SAMPLING FOR ADULT COCCINELLIDS AND THEIR NUMERICAL RESPONSE TO STRAWBERRY APHIDS (COLEOPTERA:COCCINELLIDAE: HOMOPTERA:APHIDIDAE)

Abstract

Searching for adult coccinellids in large cages placed over sections of strawberry fields produced an average of 10 times as many coccinellids per metre of row as a relative method of sampling. Methods of converting relative indices to absolute indices of abundance were found. Results suggest that the frequently observed slow increase in abundance of aphid predators in response to increasing aphid abundance may be an artifact resulting from using relative indices of abundance that make no correction for the effects of hunger on predator activity. Calibrating the samples shows that numbers of adult coccinellids follow the trend of aphid abundance closely enough that coccinellid numbers may be predictable.