Stingless bees (Meliponini tribe) are vital pollinators in tropical and subtropical ecosystems and have growing importance in sustainable agriculture and honey production. Like honey bees (Apis mellifera), stingless bees are vulnerable to various pests, including mites, particularly from the genera Proctolaelaps, Tropilaelaps, and Melittiphis. While the Varroa mite is a primary concern for honey bees, certain mites can also parasitize stingless bees—though the biology and impact are less studied.
As meliponiculture expands, there’s increasing interest in developing mite-resistant stingless bee strains through selective breeding. This method offers a sustainable, chemical-free approach to colony health management and conservation.
1. Background: Mite Infestations in Stingless Bees
While stingless bees are generally less susceptible to mites than Apis mellifera, infestations can occur, especially in managed colonies or under stressful conditions.
Common Mite Threats:
- Proctolaelaps spp.: Found in brood cells and on adult bees.
- Tropilaelaps spp.: Occasionally observed in tropical stingless bees, though more commonly a threat to honey bees.
- Predatory mites or opportunists in weak or unmanaged hives.
Effects of Mites on Stingless Bees:
- Reduced brood viability.
- Deformed adult bees.
- Colony stress or collapse in severe infestations.
- Secondary fungal or bacterial infections.
Because chemical treatment options for stingless bees are limited and often unsafe, breeding for natural resistance is an ideal long-term strategy.
2. Why Selective Breeding Is Important for Stingless Bees
- Chemical-free solution: Stingless bees are highly sensitive to synthetic treatments.
- Adapted resilience: Local populations may possess natural resistance traits.
- Long-term sustainability: Reduced need for intervention and maintenance.
- Improved productivity: Healthier colonies produce more honey, pollen, and propolis.
3. Key Traits for Mite Resistance in Stingless Bees
Research into specific mite-resistance traits in stingless bees is still emerging, but lessons from honey bee breeding and preliminary studies suggest several potential targets:
A. Hygienic Behavior
- Bees detect and remove infested or dead brood from cells.
- Reduces mite reproduction and pathogen spread.
B. Grooming Behavior
- Adult bees clean themselves and others to remove mites.
- Observed in some stingless bee species like Tetragonula and Melipona.
C. Brood Cell Sealing and Structure
- Some species may seal brood cells more effectively, reducing mite entry.
- Denser cerumen barriers could limit mite spread.
D. Microbial and Symbiotic Defenses
- Beneficial microbes may inhibit mite survival.
- Selection for colonies with healthy microbiota can indirectly support resistance.
E. Tolerance Traits
- Colonies that maintain productivity despite low to moderate infestations.
- May involve stronger immune response or virus resistance.
4. Steps in Selective Breeding for Resistance
Step 1: Baseline Assessment
- Identify colonies with no or low mite infestation under similar environmental conditions.
- Regularly monitor for mites using:
- Visual inspection of brood and adult bees.
- Sticky traps or bottom board analysis.
- Microscopic examination of cerumen, pupae, and debris.
Step 2: Trait Identification
- Record colonies showing:
- Active hygienic or grooming behavior.
- Strong brood patterns and low deformities.
- Resistance over multiple seasons or during stress periods.
Step 3: Colony Evaluation and Ranking
- Use a scoring system to rate colonies by:
- Mite load.
- Honey/pollen production.
- Brood viability.
- Behavioral resistance (e.g., cleaning, aggression toward mites).
Step 4: Controlled Propagation
- Use divisions or grafting to propagate top-performing colonies.
- Maintain genetic records where possible.
- Minimize breeding from heavily infested or collapsing colonies.
Step 5: Re-evaluation and Continuous Selection
- Continue evaluating each generation.
- Avoid inbreeding by introducing unrelated but high-performing genetics.
- Collaborate with other meliponiculturists to expand the gene pool.
5. Breeding Techniques in Meliponiculture
Colony Splitting (Division)
- The primary propagation method in stingless beekeeping.
- Select only healthy, resistant colonies for division.
Queen Selection
- In species where queens can be reared manually (e.g., Melipona), select larvae from resistant colonies.
- Favor strong, productive queens with long lifespans and healthy brood.
Drone Control
- Difficult in open systems, but placing colonies in semi-isolated areas can improve mating control.
Monitoring Tools
- Periodic mite sampling.
- Environmental logs to link outbreaks with climate or nutrition.
- Genetic barcoding (emerging) for advanced selection.
6. Challenges in Breeding Stingless Bees for Resistance
- Limited research: Fewer studies compared to honey bees.
- Species variability: Different stingless bee species have different biology and mating systems.
- Slow propagation: Colony development and queen production are slower than in Apis mellifera.
- Lack of standardized testing methods: Need for protocols tailored to each stingless species.
7. Integrating Breeding with Management
Selective breeding should be part of a holistic health strategy that includes:
- Proper colony nutrition (pollen and nectar sources).
- Controlled humidity and temperature in hive boxes.
- Sanitation of hive tools and equipment.
- Avoiding colony stress (transfers, exposure, competition).
- Regular monitoring and removal of weak or infested colonies.
8. Case Studies and Global Initiatives
Brazil & Latin America
- Studies on Melipona scutellaris, Scaptotrigona postica, and Tetragonisca angustula show potential for resistance traits.
- Local breeding projects and meliponiculturist networks share best practices.
Southeast Asia
- Interest in breeding Tetragonula species with higher grooming activity and better brood survival.
Africa and Australia
- Growing awareness of native stingless bee conservation and breeding for environmental resilience.
9. Conclusion
Selective breeding for mite-resistant stingless bees offers a promising, environmentally responsible path for improving colony health and productivity. While still in early development compared to honey bee programs, regional research and beekeeper collaboration can lead to strong, locally adapted lines of resilient stingless bees.
As meliponiculture grows globally, integrating selective breeding with good hive management and ecological conservation will be key to the sustainable future of these essential pollinators.