16.

HEATH, A., McLEOD, L., KALISZEWSKA, Z.A., FISHER, C.W.S. & CORNWALL, M. 2008. Field notes including a summary of trophic and ant-associations for the butterfly genera Chrysoritis Butler, Aloeides Hübner and Thestor Hübner (Lepidoptera: Lycaenidae) from South Africa. Metamorphosis 19(3): 127-148.

HEATH, A. & PRINGLE, E.L. 2007. Biological observations and a taxonomic review based on morphological characters in the myrmecophilous genus Chrysoritis Butler (Lepidoptera: Lycaenidae: Aphnaeini). Metamorphosis 18(1): 2-44.

RAND, D.B., HEATH, A., SUDERMAN, T. & PIERCE, N.E. 2000. Phylogeny and life history evolution of the genus Chrysoritis within the Aphnaeini (Lepidoptera: Lycaenidae), inferred from mitochondrial Cytochrome oxidase I sequences. Molecular Phylogenetics and evolution 17: 85-96.

TITE, G.E. & DICKSON, C.G.C. 1973. The genus Aloeides and allied genera (Lepidoptera: Lycaenidae). Bulletin of the British Museum of Natural History (Entomology) 29: 225-280.