The Biology Of Eustigmata Tamaricina

Eustigmata tamaricina is only species of psyllids which could form galls on Tamarix in the north of Xingjiang, China. The brush-like galls could be found both in Fukang and Daheyan area where Tamarix are growing. In fact, this kind of psyllids can form flower-galls as well as leaf-galls on Tamarix ramosissima Ldb. Both of galls were formed by nymphs of Eustigmata tamaricina in different time. Eustigmata tamaricina completes one generation every year, wintering with diapased 4th nymph on old branch of Tamarix. The 4th nymph stop diapause in middle of May next year. Then they feed the top of new branch of Tamarix, and cause the leaf-galls there. The 4th nymph will become the 5th nymph after feeding in galls in a short time. Adults were observed in first ten-day period of June. Adult have a short life-span and are not active very much. It is necessary for new adult to feed on branch about 3-5 days to develop ovary. Female and male have almost equal population. Female adults oviposited eggs inside calyx on Tamarix ramosissima after mating. First nymph will get into buds to feed germen by piercing-sucking mouthpart as soon as hatched, which stop flowering and make it becoming galls. From first to 3th nymph complete their development in flower-galls. They have a low death-rate since protection of galls. the 4th nymphs were observed in the end of July at the moment that the period of summer-diapause may begin. The 4th nymph living in flower-galls were active and feeding sometime but can not become 5th nymph. In the middle of October, the 4th nymphs imigrate from flower-galls to old branchs of Tamarix, where they start the period of winter-diapause without any active behavior in the whole wintertime. Eustigmata tamaricina are narrowly host specific. Primary host-specificity testing indicated that the whole life circle could complete only on Tamarix ramosissima.Both leaf and flower galls provide a good protection to the nymphs of Psyllids, but the reach of life-table indicated that wintering and parasiting on nymphs are important factor for the fluctuation of population in field.The study of diapause indicated that the diapause of Eustigmata tamaricina was related to light-period, temperature and food. Only by the condition of long light-period and low temperature could the wintering 4th nymph be interrupted the winter-diapause. Besides, we found the wintering 4th nymph got a quite elaborate way to keep the balance of water supply in body.