The quality of the egg‐parasite Trichogramma maidis Pintureau et Voegelé, reared from the two factitious hosts, Ephestia kuehniella Zell. and Sitotroga cerealella (Olivier), has been assessed in laboratory and field experiments. Biological parameters like fecundity, longevity, sex ratio, activity and parasitization rate were measured in adults reared from both hosts. Host eggs of E. kuehniella are larger than those of S. cerealella and, as a consequence, adult parasites reared in E. kuehniella are bigger. This difference in size, however, is the only distinction between adults reared from either hosts. Other characteristic quality traits, such as fecundity, locomotion and sex ratio were equal. Field experiments showed a slight tendency for a higher potential of adult parasites reared in E. kuehniella in parasitizing natural host eggs. It is concluded that both factitious hosts are equally suitable for massrearing T. maidis in terms of quality of the adult egg‐parasites. Zusammenfassung Untersuchungen zur Qualität des Eiparasiten, Trichogramma maidis Pintureau et Voegelé, bei Zucht auf Eiern der beiden Ersatzwirte Ephestia kuehniella Zell. und Sitotroga cerealella (Olivier) Der Eiparasit, Trichogramma maidis Pintureau et Voegelé, wird in Europa zur biologischen Bekämpfung des Maiszünslers, Ostrinia nubilalis Hübn., eingesetzt. Die Massenzucht erfolgt entweder auf Eiern der Mehlmotte, Ephestia kühniella Zell, oder der Getreidemotte, Sitotroga cerealella (Olivier). Es ist bekannt, daß die Qualität der Eiparasiten, und dadurch der Bekämpfungserfolg, vom Wirtsei abhängig ist. In der vorliegenden Studie wurden Qualitätskriterien wie zum Beispiel Fekundität und das Parasitierungspotential im Freiland an adulten T. maidis gemessen, die auf Eiern der Mehl‐ bzw. Getreidemotte gezüchtet waren. Es zeigte sich, daß die Parasitenweibchen aus Mehlmotten‐Eiern größer sind. Neben diesem Merkmal konnten keine signifikanten Unterschiede zwischen adulten Parasiten, die sich auf den beiden Wirten entwickelt hatten, gefunden werden. Unter Feldbedingungen erwiesen sich die Parasiten aus Ephestia‐Eiern tendenzmäßig leicht überlegen. Generell läßt sich aber eindeutig sagen, daß sich Mehl‐ und Getreidemotten, bezüglich der Qualität von T. maidis, als Ersatzwirte gleich gut eignen. Ob dieser Eiparasit auf dem einen oder andern Ersatzwirt gezüchtet wird, darf daher alleine von wirtschaftlichen Überlegungen abhängig gemacht werden.

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An accurate comprehension of celerity (flood wave speed) dynamics is a key step for understanding flood wave propagation in rivers. We present the results of empirically estimated celerity values in 12 Brazilian rivers, and analyse the behaviour of celerity-discharge relationships (CxQ). Celerity was estimated with a reach-scale (RS) method, based on the peak travel time between stations; and with a local-scale (LS) method, based on the derivative of discharge-cross-section area relationships surveyed at gauging stations. The results indicate that the magnitudes of celerity values obtained by the methods are reasonably comparable, and can rarely be considered constant, varying with river discharge. Three reaches presented differing CxQ relationships at local and reach scales, which suggests that in situ cross-sections at gauging stations should not be extrapolated as representative of the whole reach for flood routing studies, and that CxQ relationship assessments might provide relevant insights for hydrological modelling.

Parasitoid host selection is mainly mediated by chemical cues, which can be adjusted by experience, changing their innate behavior. Therefore, this study evaluated if immature experience (pre-imaginal conditioning) on eggs and volatiles from different host eggs has influence on parasitism and chemotaxic behavior of Telenomus podisi Ashmead and/or Trissolcus basalis Wollaston (Hymenoptera: Scelionidae). Both wasp species were submitted to a multiple-choice parasitism test among Euschistus heros (Fabricius), Piezodorus guildinii (Westwood), and Nezara viridula L. (Hemiptera: Pentatomidae) (Hemiptera: Pentatomidae) egg masses. Eggs from these three stink bugs were equally offered to female parasitoids. After that, adults which emerged from each host were also exposed to parasitism in a multiple-choice test for up to an additional generation. Moreover, in olfactometer "Y," the behavior of innate and experienced T. podisi females to volatiles from hosts' egg extracts was tested, to study their learning and memory ability. The original host had influence on T. podisi parasitism; however, T. basalis always parasitized more N. viridula eggs independently of its last rearing host. Innate T. podisi females responded positively to E. heros and P. guildinii egg volatiles, but this behavior was not observed in N. viridula. When T. podisi females were experienced on egg volatiles from a new host, they showed significant learning and memory ability for the specific host volatile for, at least, 24 h. Experienced wasps responded positively to N. viridula and through this result we have evidences about the possibility to manipulate wasp's preferences to a specific target host.