In this study, the effects of the Bt-toxin Cry1Ab and a soybean trypsin inhibitor (SBTI) on intestinal bacterial communities of adult honeybees (Apis mellifera) were investigated. It was hypothesized that changes in intestinal bacterial communities of honeybees may represent a sensitive indicator for altered intestinal physiology. Honeybees were fed in a laboratory set-up with maize pollen from the Bt-transgenic cultivar MON810 or from the non-transgenic near isoline. Purified Cry1Ab (0.0014% w/v) and SBTI (0.1% or 1% w/v) represented supplementary treatments. For comparison, free-flying honeybees from two locations in Switzerland were analysed. PCR-amplification of bacterial 16S rRNA gene fragments and terminal restriction fragment length polymorphism analyses revealed a total of 17 distinct terminal restriction fragments (T-RFs), which were highly consistent between laboratory-reared and free-flying honeybees. The T-RFs were affiliated to Alpha-, Beta-, and Gammaproteobacteria, to Firmicutes, and to Bacteriodetes. Neither Bt-maize pollen nor high concentrations of Cry1Ab significantly affected bacterial communities in honeybee intestines. Only the high concentration of SBTI significantly reduced the number of T-RFs detected in honeybee midguts, a concentration that also increases bee mortality. Therefore, total bacterial community structures may not be a sensitive indicator for providing evidence for the impact of insecticidal proteins on honeybees at sublethal levels.
-In order to assess the potential impacts of transgenic plants on larvae of the honey bee, Apis mellifera, information on pollen consumption is needed. We here report on experiments that were conducted with small bee colonies kept in field cages (8 × 14 m) containing only flowering maize plants as protein source. Fully grown worker bee larvae were found to contain between 1720 and 2310 maize pollen grains in their gut before defecation, corresponding to 1.52-2.04 mg of pollen consumed per larva. On average, 74.5% of pollen grains were completely digested while 23.3% were partially digested and 2.2% remained undigested. Our data indicate that the contribution of the protein by directly feeding larvae with pollen is less than 5% in relation to the total amount of protein necessary for complete larval development. We suggest that our measurement for pollen consumption should be taken into account when establishing dose regimes to assess the risk that transgenic plants pose for honey bee larvae.Apis mellifera / pollen consumption / transgenic plant / agrochemical / maize / risk assessment
Biological control is widely successful at controlling pests, but effective biocontrol agents are now more difficult to import from countries of origin due to more restrictive international trade laws (the Nagoya Protocol). Coupled with increasing demand, the efficacy of existing and new biocontrol agents needs to be improved with genetic and genomic approaches. Although they have been underutilised in the past, application of genetic and genomic techniques is becoming more feasible from both technological and economic perspectives. We review current methods and provide a framework for using them. First, it is necessary to identify which biocontrol trait to select and in what direction. Next, the genes or markers linked to these traits need be determined, including how to implement this information into a selective breeding program. Choosing a trait can be assisted by modelling to account for the proper agro‐ecological context, and by knowing which traits have sufficiently high heritability values. We provide guidelines for designing genomic strategies in biocontrol programs, which depend on the organism, budget, and desired objective. Genomic approaches start with genome sequencing and assembly. We provide a guide for deciding the most successful sequencing strategy for biocontrol agents. Gene discovery involves quantitative trait loci analyses, transcriptomic and proteomic studies, and gene editing. Improving biocontrol practices includes marker‐assisted selection, genomic selection and microbiome manipulation of biocontrol agents, and monitoring for genetic variation during rearing and post‐release. We conclude by identifying the most promising applications of genetic and genomic methods to improve biological control efficacy.
The coccinellid Harmonia axyridis (Pallas) has been used for augmentative and classical biological control in many environments. More recently it has invaded large parts of Europe and negative effects for native populations of aphidophagous coccinellids are beginning to emerge. Here we investigate intraguild predation (IGP) between H. axyridis and eleven native non-target European coccinellids, including less common species which have not been studied so far within this context of non-target effects. When first-instars of H. axyridis were paired with the native species, only Anatis ocellata (Linnaeus) and Calvia quatuordecimguttata (L.) were significantly superior to the former whereas H. axyridis was superior in three cases, i.e. against Aphidecta obliterata (L.), Coccinella septempunctata L. and Hippodamia variegata (Goeze). Non-significant results were obtained for all other pairings. Similar tests with the fourth larval instar revealed stronger IGP rates and H. axyridis was found to be superior in the interactions with Adalia bipunctata (L.), Adalia decempunctata (L.), A. obliterata, Calvia decemguttata (L.), C. quatuordecimguttata, C. septempunctata, H. variegata, Oenopia conglobata (L.) and Propylea quatuordecimpunctata (L.) whereas nonsignificant results were obtained for interactions with two other native species. Another experiment revealed that H. axyridis was able to prey more successfully upon egg of most native coccinellid species than vice versa. However, C. quatuordecimguttata eggs seem to be more protected against predation than those of the other species. Survival of first-instar H. axyridis was higher on conspecific eggs compared to eggs of any other species tested. Our results suggest that H. axyridis may become a threat to a wide range of native aphidophagous coccinellids sharing similar ecological niches except species showing high potential for chemical or physical protection.
The fall armyworm (FAW, Spodoptera frugiperda) originates from the tropical and sub‐tropical regions of the Americas. Recently it was reported for the first time in Africa and has since spread rapidly across more than 30 countries in the continent. Chemical pesticides are being promoted and used for FAW management, but where application practices and/or the active ingredients are unsafe there is a need to make effective, low‐risk products available. Given that biopesticides such as microbials and microbial extracts, macrobials and semiochemicals are generally considered to be lower risk options for pest management, they are a promising avenue for exploration. When used in conjunction with good crop management, they can help to keep pest levels under control, reducing the need to apply other pesticides. This study provides a basis for designing interventions to make biopesticides more widely available for FAW control in Africa. It summarizes assessments of the registered pesticides and biopesticides for 30 countries, 11 in FAW's native range and 19 in Africa. The report identifies biopesticide active ingredients (AI) which are registered for use against FAW and provides an assessment of how appropriate these will be for use by smallholder farmers in Africa. For each biopesticide AI identified, detailed profiles were developed which covered the efficacy of the AI against FAW; the human health and environmental hazards associated with the AI; the agronomic sustainability of the AI; and whether or not the AI is practical for smallholder farmers to use. Using these data, a list of priority biopesticides for which follow‐up action is recommended was compiled. Fifty biopesticide AI were identified, which have been registered in one or more of the 30 countries for FAW management. Twenty‐three of these are recommended for follow‐up, for example field trials or bioassays.
-In order to assess the risks of transgenic crops for honey bee colonies, we studied the development of hypopharyngeal glands of adult workers. We introduced 50 newly emerged adult bees into small, queenright colonies of c. 250 bees. Bees were fed either Bt-transgenic maize pollen (MON 810) or a sugar solution containing either purified Bt-toxin (Cry1Ab, 0.0014% w/v) or Kunitz soybean trypsin inhibitor (SBTI) at two concentrations (0.1% and 1% w/v). Neither the Bt maize pollen nor the Bt toxin showed any effect on bee survival or on the development of hypopharyngeal glands after a period of 10 days' feeding. In contrast, treatment of newly emerged bees with SBTI (0.1 and 1%) for 10 days significantly reduced the mean weights of the hypopharyngeal glands and the mean diameter of the glands' acini. While small amounts of Bt toxin were detected by ELISA in the hypopharyngeal glands of bees fed the Bt-sugar solution, SBTI could not be detected in gland samples by Western blotting.Apis mellifera / Cry1Ab / Kunitz soybean trypsin inhibitor / transgenic plants / risk assessment
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