The effect of temperature on the development of the predators Nephus includens (Kirsch) and N. bisignatus (Boheman) (Coleoptera: Coccinellidae), was studied. The development time of immature stages and the pre-oviposition period of adult females for the two predators was recorded at eight constant temperatures (10, 15, 20, 25, 30, 32.5, 35 and 37.5°C). The beetles were reared on eggs, nymphs and female adults of Planococcus citri (Risso) (Homoptera: Pseudococcidae) that had developed on squash (Cucurbita pepo) and on sour orange leaves (Citrus aurantium). Using the linear mode! for the biological cycle of N. includens on squash and on sour orange leaves, the developmental zeros (lower temperature thresholds) were estimated to be 10.9 and 11.0°C respectively and the thermal constants, 490.5 and 472.8 day-degrees respectively. Using the Lactin model the lower thresholds were estimated to be 11.1 and II.2°C respectively and the upper thresholds 36.1 and 36.0 U C respectively. For the biological cycle of N. bisignatus, using the linear model, the lower thresholds were estimated to be 9.4°C on squash and 9.3°C on sour orange leaves and the thermal constants were 614.3 and 647.9 day-degrees respectively. Using the Lactin model the lower thresholds were estimated to be 9.9 and 10.0"C respectively and the upper thresholds, 34.7 and 35.0"C respectively. The survival rate of N. includens instars at 10, 15, 20, 25, 30, 32.5, 35 and 37.5°C on squash and on sour orange leaves was respectively 0, 34.9, 63.2, 70.6, 63.3, 54.5, 19.8, 0, and 0, 32.2, 61.0, 68.0, 68.3, 56.6. 17.6, 0%. The survival rate of N. bisignatus instars at 10, 15, 20, 25, 30, 32.5 and 35°C on squash and on sour orange leaves was respectively, 0, 39.9, 61.1, 60.7, 47.2, 26.4, 0 and 0, 35.7, 65.7, 68.0, 44.2, 29.1, 0%. The results show that N. includens has a shorter biological cycle than N, bisignatus, whereas the latter species has lower temperature thresholds.

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Phenological and some biological characteristics of Hippodamia (Adonia) variegata (Goeze) (Coleoptera: Coccinellidae), such as voltinism, hibernation, number of progeny produced by each generation, mating activity and sex ratio were studied, in order to evaluate the significance of this predator. The study of phenology was conducted in outdoor cages in Kifissia (Athens), during 1999-2001 and as prey was given Dysaphis crataegi (Kaltenbach). Hippodamia variegata completed seven generations between April and November. The hibernating population of H. variegata consisted of adults of 6th and 7th generations. The fecundity of the predator was studied under constant conditions [25°C, 65% R.H. and 16:8(L:D)h photoperiod] in the laboratory and some population parameters were calculated: The total fecundity ranged between 789 and 1256 eggs, while the mean total fecundity was 959.6 eggs. The greatest proportion of eggs (45%) was oviposited in clutches of 11-20 eggs. The net reproductive value (R 0 ) was found to be 425.9 females/female, the intrinsic rate of increase (r m ) 0.178 females/female/day and the mean generation time (T) 34.0 days.

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Abstract. The main effects and interactions of adult age, access to food and host deprivation, on the egg load of Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), a larval parasitoid of Ephestia kuehniella (Lepidoptera: Pyralidae) and other pyralids, were studied in the laboratory. Intraspecific variation in the number of ovarioles was also studied. There was a positive and significant correlation between wasp size and both egg load and ovariole number, with the reproductive system of large wasps containing significantly more ovarioles and mature eggs than small wasps. Newly emerged adult wasps contained 27 AE 2.4 ovulated (mature) eggs in their lateral oviducts. Access to food and host deprivation were the only conditions under which egg load increased with parasitoid age. Wasps that had access to hosts immediately after emergence showed a significant decline in their egg complement, irrespective of food presence. Under conditions of both host and food deprivation, there was practically no alteration of egg load with parasitoid age. A three-way analysis of variance revealed that egg load varies significantly with food or host access but not with parasitoid age. All interactions among the three factors were significant. It is confirmed that there is no egg resorption in V. canescens and that egg production stops in the absence of food.