[Effects of volatiles from chestnut on host preference of adult Conogethes punctiferalis (Lepidoptera: Pyralidae)].

Through field survey and the tests of behavioral response, EAG response, and multiple-choice oviposition, this paper studied the effects of volatiles from Nongda No. 1 chestnut (NC) and Heyuan oil chestnut (HC) on the host-selection behavior of adult Conogethes punctiferalis. The field survey in 2004-2008 showed that the moth-eaten rate of NC fruits by adult C. punctiferalis was 16.1%-25.3%, while that of HC fruits was less than 5%. The volatiles from NC fruits and leaves were more attractive to female than to male moths, and the fruit volatiles were more attractive than leaf volatiles. However, the volatiles from HC fruits and leaves were not attractive to both female and male moths. The EAG response showed that female moths had significantly higher response to NC fruit volatiles than to HC's, but male moths had no significant difference in this response. For both NC and HC, the EAG responses of female and male moths to fruit volatiles were higher than those to leaf volatiles. The number of eggs laid by female moths was much greater on NC fruits than on NC leaves and on HC fruits and leaves, but had no significant differences on the latter three.

[Relationships between mound size and captured ergate amount of Solenopsis invicta].

By the method of bait trapping, this paper studied the relationships between mound size (mound volume and mound surface base area) and captured ergate amount of Solenopsis invicta in wasteland and greenbelt. In wasteland, with the increase of mound size, the amount of captured S. invicta ergates increased rapidly at first, slowed down then, and kept stable at last. When the mound volume and surface base area were 11634 cm3 and 1308 cm2 respectively, the captured ergate amount reached the maximum, being 291 individuals per trap. Similar patterns were observed in greenbelt. The increase of captured S. invicta ergate amount slowed down rapidly when the mound volume was larger than 18089 cm3, and reached the maximum (232 individual per trap) when the mound volume was 25974 cm3. The Weibull equation could better describe the relationships between the mound volume and mound surface base area and the captured ergate amount of S. invicta.

[Population life parameters and relative fitness of alpharmethrin-resistant Bactrocera dorsalis strain].

Based on the observation of the development and reproduction of experimental populations of alpharmethrin-resistant and susceptible Bactrocera dorsalis strains at (28 +/- 2) degrees C, the life tables of the populations were established, and the differences in the relative ecological fitness of the two strains was analyzed. The results showed that comparing with alpharmethrin-susceptible B. dorsalis strain, the resistant one had longer durations of development stages, average generation, and previposition, its fecundity was not stable and lower, and the hatch of eggs and the emergence of adults were depressed. The fecundity of the susceptible and resistant strains was 324.0 and 240.7, respectively. Based on the life tables, the population trend index (I) of resistant strain was 79.10, while that of susceptible strain was 116.97. The net reproduction rate (R0) and the intrinsic rate of increase (rm) of resistant strain were 1414.00 and 7.9463, while those of susceptible strain were 2184.00 and 8.3809, respectively. The relation fitness of resistant strain was only 0.6474. All of the results revealed that the resistant strain was at an obvious inferior position of reproduction and development.

[Foraging intensity of ants in Solenopsis invicta Buren (Hymenoptera: Formiciddae) invaded and un-invaded habitats].

By the methods of bait (honey, peanut oil, sausage, and mealworm larvae) trap, this paper studied the searching time, recruitment time, and recruitment number of ants in 3 typical habitats invaded and un-invaded by red imported fire ant (Solenopsis invicta) in South China, and analyzed the effects of S. invicta invasion on the foraging intensity of native ants. In S. invicta invaded lawn, the searching time of ants for mealworm larvae and peanut oil was significantly shorter, compared with that in S. invicta un-invaded area. Less difference was observed in the searching time for the 4 baits between S. invicta invaded and un-invaded wasteland, but the recruitment time for peanut oil was significantly longer in invaded than in un-invaded area. The searching time and recruitment time of the ants for the 4 baits had less difference between the invaded and un-invaded litchi orchard. 30 min after setting bait traps, the recruitment number of S. invicta workers on peanut oil, mealworm larvae, and sausage in invaded lawn, and on peanut oil in invaded wasteland was larger than that of native ants, but no significant difference was found in the recruitment number of S. invicta workers and native ants on the baits in invaded litchi orchard.

[Influences of Solenopsis invicta buren invasion on the native ant communities in different habitats in Guangdong].

By using pitfall and bait traps, an investigation was made on the diversity and similarity of ant communities in the areas infested and un-infested with Solenopsis invicta Buren in Shenzhen of Guangdong. The results showed that under the invasion of S. invicta, the ant species number in lawn and wasteland reduced obviously, with a decrease of 6 in lawn and 3 in wasteland, and the native dominant ant species in lichee orchard, especially in wasteland and lawn, were replaced by S. invicta. With the infestation of S. invicta, the diversity and evenness of ant communities in wasteland and lawn decreased but the predominance increased obviously, while it was in adverse in lichee orchard. The similarity coefficients of the ant communities between S. invicta infested and un-infested lichee orchard, wasteland and lawn were 0.6316, 0.5882 and 0.2941, respectively.

[Comprehensive assessment on management measures of rice insect pests].

Based on the investigation of arthropods biodiversity and insect pests controlling effect in the paddy fields of demonstration area of organic rice production in Guangzhou, a comprehensive assessment on the economic, social, and ecological profits and costs of organic rice production in study area was conducted by using analytic hierarchy process (AHP). The results indicated that among all insect pests controlling measures, organic rice planting had the best comprehensive benefits, with a weight value of 0.5355. Ecological cost played a dominant role in comprehensive costs, and that of traditional pesticide-based insect pests control was most cruel, with a weight value of comprehensive costs being 0.6252. From the viewpoint of the ratio of comprehensive profits to comprehensive costs (RPC), organic rice planting was better than any other insect pests controlling modes, whose RPC was 2.4776, being accorded with the requirement of sustainable development of agriculture.

[Spatial correlation of active mounds locative distribution of Solenopsis invicta Buren polygyne populations].

By using geostatistic method, this paper studied the spatial distribution patterns of the active mounds of Solenopsis invicta Buren polygyne populations in Wuchuan and Shenzhen, and built up the spherical models of the interval distances and semivariances of the mounds. The semivariograms were described at the two directions of east-west and south-north, which were obviously positively correlated to the interval distances, revealing that the active mounds in locative area were space-dependent. The ranges of the 5 spherical models constructed for 5 sampling plots in Wuchuan were 9.1 m, 7.6 m, 23.5 m, 7.5 m and 14.5 m, respectively, with an average of 12.4 m. The mounds of any two plots in this range were significantly correlated. There was a randomicity in the spatial distribution of active mounds, and the randomicity index (Nugget/Sill) was 0.7034, 0.9247, 0.4398, 1.1196 and 0.4624, respectively. In Shenzhen, the relationships between the interval distances and semivariances were described by 7 spherical models, and the ranges were 14.5 m, 11.2 m, 10.8 m, 17.6 m, 11.3 m, 9.9 m and 12.8 m, respectively, with an average of 12.6 m.

[Geostatistic analysis of spatial pattern of Fruhstorferiola tonkinensis Will].

By the methods of geostatistics, this paper studied the spatial pattern of Fruhstorferiola tonkinensis nymphs in mulberry fields of north Guangdong. The results showed that the semivariogram of F. tonkinensis nymphs at all development stages could be described by spherical model, implying an aggregative distribution, and the range of their spatial correlation was 1. 973, 1. 968, 2. 169, 2. 302 and 4. 307 m from 1st to 5th instars. Based on the information obtained from investigation site, the isoclines maps of the instars were created by the geostatistical software Surfer 8. 0 with Kriging interpolation, and the resulting maps gave a clear indication about the spatial patterns of the instars. Unlike other locusts, the younger instars of F. tonkinensis had an aggregative distribution, while the elder ones were dispersive in distribution.