Biological characteristics of the one-character bamboo elephant (Characteristics of the Hangzhou Bam

One-character Bamboo Elephant is also known as Hangzhou Bamboo Elephant. Domestically distributed in Shaanxi, Jiangsu, Anhui, Zhejiang, Jiangxi, Fujian, Hunan and other provinces, and abroad in Vietnam. Damage moso bamboo, osmanthus bamboo, light bamboo, rigid bamboo, red shell bamboo, bamboo and golden bamboo. The adults feed on the flesh of the bamboo shoots, while the larvae damage the bamboo shoots. After the shoots mature into bamboo, there are numerous insect holes, the bamboo internodes are shortened, the bamboo is stiff, and the heads are broken. In severe cases, the bamboo loss rate is more than 50%.

The adult body is prismatic, and the female body is 17 mm long, milky white to light yellow. The head tube is 6.5 mm long, black, slender, and has a smooth surface. Male insects are 15 mm long and reddish brown. The head tube is 5 mm long, thick and short, with spiny protrusions. The head is black; the antennae are placed in the antennal groove at the base of the head tube. The posterior edge of the pronotum is curved in an arch shape, with a long fusiform black spot in the middle; the ventral surface of the chest is black. There are 9 longitudinal grooves composed of engraved dots on each elytra. There are two black spots on each wing. The shoulder corners and outer and inner corners are black. The distal segment of the abdomen is exposed outside the elytra, and 5 segments are visible on the ventral surface, which are black, and there are reddish-brown triangular spots on both sides of the first segment and the distal segment.

The eggs are oblong in shape, with a diameter of 3.1 mm. When first laid, they are jade-white and opaque. It gradually turns milky white, and half of the egg is translucent before hatching.

The newly hatched larvae are 3 mm long, soft, transparent, milky white, with a white backline. Mature larvae are 20 mm long and beige in color. The head is auburn, the mouthparts are black, the body has wrinkles, the valve is not obvious, the topline is light yellow, and the tail has dark yellow protrusions.

The pupal body is 15 mm long, dark yellow, with black legs and wing tips, and hard and protruding anal spines.

Biological characteristics: Most of the young bamboos in Jiangsu and Zhejiang have one generation per year, and most of the moso bamboos have one generation every two years. The adults overwinter in soil cocoons one meter deep under the soil. Adults are unearthed in late April and early May in Zhejiang. They mate and lay eggs in early or mid-May. The eggs hatch in 3-5 days. From late May, mature larvae gradually fall to the ground and build earth chambers to pupate. The unearthed adult insects can become active after sunrise and dryness. On sunny days, they are most active between 8:00 and 11:30 am and between 2:30 and 5:30 pm. Most of the males are usually flying, and they fly slowly and hummingly. If disturbed by the sound, it will fall to the ground. It is rarely active on rainy days and at night, often hiding under the roots of weeds or fallen leaves. After the adults are unearthed, they can feed on the bamboo shoots. When nibbling, head down, insert the head tube into the bamboo shoots at an angle of 45°-60° to supplement nutrition. After eating the bamboo shoot meat in one hole, pull out the head tube, move upwards 5-10 mm, and then insert it again. Feeding inside the bamboo shoots, one adult can continuously chew 6 to 18 holes, and then fly to another bamboo shoot to continue feeding. At the holes in the bamboo shoots, the flesh of the bamboo shoots is sunken inward, the material is stiff, and the shoot joints no longer grow.

After the adults are replenished with nutrients, they mate immediately. Generally, the females rest on the bamboo shoots to feed, while the males fly to find mates. The male flies in the forest in a wave-like pattern, flying to the bamboo shoots that are more than 1 meter high and the Moso bamboo shoots that are more than 2 meters high. Then they fly upward to the shoot tips, looking for females. If a female is found, they will rest on the side of the female's body. Mating takes place within half an hour and takes 3-25 minutes. It is common for 2 or 3 male worms to compete with each other for one female. The female worms feed while mating and never stop. Both male and female adults can mate multiple times. When the female lays eggs, she first rests on the bamboo shoot, heads downward, and bites the edge of the bamboo shoot hoop with the head tube. The head tube is perpendicular to the bamboo shoot, the front and rear thorax are close to the bamboo shoot, the hind legs stand up, the abdomen is upturned, and the antennae are in line with the bamboo shoot. The head tube is vertical, and the head tube is swung left and right to bite into the bamboo shoots, forming an oviposition hole with a surface diameter of 1.3 mm, an internal diameter of 3 × 5 mm, and the same length as the head tube. The adult pulls out the head tube, turns its body, lifts its head upwards slightly, holds the bamboo shoots with its feet, and presses its abdomen close to the bamboo shoots. It extends its ovipositing tube into the oviposition hole and lays one, or occasionally two, eggs. After laying eggs, the female turns her head back, crawls 3-5 centimeters diagonally downward along the bamboo shoots, and then bites the egg-laying hole. Each time she bites an egg-laying hole, it takes 10 minutes. Eggs are laid between the last branch of the bamboo shoots and the bamboo shoots, mostly in the middle. One bamboo shoot node can lay 3-5 eggs, and one bamboo shoot can lay up to 80 eggs.

The newly hatched larvae feed in the spawning holes, and the damaged parts stop growing. The food intake of 3rd instar larvae gradually increases. The larvae mostly bite the meat or twigs at the shoot nodes and generally do not move. The larvae are aggressive. When two larvae meet, they are often bitten or killed. If the body wall is bitten, the scars will heal and peel off during the peeling process. The larvae are motionless before molting. After molting, they are all pink and white. They return to normal after 1 hour and continue to feed. After the larvae mature, they feed outside the bamboo shoots and bite a round hole with a diameter of 7-9 mm. Below the hole is a slope flattened with crushed bamboo shoot fibers. From late May to early June, the larvae eat along the bamboo shoots. If the slope slides, find a suitable ground to bury the soil in. At a depth of 8 to 15 cm, build an oval earth chamber with a length of 20 to 25 mm. If the earth chamber is broken, it can be rebuilt. The larvae lie head-up in the earth chamber and turn into pupae in 10-15 days.

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