Study On The New Technology Of Surveillance And Control Of Aedes Albopictus

Dengue and Dengue hemorrhagic fever is a mosquito-born disease,and several major outbreaks of dengue fever have occurred in the twenty century with millions of cases.We concentrated on developing a new method to investigate and control A. albopicuts and other container-breeding mosquitoes,and suceeded in developing a new sticky ovitrap for the surveillance of A.albopictus in China.Which is very helpful to survey and control the epidemic of Dengue in China.We conducted some experiments such as studies on the oviposition pattern of A.albopictus,attractancy or repellence of the different grass or leaf infusions to the gravid A.albopictus and the new way to control A.albopictus larvae using CuSO₄ to improve the sticky ovitrap.Which could contribute to control A.albopictus and other container-breeding mosquitoes.The major results of the thesis are as followed:The effect of the sticky ovitrap on collecting A.albopictus(Diptera:Culicidae) in the fields were evaluated in Wuhan,China.A.albopictus accounted for 89.97%of the mosquitoes collected by sticky ovitraps,and 63.97%of them were A.albopictus with all clearly visible chracteristics.Culex quinquefasciatus or Culex pipiens pallens,Culex bitaeniorhynchus and Culex tritaeniorhynchus together made up 9.70%of mosquitoes. The percentage of unidentifiable mosquitoes was 0.44%.More A.albopictus females were collected than males,and 99.70%of tarsi of mosquitoes attached on the sticky strips were clearly visible,and the percentage of mosquitoes with the clearly visible thorax or abdomen or proboscis were 70%or so.86.67%of mosquitoes were stuck at the bottom of the sticky strips,and only few of them were stuck on the upper and middle of the sticky strips.The mean adults of A.albopictus measured by sticky ovitraps were correlated well with the mean eggs of A.albopictus detected by the standard ovitraps in 2006.The females captured by sticky ovitraps were correlated well with the eggs collected by ovitraps or the adults collected in man-biting experiments,and the linear regressions were found between eggs and females,eggs and adults,or females and adults.Gravid A.albopiclus laid significantly more eggs in standard red ovitraps baited with the Bermuda-grass infusion with average 68.87 eggs per ovitrap than those in the similar ovitraps containing plain tap water with average 23.99 eggs per ovitrap in the insectary, and more eggs were found in standard red ovitraps baited with the Bermuda-grass infusion with average 670.95 eggs per ovitrap than in the similar ovitraps containing plain tap water with average 386.22 eggs per ovitrap in the field.In the corresponding assays with sticky ovitraps,however,it was only in the insectary that significantly more A. albopictus female were caught in the cup using the Bermuda-grass infusion with average 7.62 females per trap than those in the cup with the tap-water with average 2.66 females per trap.While in the field there were no difference in the females captured between the Bermuda-grass infusion with average 5.58 females per trap and the tap-water control with average 4.79 females per trap.There were no difference in collecting A.albopictus female between any of six infusions made from the leaves of the camphorwood tree (Cinnamomum camphora),box(Buxus sinica var.insularis),green bristle grass(Setaria viridis),bermuda grass,lotus magnolia(Magnolia grandiflora) or a bamboo (Phyllostachys pubescens) with tap water in the field.The gonotrofic circle of A.albopictus wass ca.4 days,the gravid female began to lay eggs after 3-4 days bloodfed.The peak of oviposition occurred in the fourth day with 46.64%eggs being laid.Since then the gravid female decrease to lay eggs greatly with only 6.85%eggs laid in the sixth day,and a few female kept laying eggs in the tenth day. Oviposition of A.albopictus from Wuhan was almost exclusively diurnal with 91.90% eggs being laid during the full photophase in the field.A large,well defined peak of oviposition(comprising about 56.25%eggs laid) occurred in the laboratory during the one or two hours before sunset while a broad peak of oviposition occurred in the mid afternoon in the field with 32.51%eggs collected between 12:00 and 15:00,24.95%eggs between 15:00 and 18:00,and 31.86%eggs between 18:00 and 20:00.A.albopictus exhibited skip oviposition with laying eggs in instalment in several cups.55.56%of females laid eggs from one gonotrophic circle one time and 44.44%of them deposited eggs more than two times in a day during the 24h exposure.However,the proportion of females depositing eggs more than two times increased to 65.80%during the 3h exposure and only 34.20%of females deposited eggs one time.In response to 7 cups of water alone,individual A.albopictus laid eggs in 3.66±0.19 cups and the mean percent of eggs laid in any cup in the cage was not more than 25%eggs.In response to the larvae culture water in the cup No.3,the mean number of cups used by individual A. albopictus was 4.18±0.19 and the mean percent of eggs laid in the cup No.3 was 30.49±3.62%.In response to the red velour strip in the cup No.3,the mean number of cups used by individual A.albopictus was 3.05±0.23 and the mean percent of eggs laid in the cup No.3 was 44.78±5.17%.In response to the red velour strip and the larvae culture water in the cup No.3,the mean number of cups used by individual A.albopictus was 2.03±0.12 and the mean percent of eggs laid in the cup No.3 was 75.95±3.14%.The development of A.albopictus larvae and eggs could be affected by metallic copper.Exposed to the water infused with the dose of 10g/L of copper for 30 days,the larvae developed slowly and kept staying atâ… orâ…¡stage while most of larvae in the tap water developed toâ…¢orâ…£stage in the second day.Metallic copper were poisonous to A.albopictus larvae.After being exposed to the water infused with the dose of 40g/L of copper for 50 days,All the larvae were dead at the first day.When the copper were infused for 10 days,A.albopictus eggs were placed in the infusion.30%eggs hatched for the dose of 10g/L of copper,37%eggs hatched for the dose of 20g/L of copper,and 86% eggs hatched for the dose of 40g/L of copper,while 99%eggs hatched in the tap water as control.Eggs kept hatching exposed to 1mg/L CuSO₄ while no eggs hatched exposed to 10mg/L CuSO₄ or 100mg/L CuSO₄.Allâ… orâ…¡larvae were dead after 24h exposure of 1mg/L CuSO₄,10mg/L CuSO₄ or 100mg/L CuSO₄.CuSO₄ are poisonous toâ…¢orâ…£larvae,and all larvae were dead after 3 days exposure of 100mg/L CuSO₄.No larvae were found in the containers containing 100mg/L CuSO₄ during five weeks exposure while A.albopictus larvae were found in all the containers with tap water after one week in the field.Effect of 100mg/L CuSO₄ on controlling A.albopictus larvae decreased as time gone.