Studies On Thaumetopoea Pityocampa Population Genetic Differentiation And It's Egg Parasitoids

The winter pine processionary moth,Thaumetopoea pityocampa Denis & Schifferm(u|¨)ller (Lepidoptera Notodontidae),is a very popular distribution pest,which can cause most severe damages to various native and exotic pine and cedar species in Southern Europe, Mediterranean region and North Africa.Not only because it can cause gregarious defoliating leading to the tree in weak development,even death,but also,because it has urticating hairs and may cause strong allergic reactions in humans and warm-blooded domestic animals.In recent years,because the increased winter temperatures by a consequence of climate warming,it's extent of damages has increased.Range expansion to upper latitudes or elevations has been reported,the outbreak of this pest in some area which not suffer the damage before.,so it is payed more attention to in Europe.In this paper,.using the SSR technic, the population genetic differentiation and population structure are studied.The changes of its population genetic structure,the influnce of mountainous ranges for its spreading corridors, the influence of host tree species are also studied;By studying its egg masses which take from the different spread area at Alpes in France,its egg parasitoid are studied,so that to understand the law of its spreading and the control strategy.The main conclusions are as follow:T.pityocampa SSR molecular marker system has set up,and 5 microsatellites(pp07,pp40,pp42,pp50,pp55)are used in this paper,PCR reaction system also discussed,T.pityocampa.population genetic structure SSR finger-print marker system is set up.The genetic differentiation of T.pityocampa geographical population on different area has studied with the microsatllite marker,the results reveal,from genetics pointview,southern populations have great genetical changes,and northern populations have less.All populations are in Mardy-Weinberg equilibrium,namely the population mating is randomly.Not through the process of species selection,father-relationship,drafting and migration;the smallest genetic differentiation among populations is 0.082%,that is between Hasparren and Pierroton, the 36%between Beaune and Dry is largest.Moreover,genetic distance and geograghical distance has a very close relationship.The genetic differentiation of T.pityocampa population on different host tree has been studied using SSR.,The differentiation among groupes is 1%,The differentiation among populations is 5%.On the other hand,the Fst of the populations on different host at the same area or the same environment conditions also surpport this result.For example,the Fst between population on P.halpensis and the population on P.pinaster at Villerouge is 0.001, very low,and the Fst of two population at Osseja is 0.004.These results indicate that the host can not improve the differentiation.Moreover,all these host pine tree is very suitble for this pest,so for controlling the pest,to change pine tree species is not efficient,and for evaluating the risk of this pest expranding,all area with these pine species will be risk to the pest damage.It is determined that the central high plateau in France is a topographical barrier to dispersal for T.pityocampa Using the 5 microsatellite,a lots of information of population evolving revealed.At the same time,they are confirmed with these 5 microsatellites:the genetic differentiation among populations are changing according to the distance among them.,central high plateau have played and are playing a major role and divided two isolate corridors for their dispersal.The pest in France pour into north from the south where the populations have most genetic differentiation,so it has a more strong capability for dispersal than papers reported before,and it is sure that in the future it maybe will expansion rapidly. For evaluating this event,it is necessary to determine if the male and femal all have strong flying capabilitiesThe migrating corridors is understanded preliminary.Two big gene flow are separated by the central high plateau barrier:the western plain and Rhone-Saone system is the two migrating corridors and they are isolation no exchange.Determine the species and dominat species of Thaumetopoea pityocampa egg parasitoid. 229 Egg-masses of the pine processionary moth,T.pityocampa,collected at 9 different locations and different parts of pine tree-tops from core,prefront and front area of Alpes in France,were studied.in order to determine the rate of parasitizing and the number of parasitoid generations.Three species of egg parasitoids were found.The most abundant are Ooencyrtus pityocampae(Merc.)and Eutetrastichus servadeii(Dom).,the average number is about 27.8 on each egg-mass,and Trichogramma spp.is less frequent.the average number is about 0.3 on each egg-mass,The species attacked all parts of the egg-batches,.Ooencyrtus pityocampae (Merc.)and Eutetrastichus servadeii(Dom)can be used as a natural enemy for biocontrol of T. pityocampa.The egg study results also indicate the length of egg-masses in all area are all the same and can not influent the rate of parasize.The changes of the rate of parasitize of parasitoid in different area are studied.The highest rate is over 17%,it means egg-prarsitoid is playing a very important role in natural control of T.pityocampa.But it is very different at different area,from 17%in the core area down to 0.9%in the front area.The rate of hatching of larvae in different areas also change very greatly,from 72.5%in the core area down to 93.2%in the front area.so the egg prasitoids do a great impact on pest mortality.So compare with the pest population,the number of individuals in each population in new area is lower than in core area,it is according with the general law of the development of enemy.along with it's host.