Tempo de busca e de manuseio de larvas de Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) alimentadas com Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae)

Searching and handling time of Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) larvae fed on Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae). The objective of this research was to determine the searching and handling times of three larval instars of C. externa fed on U. ambrosiae at densities of 30, 40 and 50 per vial, with the feeding of the larvae at the preceding instars being U. ambrosiae nymphs or Sitotroga cerealella (Olivier, 1819) eggs. The larvae were maintained at 25 ± 2 ºC, 70 ± 10% RH and a 14-h photophase. A completely randomized design in a 6 x 3 factorial scheme with 12 replicates was adopted. The shortest searching time was found for the 2nd and 3rd instar larvae of C. externa, and this parameter was variable depending on the feeding given to the larvae previously. The handling time was similar for the 1st, 2nd and 3rd instar larvae. The longest searching time was found at an aphid density of 30, as compared to densities of 40 and 50 prey, with which there were no significant differences. Prey density did not have any influence on handling time.

Potencial de alimentação de Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) em diferentes densidades de Uroleucon ambrosiae (Thomas, 1878) (Hemiptera, Aphididae)

Feeding potential of Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) in different densities of Uroleucon ambrosiae (Thomas) (Hemiptera, Aphididae). The feeding potential of 2nd and 3rd instar larvae of Chrysoperla externa (Hagen, 1861) in relation to different densities of 30, 40 and 50 nymphs of Uroleucon ambrosiae (Thomas, 1878) at 3rd and 4th instars was evaluated. The treatments were individualized into 2.5 cm in diameter and 8.5 cm tall flat bottom glass vials and maintained in a controlled environmental chamber at 25±2 ºC temperature, 70±10% RH and 14 h photophase. A completely randomized experimental design with 10 replications was used. The consumption of the prey nymphs by the predator larvae was evaluated after 1, 2, 4, 8, 16 and 24 h from the beginning of the experiment and at every subsequent 24 h period until 2nd instar larvae molted or 3rd instar larvae pupated. Results have shown that for 2nd instar larvae, during the 1 h to 24 h period, there was a decreasing prey consumption at the 30 and 40 prey densities. However an increase in the consumption at the 50 prey density was observed. After this period, C. externa larvae presented a progressive increase on nymphs consumption as a function of the prey density. The same occurred with de 3rd instar predator larvae in all treatments. When daily mean consumption was evaluated the predator/prey ratio was 1:23, 1:27 and 1:33 for 2nd instar larvae and 1:27, 1:33 and 1:41 for 3rd instar larvae at 30, 40 and 50 nymph densities, respectively.

Married to intolerance: Attitudes towards intermarriage in Germany, 1900-2006

Marriage is amongst the biggest decisions in life. In general, there is a tendency towards assortative matching people marry others who are relatively similar to themselves. Intermarriage between different social, religious and ethnic groups in most societies is relatively rare (Blossfeld and Timm 2003). Where it occurs, it is associated with more rapid assimilation (Meng and Gregory 2005). The frequency of intermarriage can therefore serve as a useful indicator of tolerant attitudes towards a minority, and of the desire to integrate (Bisin, Topa, and Verdier 2004).In this paper, we analyze under which conditions intermarriage can be used as an indicator of tolerance, and whether such tolerant attitudes persisted in Germany during the last century. We combine information on individual-level attitudes from the German social survey (GESIS) with historical data on marriage patterns.

Productividad, competencia e innovación en la banca privada española (1900-1914)

This study investigates the productivity differences and its sourcesacross a set of banks during the last years of the liberal era of theSpanish banking system (1900-1914). These years were characterised bymajor qualitative and quantitative changes in the banking industry includinga sharp increase in the size of the system, in the number of firms, andin its regional distribution. Employing DEA productivity analysis andthe Malmquist index, we discover that these changes were accompanied bya generalised increase in the efficiency of least productive banks. Also,we observe that the crisis of some regional banking groups, like theCatalan, can be linked with its low productivity levels. In consequence,in the light of our productivity evidence, we conclude that the increasein competition was beneficial for the system because helped to the successof the most efficient banks.

[Collection Jules Beau. Photographie sportive] : T. 13. Année 1900 / Jules Beau

Donateur : Touring-Club de France