Feeding insects is the most commonly used method to study insects. Through the breeding work, we can observe many biological phenomena that are not easy to see in nature, and we can learn more about the activities, habits and behaviors of insects, as well as their responses and requirements to living conditions. Especially with the development of insect ecology, physiology and drug toxicology, it is required to provide a large number of insects as experimental materials. In the biological control of pests, it is often necessary to cultivate a large number of natural enemies for pest control in a short time, so the technology of raising a large number of insects has also developed rapidly. In recent years, the success of artificial comprehensive feeding experiment has created favorable conditions for insect feeding. In this way, raising insects indoors or under artificially controlled environmental conditions can avoid the adverse effects in nature and carry out insect reproduction and scientific research at any time. It brings great convenience to insect research.
The methods of raising insects often vary according to the purpose of raising them. According to the purpose of feeding, it can be generally divided into:
1. Feeding of individual development and life cycle: The purpose is to understand the development and changes, living habits, life rules and generations of insects. Explore the favorable opportunity and method of pest control. The number of insects raised in this way is not necessarily, but it needs long-term observation. If you want to know the experience period of each insect state and the age of larvae, you must raise them separately. In order to make indoor breeding conform to natural conditions as much as possible, in addition to the requirements of natural conditions, field observation and breeding should be carried out when necessary to reflect natural conditions more accurately.
2. Feeding of insect state research: The purpose is to understand the response and requirements of insects to environmental conditions, so as to grasp the relationship between the occurrence and decline of insects and environmental factors, and provide scientific basis for prediction and prevention. This feeding method is carried out under artificially controlled environmental conditions, and a set of instruments and equipment is needed to measure the response of environmental conditions to insects. The number of worms is not necessary and the time is not very long, but we should pay strict attention to the consistency and difference of environmental conditions.
3. Feeding of experimental materials or natural enemies: The purpose is to cultivate a large number of insects in a short time for drug efficacy determination or other scientific research. In addition to a large number of tested insects, they also need to have the same physiological development status, so the feeding conditions must be consistent in order to cultivate individuals with the same quality.
The feeding method of natural enemies is also a method of mass reproduction, but the feeding of natural enemies is more complicated, and some must feed parasitic pests of natural enemies to create parasitic conditions for natural enemies. In addition, there is a set of storage and feeding techniques to accumulate enough natural enemies and choose favorable opportunities to release them in the field.
4. Classification and identification feeding: Sometimes the eggs, larvae or pupae of an insect are collected, and its species can only be identified when it is raised to the adult stage, so it is necessary to raise it. This is relatively simple, and the time is not long. It is also a common method in classification and identification.
Tools and equipment for raising insects
(a) Common tools for keeping insects
Tools for raising insects can be designed and made by themselves according to the species of insects, life characteristics and the principle of saving. Such as cans, glass cabinets, porcelain cans, wooden cases, cartons and so on. Can be raised. Here are some of the most commonly used tools and how to use them.
1, glass Petri dishes: 6 cm in diameter, 10 cm, 15 cm and other different specifications. Suitable for feeding larvae and easy to observe. Generally, fresh food can keep a certain humidity in the dish. If it is the egg stage, you can put absorbent cotton balls in the dishes to keep them moist.
2. vial: 1× 8cm, 2× 8cm and other specifications. Suitable for feeding single small insects, which is convenient for inspection and observation. As long as you put in new food, put in insects, tie your mouth with gauze, put it on a pipe rack, and update the food every day, you can observe the life of insects.
3. Glass tube or glass lampshade; Glass has specifications such as 26× 20cm, 12× 5cm. It is often used to cover potted plants to raise insects. As long as the upper barrel mouth is covered with gauze or copper gauze, insects can't escape. This method is suitable for tiny insects, especially pests with piercing-sucking mouthparts, and it is easy to observe without changing food every day.
Horse lampshades or kerosene lamp covers can also breed insects. You can also tie the big end of the lampshade of kerosene lamp with gauze, put cotton on the small end to wrap the plant on the stem, so that the root is exposed outside the lampshade, and then insert the small end into a jar filled with clean water, so that the plants can still absorb water and grow, and insects can eat and live in the lampshade.
4. Insect Petri dishes: There are various insect culture tanks with different diameters, which are generally used for mass reproduction. As long as the bugs are put in the jar, fresh food is put in, the jar mouth is covered with gauze or copper gauze, and the food is updated in time, it can be carried out smoothly.
5. Insect-rearing veil: Insect-rearing veil is a round or square frame made of iron sheet, and then welded with copper wire or iron wire. You can also cover the tin frame with gauze or nylon wire. The lower part of the veil is open, so that it can be covered on the flowerpot to raise insects. The length and caliber of the veil are determined by the size of potted plants. Generally, the mouth diameter is a little smaller than that of a flowerpot. Some leave a few protruding feet at the lower end of the iron frame so that they can be inserted into the soil to avoid being blown down by the wind. Generally, the size is about 20×30 cm. Some openings can also be made into movable covers. When plants grow too high, two gauze covers can be used to connect them. Such a veil is suitable for raising insects who like dry and ventilated environment. It can also be directly covered on field plants for field feeding. Suitable for raising insects of all sizes in the wild.
6. Bug box: The shelf of the bug box is made of wood, and the production specifications are varied. Some ends and back walls are made of wood, with iron wires or copper wires on both sides. There is an openable glass door in front and a drawer made of tin at the bottom, which is filled with soil for some insects to pupate in the soil.
7. Some insect feeding boxes can be heated for use. This kind of box is made of wood except that the front wall can be opened and closed. When raising insects in winter, if the temperature is not enough, you can install light bulbs or other heating equipment in the insect box to make the work go on as usual. This kind of box is relatively large in size. It can be used to put small potted plants to raise insects, and it can also be used to put more fresh food into it for overall feeding.
(2) Equipment commonly used for raising insects:
Many insects can be carried out in ordinary rooms. As long as the indoor light is sufficient and the air is ventilated, the feeding work can be carried out smoothly. Conditional units can build specialized sheep and insect feeding rooms or artificial climate feeding rooms. Under the current situation, it is relatively simple and easy to use large insect boxes, insect houses and soil greenhouses in the field.
1. Large insect box: This insect box is a wooden frame with a length of 2m and a height of 1.8m (as the case may be). Window screens, copper nets or nylon nets are nailed around and at the top, and four wooden feet are buried underground. One side of the car is provided with an openable and closable door for entering the work. Put the crops that insects like to eat in cages, and set up instruments of temperature, humidity and light (preferably automatic recording) to understand the relationship between insect life and conditions.
2. Field feeding room: The field feeding room should be built in a place with high terrain, good drainage and close to trees, or trees should be planted at a distance of six meters from the room to prevent sandstorms and summer sun exposure. Excessive indoor temperature is not conducive to the survival of insects.
The feeding room includes a small room for daily work and a large gauze net. Feeding is carried out in a large gauze net. The small room can be used for detailed work such as storage and identification. This kind of feeding room is generally long from east to west and short from north to south. It is necessary to have hydropower equipment and accurate recording instruments such as temperature, humidity and luminosity, and build brick troughs suitable for planting insects' favorite crops. Internal planning and layout are convenient for feeding and observation, and make full use of space.
3. Earth greenhouse: mainly used for raising insects in winter. The structure of a greenhouse is roughly similar to that of a greenhouse for growing vegetables in winter. The most primitive is the paper window furnace room, and the modern is the glass electric artificial climate room.
To build a greenhouse, you should choose one without shading. Frame columns are made of metal or wood. The roof and the east and west sides are glass, and each room has a certain number of windows that can be opened and closed. Thick grass curtains should be installed on the outside of the glass part to keep warm, so as to cover it at night. Around and in the middle of the room, except for the 2-foot-wide passage, the whole building was built into a long cement pool with a width of about 1 m and a depth of about half a meter, which was used to grow insect-rearing plants. On the cement pool, you can also set up a wooden frame on which potted plants are placed to raise insects, making full use of space. There should be water, electricity and other instruments indoors to facilitate the measurement of temperature and humidity changes.
4. Artificial climate box: The artificial climate box can adjust temperature, humidity and light, and is mainly used for the determination of insect biology.
Three. General techniques and methods of raising insects
(1) Cleaning and disinfection during feeding.
The environment, feeding tools and food for raising insects must always be kept clean and disinfected when necessary. If the feeding environment is too wet and dry, the air is dirty, and the cleaning work is not done well, insects will often be parasitic by microorganisms, moldy and rotten, leading to a large number of insect deaths, and even all previous efforts will be abandoned. So cleaning and disinfection must be done well.
1. Cleaning and disinfection of feeding utensils: Generally, glassware used for feeding should be cleaned with soap, decontamination powder or caustic soda. If a hungry glass dish is infected by bacteria or viruses, it must be heated in an oven at 160℃ 1 hour. In addition, it can also be disinfected by boiling or chemicals.
Sterilization of feeders and wood products can be carried out with 1: 50 bleaching powder suspension. In addition, using 1.5% formalin (formaldehyde) solution to disinfect utensils also has a good effect, but metal utensils cannot be used.
2. Cleaning and disinfection of food: use natural feed, require food to be fresh and clean, do not feed rotten or soaked food, update it every day, remove feces, and clean utensils and environment. Artificial feed should be autoclaved, and some mildewproof agents should be added to the feed, such as n-butyl p-hydroxybenzyl alcohol and sodium benzyl alcohol (sodium benzoate) or sorbic acid.
3. Disinfection of worms: When microorganisms are attached to the surface of eggs, they are usually soaked in 0. 1% mercuric chloride solution for a few minutes, and then washed and disinfected with alcohol. However, it affects the hatching of some insect eggs and needs to be detected in advance. In addition, 1.5% formalin solution can also be washed and disinfected on the surface of eggs or larvae in vitro. Wash with distilled water after disinfection. Bleaching powder suspension can be used as an egg surface disinfectant for some insects, and has no effect on hatching and development.
(2) Feeding of each insect state
1. Adult feeding: Many species with incomplete metamorphosis have the same feeding habits and feeding methods as adults. All completely metamorphosed species have completely different food habits from larvae. Therefore, when feeding adults of this kind of insects, we should pay attention to understand their feeding characteristics and give them necessary supplementary nutrition. In order to make the sexual organs mature, mate and lay eggs.
Different kinds of insects have different needs for supplementary nutrition. Generally according to the nature of supplementary nutrition, it can be divided into liquid food, solid food and semi-solid food.
(1) liquid food: such as water, sugar solution, milk, blood, honey water, etc., the concentration is generally between 1- 10%, so it is not advisable to be too thick. Liquid feed is often used for many kinds of LEPIDOPTERA, Diptera and HYMENOPTERA insects.
The simplest way to supply liquid food is to put liquid food into a container for food, or put liquid food soaked with absorbent cotton into a container for food, but this method is easy to dry food or be contaminated by fungi. The improved method is to pour the juice into a small bottle, and then invert the small bottle in a glassware with absorbent paper or absorbent cotton at the bottom. The exposed absorbent paper or absorbent cotton can be supplied to insects at any time. You can also keep it in a small bottle with gauze twist at the mouth, so that gauze twist can attract liquid food to rise to food. For adults who absorb nectar, a bottle filled with water can be inserted into their favorite flowers as food. For flies, put a few more corks in a glass dish filled with liquid to stop the flies from eating.
(2) Solid or semi-solid food: all kinds of dried fruits and sweets can be eaten by some adults as long as the surface is soaked. For example, softened raisins and prunes are good foods for many species of Diptera and Hymenoptera.
To raise parasitic bees, broken sugar and honey are often used as solid feed. After honey is heated, crushed sugar is added, and after the sugar solution is dissolved and cooled, it is made into a block. This food can be slightly dissolved in the humid atmosphere for parasitic bees to feed on.
Another semi-solid food is made by heating 1% potato with water, and then adding 20g sucrose and 50mg honey into 100ml solution. Before solidification, this mixture is dripped on cardboard to make droplets or strips, which are suitable for many parasitic bees to feed.
Dried milk powder and red pond can also be used as feed for some flies, which is convenient to use and not easy to ferment.
Experience has proved that cotton breeders need to feed a certain amount of aphids and molasses in addition to supplying cotton seedlings in order to live normally. If aphids and molasses are not supplied, cotton bugs will die in large numbers.
As for adults who feed on plant leaves, such as locusts and leafhoppers, as long as they are supplied with fresh host leaves that they like to eat, they can live normally.
(3) Adult mating:
Many insects need certain conditions when mating, such as butterflies, flies and dragonflies. , must fly for a certain period of time, even mating in flight. For this kind of insects, if the feeding space is not large enough, they can't meet the mating requirements. Therefore, among all the breeders at present, butterflies have not been found to fly around to mate. On the other hand, some species, such as wheat moth, can increase the chance of male and female meeting, and it is easy to mate and lay eggs in smaller food containers. In the process of feeding, males often come out early and females are a day or two late. This phenomenon is most suitable for sexual intercourse, sometimes only females appear, but males are lacking. In this case, we can use the sexual attraction of female insects to lure males in nature to mate. The method of seduction is to put the mature female into a trap-type sarong (Figure 28). And taking precautions in an appropriate place outdoors can attract many male individuals. Some species can be lured during the day, while others can be lured at night.
(4) Adult spawning:
Insects have strict requirements on the hungry places where they lay eggs. Generally speaking, the smell of food eaten by its larvae is often an important stimulus for spawning. So be sure to put food that can cause spawning when feeding. However, some species need other stimulation conditions besides olfactory stimulation, such as suitable temperature, humidity and light. Some insects have selective requirements for smoothness, roughness, hairiness and creases. For example, wheat moths like to lay their eggs in folded paper seams, while corn borers, pear moths, dead leaf moths and some bedbugs like to lay their eggs on smooth surfaces. So put some wax paper, cellophane and plastic paper in the feeder so that insects can lay eggs on it. Myxomycetes like to lay eggs in cracks in hay. Put straw, cereal grass, gauze strips and folded paper strips in the feeder to let them lay eggs. Some people like to lay eggs in wet places, such as leafhoppers and flies. Put moisture-absorbing cotton, gauze and absorbent paper in the feeder and let them lay eggs. For insects living in the soil, the soil should be released. For example, crickets can be produced in any wet soil, while migratory locusts prefer to be produced in compacted sand.
In a word, in order to realize the oviposition behavior of insects, we must carefully design the oviposition environment and habits of insects in nature, otherwise we will be restricted.
2, egg feeding:
In order to hatch insect eggs normally, attention should be paid to maintaining a certain temperature and humidity. Especially in the case of high temperature, it is more important to keep humidity. Moisturizing can be done by covering eggs with wet gauze, or putting soaked cotton balls in a feeder, or putting eggs in glass in a container filled with water. Egg stage is the best time to preserve insects. If you don't want the eggs to hatch temporarily, you can keep them at a suitable low temperature. Generally, the storage temperature is between 0 and 5℃.
3. Feeding of larvae
Before feeding, plant plants that insects feed on so as to be ready for feeding at any time. In order to keep the food fresh, you can insert the cut shoots or seedlings into water or wrap them with wet cotton. It is more convenient to feed in potted plants.
When the newly hatched larvae change food, they can gently pour the old food together with the worms on a piece of white paper, and then gently sweep the new food with a clean brush.
When feeding larvae in groups, attention should be paid to population density. Too dense density will affect weight and development, and it is easy to be infected with diseases. Larvae with cannibalistic habits, such as cutworms, cotton bollworms, armyworms, root-cutting ladybugs and longicorn beetles, should be raised separately.
4. Feeding in pupal stage
According to the pupation habit of larvae, prepare the incubation site in advance. Many moth larvae like to pupate in cracks in bark or branches. Some people spin silk to make cocoons. So you can put some folded notes, crumpled paper balls, or bundles of barnyard grass. You can pupate them.