Comparing classical and geometric morphometric methods to discriminate between the South African honey bee subspecies Apis mellifera scutellata and Apis mellifera capensis (Hymenoptera: Apidae)

Abstract

There are two endemic subspecies of western honey bees (Apis mellifera L.) in the Republic of South Africa (RSA), A.m. capensis and A.m. scutellata . They have traditionally been identified using morphometric characteristics, but geometric morphometric data from honey bee wings are easier to collect, possibly making them a useful alternative for identifying these subspecies. We compared the accuracy of both morphometric and geometric morphometric methods using linear discriminant and classification and regression tree analyses. We found that using geometric wing shape data from both forewings and hindwings resulted in a lower classification accuracy (73.7%) than did using models derived from the full set of standard morphometric data (97% accurate) in cross-validation. Tergite color and average ovariole number were the most important features for discriminating between the two subspecies. Finally, we used Kreiger interpolation to construct maps illustrating probable distributions of A.m. capensis and A.m. scutellata in the RSA.

Mitochondrial genomes illuminate the evolutionary history of the Western honey bee (Apis mellifera)

“…To date, over 30 separate subspecies (or ‘geographical races’) have been described 3 – 7 . The distinctiveness of subspecies is in many cases not readily apparent by examining live or pinned individuals and identification has to be carried out based on quantitative morphometric 6 , 8 , 9 or molecular analyses 5 , 10 , 11 . The classification of honey bee subspecies has important practical implications for apiculture.…”

Monthly Changes in Honey Bee Forewings Estimated Using Geometric Morphometrics

“…It had been based on the cubital index (Alpatov, 1948;Goetze, 1959), which is a proportion of two vein lengths, but later the angles between wing vein intersections were included in the measurements (DuPraw, 1965). Recently, the wings have been described according to the coordinates of landmarks located in forewing vein intersections (Francoy et al, 2008;Tofilski, 2008;Barour & Baylac, 2016;Ángel-Beamonte et al, 2018;Bustamante et al, 2020;Dukku & Danailu, 2020;). This method, called geometric morphometrics, has proven to be effective in the discrimination of honey bee subspecies (Gerula et al, 2009) and lineages (Nawrocka et al, 2017).…”

Diversification of Morphological Features of the Dark European Honey Bee of the ‘Augustow M’ Line

“…However, comparisons of the two methods have revealed that the geometric morphometry is just slightly more effective than the standard one in the discrimination between bee subspecies [ 40 ]. Then, Bustamante et al [ 42 ] found that the application of the geometric morphometry for the comparison of two bee subspecies was less accurate (73.7%), even taking into account data after studying all wings in comparison to the analysis of data obtained using the standard morphometry (97%). DNA tests are often used to eliminate hybridized specimens from protected populations [ 40 , 43 , 44 ] but a selection based on DNA markers as the single criterion can lead to a loss of genes making the phenotype.…”

“…Even though we have a number of methods, the conventional morphological evaluation has not become any less important. Researchers still value the method and use it willingly [ 40 , 42 , 45 ]. Note that the standard morphological method makes it possible not only to reliably measure such features as the body size or proboscis length but also to track the diversification of such features.…”