ACTIVITY PATTERNS OF TERMITE-EATING LAND PLANARIANS MICROPLANA-TERMITOPHAGA (PLATYHELMINTHES, TRICLADIDA)

The land planarian Microplana termitophaga is one of three invertebrat e predators feeding at the open chimneys of the mound of the termite O dontotermes transvaalensis in Harare. This paper records over 4000 fie ld observations of the mound and reports on the planarians over three rainy seasons from 1990 to 1993. Microplana termitophaga is crepuscula r with a large early morning and a smaller evening activity peak. Rain fall appears to be of over-riding importance; activity is confined to the rainy season, occurring once the cumulative rainfall reaches 150-2 50 mm and being suspended during longish dry spells. Activity is also favoured by ambient relative humidity above 70%, light intensity below 50,000 lux (but not total darkness) and ambient temperature between 1 3 and 23 degrees C. Planarians on sun-exposed, but not on shaded, moun ds disappeared after a drought. Dispersal occurs during prolonged wet weather. Microplana termitophaga occurs with two predatory spider spec ies and a commensal phorid fly and they all utilize the same termites. These four species exhibit temporal separation, probably related to t heir specific micro-climatic needs.