Propolis Consumption Reduces Nosema ceranae Infection of European Honey Bees (Apis mellifera)

Abstract

Nosema ceranae is a widespread obligate intracellular parasite of the ventriculus of many species of honey bee (Apis), including the Western honey bee Apis mellifera, in which it may lead to colony death. It can be controlled in A. mellifera by feeding the antibiotic fumagillin to a colony, though this product is toxic to humans and its use has now been banned in many countries, so in beekeeping, there exists a need for alternative and safe products effective against N. ceranae. Honeybees produce propolis from resinous substances collected from plants and use it to protect their nest from parasites and pathogens; propolis is thought to decrease the microbial load of the hive. We hypothesized that propolis might also reduce N. ceranae infection of individual bees and that they might consume propolis as a form of self-medication. To test these hypotheses, we evaluated the effects of an ethanolic extract of propolis administered orally on the longevity and spore load of experimentally N. ceranae-infected worker bees and also tested whether infected bees were more attracted to, and consumed a greater proportion of, a diet containing propolis in comparison to uninfected bees. Propolis extracts and ethanol (solvent control) increased the lifespan of N. ceranae-infected bees, but only propolis extract significantly reduced spore load. Our propolis extract primarily contained derivatives of caffeic acid, ferulic acid, ellagic acid and quercetin. Choice, scan sampling and food consumption tests did not reveal any preference of N. ceranae-infected bees for commercial candy containing propolis. Our research supports the hypothesis that propolis represents an effective and safe product to control N. ceranae but worker bees seem not to use it to self-medicate when infected with this pathogen.

Extracts from Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. Roots: A New Hope Against Honeybee Death Caused by Nosemosis

“…In several studies, essential oils such as mint ( Mentha pepper L.), melissa ( Melissa officinalis L.), coriandrum ( Coriander sativum L.), thyme ( Satureja hortensis L.) oils, other phytochemicals such as caffeine, clove oil, gallic acid, kaempferol and p-coumaric acid, and even propolis expanded honeybee longevity and to some extent, reduced nosemosis levels [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Such phytochemicals as clove oil, laurel extract and sulforaphane, moderately decreased Nosema -infection, but at the same time, strongly reduced honeybee lifespan [ 33 , 36 , 37 ]. Other tested phytochemicals, such as amygdalin, anabasine, aucubin, catalpol, nicotine and thymol, had no effect against Nosema infection [ 33 , 36 , 37 ].…”

“…Such phytochemicals as clove oil, laurel extract and sulforaphane, moderately decreased Nosema -infection, but at the same time, strongly reduced honeybee lifespan [ 33 , 36 , 37 ]. Other tested phytochemicals, such as amygdalin, anabasine, aucubin, catalpol, nicotine and thymol, had no effect against Nosema infection [ 33 , 36 , 37 ].…”

Impact of Protoporphyrin Lysine Derivatives on the Ability of Nosema ceranae Spores to Infect Honeybees

“…Due to the lack of an effective nosemosis suppressant, various compounds, e.g., essential oils and plant extracts, have been subjected to intensive research [40]. Additionally, propolis, produced from resinous substances collected from plants and used by bees to protect their nests from parasites and pathogens, is studied as an alternative to fumagillin [41,42]. Promising compounds for the treatment of nosemosis are porphyrins [43].…”

North American Propolis Extracts From Upstate New York Decrease Nosema ceranae (Microsporidia) Spore Levels in Honey Bees (Apis mellifera)

“…In addition to self-medication effects, propolis components (e.g., ethanolic extracts) harvested from bees in Asia and Europe have been shown to lower mortality and Nosema infections in Asian honey bees (Apis cerana), dwarf honey bees, (Apis florea) and European honey bees (Yemor et al, 2015;Suwannapong et al, 2018;Mura et al, 2020). Recently, Arismendi et al (2018) reported that methanolic Chilean propolis extracts reduce N. ceranae loads and increase survival of European honey bees (A. mellifera).…”

“…Recently, Arismendi et al (2018) reported that methanolic Chilean propolis extracts reduce N. ceranae loads and increase survival of European honey bees (A. mellifera). Mura et al (2020) reported that ethanolic Spanish propolis extracts reduce N. ceranae loads in European honey bees and identified high concentrations of caffeic acid, ferulic acid, ellagic acid, and quercetin derivatives in their extracts. Bee species, extraction methods, and especially geographical origin of propolis all have an effect on its bioactivity, most likely on account of variations in chemical composition (Huang et al, 2014).…”