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dc.contributor.authorVan Dijken, M.J.
dc.contributor.authorNeuenschwander, P.
dc.contributor.authorVan Alphen, J.J.M.
dc.contributor.authorHammond, W.N.O.
dc.date.accessioned2019-12-04T11:34:07Z
dc.date.available2019-12-04T11:34:07Z
dc.date.issued1991
dc.identifier.citationVan Dijken, M.J., Neuenschwander, P., Van Alphen, J.J.M. & Hammond, W.N.O. (1991). Sex ratios in field populations of Epidinocarsis lopezi, an exotic parasitoid of the cassava mealybug, in Africa. Ecological Entomology, 16, 233-240.
dc.identifier.issn0307-6946
dc.identifier.urihttps://hdl.handle.net/20.500.12478/5900
dc.description.abstract1. In cassava fields in Africa, population sex ratios of Epidinocarsis fopezi vaned from 0.44 (males to total parasitoids) at low host densities to highly male-biased ratios of 0.70 at high host densities. 2. This variability is caused by the difference in allocation of sons and daughters to hosts of different sizes, through the following mechanisms: (a) small, i.e. second instar, hosts are mainly used for the production of male offspring, whereas in large, i.e. third instar, hosts a variable, female-biased sex ratio is produced; (b) E.fopezi does not selectively oviposit into large hosts but always accepts both small and large hosts for oviposition upon encountering; (c) in the field, this parasitoid is time-limited, and not egg-limited. On the basis of an optimal diet model, such general host acceptance is shown to be the best strategy. 3. Thus, sex ratio increases with host density for three reasons: the proportion of small hosts encountered in the field increases with increasing host density, small hosts are used for male production, and hosts are always accepted when encountered.
dc.description.sponsorshipThe Netherlands Ministry for Development Cooperation
dc.description.sponsorshipInternational Fund for Agricultural Development
dc.language.isoen
dc.subjectCassava
dc.subjectFields
dc.subjectProduction
dc.titleSex ratios in field populations of Epidinocarsis lopezi, an exotic parasitoid of the cassava mealybug, in Africa
dc.typeJournal Article
dc.description.versionPeer Review
cg.contributor.affiliationLeiden University
cg.contributor.affiliationInternational Institute of Tropical Agriculture
cg.coverage.regionAfrica
cg.coverage.regionWest Africa
cg.coverage.countryNigeria
cg.isijournalISI Journal
cg.authorship.typesCGIAR and advanced research institute
cg.iitasubjectCassava
cg.iitasubjectPlant Production
cg.accessibilitystatusLimited Access
local.dspaceid105830


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