The performance of two aphid parasitoids, Aphidius colemani Viereck and Aphidius matricariae (Haliday), against Aphis gossypii Glover on greenhouse cucumber (Cucumis sativus L.) and Myzus persicae (Sulzer) on sweet pepper (Capsicum annuum L.) were evaluated at various constant temperatures. Biological parameters of both parasitoids including developmental time, pupal survivorship, percentage of parasitism, and sex ratio of the progeny were studied at 5, 10, 15, 20, 25, 30, and 35 degrees C. At 25 degrees C, an average of 10.0 +/- 1.1 and 9.8 +/- 1.1 d was needed for A. colemani to complete its development from oviposition to adult eclosion on A. gossypii and M. persicae, respectively. The corresponding average times needed for A. matricariae were 11.9 +/- 0.9 and 11.5 +/- 1.1 d, respectively. The lower developmental thresholds for A. colemani reared on A. gossypii and M. persicae were estimated from linear regression equations to be 2.97 and 2.65 degrees C, respectively, whereas these values for A. matricariae were 3.37 and 3.51 degrees C, respectively. Parasitization rate of both parasitoid species, recorded as percent aphids mummified, increased almost linearly with increasing temperature to reach a maximum at 25 degrees C and decreased at 30 degrees C. The optimal temperatures for development of A. colemani and A. matricariae were approximately 30 and 25 degrees C, respectively, and high mortality occurred at higher temperatures. The Lactin 2 and Briere 1 developmental models were accepted based on their excellent goodness-of-fit to the data (residual sum of square and coefficient of determination) and estimable temperature thresholds and are strongly recommended for the description of temperature-dependent development of A. colemani and A. matricariae.

The functional response of two aphid parasitoids, Aphidius colemani Viereck and Aphidius matricariae (Haliday) (Hymenoptera: Aphidiidae), on the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), was examined. Five constant temperatures (10, 15, 20, 25, and 30°C) and six host densities (2, 4, 8, 16, 32, and 64) were used during a 24-h period. At each temperature, 2-64 third-instar nymphs of A. gossypii were exposed to individual wasp mating pairs. A type II functional response model for both parasitoid wasps was fit separately for each temperature. The results showed that instantaneous attack rate (a) in A. colemani increased linearly as the temperature increases from 10 to 30°C, but in A. matricariae, (a) increased almost linearly with temperature to reach a maximum at 25°C, and then decreased at 30°C, displaying an asymmetrical domeshaped pattern. The highest instantaneous attack rate for A. colemani and A. matricariae were calculated 0.940 ± 0.144 day À1 at 30°C and 0.687 ± 0.157 day À1 at 25°C, respectively. Handling time (T h ) for A. colemani was inversely proportional to temperature and ranged from 0.093 ± 0.026 day at 10°C to 0.032 ± 0.004 day at 30°C, but in A. matricariae, (T h ) was between 0.078 ± 0.015 day at 10°C and 0.036 ± 0.014 day at 20°C. A. colemani achieved higher parasitism rate than A. matricariae at higher temperatures. This observation suggests that A. colemani maybe more effective for biological control of the cotton aphid during warmer periods.

Temperature-dependent development, survivorship and reproduction of the cotton aphid, Aphis gossypii on Cucumis sativus L. were evaluated at six constant temperatures (10, 15, 20, 25, 30 and 35°C). Developmental periods of immature stages varied from 20.70 days at 10°C to 3.81 days at 30°C. The population failed to survive at 35°C. As temperature increased, the intrinsic rate of increase (r m ) followed a typical asymmetrical dome-shape pattern, with maximum value of 0.419/day at 25°C. Survival of immature stages differed from 55.97% to 93.14% within the range of 10-30°C. The average adult longevity ranged from 8.56 days at 30°C to 17.00 days at 25°C. Three mathematical models were compared for accuracy in predicting the developmental rate of A. gossypii, and estimating its temperature thresholds and optima. The developmental threshold was estimated to be 6.19°C, and the thermal constant was 97.09 degree-days, using the linear model. The Briere 2 and Lactin 2 models were accepted for success to satisfy criteria of goodness-of-fit (residual sum of square and coefficient of determination) and estimable temperature threshold parameters and highly recommended for the description of temperature-dependent development of A. gossypii. No other data are available in using nonlinear models to describe the relationship between temperature and A. gossypii development.

Bacterial endosymbionts play important roles in ecological traits of aphids. In this study, we characterize the bacterial endosymbionts of A. gossypii collected in Karaj, Iran and their role in the performance of the aphid. Our results indicated that beside Buchnera aphidicola, A. gossypii, also harbors both Hamiltonella defensa and Arsenophonus sp. Quantitative PCR (qPCR) results revealed that the populations of the endosymbionts increased throughout nymphal development up to adult emergence; thereafter, populations of Buchnera and Arsenophonus were diminished while the density of H. defensa constantly increased. Buchnera reduction caused prolonged development and no progeny production. Furthermore, secondary symbiont reduction led to reduction of the total life span and intrinsic rate of natural increase as well as appearance of the deformed dead offspring in comparison with the control insects. Reduction of the secondary symbionts did not affect parasitism rate of the aphid by the parasitic wasp Aphidius matricariae. Together these findings showed that H. defensa and Arsenophonus contributed to the fitness of A. gossypii by enhancing its performance, but not through parasitoid resistance.

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The parasitoids (Hymenoptera, Braconidae, Aphidiinae) of the cowpea aphid, Aphis craccivora Koch, were investigated throughout two far distant provinces, Tehran and Sistan-Baluchestan. Colonies of the cowpea aphid were collected from different host plants and reared under laboratory conditions until the parasitoids emerged. The aphids were parasitized by an expected range of parasitoids. The species were Aphidius colemani Viereck, Lysiphlebus fabarum (Marshall), Lysiphlebus confusus Tremblay and Eady, Lysiphlebus testaceipes (Cresson), Binodoxys acalephae (Marshall), Binodoxys angelicae (Haliday), Praon volucre (Haliday) and Ephedrus persicae Froggatt. L. testaceipes is reported here for the first time in Iran. The most common species was L. fabarum followed by B. acalephae and L. confusus. A key is provided for identification and host plant associations are considered.

Host stage preference, functional response and mutual interference of Aphidius matricariae (Haliday) (Hym.: Braconidae: Aphidiinae), parasitoid of the black bean aphid, Aphis fabae Scopoli (Hom.: Aphididae) were investigated in a growth chamber at a temperature of 25°C, 65% relative humidity and a photoperiod of 16 h light : 8 h dark on the PP8 variety of sugar beet. Nicholson's model and linear regression were used to determine per capita searching efficiency and interference coefficient, respectively. The highest parasitism percentage was observed on the third instar nymphs of A. fabae in both choice and no-choice preference tests. There was significant difference between rates of parasitism on different stages of A. fabae (P < 0.01). Using logistic regression, a type II functional response was determined for A. matricariae. The Holling and Rogers models were used for estimating searching efficiency (a) and handling time (Th). The data was fitted by the Rogers equation better than by the Holling disc equation based on the R 2 values. The estimated values of searching efficiency and handling time were 0.040 Ϯ 0.013/h and 3.439 Ϯ 0.383 h, respectively. The per capita searching efficiency decreased significantly from 0.272 to 0.139 as parasitoid densities increased from one to five. Therefore, different host-parasitoid ratios could affect the efficacy of A. matricariae.

The genus Gasteruption Latreille, 1796 (Hymenoptera: Evanioidea: Gasteruptiidae: Gasteruptiinae) from North Iran and Turkey is revised, keyed and fully illustrated for the first time. In total 36 species are treated of which 33 are recorded from Turkey and 23 from Iran. Fifteen species are new for science: Gasteruption aciculatum van Achterberg, sp. n., Gasteruption agrenum van Achterberg, sp. n., Gasteruption brevibasale van Achterberg & Saure, sp. n., Gasteruption coriacoxale van Achterberg, sp. n., Gasteruption flavimarginatum van Achterberg, sp. n., Gasteruption heminitidum van Achterberg, sp. n., Gasteruption henseni van Achterberg, sp. n., Gasteruption ischnolaimum van Achterberg, sp. n., Gasteruption nigrapiculatum van Achterberg, sp. n., Gasteruption paglianoi van Achterberg & Saure, sp. n., Gasteruption pseudolaticeps van Achterberg, sp. n., Gasteruption punctifrons van Achterberg, sp. n., Gasteruption schmideggeri van Achterberg & Saure, sp. n., Gasteruption scorteum van Achterberg, sp. n. and Gasteruption smitorum van Achterberg, sp. n. Twenty-one species are reported new for Turkey and 16 species new for Iran. Fifteen new synonyms are proposed: Foenus terrestris Tournier, 1877, Gasteruption trifossulatum Kieffer, 1904, and Gasteruption ignoratum Kieffer, 1912, of Gasteruption caucasicum (Guérin-Méneville, 1844); Gasteruption daisyi Alekseev, 1993, of Gasteruption dolichoderum Schletterer, 1889; Gasteruption assectator var. nitidulum Schletterer, 1885, of Gasteruption freyi (Tournier, 1877); Gasteruption schossmannae Madl, 1987, of Gasteruption hastator (Fabricius, 1804); Gasteryption fallaciosum Semenov, 1892, Gasteruption dubiosum Semenov, 1892 and Gasteruption obsoletum Semenov, 1892, of Gasteruption insidiosum Semenov, 1892; Gasteryption schewyrewi Semenov, 1892, of Gasteruption jaculator (Linnaeus, 1758); Gasteruption floreum Szépligeti, 1903, of Gasteruption lugubre Schletterer, 1889; Gasteruption trichotomma Kieffer, 1904, and Gasteruption palaestinum Pic, 1916, of Gasteruption merceti Kieffer, 1904; Gasteryption foveiceps Semenov, 1892, of Gasteruption nigrescens Schletterer, 1885, and Gasteruption libanense Pic, 1916, of Gasteruption syriacum Szépligeti, 1903. Gasteruption lugubre Schletterer, 1889, is recognised as a valid species. Lectotypes are designated for Ichneumon assectator Linnaeus, 1758; Ichneumon jaculator Linnaeus, 1758; Foenus terrestris Tournier, 1877; Foenus freyi Tournier, 1877; Foenus nigripes Tournier, 1877; Foenus goberti Tournier, 1877; Foenus granulithorax Tournier, 1877; Foenus minutus Tournier, 1877; Foenus borealis Thomson, 1883; Faenus diversipes Abeille de Perrin, 1879; Foenus rugulosus Abeille de Perrin, 1879; Faenus obliteratus Abeille de Perrin, 1879; Faenus undulatum Abeille de Perrin, 1879; Faenus variolosus Abeille de Perrin, 1879; Gasteruption distinguendum Schletterer, 1885; Gasteruption laeviceps Schletterer, 1885; Gasteruption thomsonii Schletterer, 1885; Gasteruption foveolatum Schletterer, 1889; Gasteruption sowae Schletterer, 1901; Gasteruption foveolum ...