Host-finding behaviour of the rabbit flea, Spilopsyllus cuniculi with special reference to the significance of urine as an attractant.

Both fed and unfed rabbit fleas can move relatively slowly upwind towards a host. The speed of movement is too slow for direct host location from more than a few cm. Fleas are strongly attracted to a urine bait, will remain gathered around it, and can move rapidly on to a host when one is present. The attraction is produced by physiologically realistic amounts of urine, little increase being obtained from volumes greater than 15 ml, even over a tenfold range. The range of movement of fleas towards a urine bait obtained in our experiments was greater than 6 m but less than 9 m. The maximum survival time in pasture during summer and autumn was between 14 and 21 days. The attractants are contained in urine and not in faeces, and are not restricted to the urine of rabbits or even of lagomorphs. Strong attraction was obtained towards hare and rat urines, and a low degree of attraction towards dog and human urine. Concentrated homogenates of rabbit anal glands gave low attraction.