Anastatus orientalis Yang et Gibson(Hymenoptera : Eupelmidae) is the egg parasitoid of lantern-fly Lycorma delicatula. The natural parasitism showed that: (1)the highest parasitism rate of egg masses was 68.96% in Yantai Shandong; (2)the highest parasitism rate of eggs was 32.98% in Haidian Beijing; (3)the eggs of parasitoids hatched and emerged earliest in Yangling Shaanxi; emergence time of different populations in Yantai, Guangang Tianjin, Qinhuangdao Hebei and Haidian was similar; (4) the sex ratios were various among the populations ranging from 1.92 to 1.94; (5) parasitism rates of egg masses on Populus sp., Salix sp. and Toona sinensis were not significantly different, the highest parasitism rate of egg masses was 64.3% on T. sinensis, and the lowest rate was 27.4% on Ailanthus altissima; (6)parasitism rates of eggs on Populus sp., Salix sp., T. sinensis and A. altissima were not significantly different, about 30% averagely.
We assessed the life history parameters and temperature requirement of a Korean population of the endoparasitoid Aphelinus asychis Walker (Hymenoptera: Aphelinidae), using Aphis gossypii Glover (Hemiptera: Aphididae) as a host. We Þrst measured the time from egg to mummiÞcation (i.e., pupation) and mummiÞcation to adult emergence (i.e., pupal period) at 25ЊC. The pupal period was signiÞcantly longer than the egg to pupation period in both genders, unlike in other regional populations of the species. Females produced an average of 342.9 mummies, the highest reported fecundity among the various regional populations of this species. Age-speciÞc realized fecundity peaked between the 4th and 7th day (23.3Ð24.8 mummies a day). The intrinsic rate of increase (r m ) was 0.255 offspring per female per day. The parasitoids were then reared at eight constant temperatures between 15 and 32.5ЊC. The developmental time from egg to adult emergence decreased from 27.8 to 9.8 d. The lower developmental thresholds (T 0 ), estimated by linear regression, for the egg to mummy, mummy to adult, and egg to adult stages were 6.7, 6.8 and 6.7, respectively. The thermal constants for each of the three periods were 115, 126, and 243 DD. We compared these parameters with published data of A. asychis from other regions reared on different hosts and representative species of aphid parasitoids in Aphidiinae (Braconidae) reared on hosts including A. gossypii. The T 0 Õs of A. asychis were higher than those of Aphidius colemani and Aphidius matricariae when using A. gossypii.
The pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) is a cosmopolitan and polyphagous species. An evaluation of A. pisum’s demographic parameters and growth was carried out after rearing aphids on faba bean plants (Vicia faba) under five different temperature conditions (10 °C, 15 °C, 20 °C, 25 °C and 30 °C). We analyzed the raw life history data, including developmental time, survival, longevity and reproduction, using an age-stage, two-sex life table to consider variable developmental rates among individuals. The population fluctuation of A. pisum determined the stage-specific population structure and potential population growth under different temperature conditions. A. pisum individuals developed successfully from nymphs to adults at all temperatures in this study. The developmental rate of A. pisum increased as the temperature increased. Our results indicated that A. pisum showed a higher pre-adult mortality, lower total fecundity and a negative intrinsic rate of increase at 30 °C. The highest intrinsic rate of increase (0.30) and finite rate of increase (1.35) were observed at 25 °C. Comparisons of population parameters and their analytical methods between different A. pisum populations from other geographic areas are also discussed.
With the comparison of native Orius strigicollis (Poppius) to European O. laevigatus (Fieber), we investigated biological characteristics such as developmental period, fecundity, life span, predation ability, and augmentation after release. Experiments were carried out at five temperature condition, 15℃, 20℃, 25℃, 30℃, and 35℃. In the case of O. strigicollis, egg period was 3.1~14.9 days (hatchability: 46.7~88.2%), and developmental period of nymphs was 9.4~42.8 days (survival rate: 2.4~96.5%). Fecundity at each temperature was 28.
This study compared the Aphelinus varipes and Aphelinus asychis in terms of how they parasitized the cotton aphid, Aphis gossypii and green peach aphid, Myzus persicae. Host-feeding, parasitism, emergence, the proportion of females and development time were all studied at 15, 20, 25 and 30℃ in controlled climate cabinets. When A. gossypii were provided for the two aphid parasitoids, the number of aphids killed by host-feeding for A. varipes (5.4 and 9.7 aphids) at 15℃ and 25℃ was higher than those for A. asychis (2.0 and 2.9 aphids). At 15℃ and 30℃, the parasitized A. gossypii were higher in A. varipes (11.1 and 21 aphids) than in A. asychis (7 and 12.3 aphids). The emergence rate was also significantly different between A. varipes (83.3%) and A. asychis (69.4%). The proportion of females was higher for A. asychis (75.2 and 73.9%) than for A. varipes (19.5 and 48.6%) at 15℃ and 30℃, respectively. No significant differences were found in development time between the two parasitoids. When M. persicae were provided for the two parasitoid species, the host-feeding number and the emergence rate of two parasitoids were not different at all four temperatures. The M. persicae were more highly parasitized by A. varipes (12.1 and 17.1 aphids) than by A. asychis (6.1, 10 aphids) at 20 and 25℃. The proportion of females for A. varipes (65.3 and 90.0%) was higher than that for A. asychis (34.4 and 78.8%) at 15℃ and 25℃. The development time from oviposition to the adult emergence of A. varipes (19.9 d) was significantly longer than that of A. asychis (16.5 d) at 20℃. Development times decreased with increasing temperature for both in two parasitoid species.
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