Bees are one of the important economic insects domesticated in captivity and have been raised for more than 3,000 years. In life, bees are often used as symbols of "hard work", "team" and "cooperation". The worker bee group in the bee is more clear division of labor and efficient collaboration. It is therefore considered one of the most socialized insects. What makes bees such a socialized division of labor an animal? Recently, the bee proteomics innovation team of the Institute of Bee of the Chinese Academy of Agricultural Sciences revealed the neural regulation mechanism of the division of labor of the worker bee from the perspective of neuropeptide regulating the physiological response threshold, which provided a new perspective for studying the plasticity of animal behavior. The results of the research were published in eLife.
Why are bees able to divide labor at a high level?
The oldest fossil of bees found by scientists to date is about 100 million years ago, the early Cretaceous period. "In the long process of evolution, bees have formed the highly socialized bee colonies we see now," said Bin Han, an associate researcher in the Bee Proteomics Innovation Team.
In the colony, the queen is responsible for laying eggs; the male peak is responsible for mating with the queen, and the worker bee takes care of almost everything else.
There are three types of bees in a bee colony. Courtesy of the Chinese Academy of Agricultural Sciences
Bees of different "professions" have shapes and biological characteristics appropriate to their work. For example, the queen bee has a bulging abdomen and a highly developed ovaries, which can lay up to 1,000-2,000 eggs a day.
The division of labor bees is more complex. Young worker bees aged 1-2 weeks are mainly engaged in larval feeding, also known as feeding bees. The secretions of the subpharyngeal glands and upper jaw glands of the bees, which we often refer to as "royal jelly", provide nutrients for the larvae. The feeding bees continued to develop and began to "change careers" into the collection work, becoming the collecting bees. There is a more elaborate division of pollen collection and nectar collection among the collecting bees. The collecting bees' subphingorngeal glands degenerate, the salivary glands develop, and the invertase in the saliva converts the polysaccharides in the nectar into simple sugars, eventually producing mature honey.
All in all, bees have survived and developed in a long period of evolution and continuous adaptation, forming a division of labor that is now highly socialized.
Bees are true social animals
Han Bin told reporters that the types of social animals can be divided into subsocial animals, quasi-social animals, semi-social animals and true social animals. Bees are true social animals and are highly socialized species in nature.
Bees meet the three characteristics of eusocial animals, first, the division of labor in reproduction, the mating of the queen bee with the male peak, and the queen of the bee laying eggs. Second, generations overlap. Generation overlap refers to the existence of more than two generations in a mature group. In the colony, the queen bee is the mother, and most of the worker bees are its offspring. Third, mature offspring work together to care for immature individuals. The worker bees in the colony all have a period of time when they will complete the task of feeding the larvae.
Worker bees that collect nectar or pollen. Courtesy of the Chinese Academy of Agricultural Sciences
In addition to bees, hymenoptera ants and wasps and cockroaches termites in insects are also truly social. The only known eusocial animals in mammals are the naked mole rat and the Damalaran mole rat in the family Hamalalan.
Study the principle of social division of labor in bees
Bees are a pattern insect whose behavior is easily observable: the beak extension reflex. When a bee's tactile and olfactory receptors are stimulated, the bee sticks out its mouthpart, the beak, which is the beak extension reflex.
Beak extension reflexes are widely used in the study of bee behavior, as well as learning and memory. Based on beak extension reflex, this study used different concentrations of sugar water, pollen and larvae to stimulate nectar collection bees, pollen collection bees, and feeding bees.
Bees have slender mouthparts. Courtesy of the Chinese Academy of Agricultural Sciences
HanBin's team found that there were significant differences in the response of bees to different stimuli in different divisions of labor. In simple terms, collecting bees respond better to nectar and pollen than larvae, and feeding bees respond stronger to larvae than nectar and pollen. This shows that the worker bees with a clear division of labor are very "sensitive" to their duties.
Schematic diagram of the physiological response threshold of the tachykinin signal worker bee. Courtesy of the Chinese Academy of Agricultural Sciences
The team conducted a study at the molecular biological level, Han Bin introduced, the research team made a difference in the neural peptides of the bee brain, and used neuropeptide injection and RNA interference to prove that tachykinin can specifically regulate the response threshold of the worker bee in relation to its behavior specificity, but has no effect on the stimulation unrelated to the task. The whole experiment is from the discovery of behavior, to the level of molecular biology to study, and then back to the process of behavior to verify the discovery.
There are two major breeds of live bees in China: the Middle Bee and the Italian Bee
Han Bin's team found that tachykinin signaling plays an important role in regulating the differences in collection and feeding behavior between Chinese bees and Italian honeybees. So what are the physiological and behavioral differences between these two bees? How is this reflected in this study?
At present, the two main species of bees raised in China are the Chinese honey bee and the Italian honey bee. The Chinese honey bee is a native bee species in China, and the Italian honey bee is an excellent product introduced in the early last century. Although the two are close relatives, due to long-term geographical isolation, reproductive isolation has been formed between the two species of bees, and there are also great differences in physiology and behavior.
The Chinese bee is a unique native bee species in China, a species of oriental bee, and there are other subspecies in other Asian countries. The bee has strong stress resistance, good resistance to unfavorable environmental factors such as low temperature and high altitude, and is good at using sporadic honey source plants, so it is suitable for breeding in mountainous areas and high altitude areas. They can survive the harsh winter of -30 °C to -40 °C in natural tree holes, and can fly out of the nest at a temperature of 10 °C to collect. At temperatures of 40°C, medium-bees can also collect, build spleens and reproduce as usual.
It is a typical Western bee with high yields of royal jelly, honey and pollen. But the bee can't resist a pest that seriously endangers the survival of bees: bee mites, and humans must help control mites to maintain normal population reproduction.
Comparison of the two types of bees (left is the bee, right is the middle bee). Courtesy of the Chinese Academy of Agricultural Sciences
Han Bin introduced: "After comparing the neuropeptide content of the brain of the middle bee and the bee, it was found that the expression of tachykinin in the bees collected by the bees wasps wasp wasts was lower than that of the bees, indicating that the tachykinin may be one of the important regulatory factors for the more sensitive of the bees to sporadic honey sources, and other factors need to be further studied." ”
Han Bin's bee proteomics innovation team mainly conducts basic and applied research on bee biology, with the purpose of guiding beekeeping production and practice by analyzing the molecular mechanisms related to bee economic traits. The team studied the collection behavior and feeding behavior of bees, which was directly related to bee pollination, honey production, and royal jelly production, that is, bee breeding and bee product production in China; similarly, the practical problems in beekeeping were also the guiding direction for the team to explore the topic.
Beijing News reporter Zhou Huaizong intern Liu Wenjing
Edited by Zhang Shujing Proofread by Chen Diyan
Source: Beijing News