Key Technical Points and Management Methods for Uniform Silkworm Larva Development
Uniform silkworm larva development is the primary guarantee for implementing automated mounting of silkworms, and an important prerequisite for ensuring high-quality and high-yield silkworm cocoons. To achieve uniform silkworm larva development, the following aspects of work must be done well:
1. Properly protect the silkworm eggs after receiving them to promote uniform hatching
Immediately after receiving the silkworm eggs, pour them out and spread them evenly in a foil-lined tray with white paper, and keep them in an environment with a temperature of 26°C, a wet-dry difference of 1.5-2°C, and darkness (covered with black cloth) for protection. On the morning of the hatching day at 4-5 o'clock, uncover the covering and turn on the light for photosensitivity to promote uniform hatching. At 8-9 o'clock, collect the newly hatched ants (first-instar larvae). If not all are collected by the end of the day, continue protection according to the above requirements, and collect again the next morning. The newly hatched ants collected on the second day should be placed on silkworm racks 1-2 layers higher than those from the first day. At the same time, give 1-2 more feedings of mulberry leaves per day. Once their growth is basically consistent with the silkworms from the first day, stop giving extra leaves, and frequently exchange positions between layers so that all silkworms are completely consistent in experiencing temperature, humidity, light, and eating mulberry leaves, thereby promoting uniform population development.
2. Select and pick appropriately mature mulberry leaves to ensure uniform silkworm larva development
Mulberry leaves are the only feed for silkworms. The quality of mulberry leaves directly affects the development of silkworms. In particular, uneven maturity of mulberry leaves (some old, some tender) is most likely to cause large developmental disparities in the silkworm population. Therefore, selecting and picking mulberry leaves suitable for silkworm development is particularly important.
According to the physiological characteristics of silkworms at different stages: for first-instar silkworms, pick the 2nd-3rd open leaves counting from the top of the mulberry branch downward; for second-instar silkworms, pick the 4th-5th leaves; for third-instar silkworms, pick the 6th-8th leaves; and from fourth to fifth instar, pick from the lower end of the branch upward, leaving the newly grown mulberry leaves at the top of the branch to nourish the tree. Mulberry leaves picked this way can ensure the needs of silkworm body development. Each time before feeding, first distribute the silkworms evenly so they are uniformly distributed. The amount and frequency of feeding must also be consistent, so that the silkworm population develops uniformly.
3. Delay the first feeding after molting to compress batches and promote uniformity
The first feeding of mulberry leaves after silkworms wake from sleep (molt) is called "xiangshi" (post-molt feeding). Delaying the post-molt feeding to compress batches is a key step in promoting uniform silkworm populations. Under normal circumstances, as long as strict requirements are followed during ant collection and rearing, silkworm development is quite uniform. However, in production, the post-molt feeding step is often not handled well, which can cause the same batch of silkworms to split into two batches, or even three batches, bringing much inconvenience to rearing management.
Based on the characteristic that silkworms have particularly strong hunger tolerance after molting (waking from sleep), the post-molt feeding time must be delayed. That is, one must wait until all silkworms in a batch have completely finished molting and are crawling around with a strong desire to feed before disinfecting and giving the post-molt feeding (mulberry leaves). Moreover, this must be done for every molting period to achieve the goal of compressing batches and promoting uniform silkworm populations. Otherwise, if leaves are given too early, the silkworms that woke earlier eat mulberry leaves sooner, and those that woke later eat later, naturally and artificially causing large developmental disparities in the silkworm population, which easily induces silkworm diseases, is inconvenient for rearing management, and is even more unfavorable for automated mounting.
In summary, to achieve uniform silkworm population development: first, seriously do a good job of protecting silkworm eggs after receiving them to promote uniform hatching; second, strengthen management during rearing so that the mulberry leaves the silkworms eat conform to their physiological characteristics, and the population is consistent in the quality and quantity of mulberry leaves eaten, and consistent in experiencing temperature, humidity, and light; third, delay the post-molt feeding as much as possible, waiting until the entire batch of silkworms has completely finished molting before feeding, to ensure uniform silkworm population development.