An appraisal of subspecific classification of Apis mellifera L. in parts of West and Central Africa through landmark-based geometric morphometric analysis of forewings

To appraise the subspecific classification of Apis mellifera L. in West and Central Africa, 1663 workers from 175 colonies from 44 localities, were sampled throughout Nigeria and parts of Niger, Cameroon and Chad. The samples were analysed with reference subspecies (A. m. adansonii (N = 12), A. m. jemenitica (N = 14) and A. m. scutellata (N = 12)), using geometric morphometric analysis, based on 19 landmarks on the left forewings of workers. The analysis allowed separating size and shape of the wing. Hierarchical cluster analysis followed by stepwise discriminant analysis (DA) grouped the colonies into two morphoclusters with a cross-validation classification rate of 96.6%. ANOVA revealed a significant difference (p A. m. jemenitica and A. m. scutellata but an insignificant difference (p > 0.05) between them and A. m. adansonii in respect of size. MANOVA revealed a significant difference (p A. m. scutellata and A. m. adansonii, respectively, with a posterior probability of ≥95%. However, when shape and size were combined, DA assigned 28.40%, 21.02% and 10.23% of the unknown colonies to A. m. adansonii, A. m. scutellata and A. m. jemenitica, respectively, with a posterior probability of ≥95%. Thus, though this classification is not definitive, it suggests that the unknown colonies are morphologically closer to adansonii and scutellata than jemenitica. However, in order to avoid further confusion in the nomenclature of the honey bees of this region, it is recommended that A. m. adansonii could be retained as their sole subspecific name, pending further studies.