Pasture seed theft by ants in northern New South Wales

Abstract

To obtain probability information for the theft of oversown seed by ants in northern New South Wales, the seasonal pattern of theft of both bare and coated seed of Trifolium repens, Medicago sativa, Festuca arundinacea and Phalaris tuberosa was monitored at both Armidale and Tamworth. Average values for seed removed within 24 hours of placement ranged from < 1 per cent at Armidale and c. 25 per cent at Tamworth during winter to summer values of c. 40 per cent and c. 90 per cent for the two locations respectively. It was concluded that the theft of oversown seed by ants could be a problem in any month at Tamworth and in all but the winter months at Armidale. At both locations more phalaris seed was taken than seed of other species. Using coated seed significantly reduced theft at both locations. However, it was considered that the coating effect may often be of little practical value. At Armidale, theft rates from sites on a lateritic podsol were on average 47 per cent greater than the rates observed at sites on a black earth soil type. Theft rate was related to mean air temperature at both Armidale and Tamworth. For both bare and coated seed the theft rate for a particular temperature was generally much greater at Tamworth than at Armidale. Because of the spatial variability of theft encountered at both locations it was concluded that a simple exponential type extrapolation from the 24 hour theft data for longer periods of time would be unwise.