title: Effect of fungal colonization of wheat grains with Fusarium spp. on food choice, weight gain and mortality of meal beetle larvae (Tenebrio molitor).
abstract: Species of Fusarium have significant agro-economical and human health-related impact by infecting diverse crop plants and synthesizing diverse mycotoxins. Here, we investigated interactions of grain-feeding Tenebrio molitor larvae with four grain-colonizing Fusarium species on wheat kernels. Since numerous metabolites produced by Fusarium spp. are toxic to insects, we tested the hypothesis that the insect senses and avoids Fusarium-colonized grains. We found that only kernels colonized with F. avenaceum or Beauveria bassiana (an insect-pathogenic fungal control) were avoided by the larvae as expected. Kernels colonized with F. proliferatum, F. poae or F. culmorum attracted T. molitor larvae significantly more than control kernels. The avoidance/preference correlated with larval feeding behaviors and weight gain. Interestingly, larvae that had consumed F. proliferatum- or F. poae-colonized kernels had similar survival rates as control. Larvae fed on F. culmorum-, F. avenaceum- or B. bassiana-colonized kernels had elevated mortality rates. HPLC analyses confirmed the following mycotoxins produced by the fungal strains on the kernels: fumonisins, enniatins and beauvericin by F. proliferatum, enniatins and beauvericin by F. poae, enniatins by F. avenaceum, and deoxynivalenol and zearalenone by F. culmorum. Our results indicate that T. molitor larvae have the ability to sense potential survival threats of kernels colonized with F. avenaceum or B. bassiana, but not with F. culmorum. Volatiles potentially along with gustatory cues produced by these fungi may represent survival threat signals for the larvae resulting in their avoidance. Although F. proliferatum or F. poae produced fumonisins, enniatins and beauvericin during kernel colonization, the larvae were able to use those kernels as diet without exhibiting increased mortality. Consumption of F. avenaceum-colonized kernels, however, increased larval mortality; these kernels had higher enniatin levels than F. proliferatum or F. poae-colonized ones suggesting that T. molitor can tolerate or metabolize those toxins.
authors.affiliation: Institute of Crop Science and Resource Conservation (INRES-Phytomedicine), Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany.
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Molecular Phytopathology and Mycotoxin Research, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Döll
authors.affiliation: Molecular Phytopathology and Mycotoxin Research, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: Raana
authors.initials: R
authors.lastname: Dastjerdi
authors.affiliation: Molecular Phytopathology and Mycotoxin Research, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: Petr
authors.initials: P
authors.lastname: Karlovsky
authors.affiliation: Institute of Crop Science and Resource Conservation (INRES-Phytomedicine), Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany.
authors.forename: Heinz-Wilhelm
authors.initials: HW
authors.lastname: Dehne
authors.affiliation: Institute of Crop Science and Resource Conservation (INRES-Phytomedicine), Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany.
authors.forename: Boran
authors.initials: B
authors.lastname: Altincicek
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000254:growth & development* / Q000382:microbiology; D002523:Edible Grain / Q000254:growth & development / Q000382:microbiology*; D005247:Feeding Behavior; D005670:Fusarium / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007300:Insect Control; D007814:Larva / Q000254:growth & development* / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D015996:Survival Rate; D014908:Triticum / Q000254:growth & development / Q000382:microbiology*; D015430:Weight Gain