| Blattella germanica is the most widely distributed species of Blattaria, closelylinked to daily life, the global climate warming, acceleration of the process ofurbanization, the change of the eco-environment, and the reproduction, migration andirradiation habit of the Blattella germanica, especially the drug-resistance because ofabuse of insecticides has made the Blattella germanica the most general and hardestcontrol urban pests. Therefore the study of the Blattella Germanica’s biologicalcharacteristics and the group trait of the drug-resistance, the regulation of urbanpopulation quantity change, and the discussion on the biological characteristics andthe group trait of the drug-resistance, could provide the theoretical basic for makingscientific and effective prevention strategies, and can be applied.The study is divided into 3 parts PartⅠ：The growth and reproduction ofBlattella germanica under environment factors. Method Tests were made in theclimate chamber, Set 16℃, 18℃, 22℃, 26℃, 30℃and 34℃, and the temperaturedifference was±0.5℃, the photoperiod was LD12:12h, the intensity of illuminationwas 4000lux, the relative humidity was （65+5）% RH, to observe the growth of theBlattella germanica, calculate the effective accumulated temperature anddevelopmental threshold temperature Of every stage according to the law of effectiveaccumulated temperature. The photoperiod was LD16:8h, LD12:12, LD8:16h（theintensity of illumination was 4000lux） and LD0:24h, the temperature was 26℃, thetemperature difference was±0.5℃, the relative humidity was （65+5）%, to observe thegrowth, reproduction and rhythm of life history of the nymph under differentphotoperiods. Set no water and food, only water, only food three conditions, toobserve the survival rate of the nymph. Result The growth period of various stagesunder 18℃was the longest, the preoviposition was 20.67±2.03d; the egg was45.33±0.33d; the nymph was 109.67±2.91d; the one complete generation was175.67±2.91d. The growth period of various stages under 34℃was the shortest, the preoviposition was 4.67±0.33d; the egg was 10.33±0.67d; the nymph was34.67±0.88d; the one complete generation was 49.67±1.76d. The developmentalthreshold temperature（DTT） of egg, nymph, preoviposition and one completegeneration was （14.74±0.46）,（9.95±0.92）, （20.67±2.03） and （11.26±0.72）℃. respectively. And the effective accumulated temperature（EAT） was （184.8±5.9）,（732.7±34.0）, （85.3±2.8） and （1031.1±40.1） degree day. The nymphal developmentrate was LD16:8h＞LD12:12h＞LD8:16h＞LD0:24h. under 26℃, the nymphsurvival rate and the hatching rate declined with the reduction of light, but thedifference between LD12:12h and LD16:8h was not statistically significant; thenumber of female declined significantly with the reduction of light; the index ofpopulation trend was maximum at LD16:8h, 13.22; the minimum at LD0:24h, 2.31.the survival time for different strains of Blattella germanica nymph under 3 kinds ofstress conditions was different, it was the shortest without food and water, the nymphdied the next day for the susceptible strain, the survival rate was 26.7% on the 5th day,the longest was 7 days. The nymph died the next day for the field lines, the survivalrate was 90% on the 5th day, and the longest was 14 days. With food, the susceptiblestrain died the next day, the survival rate was 50% on the 5th day, and the longest was12 days. The field lines died at the same time, the survival rate was 93.3% on the 5thday, and the longest was 19 days. With water, the susceptible strain died on the 4thday, the survival rate was 53.3% on the 20th day, and the longest was 40 days. Thesurvival rate of field lines was 66.7% on the 20th day, the longest was 59 days.Conclusions The environment, temperature and photoperiod as important ecologicalfactors, play an important role in the growth, development and reproduction of theBlattella germanica; the nymph will grow better under the LD16:8h at suitabletemperature, the photoperiod response pattern of Blattella germanica belongs to thelong-day type, the nymphal takes an important part in its life history; the field strainsare more adaptable to the environment. PartⅡ:The population characteristics ofdrug-resistance in Blattella germanica .Method Blattella germanica field strainscollected from Jinan, marked JN1, JN2, JN3 and JN4, in the bioassay method, use thedrug membrane method to determine the sensitivity of the nymph to the acephate anddeltamethrin, and calculate the cotoxicity coefficient; in the biochemical method, useacetylcholinesterase kit, glutathione s-transferase kit, to determine the change ofAChE and GSTs after acephate and deltamethrin mixed. Result Acephate KT50 nymph: JN1:56.96min, JN2:49.85min, JN3:75.78min, JN4: 35.63min, the R/S was3.1, 2.8, 4.1and 1.9；Deltamethrin KT50nymph: JN1: 20.08min, JN2:13.56min,JN3:24.03min, JN4:10.65min, the R/S was 5.5, 3.8, 6.7 and 3.0; mixture CTC: JN1:125.5, JN2: 130.9; the results showed that the enzyme activity of AChE and GSTswas associated with sensitivity, the enzyme activity of nymph was higher thandeltamethrin and acephate mixed（1:10）, the activity of AChE declined from0.8248（U/mgprot） to 0.4039（U/mgprot） after 70 minutes; the activity of GSTsincreased from 290.004（U/mgprot） to 466.752（U/mgprot）. Conclusions Thesensitivity to insecticides of different field strains Blattella germanica in the samearea is different; it shows significant population regional; different mechanism mixsuitable can effectively improve the insecticidal effect. The activity of AChE andGSTs in the nymph is higher which shows that the sensitivity to insecticides of nymphis lower than the adult, this can tell why the nymph plays an important part in the lifehistory from the physiological and biochemistry. In the actual work, it is especiallyimportant on the control of the nymph. PartⅢ：The discussion on the controlstrategy of Blattella germanica population density by the study of Blattella germanicapopulation characteristics and the population characteristics of resistance, The controlshould take physical, ecological, biological and chemical prevention, so thepopulations of the Blattella germanica can be controlled effectively. When takingchemical pesticides, reducing the pesticide target area according to the ecologicalcharacteristic, habit and its relationship with the environment of the BlattellaGermanica, taking the mixed use of the pesticide and the study of pesticideeco-selective application technology in the key habitats so as to reduce theenvironment pollution. |
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