Effects of stingless bee propolis on Nosema ceranae infected Asian honey bees, Apis cerana

Abstract

Since Nosema ceranae causes mortality in honey bee populations in both managed apiaries and in the wild, many chemical compounds have been screened and tested for their abilities to suppress populations of N. ceranae. However, the use of synthetic substances has resulted in residues in colonies and honey bee products. The development of new methods for the control of nosema disease is therefore much needed by beekeepers and bee scientists. We evaluated the effects of propolis from the stingless bee Trigona apicalis on N. ceranae-infected Asian honey bees, Apis cerana. One-day-old N. ceranae free worker bees were individually inoculated with 2 μl of 50% sucrose solution containing 80,000 N. ceranae spores per bee and then fed with 50 and 70% (v/v) propolis extract in water. All propolis-treated bees had significantly higher survival rates than untreated bees (F 5 = 92.6, p < 0.0001). Bees treated with the highest propolis concentration (70%) had the lowest infection ratio of cells, while the significantly highest spore count in a single bee was found in control bees (F 5 = 390.3, p < 0001, F 5 = 309.0, p < 0.001). These results suggest that the propolis may have toxic effects on N. ceranae spores, and could have potential use in disease management. Efectos de propó leos de abejas sin aguijó n en abejas asiáticas Apis cerana infectadas com Nosema ceranaeDebido a que Nosema ceranae causa mortalidad en las poblaciones de abejas de la miel tanto en colmenas manejadas como en el medio silvestre, muchos compuestos químicos han sido seleccionados y probados por su capacidad para suprimir las poblaciones de N. ceranae. Sin embargo, el uso de sustancias sintéticas ha dado lugar a residuos en las colonias y los productos de las abejas de la miel. El desarrollo de nuevos métodos para el control de la enfermedad de Nosema, es por tanto, muy necesario para los apicultores y científicos apidó logos. Se evaluaron los efectos de los propó leos de la abeja sin aguijó n Trigona apicalis, en abejas melíferas asiáticas Apis cerana infectadas por N. ceranae. Se inocularon individualmente abejas obreras de un día de edad libres de N. ceranae con 2 μl de solució n de sacarosa al 50% con 80.000 esporas de N. ceranae por abeja y luego se alimentaron con extracto de propó leo en agua al 50% y 70% (v / v). Todas las abejas tratadas con propó leos tuvieron tasas de supervivencia significativamente más altas que las abejas no tratadas (F 5 = 92,6, P <0,0001). Las abejas tratadas con la mayor concentració n de propó leos (70%) tuvieron la tasa de infecció n de célu-las más baja, mientras que el recuento de esporas en una sola abeja significativamente más alto se encontró en las abejas control (F 5 = 390,3, p <0,001, F 5 = 309,0, p <0,001). Estos resultados sugieren que el propó leos puede tener efectos tó xicos sobre las esporas de N. ceranae, y podrían tener un uso potencial en el manejo de enfermedades.

Propolis Counteracts Some Threats to Honey Bee Health

“…After inoculation, bees were fed propolis extract in water. Similar results were found in both experiments: all challenged bees treated with propolis lived longer than untreated challenged bees (but not longer than unchallenged bees), and those fed with a high concentration of propolis (a 50% solution of propolis extract—60 g propolis/100 mL ethanol—in sugar syrup) had lower infection rate [100]. These studies provide a starting point to investigate the biological relevance of these findings within an A. mellifera colony and how propolis in the nest environment may also be impacting gut parasites.…”

Pathogen spillover from Apis mellifera to a stingless bee

“…[32,[51][52][53]. It may be that in the wild T. hockingsi can harbour N. ceranae but not suffer adverse effects because of their access to propolis or other high-quality food, as has been observed for N. ceranae-infected A. cerana and A. mellifera [38,54]. The lack of mortality for up to 8 days following infection in our floral transmission experiment further suggests that there may be environmental factors that temper N. ceranae virulence.…”

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

“…Then, the propolis extract was filtered by suction to clean it from wax and other impurities [64]. Based on previous studies [54,56], a concentration of 50% of this extract in distilled water (v/v) was prepared for the experiments.…”

“…Recently, the therapeutic properties of propolis extracts against N. ceranae were assayed in the Asiatic honey bee species Apis florea [54,55], Apis cerana [56] and the Western Apis mellifera [57]. In the Asiatic Apis species, propolis used in the bioassays was obtained from the stingless bee Trigona apicalis, whereas in A. mellifera the propolis tested was produced by honey bees themselves.…”

“…In the Asiatic Apis species, propolis used in the bioassays was obtained from the stingless bee Trigona apicalis, whereas in A. mellifera the propolis tested was produced by honey bees themselves. In all these studies, an improvement in bee survival and a decrease in the N. ceranae spore load were observed in experimentally infected bees [54][55][56][57]. For the Asiatic Apis species, these results leave open the question of whether the honey bee's own propolis has a similar beneficial effect in reducing Nosema pathogenesis.…”