Introduction
Flightless fruit flies (Drosophila hydei) are a popular feeder insect for small insectivorous pets, such as amphibians, reptiles, fish, and invertebrates. They are valued for their small size, ease of culture, and inability to fly, which makes them easy for pets to catch. This guide outlines the requirements and timeline for culturing Drosophila hydei.
Materials Needed
Culture Containers: Plastic or glass containers with ventilated lids (16-ounce deli cups are commonly used). Foam plugs or breathable fabric for ventilation.
Culture Medium: Premixed commercial fruit fly media or homemade medium.
Common homemade recipes include a mix of instant mashed potatoes, sugar, brewer’s yeast, and water.
Optional additives: propionic acid or vinegar to inhibit mold growth, and methylparaben as a preservative.
Fly Starter Culture: A small number of adult Drosophila hydei flies to start the culture.
Excelsior or Coffee Filters: Excelsior (wood wool) or crumpled coffee filters to provide surface area for flies to climb and lay eggs.
Water Spray Bottle: For maintaining moisture in the culture.
Additional Tools: A fine mesh strainer to separate flies from the medium if needed. Tweezers or small brushes for handling flies.
Preparation and Setup
Prepare the Culture Medium: Follow the instructions for commercial media or mix the ingredients for homemade media. Ensure the medium has a consistency similar to thick oatmeal. Place approximately 1-2 inches of medium in the bottom of each culture container.
Add Climbing Material: Place excelsior or crumpled coffee filters on top of the medium to provide surface area for the flies.
Introduce Flies: Transfer a small number of adult flies (around 20-30) from the starter culture into the new culture container.
Cover and Ventilate: Secure the lid with ventilation material to prevent flies from escaping while allowing airflow.
Maintenance and Timeline
Initial Setup:
Day 1: Prepare the culture medium and introduce adult flies.
Egg Laying:
Days 1-7: Adult flies will lay eggs in the culture medium. Ensure the medium remains moist but not soggy. If it dries out, lightly mist with water.
Larval Stage:
Days 4-14: Eggs hatch into larvae (maggots) that feed on the culture medium. They will grow rapidly during this period.
Pupal Stage:
Days 10-20: Larvae pupate on the surface of the medium or climbing material. Pupae appear as small, dark, cylindrical shapes.
Emergence of Adult Flies:
Days 16-25: Adult flies begin to emerge from pupae. The exact timing can vary based on temperature and humidity.
Maintain a stable temperature of 70-75°F (21-24°C) for optimal growth and reproduction.
Harvesting Flies:
Days 25 and beyond: Cultures can be used to harvest flies to feed to pets. Gently tap the container to collect flies without disturbing the medium excessively.
Cultures can produce flies for several weeks, but it is best to start new cultures regularly (every 2-3 weeks) to ensure a continuous supply.
Creating New Cultures:
Transfer some adult flies from an established culture to a new container with fresh medium to continue the culturing process.
Tips for Successful Culturing
Temperature and Humidity: Maintain stable conditions to ensure healthy fly development. Avoid placing cultures in direct sunlight or drafty areas.
Mold and Contaminants: Prevent mold growth by using additives like propionic acid and ensuring proper ventilation. Remove any contaminated cultures promptly to prevent spreading.
Regular Maintenance: Check cultures regularly to maintain proper moisture levels and transfer flies to new cultures as needed.
Conclusion
Culturing Drosophila hydei is a straightforward process that requires minimal equipment and maintenance. By following these guidelines, pet owners can ensure a reliable and nutritious source of live food for their insectivorous pets. Regular monitoring and timely creation of new cultures will help maintain a steady supply of flightless fruit flies.