The flavonoid rutin protects against cognitive impairments by imidacloprid and fipronil

Evaluating the Effects of Flavonoids on Insects: Implications for Managing Pests Without Harming Beneficials

Flavonoids have multiple functions, including host-plant defense against attacks from herbivorous insects. This manuscript reviewed and analyzed the scientific literature to test the hypothesis that flavonoids can be utilized to manage pests without causing significant harm to beneficials. The methodology involved using recognized literature databases, e.g., Web of Science, Scopus, and CAB Abstracts, via the USDA-ARS, National Agricultural Library, DigiTop literature retrieval system. Data were compiled in tables and subjected to statistical analysis, when appropriate. Flavonoids were generally harmful to true bugs and true flies but harmless to honey bees. Flavonoid glycosides showed a tendency to harm true bugs (Heteroptera) and true flies (Diptera). Flavonoid glycosides were harmless to sawflies. Flavonoids and flavonoid glycosides produced a mixture of harmful and harmless outcomes to herbivorous beetles, depending on the species. Flavonoid glycosides were harmless to butterflies. In conclusion, specific flavonoids could function as feeding stimulants or deterrents, oviposition stimulants or deterrents, chemical protectants from pesticides, mating attractants, less-toxic insecticides, and other functions. Flavonoids could manage some insect pests without causing significant harm to beneficials (e.g., honey bees). Flavonoid-based insecticides could serve as environmentally benign alternatives to broad-spectrum insecticides against some pests, but field testing is necessary.

Oral administration of phytochemicals protects honey bees against cognitive and motor impairments induced by the insecticide fipronil

Pollution produced by exposure to pesticides is a major concern for food security because the negative impacts on pollinators. Fipronil, an insecticide broadly used around the globe has been associated with the ongoing decline of bees. With a characteristic neuroactive toxicodynamic, fipronil leads to cognitive and motor impairments at sublethal dosages. Despite of regional bans, multilevel strategies are necessary for the protection of pollinators. Recent evidence suggests that specific nutrients in the diets of bees may induce protection against insecticides. Here, we evaluated whether the administration of three phytochemicals, namely rutin, kaempferol and p-coumaric acid provide protection to the Africanized honey bee Apis mellifera against oral administration of realistic dosages of fipronil. We tested the potential impairment produced by fipronil and the protection induced by the phytochemicals in learning, 24h memory, sucrose sensitivity and motor control. We found that the administration of fipronil induced a concentration-dependent impairment in learning and motor control, but not 24h memory or sucrose sensitivity across a 24h window. We also found that the administration of rutin, p-coumaric acid, kaempferol and the mixture was innocuous and generally offered protection against the impairments induced by fipronil. Overall, our results indicate that bees can be prophylactically protected against insecticides via nutrition, providing an alternative to the ongoing conflict between the use of insecticides and the decline of pollinators. As the studied phytochemicals are broadly present in nectar and pollen, our results suggest that the nutritional composition, and not only its production, should be considered when implementing strategies of conservation via gardens and co-cropping.

Land use influences the nutrient concentration and composition of pollen and nectar rewards of wildflowers in human-dominated landscapes

Plant biodiversity is crucial to satisfy the trophic needs of pollinators, mainly through nectar and pollen rewards. However, a few studies have been directed to ascertain the intraspecific variation of chemical features and the nutritional value of nectar and pollen floral rewards in relation to the alteration of landscapes due to human activities. In this study, by using an existing scenario of land use gradients as an open air laboratory, we tested the variation in pollen and nectar nutrient profiles along gradients of urbanization and agriculture intensity, by focusing on sugar, aminoacids of nectar and phytochemicals of pollen from local wild plants. We also highlighted bioactive compounds from plants primary and secondary metabolism due to their importance for insect wellbeing and pollinator health. We surveyed 7 different meadow species foraged by pollinators and common in the main land uses studied. The results indicated that significant variations of nutritional components occur in relation to different land uses, and specifically that the agricultural intensification decreases the sugars and increases the antioxidant content of flower rewards, while the urbanization is positively associated with the total flavonoid content in pollen. These effects are more evident in some species than in others, such as Lotus corniculatus L. (Fabaceae) and Malva sylvestris L. (Malvaceae), as shown by the untargeted metabolomic investigation. This study is crucial for understanding the nutritional landscape quality for pollinators in association to different land uses and sets a base for landscape management and planning of pollinator-friendly strategies by improving the quality of plant rewards to provide benefits to pollinator health in various environmental contexts.

Investigation of the Relationship between Genetic and Breeding Characteristics of WBPH Behavior according to Resistant Materials in Rice

Rice accounts for most of the calories consumed by the world's population. However, the whitebacked planthopper (WBPH), Sogatella furcifera (Horvath), is an insect that can cause rice yield loss. WBPH sucks the stems of rice and negatively affects yield and grain quality. Therefore, numerous insecticides have been developed to control WBPH in rice fields. However, chemical pesticides cause serious problems such as environmental pollution and ecosystem disturbance. Here, we research the possibility of using previously reported rice extracts obtained using methanol, Chrysoeriol 7(C7) and Cochlioquinone-9 (cq-9), as potential insect repellents. WBPH was caged with C7 or cq-9 and monitored, and the WBPH behavior was recorded. The number of WBPHs approaching the periphery of the C7 and cq-9 was very low. In cages containing the C7 and cq-9, only 13 and 7 WBPHs out of 100, respectively, walked around the material. In addition, foliar spraying with C7 and cq-9 did not negatively affect the plant height. The expression level of genes related to resistance was maintained at a high level in the resistant lines when treated with WBPHs alone, but was at a similar level to those of the controls when treated with C7 or cq-9. Interfering with WBPH access did not adversely affect the plant phenotype. Recently, people's interest in the environment has increased, and the use of plant-derived materials is also increasing. There is a new trend towards using plant extracts as an environmentally friendly means of managing resistance to WBPH during the rice cultivation period, while also avoiding environmental pollution.