Diversity of honeybee Apis melifera (Hymenoptera: Apidae) Sub-species and their Assocaiated Arthropod pests in Cameroon

Abstract

Conservation of Apis mellifera requires detailed knowledge of the subspecies identity, diversity and factors threatening their survival. Despite the increasing reports on the spread and damage caused by both exotic and indigenous honey bee pests to bee populations in many parts of Africa, there is dearth of knowledge on the ecology of honey bees and their pests in Central Africa and Cameroon in particular. Furthermore, management practices such as use of different beehive types across Africa may affect bee health. This study was undertaken to fill these knowledge gaps and provide information to aid the conservation of African honey bees. Field surveys for honey bees and their pests were conducted in apiaries located in four major ecological zones in Cameroon in 2014 using standard sampling protocols. Morphometric analysis revealed the presence of three morphotypes of A. mellifera in Cameroon, namely, two savannah highland and one forest lowland populations. Genetic diversity and phylogenetic studies revealed that these morphotypes constituted five A. mellifera subspecies haplotypes that were adapted to different geographic locations. Three of these haplotypes represent new A. mellifera mtDNA haplotypes, one of which occurred in the range of the previously reported Apis mellifera jemenitica. The new subspecies haplotypes were restricted to the highland savannah and were genetically closely related to the lowland Apis mellifera adansonii, the dominant haplotype in Cameroon. This suggests that honey bee populations of Cameroon are made of distinct subspecies haplotypes with the same common ancestral origin that are adapted to distinct geographic locations. The conservation of these bee populations within their local environment is therefore recommended to maintain their genetic identities. Pest assessments of honey bee colonies revealed that these A. mellifera populations were associated with diverse arthropod pests such as Varroa destructor, Aethina tumida, dynastid beetles, Galleria mellonella, Achroia grisella, Acherontia sp, Braula sp, and Megaselia scalaris. Through molecular phylogenetic analysis this study revealed for the first time the occurrence of the Korean haplotype of V. destructor and M. scalaris in Cameroon and a unique haplotype of A. tumida in honey bee colonies. These pests represent a threat to bee health in Cameroon and other parts of Africa. Pest infestation levels were found to vary across ecological zones and between seasons, suggesting that environmental factors may influence their distribution and abundance. The synergistic effect of the major pests, V. destructor and A. tumida with other less frequent pests such as wax moths, were identified as contributing factors to colony losses. Beehive type was found to have an influence on colonization and infestation of pests such as G. mellonella. Using the right beehive type may therefore ease colonization and reduce infestation by some pest species. This study therefore revealed that honey bees of Cameroon are made of diverse populations adapted to different geographic locations and associated with diverse arthropod pests. The impact of these pests to bee health is discussed in details and available management options provided. This study therefore contributes to the existing knowledge on the ecology of honey bees and their pests in Cameroon.