Appendage Regeneration In Eupolyphaga Sinensis

Leg or antenna regeneration was found in Eupolyphaga sinensis (Walker). The characteristics of the regeneration were examined in this research. The results showed that nymphs at all the instars had regeneration ability and legs amputated from any position could regeneration. Regeneration legs could be amputated and regenerate too. Tarsus of the regenerated leg was one segment smaller than the normal tarsus, which had five segments. If two femurs matched were amputated, the regeneration legs usually developed uncompleted, one regenerated legs was larger than the other one. Generally, the regenerated legs were smaller and the color lighter. But growth rate of the regenerate legs was faster. Legs amputated from femur and tarsus, if regeneration occurred, could grow back to the normal size after two times ecdysis.Influence of leg amputation time and amount on duration and difference between regeneration instar and normal instar development of nymph were studied. The regeneration critical period in this species were from 12 to 14 hatched days at trochanter-femur junction amputation of a hind leg and from 9 toll hatched days at tarsus amputation of a hind leg following feeding the 4th instar nymph. The regeneration critical period was from 21 to 26 hatched days after amputated at trochanter-femur junction of a hindleg at the 8th instar nymph. The removal of appendage at trochanter-femur junction amputation of the 4th and 8th instar nymph a hind leg, followed by regeneration, leaded to an increase in the duration of the intermoult. The mean time between operation and postoperative moulting was close to the normal instar duration, but the whole duration of the individuals with amputation operation took more time than normal to complete instar development. The 4th instar nymph regenerated the lost hindleg tarsus during the different days after postoperative moult, the time of many insect between operation and postoperative moult were shorter than the normal duration of 4th instar, and decreased gradually follow the operation days increasing.But the duration of 4th instar were longer than the normal duration except 7 days operation group. The most of 4th and 8th instar nymph amputated a hindleg between trochanter-femur junction, 4th instar nymph amputated a hindleg tarsus at the different days couldn't regenerate lost leg after postoperative moult, the duration of these instar were shorter than normal instar.In 3-days old 4th instar nymphs amputated different amount legs, the duration of the instar increased with the degrees of amputation, though nymphs amputated a hind legs or a pair of metathoracic developed with no significant difference. Instars did not influence the effect of amputation on duration of instar development. Mean duration of these instars was all longer than the normal duration, and the addition time was equal to the time from the preoperative moulting to operation. However the other insect didn't regenerate the lost leg after postoperative moult the time from operation to postoperative moult were very short, most of their duration were shorter than the normal duration of these instars.After the nymph one metathoracic amputated respectively at the base of femur, tibia or tarsus, the insect body may distinguished its loss the different segments, the regeneration leg was formed in the terminal segment of remnant leg which were respectively coax, femur or tibia.After the nymph one leg amputated respectively at the base of femur, tibia, tarsusⅠor tarsalⅡ, regeneration is incomplete in that the tarsus only four segments of the five tarsal segments normally found in the nymph, but regeneration leg have five tarsal segments which amputated respectively at the base of tarsalⅢ, tarsalⅣ, tarsalⅤor tarsal claws. When a lost leg segment was not beyond tarsalⅡ, the insect body retained these segments gene fragment not to lose, the regeneration leg was complete.Regenerating leg was formed and growing up in remnant leg coax and trochanter, the process could be divided into four main periods, namely: (a) Soon after amputation, the wound is sealed by a clot of haemolymph which hardens to form a scab; (b) the coxal musculature regressed and the tracheal system of the coxa commenced its withdrawal from the trochanteral stump, and the blastema appeared fully formed but undifferentiated; (c) the femur and tibia become differentiated and the tibio-tarsal joint was recognizable and growing; (d) preparation for regenerate releasing.Ultrastructure of the full initial period the cell group of regenerating leg blastema were investigated with transmission electron microscopy. The regenerating leg blastema cell group mainly included following several structures from outside to in: (1) epithelium layer was comprised of a layer of epithelial cells with a distinct apical microvilli border which is the single-layer cell, the intercellular space connection is extremely close; (2) on epithelium layer richly contains the nerve fiber; (3) regenerating leg blastema was comprised mainly of the fission proliferation ability very strong regeneration cell group; (4) trachea-system was located regenerating leg blastema to approach with nearby base festival muscle joint and the blastema interior.The regeneration cell group, the nervous system and trachea system of regenerating leg blastema simultaneously appeared and growing up. Regenerating leg growth was provided the metabolism the matter energy by the microvilli of epithelial cell and the organization interior trachea and the fat body.The different instars nymph and adult's antenna segments number gradually increased from 13-15 segments of 1th instars to female adult's 62～73 segments and male adult's 60～77 segments, male adult's antenna length for a female insect's two times. The different instars nymph at the beginning of age was able to regenerate and increase the antenna segments number after antenna amputated and ecdysised. The 1-10 instars nymph antenna were 3 segments after amputated and ecdysised, antenna segments number gradually increased from 5 segments of 2th instars to adult's 24～28 segments. The 5th instars antenna segments number had a difference in the certain scope, moreover would increase the segments number change along with the nymph instars increasing.The 4th instars nymph at the beginning of age especially were 0～2,3,5,10,15 or 20 segments after amputated and ecdysised, antenna segments number especially were 11～12,13～15,15～19,18～21,19～25 or 24～27 segments, the antenna segments number had the change in the certain scope. The 4th instars nymph 20 segments basically restored the normal segments number after amputated and ecdysised, and amputated the antenna not to be big to the antenna segments number influence.The different hatched days of 4th instars nymph antenna were 3 segments after amputated and ecdysised, the nymphs antenna segments from 0 to 8 hatched days could regenerate and added to 13～15 segments, but the antenna of nymphs exceed 12 hatched days could proliferate and added to 5～6 segments. The critical period for regeneration antenna was from 9 to 11 hatched days, and antenna regeneration rate respectively were 71.5%, 50% or 42.8%.