High-level Values Research Articles

Seasonal decline in intracolony genetic relatedness in eastern tent caterpillars: implications for social evolution

Genetic relatedness in social insect colonies may vary spatially or temporally as a result of changes in colony membership due to immigration or to variation in patterns of maternity and paternity. We estimated relatedness for eastern tent caterpillars (Malacosoma americanum) in laboratory colonies derived from egg masses using multilocus genotypic data derived from electrophoresis. This estimate is compared with estimates obtained from colony samples taken in the field at four intervals spanning the larval developmental season. We found that average intracolony relatedness is close to 0.5 initially but declines through the developmental season due to colony merging, showing that caterpillars do not discriminate between siblings and nonsiblings in order to preserve colony family structure. Using the intracolony values together with relatedness values for higher levels of population structure, we estimated the effective mean number of simple families represented in single colonies through the season. The overall effective number of families per tent increased from one at the time of eclosion to 1.3 by the end of the season. Average intracolony relatedness remained relatively high despite the occurrence of colony merging, apparently as a result of the low density of tents on most trees, combined with high relatedness within the original colonies. Thus, high intracolony relatedness is maintained in M. americanum populations through the effects of adult dispersal, mating, and oviposition patterns, rather than through behavioral discrimination mechanisms of the larvae. These findings underscore the importance of considering the causes of temporal variation in genetic relatedness as well as the consequences for the indirect component of inclusive fitness.

Sequential gas‐solid reactions

AbstractA model is developed describing consecutive gas‐solid reactions occurring in porous media. The model calls for independently measurable parameters and predicts two maxima in the reaction rate at intermediate conversions. The low temperature (350°C) reduction of hematite to iron in a hydrogen‐nitrogen atmosphere was used to test the model. The experimental data confirmed the expected rate maxima. The conversion predictions are very close to the data for conversions below 30%, but are systematically somewhat lower than the experimental values for higher levels of conversion. An explanation for the discrepancy is offered in terms of the description of the pore structure.

Values and Standards in Research

The manner in which social values affect the objectivity of research and reasoning in the social sciences deserves investigation. The practical need for the formulation of standards makes it necessary to consider the various technical means by which at least "relative" objectivity might be safeguarded. It will be shown that values cannot be conceived in isolation. They take their places in a hierarchy of values connected by means-ends relationships. On the higher levels of value abstraction it is relatively easy to agree; conflict arises about the concrete means of achieving "supreme" values.