2,455 publications from this institution
In singular cooperative breeders few females breed successfully, but those that acquire dominant positions can achieve high levels of breeding success, leading to strong selection for traits that enable individuals to acquire and maintain dominance status. However, little is known about the process by which females acquire dominant breeding status or the traits that enable them to do so. Female meerkats, Suricata suricatta, can acquire dominance either by inheritance after the death of the previous dominant, by displacing the incumbent dominant or at the foundation of a new group. Here we investigated the possible fitness benefits associated with these different routes to dominance and the traits that affect an individual's probability of acquiring dominance via these routes. We found that all routes to dominance had similar fitness benefits and that when a dominance vacancy arose, weight was the main determinate of succession, with age still influencing within-group succession and the eldest subordinate female, the beta, often succeeding to dominance. Since the chance that subordinate females will acquire dominance is also positively correlated with the duration of their tenure in the beta position, we tested whether beta females adjusted their growth or cooperative behaviour to avoid eviction and increased their tenure length as the beta. However, there was no indication that betas employed either strategy to increase their tenure. Given that the differing routes to dominance have equivalent fitness pay-offs and are triggered stochastically, selection probably favours flexibility rather than strategies that commit individuals to a specific route.
deposition of C3 in perilesional skin.These appearances were-consistent with pemphigus erythematosus.The HLA genotype was HLA-A1, 3/8, 18/BL, -/-/6/DRW3, DRW5.
The feeding behaviour of one troop of red colobus ( Colobus badius tephrosceles) was observed between August 1969 and June 1970 in the Gombe National Park. Similar observations were made on two troops of red colobus and two of black and white colobus (C. guereza uellensis) in Kibale Forest Reserve, Uganda, between August and October 1970. The red colobus at Gombe were highly selective in their choice of food, feeding on the leaves, shoots, flowers and fruit of a wide variety of tree species. The animals appeared to choose a varied diet, eating different foods in different feeding bouts on the same day. The amount of time which they spent feeding on different foods varied seasonally, usually in association with changes in food availability. Different parts of the animals' range provided them with different kinds of food. The feeding behaviour of the red colobus troops at Kibale was similar to that of the Gombe troop. In contrast, black and white colobus at Kibale fed almost exclusively on mature leaves during at least one period of the year and fed largely on two tree species only. These differences in feeding behaviour may explain why red colobus live in large troops in large ranges while black and white colobus live in small troops in small ranges.
Malaria is the most important parasitic disease of man. It infects approximately 5% of the world’s population and kills somewhere between one and two million people each year. Of the four species of malaria parasites that infect humans, only <i>Plasmodium falciparum</i> is lethal. Cerebral involvement causing coma in severe falciparum malaria is a characteristic but ominous development carrying a 15–20% treated case fatality. Untreated it is considered uniformly fatal. Cerebral malaria is widely quoted as being the most common cause of coma in tropical areas of the world. <b>WHO GETS CEREBRAL MALARIA?</b> In some parts of the tropics malaria is acquired as many as two or three times every day and thus everyone in the community has malaria all the time. At the other end of the spectrum, there are many areas where the chances of acquiring malaria are relatively low. For example, along the western border of Thailand,
No abstract is provided for this article.
No abstract is provided for this article.
Males and females often have different requirements during early development, leading to sex-specific interactions between developing offspring. In polytocous mammals, competition for limited resources in utero may be asymmetrical between the sexes, and androgens produced by male foetuses could have adverse effects on the development of females, with potentially long-lasting consequences. We show here, in an unmanaged population of Soay sheep, that female lambs with a male co-twin have reduced birth weight relative to those with a female co-twin, while there was no such effect in male twins. In addition, females with a male co-twin had lower lifetime breeding success, which appeared to be mainly driven by differences in first-year survival. These results show that sex-specific sibling interactions can have long-term consequences for survival and reproduction, with potentially important implications for optimal sex allocation.
The battle between man and malaria has continued for thousands of years. Antimalarial drugs are essential weapons to fight the disease, but their efficacy is threatened by drug resistance which continues to emerge creating a major obstacle to malaria control and jeopardizing renewed hopes for elimination. As 2016 is the first year under WHO Global Technical Strategy for Malaria 2016–2030, it is a good time to ponder the progress of both sides and plan for the future.
The artemisinins are the cornerstone of current antimalarial treatments. Artesunate is the drug of choice for severe malaria. Artemisinin combination therapies are first-line treatments for uncomplicated falciparum malaria and serve as alternatives to chloroquine for the other types of malaria. These highly effective and well tolerated antimalarials have contributed substantially to global reductions in malaria deaths and complications. The first clear evidence of artemisinin resistance in Plasmodium falciparum parasites came 15 years ago in Western Cambodia. This finding had an ominous precedent. This was the same place from which chloroquine resistance arose first in the late 1950s. Chloroquine resistance, and . . .
No abstract is provided for this article.
This book takes a fresh approach to some of the classic questions in ecology. In particular, what determines where a species lives and what determines its abundance? Despite great progress in the twentieth century much more remains to be done before we can provide full answers to these questions so that reliable predictions can be made as to what will be found in unstudied areas or times. We believe that the methods described and deployed in this book point the way forward. The core message of the book is that key insights come from understanding what determines population growth rate (pgr). We believe that application of this approach will make ecology a more predictive science.
