Endosymbiont load, personality and reproductive output of maize weevils (Sitophilus zeamais)


Endosymbiotic association is frequent in insects, and endosymbionts influence a range of biological processes in these organ-isms. The endosymbiont–insect association and interdependence allegedly result from random selection where ecological trade-offs take place and usually differ between the involved species. Insect behavior is potentially affected by this associa-tion, but the focus in such studies is symbiont presence rather than load, and overall behavioral patterns, not the individual set of integrated behavioral tendencies (i.e., individual personality). This knowledge gap limits the understanding of how the endosymbiont–insect association affects insect behavior and how this translates into fertility, as a measure of fitness. Here, we assessed the endosymbiont load of maize weevils [Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)], which hosts two symbiont species—Sodalis pierantonius and Wolbachia, and their association with weevil personality and reproductive consequences. Thus, individual female weevils were subjected to oral administration of antibiotics (ciprofloxa-cin and tetracycline) to secure a range of symbiont loads, which were quantified by qPCR. Individual personality of these females was recorded before and after endosymbiont suppression, and also that of their progeny. Female weevils maintained their personality with symbiont suppression, which was not transferred to their progeny. Nonetheless, personality itself was more important in determining female reproductive output than endosymbiont load, which did not significantly alter indi-vidual integrated behavior. Thus, management tactics targeting endosymbiont suppression may not be as effective as initially anticipated, unless complete suppression of the obligatory symbiont S. pierantonius takes place.


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