An Optimized Protocol for Rearing Fopius arisanus, a Parasitoid of Tephritid Fruit Flies

FOIA Aus is a important biological control agent in Hawaii because it attacks to fritted fruit flies, which are serious economic pests throughout the tropics and especially here in Hawaii. The beauty of FOIA Aus is that it attacks the egg stage of the pest insect, thereby controlling the insect at an early stage. In the following clips, you'll be able to see closeups of how we rear FOAs Aus in a laboratory setting.

And at the end of this program, you'll see some discussions of how this particular parasitoid has been used in a successful release program in French Polynesia. We'll begin our protocol with adult parasites that are ready to osis into eggs of a host fruit fly. The first step is to prepare the fruit fly eggs for presentation to the parasite.

Next, fruit fly larvae are allowed to hatch, develop and pupate. Once the fruit flies reach the pupil stage, they're sorted by size to enrich for parasites. Finally, parasites emerge and are maintained until maturation.

They then meet and are again ready to OSI into a new batch of fruit. Fly eggs. This completes the cycle.

Prepare A substrate for the fruit. Fly eggs by making auger blocks approximately 10 centimeters per side. The auger is prepared at a concentration of nine grams of auger powder per liter of water.

Using a level surface, fill the dishes to the rim with liquid auger, allowing it to solidify for at least 45 minutes. Once the auger blocks are solid, apply a single layer of tissue paper covering the top of each auger block. The tissue should stick easily to the auger because of surface moisture.

A second time rolling. Apply the fruit fly eggs to the tissue covered surface of the auger blocks. A 0.5 milliliter volume of the fruit fly eggs in suspension yields approximately 6, 000 eggs per block.

A 2.5 centimeter wide paintbrush dipped in water is used to spread the fruit, fly eggs evenly over the tissue surface. The fruit fly eggs are now placed under the bottom screen of the parasite cages to allow over position by the parasites, tapping the underside of the screen removes dead parasites, which might obstruct the fruit. Fly eggs allow the parasites to over posit overnight.

Approximately 21 hours is sufficient for a high percentage of the fruit fly eggs to be parasitized. Longer exposure risks Super parasitizing. The main Components needed for rearing the eggs after exposure to parasites are fruit fly larval diet, larval diet containers and pupation containers.

Place three to three and a half prepared auger blocks of parasitized eggs on one and a quarter liters of fruit. Fly larval diet. Place the diet container with eggs on a riser and a pupation container over a one and a half centimeter deep layer of fine grade vermiculite or wash sand.

Tape the edges of the pupation container with masking tape. Ensure that there is sufficient space between the top of the diet container and the pupation container lid for larvae to crawl out and pop into the vermiculite below. Move pupation containers to a room at 27 degrees centigrade and 80%relative humidity for one week.

Cover the containers with a heavy cloth for the first four days after one week. Open the pupation containers and remove the larval diet. We use Bre Dorsals as the host fruit fly to rear foia Airis.

Other species in the genera and Asfa and sitis are also potential hosts. If there are unputed larvae in the vermiculite, allow them to pupate overnight sieve. The pupi from the vermiculite start with a coarse sieve and a large container.

Next, use a hand sieve to remove any remaining clumps of vermiculite Eria containing opia. Ais can be partially segregated from un parasitized fruit flies by. So based on previous research, we collect only the aria between 1.65 and 2.26 millimeters in diameter er, which are smaller, contain mostly undersized parasitoids.

Larger aria contain mostly flies. A variety of methods may be employed to size sort the pupi. We will describe a mechanical method using a custom sized sorter for the collected parasitized aria.

The percentage of females increases with size place puy in the funnel at the top of the mechanical size sorter. A vibration feeder moves them to the top of a pair of slightly divergent rolling bars At a 30 degree angle. The aria drop individually into an array of slots that empty through funnels into 10 separate containers.

Put pu pees in the size range from 1.65 millimeters to 2.26 millimeters in an emergence cage for seven more days until most flies have emerged from the parasitized pupi. Next, use a fan to separate empty fly aria from those still containing live parasitoids. Okay, to maintain the colony of Opia Aus use a parasite holding cage with a removable glass front, approximately 25 centimeters and length per side.

The cage has a one square millimeter screening on the top and two of the sides. The back of the cage is covered in a rubber sheet with a nine centimeter hole for access. The bottom of the cage has a cutout covered on the inside with a one to two square millimeter screen.

Large enough to allow placement of two auger blocks with fruit, fly eggs for parasite over position. The holding cages should also have a tinted portion along the bottom quarter of the glass front to minimize parasite crowding along the front of the cage. Place approximately 11 grams of the selected aria into plastic containers, approximately nine centimeters in diameter.

This should produce about 600 to 700 parasites per cage. Size selection should result in about 60%Females attach screen lids to the containers. The lids should be covered with a two square millimeter screening, which will allow foia ais to leave the containers upon emergence, but will contain any remaining fruit flies.

Maintain the parasites at 24 degrees centigrade and about 45%relative humidity with a 1212 photo period and good ventilation streaks spun honey along the top of the cages at least three times per week. Or whenever the available honey is dry, apply the spun honey at narrow streaks using a fingertip Note that if the streaks are too heavy, the honey will drip into the cage. If the streaks are too light, the honey will dry out quickly and require frequent application place auger blocks, which are 10 centimeters square and four centimeters deep on the tops of the cages to provide moisture to the parasites.

These blocks should be changed two times Per week. In 2001, we received a, a, a small seed grant to see if we could introduce biological controls into French Polynesia to help alleviate the situation because Oriental fruit fly at that time was just causing unbelievable infestation of all the tropical fruit. The laboratory up here in Hawaii, we, we made 10 shipments.

So each one of these shipments usually amounted to about a hundred thousand Opia air sayings that actually it was quite a few more, but we would ship the Oriental fruit fly PPE with the parasitoid inside, and then we'd emerge em. So we set up a small laboratory in Tahiti and we would receive these and, and then we would emerge the FOIA Air Sanus. So over a period, maybe of about a year, we released close to a million FOIA Aans.

Overall, this is, is the most successful outside of Hawaii. When FOIA Aus was initially released in Hawaii, it has been the best example of, of biological control of fruit flies throughout the Pacific. Over the last 10 years, there's been a tremendous spread of the Bactrocera Dorsals complex around the world.

So Bactrocera Carbo has spread to South America, Suriname, and it's in Northern Brazil now. Then there's been another species called Bacter Inance, which is spread throughout Africa and is causing all sorts of havoc. And then there has also been the spread of bacter papaya.

So this success now opens up opportunities to release these FOIA Aus in South America, Africa, and in in other parts of Asia.