Comparison of development time and reproduction of typical and melanic Eurygaster integriceps (Heteroptera: Scutelleridae) under laboratory conditions

Among the sunn pest populations, melanic phenotype of Eurygaster integriceps Puton is a distinct colour morph. A set of experiments were performed to examine possible differences between typical and melanic phenotypes of E. integriceps using overwintered adults collected from Gharah-Aghaj mountains (southeast of Tehran). Melanics consisted only 0.3% of the total population. The laboratory conditions were: T = 24 ± 1 °C, RH = 60-70% and L: D = 16: 8 h. Incubation period and five nymphal instars were 7.24 ± 0.01, 4.14 ± 0.02, 7.97 ± 0.04, 6.63 ± 0.04, 7.21 ± 0.04 and 11.32 ± 0.07 days in melanics, and 7.19 ± 0.01, 4.14 ± 0.01, 7.83 ± 0.03, 6.19 ± 0.02, 6.88 ± 0.03 and 10.63 ± 0.04 days in typicals, respectively. Melanics with 44.13 ± 0.15 days had a longer developmental time than typicals with 42.33 ± 0.10 days. This difference was mainly related to the feeding instars. Durations of pre-oviposition period, oviposition period and post-oviposition period in both groups were not significantly different: 10.3 ± 0.8 days, 34.1 ± 6.4 days and 5.9 ± 1.9 days for melanics, and 10.2 ± 0.8 days, 34.9 ± 6.4 days and 4.0 ± 1.4 days for typicals, respectively. In general, reproductive table parameters showed an inferior performance of melanics compared to the typicals. There was no clear relationship between female body weight and total number of eggs in both groups. Stable population parameters (mean ± SE) of doubling time, Dt (days), mean generation time, T (days), net reproductive rate, Rо (female eggs/female), intrinsic rate of increase, rm (1/time) and finite rate of increase, λ (per day), were 13.68 ± 0.68, 60.69 ± 1.71, 20.67 ± 4.09, 0.0502 ± 0.0025 and 1.0515 ± 0.0026 in melanics, respectively. The respective values for typicals were 12.79 ± 0.50, 62.60 ± 2.13, 29.11 ± 5.26, 0.0541 ± 0.0021 and 1.0556 ± 0.0022. None of these parameters were significantly different between two groups. Relatively inferior characteristics of melanics observed in this study need further experiments on their successive generations to elucidate reproductive performances of the group

Morphometric Analysis of Two Populations of Eurygaster maura (Het.: Scutelleridae) in Iran

Morphometric differentiations may explain biogeographic distinctions among populations of a given species. The possibility of morphometric distinctions between two populations of Eurygaster maura L. collected from the northeast (Golestan province) and the northwest (Azarbayejan province) of Iran was examined using principal component analysis over 25 body measurements (eight absolute and 17 proportional, separately). The northeast individuals were relatively larger and darker in colour than those of the northwest; total body lengths of the former were 13.56 ± 0.49 and 13.25± 0.38 mm (female and male, respectively), and the respective values for the latter were 12.74 ± 0.39 and 12.63 ± 0.49 mm. Generally, proportional indices including genital width had positively the highest contributions to population discrimination. Different habitats and climatic conditions may explain, in part, these morphological variations between the studied populations

New records of the predatory stinkbugs (Het.: Pentatomidae: Asopinae) from Iran

تاکنون تعدادی از سن‌های شکارگر زیرخانواده‌ی Asopinae از ایران گزارش شده ‌است. در تحقیق حاضر، گونه‌های bidens (L.) Picromerus و Arma custos (F.) از این زیرخانواده از کناره‌ی جنوبی دریای خزر به عنوان گزارش جدید برای کشور معرفی می‌گردد. گونه‌ی اخیر در حال تغذیه از لاروهای پروانه‌ی سفید آمریکایی،Hyphantria cunea (Drury)، در مرداد ماه مشاهده شد. حشرات کامل این شکارگر نیز در حال زمستان‌گذرانی زیر بقایای گیاهی ملاحظه گردید. اطلاعاتی درباره‌ی مشخصات کلی و پراکنش این سن‌ها نیز ارایه شده ‌است

Biological and predatory characteristics of Andrallus spinidens (Hem.: Pentatomidae) on fourth instar larvae of Spodoptera littoralis (Lep.: Noctuidae), under laboratory conditions

Biological and predatory characteristics of Andrallus spinidens (F.) on fourth instar larvae of Egyptian cotton leafworm, Spodoptera littoralis (Bois.), were investigated, under laboratory condition, at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16: 8 L: D h. The analysis was based on an age-stage, two-sex life table. The intrinsic rate of increase (rm), finite rate of increase (λ), net reproductive rate (R0), gross reproductive rate (GRR) and mean generation time (T) of A. spinidens on S. littoralis were 0.0821 day-1, 1.0821 day-1, 102.77 offspring, 192.61 eggs and 58.68 day, respectively. The mean reproductive value of A. spinidens was estimated as 342.58 ± 48.18 eggs per female. The intrinsic birth rate (b) and intrinsic death rate (d) for A. spinidens on S. littoralis were 0.0894 and 0.0073, respectively. The first stage nymphs of A. spinidens live only on water but the second, third and fourth stage nymphs fed on 12.22, 26.22 and 41.28 of S. littoralis larvae, respectively. The fifth stage nymphs were more voracious and preyed on more than 70% of the larvae (94.36). At the adult stage, both male and female of A. spinidens were able to kill up to 85% of the larvae. In conclusion, the results prove that this predator pentatomid bug can be used as an efficient biological control agent against the noctuid pest, S. littoralis

Life history parameters of Thrips tabaci (Thys.: Thripidae) on cucumber, sweet pepper and eggplant under laboratory conditions

Onion thrips, Thrips tabaci Lindeman, is one of the most important pests of vegetables and ornamentals all over the world. Its role has been proved in the transmission of different viruses to several plants. In this study, life history parameters of T. tabaci were calculated on three host plants, cucumber, sweet pepper and eggplant. Experiments were conducted at 25 ± 1οC, 60 ± 10% R.H. and photoperiod of 16: 8 (L: D) hours. The results showed that host plants affect life history of onion thrips significantly. Intrinsic rate of population increase (rm) was 0.296, 0.158 and 0.234 female on female per day on cucumber, sweet pepper and eggplant respectively. Other parameters like λ (finite rate of increase) were 1.334, 1.171 and 1.264; T (mean generation time) were 14.879, 19.092 and 16.779; DT (doubling time) were 2.343, 4.384 and 2.956 days. Finally, R0 (net reproductive rate) was 81.581, 20.461 and 51.141 female/female in one generation. With regard to highly significant effect of host plants on life history parameters of onion thrips, it is probable that this problem could be used for control of onion thrips on sweet pepper more effectively than on cucumber and eggplant

BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity

RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA

Residential energy use in Oman: a scoping study

The Authority for Electricity Regulation (AER) Oman is addressing the nationally important issue of energy efficiency in residential premises. Reducing energy use in Oman’s residential sector has the potential to reduce the cost of energy subsidies, the consumption of indigenous gas resources and the cost of constructing the infrastructure required to meet growing peak demand. Improving the efficiency of the residential stock may also create benefits for the Omani public through more comfortable living conditions and reduced energy costs. In order to deliver these benefits, it is first necessary to measure and evaluate the current state of the built stock to understand how energy is used. This is not a simple task because energy use at the residential level is driven by the complex interaction between the household’s demands for energy services, the building fabric and its systems. In recognition of this challenge, AER contracted PassivSystems (an innovative home energy management services company) and the Energy Institute, University College London (a world-leading centre of energy research) to carry out