Ecology of ragadia makuta (lepidoptera: satyrinae) in tropical rainforests of Sabah, Malaysia.

Abstract

The satyrid butterfly Ragadia makuta Horsfield was studied in lowland dipterocarp rainforest in Sabah, Borneo. Data were collected monthly from March 1999 to February 2000 in two habitat types, unlogged forest and forest that had been selectively logged 10 to 11 years previously. THe primary aim was to investigate the effects of selective logging on R. makuta abundance and distribution. Transect walk-and-count and point sampling techniques were used to record satyrinae, morphinae and riodinidae butterflies plus one species of Danaidae (Idea stolli). Butterflies were sampled at 80 observation stations along 8 km of transects in logged and unlogged forests.
Measurements of vegetation structure showed that effects of logging were still evident 10 years after logging. Logged forests had lower canopy and understorey cover and fewer large trees but a larger proportion of pioneer Macarangga spp. compared with unlogged forest. R. makuta abundance was not affected by selective logging. Habitat requirements of R. makuta were investigated and in both unlogged and logged forests, R. makuta was more abundant in areas with greater cover of its larval host plant (Selegenella spp). There was some evidence for R. makuta changing its habitat requirements from unlogged forest to logged forest but these changes were relatively small.
The distribution and abundance of R. makuta varied from month to month in relation to rainfall. Rainfall one month before surveys was negatively correlated with R. Makuta abundance. This indicates that rainfall may affect adult abundance through its impacts on larval development and survival.
The use of R. Makuta as biodiversity indicator for other butterflies was examined. R. makuta abundance was positively correlated with diversity of other satyrid and rionidid butterflies. This suggested that R. makuta could be used as indicator of other understorey butterflies and that R. Makuta may be an important tool for conservation studies.