Bee sesame fly

The bee sesame fly is also known as Drosophila melanogaster and Musca domestica. It is an internal parasitic fly that parasites larvae in the body and feeds on its hemolymph and muscles. In addition to parasitic on bees, there are pill wasps and other wild bees. Found in some areas of Inner Mongolia, Hubei and Heilongjiang in China.

1. Morphological characteristics

The adult is silvery gray and 6-9 mm in length. There are white stripes between the head compound eyes, the forehead and face are covered with yellow hair, the chin is slender, yellow, the antennae are also yellow, the forehead is very wide, the male accounts for about 1 inch of the head width. The back of the chest is dark gray, the male longitudinal strip is slightly obvious, and there is almost no longitudinal strip in the female. The wing is transparent, the axillary flap is almost pure white, the edge is yellowish, the balance rod is white, in the shape of a flask. The abdomen of the male bee fly has large black spots and powder indumentum, and the second dorsal plate has three often fused black spots. The abdomen of the female is completely covered with yellow-gray powder. The newly hatched larvae are 0.7-0.8 mm long and 0.17 mm wide. The larvae develop into mature larvae in honeybees, 11-15 mm long and 3 mm wide. The insect body is stout in the middle, pointed at both ends and milky white. The pupa is peri-pupa, 0.4-0.7 mm long.

2. Biological characteristics

Female and male bee flies usually move outside the hive, while pregnant females hover over the hive and like to perch on hives painted blue, white, gray and glossy. In bee flight, when the female flies quickly catch up with the bees, they give birth to larvae on the bees. The larvae pierce the intersegmental membrane of the bee's abdomen with its sharp upper jaw, drill into the bee's body and feed on its hemolymph and muscles. The affected bees died in 2-9 days, and most of them died in 4-5 days. The larva eats all the chest muscles and abdominal organs in the bee, leaving only a chitin shell. The larvae are drilled out of the chest junction of the host head or other parts and pupate in the soil. It takes 15 to 30 days to complete a life cycle and overwinters as a pupa.

Sesame flies mostly occur in summer, attacking young and adult bees. At first, the affected bees were tired and weak, and their flight speed was slow, but at last they lost their ability to fly completely, crawled feebly on the ground in front of the beehive, crawled and trembled, and died lying on their back. The damage rate of seriously damaged bees can be as high as 280.44%, and hundreds to thousands of bees die every day, seriously affecting the development and gathering power of bees. It is particularly serious in swampy areas, lakeside coastal areas, and low-lying areas overgrown with weeds.

3. Diagnostic method

Take 30 diseased bees or dead bees, remove the head and the first pair of feet, then open the chest and observe with a magnifying glass. If there is parasitism of sesame fly larvae, it can be seen in the chest muscles of bees.

4. Prevention and control methods

① kills adults and larvae

Taking advantage of the habit that the bee and sesame fly likes to inhabit the hive lid but can not distinguish the surface of the water or other objects, a white porcelain plate can be placed on the beehive, which is filled with water and makes it fall into the water and drown.

② removes diseased and dead bees

The bees in the colony are shaken out of the hive, and the healthy bees return to the nest quickly, while the diseased bees parasitized by the bee and sesame fly stay outside the hive because of slow action, and then gather the diseased bees and dead bees to burn and destroy their larvae.