Is the potential of Coccidoxenoides perminutus, a mealybug parasitoid, limited by climatic or nutritional factors?

The encyrtid Coccidoxenoides perminutus is a widely distributed parasitoid of citrus mealybug (Planococcus citri). Worldwide, it has been implicated in successful biocontrol in only a few widely separated localities. C perminutus contributes little to control P. citri in field situations in south-east Queensland, Australia, but invades insectary cultures and reduces mealybug populations considerably under these controlled conditions. This discrepancy between poor field performance and good performance under controlled conditions was investigated to establish whether climatic factors inhibit the field performance of this species in the biological control of P. citri. Subsequent laboratory examination of the influence of varied humidities and temperatures on the activity levels and survival of C perminutus revealed a low tolerance for high saturation deficits (i.e., low % RH at high T degreesC) with reduced reproductive output. The influence of different food sources on adult survival and reproduction was also quantified, to establish if the adverse effects of climate could be overcome by supplementing adult diet. Neither honeydew from their mealybug hosts nor nectar from Alphitonia flowers significantly enhanced parasitoid survival. A subsequent test of five nectar species revealed a significant difference in their influence on C. perminutus survival and reproduction, with only Alpinia zerumbet proving to be as suitable as honey. The floral species that proved suitable in the laboratory need to be checked for their attractiveness to C perminutus in the field and for their ability to enhance the survival and reproductive output of parasitoids. This information suggests that the prevailing dry conditions in south-east Queensland citrus-growing areas apparently impede successful biological control of P. citri by C perminutus, but possibilities are available for habitat manipulation (by providing suitable nectar sources for adult parasitoids) to conserve and enhance C perminutus activity in the field. (C) 2004 Elsevier Inc. All rights reserved.

Ethics and health systems research in 'post'-conflict situations

Although considerable attention has been given to ethical issues related to clinical research in developing countries, in particular related to HIV therapy, there has been limited focus on health systems research, despite its increasing importance in the light of current trends in development assistance. This paper examines ethical issues related to health systems research in 'post'-conflict situations, addressing both generic issues for developing countries and those issues specific to 'post'-conflict societies, citing examples from the author's Cambodian experience. It argues that the destruction of health infrastructure results in a loss of structures and processes that would otherwise protect prospective research subjects who are part of vulnerable populations. It identifies the growth of health systems research as part of a trend towards sectoral and programmatic development assistance, the emergence of 'knowledge generation' as a form of research linked to development, and the potential for conflict where multilateral and bilateral donors are both primary funders and users of health systems research. It also examines the position of the health system researcher in relation to the sponsors of this research, and the health system being analysed.