Recent spatial and temporal changes in body size of terrestrial vertebrates: probable causes and pitfalls

Geographical and temporal variations in body size are common phenomena among organisms and may evolve within a few years. We argue that body size acts much like a barometer, fluctuating in parallel with changes in the relevant key predictor(s), and that geographical and temporal changes in body size are actually manifestations of the same drivers. Frequently, the principal predictors of body size are food availability during the period of growth and ambient temperature, which often affects food availability. Food availability depends on net primary productivity that, in turn, is determined by climate and weather (mainly temperature and precipitation), and these depend mainly on solar radiation and other solar activities. When the above predictors are related to latitude the changes have often been interpreted as conforming to Bergmann's rule, but in many cases such interpretations should be viewed with caution due to the interrelationships among various environmental predictors. Recent temporal changes in body size have often been related to global warming. However, in many cases the above key predictors are not related to either latitude and/or year, and it is the task of the researcher to determine which particular environmental predictor is the one that determines food availability and, in turn, body size. The chance of discerning a significant change in body size depends to a large extent on sample size (specimens/year). The most recent changes in body size are probably phenotypic, but there are some cases in which they are partly genetic.     

Age and sex-specific variation in detectability of moose (<Emphasis Type="Italic">Alces alces</Emphasis>) during the hunting season: implications for population monitoring

The sustainability of wild ungulate harvests can be greatly enhanced if monitoring data are available to permit an adaptive management approach. Utilising data provided by hunters is potentially the most cost-effective approach. In Scandinavia, observations recorded by moose (Alces alces) hunters provide a range of indices of population density, composition and reproductive performance. These are routinely used in practical management, but there are still many questions about their accuracy and precision. In this study, we availed of the fact that virtually all individual moose on the island of Vega in central Norway were marked during the period 1992–2005. Thus, we were able to compare the observation indices provided by hunters to the known size and composition of the population. The results indicate that the hunter observation indices provided accurate estimates of variation in moose cow recruitment and twinning rates. The estimates of sex ratio closely followed the pattern of annual variation but showed a consistent pattern of over-estimating the proportion of males. Thus, males seem to visually expose themselves more often for hunters than do females. The density index, measured as number of moose seen per hunter day did not to the same extent follow the variation in population density, possibly because moose were more naive in the first years after hunting was introduced or because of reduced detection conditions due to increasing scrub and tree encroachment during the study period. The results are discussed in light of their application to management and the evolutionary pressures in moose anti-predator behaviour.     

Patterns of hunting mortality in Norwegian moose (Alces alces) populations

We used a simple life table approach to examine the age-specific patterns of harvest mortality in eight Norwegian moose populations during the last 15 years and tried to determine if the observed patterns were caused by hunter selectivity. The general opinion among local managers is that hunters prefer to shoot female moose not in company with calves to keep a high number of reproductive females in the population (and because of the emotional stress involved in leaving the calf/calves without a mother), and relatively large males because of the higher return with respect to meat and trophy. In support of the former view, we found the harvest mortality of adult females to be higher among pre-prime (1–3 years old) than prime-aged age classes (4–7 years old). This is probably because prime-aged females are more fecund and, therefore, more likely to be in company with one or two calves during the hunting season. As the season progressed, however, the selection pressure on barren females decreased, probably due to more productive females becoming ‘legal’ prey as their calf/calves were harvested. In males, we did not find any evidence of strong age-specific hunter selectivity, despite strong age-dependent variation in body mass and antler size. We suggest that this was due to the current strongly female-biased sex ratio in most Norwegian moose populations, which leaves the hunters with few opportunities to be selective within a relatively short and intensive hunting season. The management implications of these findings and to what extent the results are likely to affect the future evolution of life histories in Norwegian moose populations are discussed.Electronic Supplementary Material Supplementary material is available for this article at and accessible for authorised users.     

Loss of sulfonamide resistance in Neisseria meningitidis

Four strains of Neisseria meningitidis were studied during serial passage. From two strains which originally were sulfonamide resistant, variants developed that had altered susceptibility to sulfonamides. One of the variants became relatively highly sulfonamide-sensitive, the other exhibited merely reduced sulfonamide resistance. There was a difference in the resistance pattern for two sulfonamides (sulfaisodimidine and sulfamethoxazole), and the effect of inoculum size and growth conditions in three different media could be demonstrated. Although the patterns of susceptibility to other antibacterial agents were different for the strains studied, no further susceptibility alterations occurred in parallel to the sulfonamide sensitivity changes. The variants also lost their ability to liberate free endotoxin.     

Effectiveness of flexible routing control

Flexibility in part process representation and in highly adaptive routing algorithms are two major sources for improvement in the control of flexible manufacturing systems (FMSs). This article reports the investigation of the impact of these two kinds of flexibilities on the performance of the system. We argue that, when feasible, the choices of operations and sequencing of the part process plans should be deferred until detailed knowledge about the real-time factory state is available. To test our ideas, a flexible routing control simulation system (FRCS) was constructed and a programming language for modeling FMS part process plans, control strategies, and environments of the FMS was designed and implemented. In addition, a scheme for implementing flexible process routing called data flow dispatching rule (DFDR) was derived. The simulation results indicate that flexible processing can reduce mean flow time while increasing system throughput and machine utilization. We observed that this form of flexibility makes automatic load balancing of the machines possible. On the other hand, it also makes the control and scheduling process more complicated and calls for new control algorithms.