Biological and biochemical parameters of a flightless strain of Harmonia axyridis, fed on a pork liver-based artificial diet and on Ephestia kuehniella eggs as controls, were compared. The diet-grown larvae showed a significantly longer developmental time and a lower adult emergence rate compared to control larvae. The weights of the newly emerged adults were significantly higher for adults fed E. kuehniella eggs during their larval stages than fed the artificial diet. In contrast, larval food source had no effect on the duration of the pre-oviposition period or adult longevity. For adults fed on E. kuehniella eggs as larvae, a significantly longer pre-oviposition period, lower daily weight gain and fecundity were found for the diet-fed females compared to those fed on E. kuehniella eggs throughout the life span. The adult food source had no significant effect on longevity and fertility. Lower amino acid and fatty acid contents (in particular C16:1 and C18:3n-3) were found for the prepupae and newly emerged females obtained from diet-reared larvae compared to controls. Deficiencies in fatty acids C16:1 and C18:3n-3 were also observed in females obtained from E. kuehniella egg-reared larvae and fed on diet from adult emergence. The analyses of the foods showed deficiencies in artificial diet, especially for some amino and fatty acids. The results suggest a non-optimal composition of the artificial diet and some possibilities for its improvement. However, this polyphagous predator could be reared from first instar larvae to fully reproductive adults on a pork liver-based artificial diet.

Quantitative and qualitative parameters of Exorista larvarum (L.) (Diptera: Tachinidae) reared on two insect‐material‐free artificial media and in the factitious host Galleria mellonella L. (Lepidoptera: Pyralidae) were compared. Significantly higher puparial yields and weights were obtained in both a milk‐based and a veal homogenate‐based medium than in the factitious host. Longevity and parasitization rates were not different between the in vitro‐ and in vivo‐reared flies. Despite the greater puparial weight of the veal medium‐reared E. larvarum females, the number of eggs laid by these females on host larvae was not higher than that of females reared under the other two rearing conditions. Moreover, in a complementary experiment, with homogeneous puparial weights of milk medium‐ and host‐reared females, the former oviposited fewer eggs. Hence, puparial weight alone is not a reliable quality parameter for E. larvarum reared on artificial media. Lower amino acid content, with a deficiency in aromatic amino acids and an excess in proline, was found for in vitro third instar parasitoid larvae reared on both media compared to the in vivo‐reared ones. These results suggest a correlation between the amino acid deficiency and imbalance of medium‐reared larvae and the lower number of eggs laid by the females obtained.

The European pine sawfly, Neodiprion sertifer (Geoffroy) (Hymenoptera: Diprionidae), is a widespread and economically important forest insect. The sex pheromone communication system of this species has been previously investigated in North America, Japan and Europe, with the acetate or propionate of the alcohol (2S,3S,7S)‐3,7‐dimethyl‐2‐pentadecanol (diprionol) shown to be the main pheromone component. In some locations, male attraction either increased or decreased by the addition of the (2S,3R,7R)‐diprionyl acetate isomer. However, these studies were made with different batches of synthetic pheromones, with different types of traps and according to different procedures, so the observed differences might not reflect true geographic variation. Here we investigate the geographic pattern of male sawfly response by using identical chemicals, traps and experimental procedures at eight field sites ranging from Japan in the east to Canada in the west. We found an increased inhibitory effect of the (2S,3R,7R)‐isomer from Japan and Siberia to Europe. At the eastern sites, increasing amounts of the (2S,3R,7R)‐isomer up to and equal to the amount of the (2S,3S,7S )‐isomer, did not influence the trap catch, whereas at sites in Europe, as little as 1% of the (2S,3R,7R)‐isomer almost completely inhibited the attraction. The response of the North American population was intermediate. The only site in which the (2S,3R,7R)‐isomer was essential for the attraction of males was in Siberia. A similar pattern was found for the (2S,3R,7S)‐isomer. Both the acetate and the propionate form of the (2S,3S,7S)‐isomer were attractive by themselves in Japan, Europe and North America, and neither the (2S,3R,7S)‐isomer nor the (2S,3R,7R)‐isomer alone were attractive, in the acetate or propionate form. We discuss the significance of our findings for the development of more efficient monitoring schemes and for the causes of population divergence and speciation in the European pine sawfly.

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