نشریه نامه انجمن حشره شناسی ایران
سال بیست و نهم شماره 2 (پیاپی 45، زمستان 1388)

The reproduction and population growth parameters of Anisopteromalus calandrae (Howard) on the 4th instar larvae of Callosobruchus maculatus (Fabricius) were investigated at temperature of 25 ± 1C, 20 ± 5% R.H. and a photoperiod of 16: 8 (L: D) hours. Since the parasitoid eggs are laid inside the seeds where the host larvae live, egg hatch rate (hx) was assumed to be 1 (100%). As a result of this study, the gross and net fecundity and fertility rates were determined to be 306.51 and 236.25, respectively. The average number of eggs produced per female per day was obtained 11.48. The intrinsic and finite rates of increase on the 4th instar of C. maculatus were 0.163 and 1.18, respectively. The mean generation and doubling times were 35.30 and 4.24 days, correspondingly. The gross and net reproduction rates were 123.36 and 109.49 females/female/generation, respectively. The results of this study on the stable age distribution showed that 62.3 % and 37.7 % of the population belonged to immature stages and adults, respectively. The possible application of these results for biological control of C. maculatus is discussed.

The olive fly, Bactrocera oleae is an important pest of olive groves. Biology of this pest was investigated on five varieties of olive under laboratory conditions at temperature 25  2C, 65  5% RH and 16L: 8D. The results showed that there is not any significant difference on the total developmental time of immature stages of olive fly reared on five olive varieties. However, developmental time of larvae on two varieties of Zard and Golouleh showed significant difference with those fed on Shenge, Roghani and Marri. The generation times estimated on Marri, Roghani, Zard, Shenge and Golouleh varieties were 93.24  5.24, 91.56  5.78, 86.74  3.92, 84.86  2.39 and 82.56  2.85 days, respectively. The mean pre-oviposition period of the fly was 5.53  0.52 days and the mean time for the female to mate once again was 10.05  0.67 days. The female oviposition rate was affected by olive varieties. The mean number of the eggs laid by each female on olive fruit varieties of Goloule, Zard, Shenge, Roghani and Marri was obtained 340  69.9, 254  20.88, 221.75  45.44, 203.25  43.5 and 110.25  50.45, correspondingly. The mean longevity of the non-feeding male and female flies was estimated 2.92  0.2 and 3.16  0.21 days and it was 75.64  6.96 and 86.16  6.18 days for well-fed male and female flies with honey and water, respectively. The mean longevity of the well-fed male and female flies decreased to 56.55  3.53 and 67.7  4.18 days, respectively, as they had matting activity and olive fruits were presented to them for female oviposition.

Biology and demography of Ommatissus lybicus de Bergevin was studied under controlled conditions at 25 ± 1, 30 ± 1 and 35 ± 1˚C and 60 ± 5% RH and 16: 8 L: D. Forty eggs of the pest (0-24 h old) were used in each temperature treatment. Developmental time was obtained 82.48 ± 0.72, 75.79 ± 0.55 and 89.85 ± 0.71 days at 25, 30 and 35˚C, respectively. Moreover, at 35˚C, most of the biological activities of the dubas bug were disrupted and individuals, especially females, incurred relatively high mortalities. Female life span was significantly higher at 25˚C (108.21 ± 1.33 days) comparing to that of the other temperatures. The net reproductive rate (R0) was 45.93 and 52.31 at 25 and 30˚C; however, it extremely decreased at 35˚C (5.82). The intrinsic rate of increase (rm) was 0.054, 0.062 and 0.029 at 25, 30 and 35˚C, respectively. Similarly, doubling time (DT) was also close at 25 and 30˚C (14.2 vs 12.3 days) but it increased dramatically at 35˚C (29.27 days). Based on life table parameters observed, it was concluded that 30˚C could be an optimum temperature for the biological activities of O. lybicus.

The biology of greenbug, Schizaphis graminum Rondani, one of the most important pests of cereals in Varamin region of Iran, was studied in laboratory at 20 ± 1˚C, 60-70% R.H. and a photoperiod of 16: 8 (L: D) hours. The experiment was carried out by rearing aphids on the leaves of six common wheat varieties including: Mahdavi, Kavir, Niknezhad, Azadi, Tabasi, and Ghods using leaf cages. The nymphal development time, mortality, longevity and adult fertility of the aphid were recorded daily. The intrinsic rate of increase (rm), finite rate of increase (λ), and doubling time (DT) parameters were calculated. Results revealed that nymphal mortality rate was very low resembling that on sensitive wheat varieties. The aphid had relatively high longevity and short nymphal development time on all mentioned wheat varieties. The lowest aphid fertility rate was obtained on Kavir comparing to the fertility yielded on Mahdavi and Tabasi that was significantly higher (P < 0.01). Estimation of the intrinsic rate of increase revealed that the wheat varieties studied were susceptible to aphid, for the reason that the aphid population increased by constant exponential rate of 0.252-0.310 female/female/day. This showed high population increase potential at suitable conditions in the absence of natural enemies. Results proved that the Niknezhad, Tabasi and Ghods were the most suitable wheat varieties for rearing the aphid. The lowest rate of fertility, intrinsic rate of increase, and finite rate of increase, and the longest doubling time of aphid population were observed on Kavir, due to lower fecundity and longer nymphal development period. Therefore, the aphid population increase potential on Kavir was lower than that on the other varieties and so, expansion of sowing Kavir in Varamin region most probably may not result in aphid population increase.

In this study, 58 scale insects are recorded from Gilan, Mazandaran and Golestan Provinces, Iran. They belong to five families: Asterolecanidae, Coccidae, Diaspididae, Eriococcidae and Pseudococcidae. The general characters and identification keys to the genera are provided. The identified species are listed and associated with the localities, collecting dates, host plants and collector names. Among these species, 25 species are recorded from the pastures and forest trees, of which Cryptococcus fagisuga Lindinger causes serious damage to Fagus orientalis. Four species, i.e. Leucaspis pusilla Löw, Eriococcus spurius (Modeer), Planococcus vovae (Nasonov) and Lopholeucaspis japonica (Cockerell) are more distributed in urban areas. Twenty four species are recorded on the fruit trees broadly: Aonidiella aurantii (Maskell), Aspidiotus nerii Bouché, Chrysomphalus dictyospermi (Morgan), Parlatoria oleae (Colveé), Ceroplastes floridensis Comstock, Coccus hesperidum Linnaeus, Pulvinaria aurantii Cockerell, Pseudococcus viburni (Signoret) and Planococcus citri (Risso). Twenty eight species are reported on ornamental plants extensively in the southern coast of the Caspian Sea: A. nerii, C. hesperidum, C. dictyospermi, P. oleae, P. citri.

The sugarcane stem borers, Sesamia cretica Led. and S. nonagrioides Lef. are the most important pests of sugarcane in Iran. The egg parasitoid wasp, Telenomus busseolae Gahan is the most important natural enemy of Sesamia spp. in Khuzestan province that play an important role in regulating populations of sugarcane stem borers. A field experiment was conducted to evaluate the performance of T. busseolae on sugarcane commercial varieties in Khuzestan province (southwest of Iran). This study was conducted in a split plot design on 4 sugarcane commercial varieties (i.e. CP69-1062, CP48-103, CP57-614 and SP70-1143) with 5 fields per variety in Khuzestan in 2007. The sampling of egg masses were carried out within the tillering stage of sugarcane (5-15 June) and the final stage of sugarcane growing (10-20 October). Our results indicated that both growth stage and variety of sugarcane had a significant effect on the egg batch density, discovery efficiency and percent parasitism. The interaction between growth stage and variety on percent parasitism and discovery efficiency were statistically different (P<0.01). The effects of growth stage, variety and interaction between them on parasitism efficiency, adult emergence and F1 progeny sex ratio were not statistically significant. The highest egg batch density, discovery efficiency and percent parasitism was observed on the CP48-103 variety. Based on our results, T. busseolae shows considerable parasitism on this variety.

During 2005-2006, an investigation was carried out on the mites associated with stored rice in Guilan province, Iran. Two species of Phytoseiid mites were collected and identified as Proprioseiopsis bregetovae (Abbasova, 1970) and Typhlodromus (Anthoseius) transvaalensis (Nesbitt, 1951). Both are reported here for the first time from Iran. The association of these two species with the habitat of stored rice is also new.

In the course of study on larval parasitoids of carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae), an hyperparasitoid wasp, Pachycrepoideus vindemmiae Rondani, was collected from pupae of Apanteles sp. (Hym.: Braconidae). The latter species is the larval parasitoid of the carob moth. The P. vindemmiae belongs to the family Pteromalidae and is a new record for Iran insect fauna.

The seed beetle, Stafor limbatus (Horn) (Col.: Bruchidae), collected from Bushehr and Yazd provinces, Iran, on Acasia sp. and Prosopis farcta, is newly recorded from Iran. It is native to southwestern United States but distributed in various parts of the world. The beetle was identified by Delobel from France.

Low prominence of natural enemies can cause suboptimal success in biological control programs. In present study, the effects of honey feeding and the availability of males were studied on the biological characteristics of Trichogramma brassicae Bezdenko. Four treatments were considered: male was available for female for merely 24 h, either with or without honey; male was continuously presented for females, either with or without honey. Twenty pairs (1 female × 1 male) of newly emerged parasitoids were placed in glass tubes and considered as the treatments. Mortality of females was recorded daily in order to indicate longevity. To determine fecundity, the emergence rate and female progeny percentage, 150 fresh Sitotroga cerealella Olivier eggs were provided for each female in the entire treatments on a daily basis. Results indicated that interaction between adult nutrition and male presence was insignificant (P > 0.01) and did not influence any of biological characteristics. Adult nutrition was more important than male presence. Honey-fed females lived 5-folds longer than the unfed females. Longevity was not significantly influenced by male presence. Fecundity of honey-fed females was 67 and 70.2 eggs; however, 18.4 and 19 eggs for unfed females. Continuous presence of male did not change fecundity. There were no significant differences in the emergence rate in all treatments and it was more than 90% for the entire treatments. Long-lived females produced more males. Percentage of female progeny was not influenced by period of male presence. Therefore, quality of parasitoids was more persuaded by diet provided rather than the period of male presence.

Multivariate analyses of the morphological variation in five geographical populations of the pod borer, Helicoverpa armigera (Hübner), was performed using 15 and 12 landmarks selected from the fore- and hindwings respectively. Using their geometric morphometric characters (26 in the forewings and 20 in the hindwings), 287 and 277 images of fore- and hindwings were made respectively. Analyses of size showed the wings of the females are bigger than those of the males (forewing: F = 3.98, P = 0.047; hindwing: F = 14.62, P = 0.000) on populations tested. The discriminant function analysis (DFA) of fore- and hindwings differentiated five geographical populations with 86.1% and 69.3%, respectively. The multivariate analysis of variance (MANOVA) of shape variables in fore- and hindwings indicated significant differences among populations as well as sexes (at least for one of the shape variables). Sex interaction within the populations was significant in fore- and hindwings, particularly based on the hindwing landmarks. The relative warp analysis (RWA) showed well-supported discrimination between sexes. The results showed significant difference between the sexes and also within the populations.

An entomopathogenic nematode was isolated by Galleria baiting technique from soil samples collected near Marand, East Azarbaijan province, North-west of Iran during 2003. Based on morphological and morphometric characters, as well as molecular data it was identified as Steinernema bicornutum Tallosi, Peters & Ehlers, 1995. Morphometrics comparison of the isolate with the type species showed no obvious differences between them. Differences in ITS-rDNA PCR-RFLP were found between the Iranian isolate, i.e. IRA7, with the type (Yugoslavian) isolate. The RFLP analysis was able to distinguish Iranian isolate from the type population of S. bicornutum in the HinfI (four restriction sites in the type vs three restriction sites in the IRA7), Hin6I (550, 250 and 250 bp in the studied isolate vs 541 and 474 in the type isolate) and AluI profiles (715, 177 and 123 in the type and 710 and 220 in the IRA7). These molecular differences are considered as intraspecific variations, and the described population from Iran is another isolate of S. bicornutum.