Control Options

Manipulation of Food Resources

Midge in freshwater ecosystems consume various types of food including detritus (Ward and Cummins 1979), bacteria (Goldfinch and Carman 2000), epiphytic plankton (Botts and Cowell 1992) and phytoplankton (Davies 1980). Variations in the quality and quantity of phytoplankton have shown a positive correlation with midge biomass (Lindegaard and Jónasson 1979; Davies 1980; Ali 2002). Studies of nuisance midge problems at wetlands on the Swan Coastal Plain have suggested that phytoplankton blooms form an important food source for midges (Davis et al. 1988; Pinder et al. 1991; Strano 2001) In a stable isotope study of midge diets, Wild and Davis (2004) found that larval midges at Yangebup Lake consumed a mixture of cyanobacteria and detritus derived from Typha sp. The role of nutrient enrichment and subsequent increases in algal and detrital biomass has already been recognised as a major driver of nuisance midge populations (Ali 1996). However, in addition to food quantity, food quality is also an important factor governing rates of growth in larval midge (Pinder 1992). The study by Wild and Davis (2004) indicated that larval chironomids can utilise both algal and detrital food sources. Further investigation is needed to determine the extent to which differing food resources influence larval midge growth rates. A study of the comparative quality of these two resources is needed to ultimately resolve the importance of each. The manipulation of larval food resources may be a potential strategy for ecological control of nuisance midge swarms in wetlands on the Swan Coastal Plain.

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Updated : 23 June, 2009