Entomological Reserve: Web Page by Adelaar Highschool for CyberFair 96

Ruimsig Entomological Reserve

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Origin and Development

In Southern Africa the butterflies most at risk are the myrmecophilous (ant associated) Lycaenidae. These species are often quite local and rare as they require the presence of both host ant and host plant as well as optimal climatic conditions. Being thus confined to a limited area, often not larger than a tennis court, these species are particularly vulnerable to any disturbance of their preferred habitat. Thus the building of a house, the construction of a road or the ploughing of a field could lead to the extinction of a rare species confined to a single locality.

Between 1977 and 1979 Stephen Henning did extensive research on ant associated lycaenid species at Ruimsig. He was able to demonstrate using behavioural studies and gras chromatography of ant and butterfly glandular secretions that butterfly larvae mimic the pheromones of ants allowing them to insinuate themselves into the ants' nests.

A small twelve hectare reserve was established for the protection of the rare butterfly Aloeides dentatis (Swierstra) (Lycaenidae). This is one of the last known colonies of this butterfly. The butterfly is restricted to this locality since it requires both the presence of its host ant, an undescribed Acantholepis species and its larval foodplant, Hermannia depressa (Sterculiaceae) that is found here.

The viability of small nature reserves is being investigated at the Ruimsig Entomological Reserve. The results of these conservation strategies could have far -reaching consequences for butterfly conservation in South Africa.

Position

Stephen and Graham Henning, with the backing of the Lepidopterists' Society and Wildlife Society of Southern Africa campaigned for the small area occupied by Aloeides dentatis to be declared a reserve. Thus this area was eventually proclaimed a reserve in 1985 by the Roodepoort City Council. The reserve is situated in Ruimsig, a township of Roodepoort, Gauteng, South Africa.

Natural features

This reserve is a first in Africa proclaimed to protect a unique grassland habitat for insects not commonly found on the Witwatersrand. Approximately 100 butterfly species have been recorded in the reserve.

The area was fenced in and during its first winter fire breaks were burnt around the perimeter to protect it from the threat of the normal highveld fires. The following season Aloeides dentatis was absent in the reserve. It was eventually rediscovered on the firebreaks. It appears that the Aloeides dentatis host ants prefer more open areas. In addition the foodplant H. depressa as is name implies lies flat on the ground and appears to be a pioneer plant growing quickly over bare patches in the veld . Where the veld is not burnt or disturbed it is completely shaded by the long dead veld grass and does not thrive at all.

This meant that this small twelve hectare reserve has to be managed quite closely to ensure the survival of the butterfly. Every winter the Roodepoort Parks Department has to come in and either burn or scrape parts of the reserve to provide suitable habitats for Aloeides dentatis. Campaigns to eliminate weeds also continues every year.

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Entomological Reserve: Web Page by Adelaar Highschool for CyberFair 96
Last Updated March 28, 1996
Email: mm@adelaar.jhb.school.za
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