Factors influencing the prevalence and infestation levels of Varroa destructor in honeybee colonies in two highland agro-ecological zones of Uganda

Abstract

Varroa mites are ecto-parasites of honeybees and are a threat to the beekeeping industry. We identified the haplotype of Varroa mites and evaluated potential factors that influence their prevalence and infestation levels in the eastern and western highland agro-ecological zones of Uganda. This was done by collecting samples of adult worker bees between December 2014 and September 2015 in two sampling moments. Samples of bees were screened for Varroa using the ethanol wash method and the mites were identified by molecular techniques. All DNA sequences obtained from sampled mite populations in the two zones were 100 % identical to the Korean Haplotype (AF106899). Mean mite prevalence in the apiaries was 40 and 53 % for the western and eastern zones, respectively, during the first sampling. Over the second sampling, mean mite prevalence increased considerably in the western (59 %) but not in the eastern (51 %) zone. Factors that were associated with Varroa mite infestation levels include altitude, nature of apiary slope and apiary management practices during the first sampling. Our results further showed that Varroa mites were spreading from lower to higher elevations. Feral colonies were also infested with Varroa mites at infestation levels not significantly different from those in managed colonies. Colony productivity and strength were not correlated to mite infestation levels. We recommend a long-term Varroa mite monitoring strategy in areas of varying landscape and land use factors for a clear understanding of possible changes in mite infestation levels among African honeybees for informed decision making.

Honey bee pathogens in Ghana and the presence of contaminated beeswax

“…Thus, a correlation with latitude might be due to some specific coincidences. In this study, no correlation was found between the Varroa levels in hives and the altitude of the sampling site, in accordance with other data from tropical climates (Chemurot et al 2016;Mortensen et al 2016).…”

“…These observations might also reflect the lower preference of the mites for worker cells in this honey bee species, explaining the fewer double or triple infestations found. This would also explain the low numbers of mites found on adult bees, and the relatively low levels observed in their brood in terms of prevalence and infection rates, similar to those reported in other east African countries (Muli et al 2014;Chemurot et al 2016;Mortensen et al 2016).…”

“…The presence of V. destructor was first described in one region in Ghana (Fazier et al 2010), while the present data shows it to be widely distributed in all the regions sampled, although the Korean haplotype was the only one found. This haplotype is considered to be more virulent than the Japanese haplotype (Anderson and Trueman 2000), and it has also been reported in other African countries (Allsopp et al 1997;Dietemann et al 2009;Fazier et al 2010;Muli et al 2014;Mumoki et al 2014;Chemurot et al 2016), supporting the hypothesis that this mite is spreading throughout the continent.…”

“…de M. 2001). Studies into the spread and distribution of Varroa destructor (Anderson and Trueman 2000) and other pathogens in South Africa (Strauss et al 2013(Strauss et al , 2014a(Strauss et al , b, 2016Mortensen et al 2016), Kenya (Fazieret al2010),Uganda (Chemurot et al 2016)or Benin (Paraiso et al 2011) support this hypothesis. However, very few surveys have been undertaken in West African countries representing a significant gap in our understanding of the incidence, prevalence, diversity and geographic distribution of honey bee diseases on that continent (Muli et al 2014;Mumoki et al 2014).…”

Can the Environment Influence Varroosis Infestation in Africanized Honey Bees in a Neotropical Region?

“…The Varroa mite is considered to be cosmopolitan (Wilfert et al 2016), and infestation level on honey bees around the world varies from 2.0 to 31.4% (Akyol et al 2006;Akyol & Yeninar 2009;Mumbi et al 2014;Muli et al 2014;Chemurot et al 2016;Giaco-bino et al 2016;Gracia et al 2017). The infestation levels of this mite are higher in A. mellifera colonies from temperate climates than colonies from subtropical climates (Giacobino et al 2016), suggesting that climate can have an important role in the host-parasite interaction (Muli et al 2014) and may influence the mite infestation rates, but the influence of climate parameters on this mite are unclear (Rosenkranz et al 2010).…”