Effects of selection and local adaptation on resilience and economic suitability in Apis mellifera carnica

Marin Kovačić,Marica Maja Dražić,Aleksandar Uzunov,Zlatko Puškadija,Ralph Büchler,Marina D Meixner

doi:10.1007/s13592-020-00783-0

Abstract

Modern techniques of selective breeding show high potential to improve economically important traits of honey bees. However, breeding may neglect fundamental rules of natural selection. The objective of this study was to analyze the effects of selection and local adaptation on some relevant breeding traits of Apis mellifera carnica. We compared open mated queens from three different origins: local Croatian genotypes that are under controlled selection since five generations (MS), a local genotype that was never under selective breeding (NS) and, finally, a non-local genotype from a long-lasting German breeding program (HS). Generally, colonies with queens from breeding programs had better scores for defensive behavior, calmness, and swarming. In contrast, colonies from the NS group showed higher expression of Varroa destructor resistance traits. Although the HS group showed the highest score in most of the behavioral traits, the low overwintering index of colonies from this group after both wintering periods indicated a lack of local adaptation. This research underlines the relevance of breeding activities for the resilience of honey bee populations and the achievement of local adaptation.

Highlights

Selective breeding of honey bees (Apis mellifera ) has a long tradition in many European countries, where it has been practiced in various ways and to differing extents (Lodesani and Costa 2003; Hatjina et al 2014a)
The analysis showed a significant effect of Month (p < 0.01) and Genotype (p < 0.05) on the number of brood cells (Supplement Table I)
The results of our experiment clearly show the benefits of long-term selection and breeding on the behavior of bees, especially for the traits defensive behavior, calmness on the comb, and swarming tendency

Summary

Introduction

Selective breeding of honey bees (Apis mellifera ) has a long tradition in many European countries, where it has been practiced in various ways and to differing extents (Lodesani and Costa 2003; Hatjina et al 2014a). Bee breeding predominantly aims at improving traits of apicultural interest that have an important impact on the beekeeping. Current efforts in selective breeding of honey bees are questioned, as they sometimes may neglect important life history traits (such as reproduction or survival) and may counteract natural selection mechanisms that could contribute to improved resilience (Neumann and Blacquière 2017; Blacquière and Panziera 2018). Honey bees inhabit comparatively small nest cavities, which leads to frequent and early swarming and smaller colonies. As a consequence, such colonies have fewer problems with the ectoparasitic mite Varroa destructor (Fries and Bommarco 2007; Loftus et al 2016). Modern beekeeping with effective control of V. destructor minimizes the natural selection pressure on bees to develop resistance mechanisms (Fries et al 2006) and to establish a balanced host–parasite relationship

Objectives

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Results

Conclusion