Dispersal in house mice

This review evaluates direct (live-trapping) and indirect (genetic) methods to study dispersal in wild house mice ( Mus musculus ) and summarizes field and experimental data to examine the causes and consequences of dispersal. Commensal house mice (associated with human habitations, farms, food stores and other anthropogenic habitats) typically show lower rates of dispersal than feral house mice (living in crops, natural and semi-natural habitats). However, early claims of long-term fine-scale genetic structure in commensal house mice (due to low rates of dispersal) are not supported by recent data. Dispersal becomes obligatory when habitat conditions deteriorate, but most dispersal occurs below the local environmental carrying capacity and is due to social interactions with conspecifics. Excursions are relatively frequent and probably allow mice to assess the quality of habitats before dispersing. Young males have the greatest tendency to disperse, apparently prompted mainly by aggressive interactions with dominant males. If they do disperse, females integrate into new groups more easily than do males. Dispersing house mice risk loss of condition or death, but may gain reproductive opportunities on arrival in a new location. House mice can be transported passively as stowaways with humans; this contributes to population persistence and genetic structure at regional scales and has allowed house mice to spread world-wide.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 565–583.     

Ectoparasites and host energetics: house martin bugs and house martin nestlings

We measured the energy cost of ectoparasitism in an experimental study of the house martin bug Oeciacus hirundinis and its main host, nestlings of the house martin Delichon urbica. Nests were randomly assigned to inoculation with 0 (control) 10, or 100 bugs during egg laying, and this resulted in statistically significant differences in parasite loads following fledging of nestlings. Parasite loads negatively affected house martin nestlings as estimated from their body mass at age 16 days and from mass loss estimated over 1 day late in the nestling period. Daily energy expenditure (KJ/d), average daily metabolic rate (ml CO₂/g h), and mass independent daily energy expenditure (kJ/mass^0.67d) did not differ significantly between experimental treatments. However, average daily metabolic rate increased with increasing intensities of ectoparasitism. Mass independent daily energy expenditure also increased with higher levels of parasite infestation. These results demonstrate that the bug imposes an energy cost on its host by elevating the level of metabolism.     

The teaching house officer

Although medical students on clinical ward rotations receive a large part of their education from house officers, very often house officers themselves have had little formal preparation as teachers. Because students and teachers work closely together under special conditions, unique educational situations are created where much more than factual information is conveyed. Although some house officers are "natural" teachers, others find such activities uncomfortable or burdensome. Most people, however, can be taught to be effective teachers, and preparation for teaching and teaching itself are beneficial for house officers and their patients as well as their students. House officers who teach enjoy the rewards that all teachers know as well as several others which are particular to the setting in which they teach. Mechanisms are suggested to maintain and develop interest in house staff teaching.     

Carbonized seeds in a protohistoric house: results of hearth and house experiments

The results of the hearth and house experiments show that different types of seeds of different cultivated plants char to different extents. Cereal grains show a lower resistance to high temperatures, whereas grape pips and pulses become completely carbonized at higher temperatures. These differences mainly depend upon the structure of the seeds (thickness of the seed coat) even if other factors (moisture content and weather), difficult to control and measure, are also involved. The experiments provide valuable information for the interpretation of archaeobotanical material found in a reconstructed protohistoric house. By comparing the laboratory results and those obtained in the field, it was possible to get much information about the carbonization process of archaeobotanical material.     

Pyroglyphid house dust mite allergens

Mites of the family Pyroglyphidae are the most important source of house dust mite allergens. A small number of allergens, namely those of groups 1, 2, 4, 5 and 7 constitute the known major and mid-potency specificities, with possible important contributions of the groups 11, 14 and 15 requiring further definition. Most of the allergens can be identified by sequence homologies and the structures of the major allergens have been solved. There are however challenges in determining the nature of the group 5 and 7 allergens and in obtaining detailed structures of the significant allergens to be used for genetic engineering.