The sense used by Trichogramma to distinguish between parasitized and unparasitized hosts

Abstract

It was demonstrated in an earlier paper of this series (Salt 1934 b ) that the chalcid parasitoid Trichogramma evanescens is able to distinguish healthy hosts from those already parasitized. The present study is an attempt to answer the question, “By what sense is that discrimination performed ? ” The material and methods used in these investigations have been fully described before (Salt 1934 a ) and, if it is recalled that Trichogramma is a minute parasitoid developing in the eggs of insects, especially moths, no further explanation is necessary for the understanding of this paper.