Gut bacterial community diversity in Carposina sasakii and Grapholitha molesta.

To clarify the community structure and diversity of larval gut bacteria in Carposina sasakii and Grapholitha molesta, the V4 regions of the 16S rDNA genes of intestinal bacteria of C. sasakii and G. molesta larvae which fed by golden delicious apple, were amplified and sequenced by Illumina HiSeq technique. The results showed that a total of 229043 high quality reads of gut bacteria in C. sasakii larvae were obtained and clustered to 2112 OTUs, which were annotated into 27 phyla, 65 classes, 124 orders, 205 families and 281 genera. 240389 reads of G. molesta were produced and clustered to 957 OTUs, which were annotated into 22 Phyla, 46 Classes, 89 Orders, 145 Families and 180 Genera. C. sasakii was dominated by the Proteobacteria (87.98%±5.29%), Firmicutes (3.91%±1.19%), Actinobacteria (1.04%±0.47%), and G. molesta was mainly dominated by Proteobacteria (50.06%±19.56%), Firmicutes (32.02%±8.48%) and Cyanobacteria (25.24%±10.28%). All of Phylum, Class, Order, Family, Genus, Species of the bacteria were significantly different between C. sasakii and G. molesta. Those results suggested that the gut bacteria community in these two fruit-boring pests was notably different, although they were both fed by apple fruit. The bacteria communities were more complex in C. sasakii than in G. molesta, which might account for different feeding and digestion mechanisms. The results could lay a foundation to reveal the association of the intestinal bacteria with these two fruit borers.

Sublethal Concentration of Beta-Cypermethrin Influences Fecundity and Mating Behavior of Carposina sasakii (Lepidoptera: Carposinidae) Adults.

The purpose of this study was to evaluate the sublethal effects of the beta-cypermethrin on calling behavior and fecundity of a major fruit-boring pest of apple, Carposina sasakii Matsumura. The mating rate, fertility (total number of eggs laid per female), and adult longevity of adults were remarkably decreased as compared with that in control when the adults were exposed to 10% lethal concentrations (LC10) of beta-cypermethrin (LC10♀ × LC10♂), and the age-specific survival rate (lx) was also negatively affected by sublethal beta-cypermethrin especially for the LC10â™€× LC10♂ mating combination. However, the age-specific fecundity (mx) was stimulated particularly in the combination of CKâ™€× LC10♂. Furthermore, the oviposition period was prolonged and the number of eggs was significantly increased for combinations of CKâ™€× LC10♂ and LC10â™€× CK♂. In the mating experiments, males in control or LC10-beta-cypermethrin treatments preferred to mate with females in control. It might be because of lower calling rate of female survivors treated with sublethal beta-cypermethrin. Our data indicate that treatment of beta-cypermethrin had a sublethal effect on the development and production of C. sasakii, and their mating behavior changes in surviving adults that may contribute to assortative mating.

[Influence of relative humidity on the Adoxophyes orana experimental population].

In order to explore the effects of relative humidity (RH) on the population growth of summer fruit tortrix moth Adoxophyes orana, the development, survival, fecundity and longevity of A. orana were assessed at 6 different constant humidities (40%, 50%, 60%, 70%, 80% and 90%), (25 +/- 1) degrees C and a photoperiod of 12L:12D in the laboratory. The results showed that immature developmental time was gradually shortened with the increasing humidity at 40%-90% RH, ranged from 30.31 d at 40% RH to 25.87 d at 90% RH. However, the survival rate for immature moth was gradually increased from 40% RH to 90% RH. Hatchability was inhibited significantly by low humidity and the lowest was 39.3% at 40% RH. And at 80% RH, the longevity of adults was the longest, the oviposition was the most (110.8 eggs per female) , and the survival rates for eggs and larvae were the highest. It resulted in the highest net reproductive rate (R0=26.46) and intrinsic rate of increase (r(m) = 0.1018). In conclusion, the development and fecundity of A. orana were promoted and improved at the higher humidity.

Age-stage two-sex life tables of Panonychus ulmi (Acari: Tetranychidae), on different apple varieties.

To understand the influence of different apple varieties on the development and reproduction of the European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae), age-stage two-sex life tables of P. ulmi on 'Fuji,' 'Starkrimson Delicious,' 'Golden Delicious,' and 'Granny Smith' varieties were constructed under laboratory conditions at 23 +/- 1 degrees C, 75 +/- 5% relative humidity, and a photoperiod of 16:8 (L:D) h. Results showed that total development time of immature females was shorter on Fuji than on the other varieties, and this was because of its shorter egg duration. Immature survival of P. ulmi was 74.51-78.00% among four apple varieties, and no significant differences were found. The total fecundity per female was significantly higher on Golden Delicious (34.12 eggs per female) than that on Fuji (27.15 eggs per female), Starkrimson Delicious (25.15 eggs per female), and Granny Smith (20.62 eggs per female). Based on the intrinsic rate of population increase, Fuji and Golden Delicious were more suitable than Starkrimson Delicious and Granny Smith.

[Host preference and fitness of aphis citricola (Hemiptera: Aphididae) to mature and young apple leaves].

In order to understand the differences of Aphis citricola in its original and final selectivity to the apple leaves with different leaf age, and to ascertain the effects of mature and young apple leaves on the growth and development, survival, and fecundity of A. citricola, this paper studied the host preference of A. citricola to mature and young apple leaves, with the related age-stage two-type life tables constructed. A. citricola more preferred to oviposit on the young leaves. There existed differences in the behaviors between oriented selectivity and penetration selectivity, and the latter was the key factor determining whether A. citricola fed and oviposited on the host. The total development time of immature A. citricola on the mature leaves was significantly longer than that on the young leaves, and the survival rate was also lower, with the aphids died at the first and fourth instar stages and at mature stage. As compared with those on the young leaves, the apterae rate of A. citricola adults on the mature leaves was lower, and the longevity and fecundity were significantly shorter and lower. The population dynamic parameters suggested that the population growth of A. citricola was quicker on the young leaves than on the mature leaves, and it was difficult for A. citricola to establish a stable population on the mature leaves.

[Spatial distribution pattern and time series dynamics of Panonychus ulmi Koch in an apple orchard of Liaoning Province, Northeast China].

Panonychus ulmi Koch is one of the important pest insects of apple production in China. To clarify the spatiotemporal dynamics of P. ulmi on the apple tree crowns in an apple orchard of Liaoning, Northeast China, an investigation with random sampling was conducted on the pest mite number at each direction and each layer of the crowns in the whole growth season from May to November 2007. The spatial distribution pattern and time series dynamics of P. ulmi were analyzed by calculating the indices of aggregation and using the parameters of Iwao model. In the early and mid growth periods of apple tree, P. ulmi within whole crown fitted negative binomial distribution, presented an aggregated pattern, and its fundamental component was the group composed of several individuals that attracted each other. The aggregation intensity showed a negative fluctuation with population density, namely, high population density but low patchiness density, and low population density but high patchiness density, and there existed definite differences at different crown directions and layers, i. e., the patchiness density was the highest in south direction and the lowest in west direction, and was higher in mid and lower layers than in upper layer, and in inner layer than in outer layer.