The use of general foraging kairomones in a generalist parasitoid

Almost no comparative studies are available on the use of general and speci fic infochemical cues by generalist parasitoids with hosts from different f amilies feeding on host plants also from different families. Based on liter ature, two hypotheses were developed and tested with host recognition cues used by the larval parasitoid Lariophagus distinguendus. This generalist pa rasitizes beetle species from different families developing in seeds of pla nt species from the Poaceae and Fabaceae. The first hypothesis predicts tha t for initial encounters with host species, natural enemies should innately use general cues. which are common to all hosts and their food plants. The second hypothesis predicts that natural enemies should learn specific cues from host plant and host after experience with a host species. The first h ypothesis was partly confirmed. L. distinguendus innately reacted to faecal cues from several host species and chemical analyses of faeces from these hosts revealed the common occurrence of chemicals that are used for host re cognition by L. distinguendus. In disagreement with the first hypothesis, p arasitoids did not innately respond to cues from plant seeds. Preference ex periments on the influence of experience demonstrated an increased host rec ognition response towards a host after experience with it. In support of th e second hypothesis, L. distinguendus females learned specific cues from he rbivore-damaged wheat, rice and cowpea seeds and from the faeces of the bea n weevil Callosobruchus maculatus.