Growth behavior of the blue blowfly Calliphora vicina maggots

Fifty-three clusters of blowfly eggs of the genus Calliphora vicina were observed in the laboratory up to the hatching stage under reproducible and virtually field-like conditions. Rearing the larvae was then continued up to pupation, the larval growth in length being recorded several times a day. As the object was to study the dependence of the larvae increase in length on the temperature conditions in vitro, the substratal humidity and food supply were kept unchanged during the entire study. The temperature ranged from 6.5 degrees C to 35 degrees C, with the temperature for the individual cluster kept constant during the entire developmental process. Data on about 5500 measured larvae were statistically evaluated. The basic result established was that in the case of the blowfly of the genus Calliphora vicina in vivo, all developmental stages relevant to the entomologic determination of the time of death depend on the temperature conditions: (1) the duration of the egg stage increases with decreasing temperature; (2) the speed of larval growth is slower at lower temperatures; (3) the maximal larval length is reached earlier at higher temperatures; (4) the mean value of maximal length decreases with increasing temperature; (5) larvae under all temperature conditions decrease in size after having reached their maximal length, the decrease in length being more rapid at higher temperatures; (6) constant temperatures over 30 degrees C lead to "stunted forms" which do not pupate and die; (7) constant temperatures under approximately 16 degrees C after the peak of growth has been reached inhibit the readiness to pupate, which causes the larvae to fall into a stationary state of rest, which will be interrupted only when the temperature is raised and resumption of the metamorphosis is thus induced. To allow rapid reconstruction of the larval age in general practice, the established growth data were set out in the form of a diagram designated isomegalendiagram, which permits temperature-fluctuation-related entomologic determination of the time of death with a maximum degree of accuracy.     

Interest in political campaigns: The influence of question order and electoral context

A split-ballot experiment shows that, when people are asked how interested they are in following political campaigns, their response depends not only on the order in which the question is asked, but also on the broader electoral context in which it is posed. When asked how interested they were in following the political campaigns immediatelyafter a question about whether or not they voted in the (1982) election, people were more likely to think they were interested in the campaign, especially if they claimed to have voted, than if they were asked about it immediatelybefore the question on whether or not they voted. This order effect, however, appears to depend onwhen the questions are asked. If asked within a few weeks after the election, there is little or no order effect. But later, as the memory of the campaign fades, the order of the questions makes a sizable difference in the results. This order effect also seems to be more pronounced among better-educated respondents, suggesting that they are more likely to feel pressured by a social norm to vote and to express an interest in political affairs, not only in real life, but in the survey interview as well. The paper concludes with a brief discussion of the implications for the design of the interview schedule used in the American National Election Studies.The research reported in this paper was supported by a grant from the National Science Foundation (SES81-11404).     

Defining risk

Risk is the focal topic in the management of many activities and technologies. For that management to be successful, an explicit and accepted definition of the term risk is essential. Creation of that definition is a political act, expressing the definers' values regarding the relative importance of different possible adverse consequences for a particular decision. Those values, and with them the definition of risk, can change with changes in the decisionmaker, the technologies considered, or the decision problem. After a review of the sources of controversy in defining risk, a general framework is developed, showing how these value issues can be systematically addressed. As an example, the approach is applied to characterizing the risks of six competing energy technologies, the relative riskeness of which depends upon the particular definition used.