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Host location in stored cowpea by the egg parasitoid Uscana lariophaga Steffan (Hym., Trichogrammatidae)
Author(s) -
Alebeek F.A.N.,
Huis A.
Publication year - 1997
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.1997.tb01425.x
Subject(s) - biology , trichogrammatidae , olfactometer , parasitoid , callosobruchus maculatus , host (biology) , hymenoptera , zoology , kairomone , foraging , ecology , botany , pest analysis
A good spatial distribution and an efficient host location behaviour are prerequisites for successful biological control of stored product pests. These attributes were investigated in the egg parasitoid Uscana luriophaga Steffan (Hym., Trichogrammatidae), foraging for clusters of Callosobrachus maculatus Fab. (Col., Bruchidae) eggs in experimental cowpea ( Vigna unguiculata Walp.) storage containers. Females have an innate tendency to move upwards in a cowpea seed stock. Host clusters above the release point have an increased chance to be found by U. lariophaga compared to clusters below the site of release, but still, significant numbers of clusters below the release point are also being visited and parasitized. In host clusters with more than 50 eggs, parasitoids are arrested and may spend their entire egg load or foraging time, leaving other clusters unexploited. Host clusters with more eggs are more frequently parasitized, irrespective of the volume of clusters or the egg density and distribution within those clusters. This increased chance of detection is thought to be the result of an increase in egg odour concentration or in the volume of the odour sphere around clusters with more eggs. This hypothesis was tested in a tube diffusion olfactometer.