Maternal investment, sex-differential prospects, and the sex ratio in wild house mice

In a population of first-generation offspring from wild-caught house mice (Mus musculus domesticus), previous evidence suggested that male fitness is more strongly affected by an increase in body weight than female fitness. This paper shows that in these mice the young are weaned at heavier weights the smaller the litter and the better the maternal body condition. These effects persisted into adulthood and were less pronounced in female young. However, contrary to expectation from conventional sex ratio theory, maternal condition and litter size had no detectable effect on sex ratios. Also, litter size did not affect sex ratios in two populations of laboratory-kept, wild-caught western (M. m. domesticus) and eastern house mice (M. m. musculus). Wild house mice, therefore, appear not to adaptively manipulate the sex ratio of offspring. It is argued that this absence of sex ratio trends might not be maladaptive, but rather that models currently used to predict sex ratio trends in rodents may not be valid. Received: 13 March 1997 / Accepted after revision: 9 August 1997     

Reduction of ammonia emission by shallow slurry injection: injection efficiency and additional energy demand

Ammonia (NH3) emission from livestock production causes undesirable environmental effects and a loss of plant-available nitrogen. Much atmospheric NH3 is lost from livestock manure applied in the field. The NH3 emission may be reduced by slurry injection, but slurry injection in general, and especially on grassland, increases the energy demand and places heavy demands on the slurry injection techniques used. The reduction in NH3 emission, injection efficiency, and energy demand of six different shallow slurry-injection techniques was examined. The NH3 emission from cattle slurry applied to grassland was reduced by all the injectors tested in the study, but there were major differences in the NH3 reduction potential of the different types of injectors. Compared with the trailing hose spreading technique, the NH3 loss was reduced by 75% when cattle slurry was injected using the most efficient slurry injection technique, and by 20% when incorporated by the least efficient injection technique. The reduction in NH3 emission was correlated with injection depth and the volume of the slot created. The additional energy demand for reducing ammonia emissions by slurry injection was approximately 13 000 kJ ha(-1) for a 20% reduction and 34 000 kJ ha(-1) for a 75% reduction. The additional energy demand corresponds to additional emissions of, respectively, 5.6 and 14.5 kg CO2 per ha injected.     

Linné, die Tiere und der Mensch. Zum 250. Geburtstag Carl von Linnés am 23. Mai 1957

The Science of Nature -     

Episodes of incivility between subordinates and supervisors: examining the role of self‐control and time with an interaction‐record diary study

Scholars have hypothesized that experiencing incivility not only negatively affects well‐being, but may even trigger further antisocial behavior. Previous research, however, has focused mainly on the relation between incivility and well‐being. Thus, little is known about the behavioral consequences of incivility. With this in mind, we conducted an interaction‐record diary study to examine whether supervisor incivility causes retaliatory incivility against the supervisor. Using the self‐control strength model as a framework, we further examined whether the target's trait (trait self‐control) and state (exhaustion) self‐regulatory capacities moderate this effect. In addition, we examined the role of time by testing the duration of the effect. When we analyzed the full data set, we found no support for our hypotheses. However, using a subset of the data in which the subsequent interaction happened on the same day as the prior interaction, our results showed that experiencing incivility predicted incivility in the subsequent interaction, but only when the time lag between the two interactions was short. Furthermore, in line with the assumption that self‐regulatory capacities are required to restrain a target from retaliatory responses, the effect was stronger when individuals were exhausted. In contrast to our assumption, trait self‐control had no effect on instigated incivility. Copyright © 2015 John Wiley & Sons, Ltd.