Reproductive biology of Varroa destructor in Africanized honey bees (Apis mellifera)

Abstract

Since its first contact with Apis mellifera, the population dynamics of the parasitic mite Varroa destructor varies from one region to another. In many regions of the world, apiculture has come to depend on the use of acaricides, because of the extensive damage caused by varroa to bee colonies. At present, the mite is considered to contribute to the recent decline of honey bee colonies in North America and Europe. Because in tropical climates worker brood rearing and varroa reproduction occurs all year round, it could be expected that here the impact of the parasite will be even more devastating. Yet, this has not been the case in tropical areas of South America. In Brazil, varroa was introduced more than 30 years ago and got established at low levels of infestation, without causing apparent damage to apiculture with Africanized honey bees (AHB). The tolerance of AHB to varroa is apparently attributable, at least in part, to resistance in the bees. The low fertility of this parasite in Africanized worker brood and the grooming and hygienic behavior of the bees are referred as important factors in keeping mite infestation low in the colonies. It has also been suggested that the type of mite influences the level of tolerance in a honey bee population. The Korea haplotype is predominant in unbalanced host-parasite systems, as exist in Europe, whereas in stable systems, as in Brazil, the Japan haplotype used to predominate. However, the patterns of varroa genetic variation have changed in Brazil. All recently sampled mites were of the Korea haplotype, regardless whether the mites had reproduced or not. The fertile mites on AHB in Brazil significantly increased from 56% in the 1980s to 86% in recent years. Nevertheless, despite the increased fertility, no increase in mite infestation rates in the colonies has been detected so far. A comprehensive literature review of varroa reproduction data, focusing on fertility and production of viable female mites, was conducted to provide insight into the Africanized bee host-parasite relationship.

Impact of Varroa destructor on honeybee (Apis mellifera scutellata) colony development in South Africa

“…Cape honeybees, however, showed no direct aggression towards Varroa mites, nor did they exhibit grooming behaviour (Allsopp 2006). He concluded that the shorter postcapping stage (between 9.6-12 days in Cape honeybees, 10-12 days in A. m. scutellata, 11.5-11.6 in Africanised honeybees compared to 11.6-12 in European honeybees (Moritz and Hänel 1984;Moritz 1985;Vandame et al 1999;Tribe and Allsopp 2001;Martin and Kryger 2002;Allsopp 2006;Calderón et al 2010) and the ability of these honeybees to eliminate reproductive Varroa mites from brood (hygienic behaviour) contributed to tolerance. No studies on the mechanisms of Varroa mite tolerance have been done on A. m. scutellata honeybees in South Africa.…”

“…A significant amount of research has been done on the genetic and behavioural composition of the invasive Africanised honeybee, with most of the research indicating that a high percentage of African characters are conserved within these populations (Schneider et al 2004;Moritz et al 2005;Whitfield et al 2006;Kraus et al 2007). In Brazil, Varroa mite infestation rates of Africanised honeybee colonies have remained very low over the years, from when the mite was first observed in the late seventies up until recent times (Rosenkranz 1999), with no reports of large scale honeybee mortality (De Jong et al 1984;Camazine and Morse 1988;Carneiro et al 2007;Calderón et al 2010). In general, tolerance to Varroa mites in Africanised honeybees has been attributed to the presence of a large number of infertile female mites (Camazine 1986;Rosenkranz and Engels 1994), the uncapping and removal of mite infested brood (Corrêa-Marques and De Jong 1998;Guerra et al 2000;Vandame et al 2002) and the mortality of both male and female mite offspring, which decreases the reproductive output of the mites (Medina and Martin 1999;Mondragón et al 2005;Mondragón et al 2006).…”

Monitoring for Resistance to Organophosphorus and Pyrethroid Insecticides in Varroa Mite Populations

“…More than 130 agricultural plants in the United States are pollinated by honey bees (McGregor 1976). The ectoparasitic mite Varroa destructor Anderson & Trueman (Acari: Mesostigmata: Varroidae) is the most serious threat to beekeeping worldwide (Cox-Foster et al 2007;Calderón et al 2009). This parasitic mite causes weight loss, malformation of wings, and a shortened life span in honey bees; the mite also serves as a vector of disease-causing agents.…”

The chemical ecology of host-parasite interaction as a target of Varroa destructor control agents

“…Africanized honey bees (AHB) are derived from A. mellifera scutellata taken to Brazil, where it has been noted that AHB are also more Varroa resistant than the European races of A. mellifera (EHB) (Calderón et al 2010). As in A. cerana , mite reproduction on AHB is less successful than on EHB.…”