Studies On The Regulation Of Gonadotrophin In Caste Differentation And Gonad Development Of Polyrhachis Vicina Ant

The Polyrhachis vicina ant belong to hymenoptera Formicida.As one of the typical eusocial insects, which is not a simple individual gathering has a strict hierarchical division of labor in the group. The group is mostly dispart into three castes: male, female (queen) and worker, they are different each other in morphology and physiology. Usually, the queen and the king are relation with reproduction;The worker is the nonreproductive individual, whose job is cleaning, foraging and rearing larvae.The P. vicina ant is the only ant that the national Ministry of Health appoint as an edible and officinal ant, which possess high nutritional value like protein, multiple microelement and multivitamin;The P. vicina ant also has high medicinal value, such as inflammation, analgesic, asthma, convulsion, protect the liver, restrain reproduction of virus, bidirectional immune regulation etc. Thus the Polyrhachis vicina ant has been extensively exploited and utilized in edible and medicine. But the prensent situation is that the P. vicina ant ants are in short supply, if it can find a way that can improve the velocity of reproduce, but no harming to the environment will be very helpful to the extensive use of Polyrhachis vicina ants.At present, the P. vicina ant brain structure, the sex hormine regulation of caste differentiation and the sex hormine regulation of gonadal development underlying swarming behavior were investigated by histology , cytology andimmunohistochemistry methods. The main results describe as follows :1. The brain structure of P. vicina ants is the same as other insects, the brain is made up of three components: the forebrain, the midbrain, and hindbrain. But there are some differences in volume: in the forebrain, the mushroom body is larger than any insects, it take up the most space of its brain. The mushroom body is the centre of learning and memory, which instructs the insects behavior, so it can be presumed that the P. vicina ant has more complex behaviour and well developed capacity of learning and memory. The optic leaf is the center of vision, its size determine the visual acuity of ant. But the result is that the optic leaf of P. vicina ant is smaller than other hymenoptera insects, that is indicate that P. vicina ant has undeveloped vision.Midbrain belong to the nerve center of olfaction, there are large nerve fibers balls in the midbrain. The rhinencephalon of P. vicina ant, which indicate that the Polyrhachis vicina ant has a well developed olfactory system.2. Gonadotrophin Follicle Stimulating hormone (FSH) and Luteinizing hormone (LH) are widespread in the vertebrate brain, They play a crucial role in the oogenesis and spermatogenesis of vertebrates, they also stimulate steroid hormone production. Control of gonad development in insect also requires brain gonadotropin. In invertebrates, there also have FSH and LH. But there is no investigation about the exist of those hormones in the brain of ant. In the present study, the immunocytochemical localization of FSH and LH in the brain of ant (P. vicina) were investigated with SABC (strept avidin-biotin complex) method. Then presume the effection of FSH and LH in ant caste differentation. The results indicated that FSH and LH existed in brain of different developmental stages. In the female, FSH immunopositive nerve cells were found in the right part of forebrain before it flying and the last instar larvae and lift part of forebrain in the male ant. But its weaker than female. LH immunopositive cells were found in the lift part of forebrain before it flying and the last instar larvae, close to midbrain;LH inmmunopositive cells found in the lift part of male ant before it flying. But there is no immunoreactivity of FSH and LH were detected in the brain of early stage larvae female ants, after flying and every stages of workers. So it indicate that FSH and LH exist in the brain of P. vicina ant. Which may regulate the labor division of P. vicina ant.3.Gonadotrophin is the sex hormone that regulate gonad development, oogenesis and spermatogenesis. We used immunocytochemical staining technique to detect the distribution of FSH and LH in spermary and ovary in P. vicina ant. The results showed : FSH and LH existed in fatbody in pro-flying female ant gonad and leydig cell in male ant gonad, FSH is also existed in primary oocyte follicular cell in the female reproductive ants, but no LH positive reaction. In the process of spermatogenesis there was no FSH and LH positive reaction. This experiment, firstly, proved the existence of FSH and LH in gonad of P. vicina.