Aphid honeydew may be the predominant sugar source for Aphidius parasitoids even in nectar-providing intercrops

Interactions between Rice Resistance to Planthoppers and Honeydew-Related Egg Parasitism under Varying Levels of Nitrogenous Fertilizer

“…Furthermore, honeydew composition is affected by crop fertilizer levels; for example, planthoppers feeding on rice grown in high-nutrient soils increase their phloem-based feeding (compared to xylem-based) and produce larger quantities of honeydew [ 31 ]. Honeydew represents a significant nutrient source for the parasitoids of phloem-feeding herbivores, such as aphids, in other cereal systems [ 32 , 33 , 34 , 35 ]; however, to our knowledge, the role of honeydew as a food for the parasitoids of rice planthoppers or leafhoppers has not yet been studied.…”

Honeydew as a newly described route of insecticide exposure to beneficial insects

“…In fact, 59% of the parasitic wasps and 44% of the hoverflies collected in spring wheat fields had recently fed on honeydew, and 55% of the parasitic wasps from winter wheat fields had fed on honeydew (Hogervorst et al, 2007). Furthermore, parasitic wasps captured in wheat fields throughout the season can be found to have recently fed on honeydew (Luquet et al, 2021). In Europe, aphids can be treated with systemic insecticides, including acetamiprid, sulfoximines, spirotetramat, and flonicamid.…”

“…Instead, honeydew is a ubiquitous carbohydrate source that is present during most of the growing season in many crops (Tena et al, 2016;Wäckers et al, 2008). It is well-known that beneficial insects feed on honeydew, either as a common food source as occurs with various species of parasitic wasps, predatory midges, and pollinators (Calabuig et al, 2015;Fratoni et al, 2019;Herrera, 1990;Hogervorst et al, 2007;Konrad et al, 2009;Lee et al, 2006;Lundgren, 2009;Luquet et al, 2021;Rogers et al, 2007;Tena et al, 2013aTena et al, , 2016Way, 1963), or as a substitute of nectar when the latter is scarce (Cameron et al, 2019;Konrad et al, 2009;Meiners et al, 2017).…”

“…One part of the current ERA is focused on evaluating the route of contamination of plant-derived food sources such as nectar, extrafloral nectar, or pollen (Gierer et al, 2019;Sanchez-Bayo and Goka, 2014). This thesis, in particular chapters 2, 3 and 4, provides information on a plant-derived food source, honeydew, which should be included in future ERA because it is a common food source in agroecosystems and forests (Calabuig et al, 2015;de-Miguel et al, 2014;Hogervorst et al, 2007;Lee et al, 2006;Luquet et al, 2021;Tena et al, 2013a;Ülgentürk et al, 2020) and it may be contaminated with systemic insecticides. In the following section, I explain why the safety of neonicotinoids and other insecticides with other mode of action than neonicotinoids should be reconsidered in future ERA.…”

“…This contaminated honeydew can be toxic for several beneficial insect species . Compared to nectar, honeydew is the primary carbohydrate source throughout the year for biological control agents (Hogervorst et al, 2007;Lee et al, 2006;Lundgren, 2009;Luquet et al, 2021;Tena et al, 2016Tena et al, , 2013bWäckers et al, 2008), and most pollinators feed on it when nectar is scarce in many agricultural ecosystems (Cameron et al, 2019;Meiners et al, 2017). However, it remains unexplored whether beneficial insects can discriminate between honeydew with or without neonicotinoids.…”