Memory in coal tits: an alternative model

Jolliffe and Jolliffe (1997, Biometrics 53, 1136-1142) proposed various models for data from an experiment on memory in coal tits. This article describes an alternative model, which fits equally well and which may be simpler to interpret.     

The 1992-1999 World Bank Schistosomiasis Research Initiative in China: outcome and perspectives.

Ongoing efforts over the last 50 years, aiming at the elimination of schistosomiasis in the People's Republic of China, have been spectaculary successful in reducing the prevalence and intensity of the infection. The endemic areas have been reduced to core regions with particular problems such as the middle and lower reaches of the Changjiang River (Yangtze), the land adjacent to the lakes of central China and certain mountainous areas in Sichuan and Yunnan. An effort to eradicate schistosomiasis as a public health problem in these areas, by means of mass chemotherapy in regions of high prevalence and selective chemotherapy in others, provided good results initially but a lasting effect proved unattainable with chemotherapy alone. A small part of the funds available for this effort were used for research and training. Overseen by a Joint Research Management Committee (JRMC), research training was intensified resulting in improved applications and a better quality of the scientific level of the research finally carried out. Several new control tools were produced which may improve future control approaches, which might achieve a more than temporary relief. In evaluating the contributions made, it was found that the great environmental variations between the eight provinces where control activities were implemented was the main reason why general use of chemotherapy only could not be entirely successful. The inclusion of a research component proved beneficial both for the short- and long-term control and the JRMC proved useful in exposing that sustained progress cannot be achieved without back-up by other approaches, e.g. snail control. Suggested future activities include strengthening of intersectoral and industrial collaboration but finding financial support for continuing the JRMC initiative in some form. It is crucial to consolidate progress made.     

Unequal distribution of local mating opportunities in an egg parasitoid

Abstract.  1. The Local Mate Competition (LMC) model predicts that, in gregarious and quasi-gregarious species, a lone female exploiting a host patch will lay only the minimal number of sons necessary to inseminate all daughters, but as the number of foundresses increases, the proportion of sons deposited by these females also increases.
2. For off-patch mating to occur, non-sperm-depleted males must leave the patch and find virgin females.
3. To investigate the distribution of matings among males, the sperm stock at dispersal and the time of dispersal were quantified for male Trichogramma turkestanica (Hymenoptera: Trichogrammatidae).
4. Matings were not distributed equally among males: some successful males acquired more matings than others. Because of this, a high variability in the sperm stock at dispersal was observed. While few males dispersed almost empty or almost full, the majority of males dispersed with enough sperm to be able to mate with females outside the emergence patch.
5. The mating capacity was thus higher than necessary for local mating and could be explained by an unequal distribution of mating opportunities and the occurrence of off-patch mating.