A study of arthropod predation of Pieris rapae L. using serological and exclusion techniques.
In investigations in New Zealand, percentage estimates of the total mortality of Pieris rapae (L.) due to ground-living arthropod predators obtained by exclusion caging were partitioned between the various predators by means of serological tests on the predator gut contents. Serological tests also permitted the evaluation of the role of Syrphid predators living on the plant, which could not be excluded by caging. Larvae of the Syrphids Melanostoma fasciatum Macq. and Syrphus novae-zealandiae Macq. were responsible for 58.3% and harvestmen (Phalangium opilio L.) for 31.5% of the total arthropod predation on larvae during the period of development from the egg to third larval instar. Total arthropod predation during this period caused 55.9% mortality of larvae based on the numbers of eggs laid.