Free access
Volume 29, Number 6, 1998
Page(s) 491 - 501
Apidologie 29 (1998) 491-501
DOI: 10.1051/apido:19980602

The matter of sampling distance and confidence levels in the subspecific classification of honeybees, Apis mellifera L.

Sarah E. Radloffa and Howard Randall Hepburnb

a  Department of Statistics, Rhodes University, Grahamstown, South Africa
b  Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa

Abstract - The effects of variations in sampling distance and confidence levels on the subspecific classification of honeybees were analysed by subjecting colony means of morphometric characters to factor analysis and stepwise discriminant analysis procedures. Analyses of honeybees from a transect from Morocco through Spain and another from Tanzania through Sudan show that the greater the distance between samples, the more distinct the morphoclusters. The length of the transect may obscure small biometric groups if the between-group variation is considerably larger than the within-group variation. Varying the levels of confidence applied to the ellipses and the discriminant a posteriori probabilities from low to high decreased the number of colonies correctly assignable to morphoclusters. Thus, sampling distance, transect length, confidence levels and their a posteriori probabilities are all just as crucial to the structure and resolution of honeybees morphoclusters as are sample size and character suites. © Inra/DIB/AGIB/Elsevier, Paris

Key words: honeybee classification / sampling / confidence levels