Influence of Temperature, Photoperiod, and Supplementary Nutrition on the Development and Reproduction of Scutellista caerulea Fonscolombe (Hymenoptera: Pteromalidae).

Scutellista ciruela Fonscolombe has a significant controlling effect on the rubber tree pest, Parasaissetia nigra Nietner. To identify the optimal conditions for the population growth of S. caerulea, we assessed how temperature, photoperiod, and supplementary nutrition affected its development and reproduction. The results demonstrated that the number of eggs laid and parasitism rates of S. caerulea were the highest at 33 °C. The developmental rate of S. caerulea was the fastest and the number of emerged adults the highest. The number of eggs laid and the parasitism rates increased when the light duration increased within a day. Females did not lay any eggs when the whole day was dark. At a photoperiod of 14:10 (L:D), the developmental duration was the shortest and the number of emerged adults was the highest. Adult life span was the longest under a 12:12 (L:D) photoperiod. During the adult stage, supplementary nutrition, such as sucrose, fructose, honey, and glucose, increased the life span of S. caerulea. The life span of S. caerulea was longer when provided with a supplementary diet of sucrose or honey, compared to other tested diets. The results suggested that the most suitable conditions for S. caerulea's population growth were the following: 30 to 33 °C, with 12 to 14 h of daylight, and the provision of sucrose or honey as supplemental diet for the adults.

Effects of mating on reproductive performance of Coccophagus japonicus Compere (Hymenoptera: Aphelinidae).

Coccophagus japonicus Compere, an endoparasitoid of Parasaissetia nigra Nietner, has great potential for biological control. To assess the influence of mating on the reproductive performance of this parasitoid, we examined the effects of mating on ovarian development, female longevity and number of eggs laid. The results showed that the egg volume in the ovary of C. japonicus first increased and then decreased with increases in the age of female adults. The peak egg volume in the ovary of mated females occurred 2 days earlier than that of virgin females. Within the female age range of 0-15 days, the numbers of eggs at stages I, II, and III first increased and then decreased with increases in the age of female C. japonicus, whereas the number of eggs at stage IV increased. The duration of the coexistence of females and males significantly influenced the length and width of the female ovaries, and the longest ovary tube and the highest number of eggs were obtained with a coexistence duration of 0 days. C. japonicus female longevity decreased with increases in the number of matings, and the number of eggs laid by females within 15 days decreased with increasing delays in mating. In conclusion, mating can shorten the longevity of C. japonicus females, and selecting newly emerged virgin females for mating can significantly improve the number of eggs laid and the breeding efficiency of the parasitoid.

Ultrastructure and distribution of antennal sensilla of the chilli thrips Scirtothrips dorsalis hood (Thysanoptera: Thripidae).

The chilli thrips, Scirtothrips dorsalis Hood, is a serious pest of numerous important vegetable and ornamental crops. Various signals, especially phytochemical cues, determine the behavior of the phytophagous thrips at host selection. The sensory abilities of S. dorsalis are poorly understood although the antennae of adult are known to possess important sensory structures in orther insects. In this study, the morphology, distribution, and ultrastructure of the antennal sensilla of the S. dorsalis were examined by using scanning and transmission electron microscopy. Microscopy observations revealed that adult male and female S. dorsalis possess filiform antennae. Each antenna comprises a scape, a pedicel, and a flagellum composed of six segments without clear sexual dimorphism in the number and distribution of antennal sensilla. The scape and pedicel exhibit Böhm's bristles, sensilla chaetica, and sensilla campaniform. The external structures of these organs reveal their mechanosensory function. In the flagellum, the most represented sensilla are the multiporous sensilla basiconica, which can be divided into three types of single-walled olfactory sensilla; three types of sensilla chaetica with mechanosensory and gustatory functions; sensilla coeloconica, which possess hollow cuticular spoke channels and represent double-walled olfactory sensilla; sensilla capitula and sensilla cavity with thermo-hygrosensory functions; and aporous sensilla trichodea with smooth cuticula and mechanosensory function. The putative function of described sensilla is discussed in ralation to host plant selection behavior of S. dorsalis.

Evaluation of chromatic cues for trapping Bactrocera tau.

BACKGROUND: Trapping technology based on chromatic cues is an important strategy in controlling Tephritidae (fruit flies). The objectives of this present study were to evaluate the preference of Bactrocera tau for different chromatic cues, and to explore an easy method to print and reproduce coloured paper. RESULTS: Chromatic cues significantly affected the preference of adult B. tau. Wavelengths in the 515-604 nm range were the suitable wavelengths for trapping B. tau. Different-day-old B. tau had different colour preferences. Virtual wavelengths of 595 nm (yellow) and 568 nm (yellowish green) were the optimum wavelengths for trapping 5-7-day-old B. tau and 30-32-day-old B. tau respectively. The trap type and height significantly influenced B. tau attraction efficiency. The number of B. tau on coloured traps hung perpendicular to plant rows was not significantly higher than the number on traps hung parallel to plant rows. CONCLUSION: The quantisation of colour on the basis of Bruton's wavelength to RGB function can serve as an alternative method for printing and reproducing coloured paper, but a corrected equation should be established between the theoretical wavelength and actual wavelength of coloured paper. Results show that a compound paper coloured yellow (595 nm) and yellowish green (568 nm) installed at 60 and 90 cm above the ground shows the maximum effect for trapping B. tau. © 2016 Society of Chemical Industry.

[Control effect of parasitic Metaphycus parasaissetiae on host Parasaissetia nigra].

A laboratory test was conducted to study the control effect of parasitic Metaphycus parasaissetiae on its host Parasaissetia nigra. The functional reactions of the parasitism conformed to the Holling Type II Equation, but the parameters of the functional reactions varied with temperature. Taking the ratio of instant attack rate to preying time (a/T(h)) as an evaluation index, the preying efficiency at 30 degrees C was the highest, with a/T(h) being 23.4211. There was a stronger interference effect in the functional reactions of the parasitism within M. parasaissetiae populations. With the increase of the population density, the amounts of parasitism decreased gradually. Hassell Equation (E = QP(-m)) could describe the relationships between the searching efficiency of M. parasaissetiae and its population density much precisely within the range of 21 degrees C - 33 degrees C. The interference increased with temperature within the range of 21 degrees C - 27 degrees C, and the interference coefficient reached the highest (0.6626) at 27 degrees C. When the temperature was raised to 30 and 33 degrees C, the interference coefficient decreased to 0.6161 and 0.5916, respectively. In the prophase of egg-laying, the parasitized P. nigra could be entirely controlled by M. parasaissetiae. However, when a few larvae were crawling out, the control effect was declined to 81.4%.