The development and decline of all the past major plagues of Chortoicetes terminifera in Australia has been analysed using all available locust data and a simulation model to estimate the course of events for periods when few locusts were reported. The model is based on the developmental biology of the locust and tnchides methods of estimating the duration of egg. nymphal and adult development and uses a pasture growth index and potential night displacement index to assess likely survival and migration.The analysis shows that five ofthe six plagues originated in the arid interior, where good spring and summer rain allowed two or three consecutive generations of successful breeding, before emigration to the agricuhural country occurred in the late summer or early autumn. This is contrary to the idea held previously that most plagues developed from local bi'eeding in established outbreak areas in the agricultural belt. The applications of these results, to improve population monitoring and control strategy' by suggesting the best timing for surveys and when control would have most effect, are discussed.

Long distance migration by adults of Chortoicetes terminifera (Wlk.) in Australia was shown to be associated with the accumulation of fat-body lipid. Lipid was accumulated if the plant growth index was 0·3 or more within a week of the final moult; when the plant growth index was less than 0·3, there was little fat accumulation. Locusts with large amounts of fat-body lipid migrated on nights with warm strong winds, while those with little persisted.

No abstract

Background: Walking impairment has a major influence on the quality-of-life of people with multiple sclerosis (MS). The Multiple Sclerosis Walking Scale assesses the impact of MS on walking ability from the patient's perspective, but in its current form, is not amenable for use in many policy decision-making settings.Objectives: Statistical 'mapping' methods were used to convert MSWS-12 scores to EQ-5D health state values. Methods:The relationship between the measures was estimated using cohort data from people with MS in South West England. Regression analyses were conducted, estimation errors assessed, and predictive performance of the best models tested using longitudinal data.Results: Model performance was in line with that of other mapping studies, with the best performing models being an ordinary least squares (OLS) model using MSWS-12 item scores, and an OLS model using the total MSWS-12 score and its squared term.Conclusions: A process has been described whereby data from a patient-reported outcome measure (MSWS-12) can be converted to (EQ-5D) health state values. These values may be used to consider the health-related quality-of-life of people with MS, to estimate quality-adjusted life-years for use in effectiveness and cost-effectiveness analyses, and to inform health policy decisions.

Damage and loss in yield of wheat crops caused by the Australian plague locust, Chortoicetes terminlfera (Walker), during the major locust plague in the spring of 1984 were assessed. Although severe plant defoliation was observed, yield was affected more by the timing of the attack than by the severity of leaf damage. Major losses in yield occurred both through leaf damage near anthesis and by severing of the whole ear during the milky ripe stage, though losses were insignificant if defoliation alone occurred more than 12 days after anthesis. The implications for control are discussed.