نشریه نامه انجمن حشره شناسی ایران
سال سی و هشتم شماره 4 (پیاپی 76، زمستان 1397)

The effects of temperature on demographic parameters of the aphid parasitoid, Aphidius matricariae (Haliday), on lettuce aphid, Nasonovia ribisnigri Mosely, were studied at five constant temperatures, 15, 20, 22, 25 and 27 ± 1°C, 65 ± 5% RH and a photoperiod of 16L: 8D h. The life table parameters were estimated using age-stage, two-sex life table procedure. Moreover, the bootstrap method was used for estimating variance, mean and standard error of the population growth parameters, at studied temperatures. All estimated parameters were considerably affected by temperature. Accordingly, nymphs of N. ribisnigri could not settle and survive on the leaves at 27°C. Thus, mummies were not formed. Developmental time of the parasitoid wasp decreased with increasing temperature from 21.21 days at 15°C to 11.19 days at 25°C. The oviposition periods were 15.21±0.12, 9.47±0.10, 5.91±0.05 and 5.6±0.09 days at the temperatures of 15, 20, 22 and 25°C. Similarly, average number of mummies was 249.74±12.6, 192.72±12.8, 105.15±6.2 and 102.3±7.0, at the mentioned temperatures, respectively. The highest intrinsic rate of increase (r) and finite rate of increase (λ) were estimated to be 0.251 and 1.285 (d–1) at 20°C, respectively. However, there was no significant difference among the estimated values regarding intrinsic rate of increase and finite rate of increase at the temperatures of 20, 22 and 25°C. The highest value of net reproductive rate (R0) was 123.06 offspring/individual) at 15°C and the shortest mean generation time (T) was 13.98 (day) at 25°C. According to the obtained results, the temperatures 20-25°C, can be considered as optimal temperature range for the biological control of the currant lettuce aphid by using A. matricariae.

This study was carried out to determine the effects of the entomopathogenic fungus, Lecanicillium longisporum Zimmermann Strain LRC 190, on survival and population growth parameters of the cabbage aphid, Brevicoryne brassicae (L.) treated by using different conidial concentrations (1×103, 1×104, 1×105, 1×106, and 1×107 conidia/ml). Experiments were conducted at 23±1oC temperature, 60±5 %RH and a photoperiod of 16: 8 h. (L: D) on cabbage seedlings, Brassica oleracea var. capitata under laboratory conditions. Based on the results the longevity of the aphid adults was significantly different based on conidial concentrations of L. longisporum (Petch) Zare and Gams. The shortest longevity of the cabbage aphid adults was 10.70±1.59 days when treated with 1×107 conidia/ml, compared to 22.65±0.94 days in control treatment. The LC50 value was 1.82×106 conidia/ml 7 days after inoculation. Net rate of reproduction (R0), intrinsic rate of increase (rm) and finite rate of increase (λ) were significantly reduced in treated aphids compared to control treatment. There was no significant difference among mean generation times (T) in populations treated with 1×105, 1×106, 1×107 conidia/ml (P>0.05). Fungal infection was detectedin lower rm values and prolonged doubling time (DT) in treated females (3.492 days at the concentration of 1×107 conidia/ml), compared to the control (2.652 days). Considering higher concentrations of L. longisporum can effectively reduce the cabbage aphid longevity, reproduction and population growth under laboratory conditions, it seems that the fungus has ability for biological control of the cabbage aphid.

Three ash psyllid species, Psyllopsis repens Loginova 1963, Psyllopsis securicola Loginova 1963 and Psyllopsis machinosus Loginova 1963, which have been distributed in the Central Asia and Europe, are important pests on genus Fraxinus spp. in the urban area of Iran. They have similar adult and larval morphology as well as same host and biology. On the other hand morphologically identification of adults and nymph, especially for females and damaged adults by removal from sticky traps is difficult. Therefore, a fast and accurate identification method is required. Here we analyzed barcode sequence variation based on two mitochondrial gene regions, cytochrome c oxidase subunit I (mtCOI) and cytochrome b (cytb) as DNA barcode, and one endosymbiont gene (wsp Wolbachia gene) among the species in southern Iran. The results of pairwise genetic distance values showed that cytb and mtCOI genes had the highest inter-specific variability. Based on the results, two species P. machinosus and P. repens which are present on one host plant together probably have been infected with similar Wolbachia strain.

Laemostenus (Antisphodrus) murastyii sp. nov. from Kamaran pass near Fereydunshahr, Zagros Mountains, Iran, is described, illustrated and compared with related species. Moreover, an identification key and a check-list of Laemostenus glasunowi species-group is provided.

Glutathione S-transferase (GST) was purified and isolated from adults of common pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer, by using ammonium sulfate precipitation and affinity chromatography using Glutathione Sepharose 4B column. The purified enzyme appeared as a single band on SDS-PAGE with an apparent molecular weight of 28.4 kDa. GST was purified 39.27-fold with a yield of 12.37% and a specific activity of 30.08 U mg-1 protein from A. pistaciae. The optimum temperature and pH of the enzyme activity were 30 °C and 9.0, respectively. The Km and Kcatvalues for GSH (Glutathione) substrate were also determined to be 0.44 mM and 152.9 s−1 and for CDNB (1-chloro-2,4-dinitrobenzene) substrate to be 0.33 mM and 207.7 s−1, respectively. GST’s activity was completely inhibited by the addition of EDTA, ZnCl2, andSDS; however, partially inhibited by CaCl2, BaCl2, CoCl2, KCl, MnCl2, Urea, MgCl2 and Hg2Cl2. The in vitro inhibition studies indicated that all kinds of conventional insecticides (i.e. imidacloprid, acetamiprid, phosalone, and amitraz) possessed inhibitory effects on the activity of purified GST. Our study broadens the biochemical information on A. pistaciae’s GST and this information will help us to understand the mechanisms of insecticide resistance in this key pest.

The male sex of Echthromyrmex sehitlerolmez Koçak & Kemal, 2008 is here described for the first time from Iran. The species was previously known based on the description of the female specimen from Turkey. This is also the first record of this species in Iran. The species was compared with Echthromyrmex platypterus, the other species of this genus. The illustration of male and female habitus and male genitalia of both species is provided.