Beekeeping Practices and Genetic Introgression
The extensive trade of queen bees and colony movement, often in response to challenges like colony loss or climate change, has resulted in genetic mixing. Particularly, non-native genetic pools such as A. m. ligustica (native to Italy), A. m. carnica, and hybrid Buckfast lines have been introduced globally. Italy, for instance, sees a rich interaction of these subspecies, with laws aimed at protecting native populations like A. m. ligustica.
Case Study: Emilia-Romagna Region, Italy
In Emilia-Romagna, a regional law was introduced in 2019 to protect A. m. ligustica from genetic pollution. A recent study analyzed honey bee samples from this region between 2020-2022, providing an up-to-date map of A. mellifera mtDNA haplotypes. This study revealed that over 97% of the population belonged to the C lineage, predominantly carrying the C1 haplotype, which is typical of A. m. ligustica. However, it also showed a small percentage of foreign genetic material from Lineages A and M, likely due to the use of hybrid queens.
The study indicates that queen breeding activities and the introduction of foreign subspecies, such as A. m. carnica, have affected local populations. It underscores the importance of monitoring genetic integrity, especially in regions like Emilia-Romagna, which is a hub for breeding native subspecies.
Implications for Conservation
The findings highlight the complexities of conserving native honey bee subspecies amid widespread genetic introgression. Maintaining genetic diversity while protecting native populations requires stricter regulations and more precise monitoring, especially with the increasing trade of hybrid and non-native queens.
The classification of A. mellifera subspecies relies on several factors, including geographic distribution, physical and behavioral traits, and DNA polymorphisms. Four to five evolutionary lineages have been identified:
- Lineage A (African),
- Lineage C (Southeastern European),
- Lineage M (Western and Northern Eurasia),
- Lineage O (Northern Middle-East), and
- Lineage Y (Northeastern Africa).
The mtDNA analysis, particularly of the COI-COII region, has been widely used to understand these phylogenetic relationships. The genetic markers in mtDNA help identify different lineages and subspecies, with the absence of the P unit in Lineage C being a distinguishing feature.
FAQs
1. Why is the conservation of native honey bee subspecies important?
Conserving native honey bee subspecies is vital for maintaining biodiversity and ecosystem services like pollination, which support agriculture and natural ecosystems.
2. What is mtDNA, and why is it used in honey bee studies?
Mitochondrial DNA (mtDNA) is inherited maternally and remains stable over generations, making it a useful tool for tracking genetic lineages and studying population genetics in honey bees.
3. How does the trade of queen bees affect genetic diversity?
The trade of queen bees can lead to genetic introgression, where foreign genetic material is introduced into native populations, potentially diluting the unique traits adapted to local environments.
4. What is hybridization in honey bees?
Hybridization occurs when different subspecies or lineages of honey bees interbreed. While this can increase certain desirable traits, it can also compromise the genetic integrity of native populations.
5. What is the significance of the regional law in Emilia-Romagna?
The law aims to protect the native A. m. ligustica subspecies by prohibiting the introduction of foreign subspecies into the region. This is crucial for maintaining the genetic purity and sustainability of local honey bee populations.
