Increased food availability raises eviction rate in a cooperative breeding mammal.

In group-living mammals, the eviction of subordinate females from breeding groups by dominants may serve to reduce feeding competition or to reduce breeding competition. Here, we combined both correlational and experimental approaches to investigate whether increases in food intake by dominant females reduces their tendency to evict subordinate females in wild meerkats (Suricata suricatta). We used 20 years of long-term data to examine the association between foraging success and eviction rate, and provisioned dominant females during the second half of their pregnancy, when they most commonly evict subordinates. We show that rather than reducing the tendency for dominants to evict subordinates, foraging success of dominant females is positively associated with the probability that pregnant dominant females will evict subordinate females and that experimental feeding increased their rates of eviction. Our results suggest that it is unlikely that the eviction of subordinate females serves to reduce feeding competition and that its principal function may be to reduce reproductive competition. The increase in eviction rates following experimental feeding also suggests that rather than feeding competition, energetic constraints may normally constrain eviction rates.

An historical overview of the first two decades of striving towards Safe Motherhood.

The paper examines some of the progress and problems encountered during the first two decades of the Safe Motherhood Initiative. Sufficient statistics are cited to identify the immensity of the persisting problems associated with maternal death and morbidity before the study focuses on some of the endeavours designed to enable women to survive their natural function of giving birth. Varying attitudes and approaches that have characterised the initiatives launched in the past 20 years are reviewed and their changing emphases noted. The stress on treating the medical causes of maternal death in the early years have been complemented by increasing attention to social and political issues as time has elapsed. The advent of the Millennium Development Goals (MDGs) has impelled efforts to provide skilled attendance for all women during childbirth; the poor, socially disadvantaged and vulnerable being those most at risk. MDG 5, concerning maternal health, is perceived as pivotal in the context of global development. Maternal death when viewed from the human rights perspective is perceived as a social injustice rather than a health disadvantage and Safe Motherhood is currently considered increasingly as a basic human right. The study offers a synthesis of concepts and actions that are contributing to building Safe Motherhood across the globe in the 21st century. In considering the factors that inhibit the degree of safety associated with giving birth, global efforts that are tackling a persisting buffer zone are identified and continuous action urged in order to strive towards the targets set for 2015.

An evaluation of the Africa Midwives Research Network.

OBJECTIVE: to evaluate the strengths and limitations of the Africa Midwives Research Network (AMRN) and provide feedback and direction to the network and the funding body. DESIGN: a qualitative study incorporating visits to three African countries and Sweden, using interviews, non-participant observation, an internet survey and review of records. SETTING: principally Tanzania, Uganda, Zambia and Sweden. FINDINGS: AMRN can be described as a small, dispersed, loosely coupled professional network which has made considerable impact on midwifery practice in the areas of its members. The biennial scientific conferences could be perceived as AMRN's flagship activity and have been notably successful, becoming renowned internationally. Around 1500 midwives have benefited from educational programmes at regional or national level. These include research methodology, evidence-based practice, scientific writing and communication skills. Attention needs to be given to some aspects of governance and organization, as well as to communication strategies including websites and newsletters. Technical support from the Karolinska Institute in Stockholm has provided good collegiate support and proved to be cost effective. KEY CONCLUSIONS: AMRN has shown resilience and continuity since its inception and has made a palpable difference to the quality of midwifery care and the professional development of midwives within the remit of its members. AMRN needs to be consolidated before expanding further. The work of AMRN is particularly pertinent in the context of the millennium development goals.

Habitual cave use and thermoregulation in chacma baboons (Papio hamadryas ursinus).

The willingness to utilise caves as shelters is held to have been important to early humans but dependent on pyrotechnology. Despite anecdotal evidence that non-human primates will also exploit caves there has as yet been no detailed account of such exploitation or of the reasons underlying it. Here we provide the first such data, on the frequency and patterning of the use of an underground cave system by baboons (Papio hamadryas)-and show that usage is determined, at least in part, by above-ground temperatures.

The challenge of preparing and enabling 'skilled attendants' to promote safer childbirth.

The worldwide challenge to reduce maternal mortality is beset by numerous and complex issues. Currently, there is a special focus on the role of midwives and others who provide skilled care, their education and the environment in which they are challenged to practice. A review of some of the historical evidence highlights and considers some critical lessons learned in preparing and utilising skilled personnel to attend women at this vulnerable time in their lives. The importance of providing an environment that enables care providers to function effectively is explored. The indispensable merit of political commitment to reducing maternal mortality becomes evident through consideration of achievements in various countries both historically and currently. It is apparent that making childbirth safer is a multifaceted issue that still presents challenges across much of the globe in the 21st century and that this can never be taken for granted in any historical phase or geographical location. In this paper I embrace a major literature search and share findings emerging from studies and activities undertaken on behalf of various national and international organizations, though it does not necessarily reflect the views of those organizations.

Cooperation, control, and concession in meerkat groups.

"Limited control" models of reproductive skew in cooperative societies suggest that the frequency of breeding by subordinates is determined by the outcome of power struggles with dominants. In contrast, "optimal skew" models suggest that dominants have full control of subordinate reproduction and allow subordinates to breed only when this serves to retain subordinates' assistance with rearing dominants' own litters. The results of our 7-year field study of cooperative meerkats, Suricata suricatta, support the predictions of limited control models and provide no indication that dominant females grant reproductive concessions to subordinates to retain their assistance with future breeding attempts.

Individual contributions to babysitting in a cooperative mongoose, Suricata suricatta.

Evolutionary explanations of cooperative breeding based on kin selection have predicted that the individual contributions made by different helpers to rearing young should be correlated with their degree of kinship to the litter or brood they are raising. In the cooperative mongoose or meerkat, Suricata suricatta, helpers babysit pups at the natal burrow for the first month of pup life and frequent babysitters suffer substantial weight losses over the period of babysitting. Large differences in contributions exist between helpers, which are correlated with their age, sex and weight but not with their kinship to the young they are raising. Provision of food to some group members raises the contributions of individuals to babysitting. We discuss the implications of these results for evolutionary explanations of cooperative behaviour.

Selfish sentinels in cooperative mammals.

Like humans engaged in risky activities, group members of some animal societies take turns acting as sentinels. Explanations of the evolution of sentinel behavior have frequently relied on kin selection or reciprocal altruism, but recent models suggest that guarding may be an individual's optimal activity once its stomach is full if no other animal is on guard. This paper provides support for this last explanation by showing that, in groups of meerkats (Suricata suricatta), animals guard from safe sites, and solitary individuals as well as group members spend part of their time on guard. Though individuals seldom take successive guarding bouts, there is no regular rota, and the provision of food increases contributions to guarding and reduces the latency between bouts by the same individual.

Costs of cooperative behaviour in suricates (Suricata suricatta).

Functional interpretations of helping behaviour suggest that it has evolved because helpers increase their direct or indirect fitness by helping. However, recent critiques have suggested that helping may be an unselected extension of normal parental behaviour, pointing to evidence that all mature individuals commonly respond to begging young (whether they are parents, relatives or non-relatives) as well as to the lack of evidence that cooperative activities have appreciable costs to helpers. Here we provide an example of one form of cooperative behaviour that is seldom performed by parents and has substantial energetic costs to helpers. In the cooperative mongoose, Suricata suricatta, non-breeding adults commonly babysit young pups at the natal burrow for a day at a time, foregoing feeding for 24 hours. Parents rarely contribute to babysitting, and babysitting has substantial energetic costs to helpers. Members of small groups compensate for the reduced number of participants by babysitting more frequently, and neither the proportion of time that babysitters are present nor the survival of litters vary with group size.

Infanticide and expulsion of females in a cooperative mammal.

In cooperative groups of suricates (Suricata suricatta), helpers of both sexes assist breeding adults in defending and feeding pups, and survival rises in larger groups. Despite this, dominant breeding females expel subordinate females from the group in the latter half of their (own) pregnancy apparently because adult females sometimes kill their pups. Some of the females that have been expelled are allowed to rejoin the group soon after the dominant female's pups are born and subsequently assist in rearing the pups. Female helpers initially resist expulsion and repeatedly attempt to return to their natal group, indicating that it is unlikely that dominant females need to grant them reproductive concessions to retain them in the group.

The source of the circulating aggregate of insulin in type I diabetic patients is therapeutic insulin.

Circulating insulin immunoreactivity (IRI) in type I diabetic patients (insulin-dependent diabetes mellitus [IDDM]) includes a covalent aggregate about twice the size of insulin. These studies were designed to determine the source and conditions promoting the accumulation of this material. Among 31 IDDMs, the aggregate made up 28 +/- 3.6% of the mean fasting plasma IRI. Five of these patients were restudied after 5 d of treatment with equidose intravenous insulin. The relative amount of the aggregate during subcutaneous treatment (40 +/- 8.0%) was indistinguishable (P greater than 0.7) from that at the termination of intravenous treatment (41 +/- 6.8%). To determine whether previous exposure to therapeutic insulin influenced the appearance and accumulation of the aggregate, we intravenously or subcutaneously infused insulin for 5 h in nine healthy volunteers (euglycemic clamp). At the termination of the high-dose intravenous infusion (10 mU X kg-1 X min-1), the concentration of the aggregate was 81 +/- 18 microU/ml, and it accounted for 2.9% of total IRI. At the conclusion of the other infusion protocols, the absolute amounts of aggregate were somewhat less, but they accounted for similar percentages. On polyacrylamide gel electrophoresis, the circulating aggregate was indistinguishable from a material of similar molecular weight contaminating commercial insulin. We conclude that the insulin aggregate found in the blood of IDDMs originates in commercial insulin. Its appearance is independent of the route of insulin administration. Prolonged and continuous use of insulin may increase its concentration but is not necessary for its appearance. The potential biologic and immunologic consequences of the aggregate are important matters that need to be addressed.

Isolation of feeding deterrents against argentine stem weevil from ryegrass infected with the endophyte Acremonium loliae.

Infection of ryegrass (Lolium perenne) by an endophytic fungus (Acremonium loliae) confers resistance against the Argentine stem weevil (Listronotus bonariensis). Extracts from ryegrass clones, infected and uninfected with A. loliae, were compared in a feeding choice bioassay, and several fractions were identified which affected stem weevil feeding behavior. One stem weevil feeding deterrent, peramine C12H17N5O, has been isolated from infected ryegrass and partially characterized as a basic indole derivative. Extracts from culturedA. loliae had no effect on stem weevil feeding behavior nor was peramine detected in the fungal cultures examined. Peramine and the other active substances are hydrophilic in contrast to the lipophilic properties reported for the neurotoxic lolitrems also isolated from ryegrass infected with A. loliae and associated with causing ryegrass staggers disorder in livestock. It is suggested that ryegrass staggers and stem weevil feeding deterrency may arise by different biochemical mechanisms.

Products of therapeutic insulins in the blood of insulin-dependent (type I) diabetic patients.

The tendency of insulin in high concentrations to self-associate and the widespread presence of insulin-degrading enzymes suggest that fragments and/or aggregates of insulin may circulate in normal and insulin-dependent diabetic (IDDM) individuals. To examine this possibility, we have analyzed, by sensitive physicochemical methods, immunoreactive insulin (IRI) taken from the blood of 9 healthy volunteers and 12 insulin-dependent diabetic patients. IRI from the blood of the normal volunteers was composed of 6000 (91.0 +/- 1.4%) and 9000 (9.0 +/- 1.4%) molecular weight (mol wt) material. By 10% polyacrylamide disc gel electrophoresis (PAGE) and reverse-phase, high-performance liquid chromatography (HPLC), the 6000 mol wt material was indistinguishable from human insulin standards and insulin fragments were not found. C-peptide reactivity in the 9000 mol wt material confirmed the expected presence of proinsulin and intermediates of proinsulin conversion. IRI harvested from the blood of 12 C-peptide-negative IDDMs, using a variety of insulin preparations, also separated into 6000 (80.5 +/- 3.9%) and 9000-12,000 (19.5 +/- 3.9%) mol wt material. By HPLC, 6000 mol wt IRI was either pork insulin (in volunteers using pure pork insulin) or a mixture of beef (approximately 90%), pork (approximately 10%) and deamidated beef (trace) insulin in those using a beef-pork mixture. However, the 9000-12,000 mol wt material had characteristics entirely distinct from proinsulin of either human or animal origin: C-peptide reactivity was undetectable using any of three sensitive radioimmunoassay systems, on PAGE it migrated more rapidly than proinsulin-like material, and in contrast to proinsulin, it was unaffected by proteolytic degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of immunoreactive insulin in human saliva: evidence against production in situ.

The presence of insulin immunoreactivity in extra-pancreatic tissues and fluids suggests multiple sites of insulin production. Immunoreactive insulin occurs in human saliva and concentrations increase after oral glucose ingestion. The goal of these experiments was to determine whether the presence of immunoreactive insulin in this extra-pancreatic site is independent of pancreatic production or merely represents the accumulation of circulating pancreatic insulin. The mean +/- SEM concentration of extracted salivary immunoreactive insulin in five normal volunteers increased during an oral glucose tolerance test from basal values of 36 +/- 3.0 to 291 +/- 40 pmol/l; however, the peak occurred 45-90 min later than in serum. On this basis, it was not possible to distinguish between the stimulation (by increased blood glucose concentrations) of insulin synthesis in the saliva glands from the accumulation of blood insulin. Therefore, we studied a group of five volunteers during intravenous infusion of insulin (1 and 10 mU X kg-1 X min-1, sequentially) and glucose (euglycaemic clamp). Under these conditions, salivary immunoreactive insulin concentrations increased significantly from 254 +/- 100 to 1919 +/- 437 pmol/l (p less than 0.05), while simultaneous mean plasma C-peptide concentrations were unchanged. Thus, the concentration of salivary immunoreactive insulin was clearly related to the amount of insulin in the blood and not to the plasma glucose concentration. Physico-chemical and immunological characterization of salivary immunoreactive insulin by dilution in radioimmunoassay, gel filtration and polyacrylamide disc gel electrophoresis demonstrated that the majority of it was indistinguishable from insulin standards.(ABSTRACT TRUNCATED AT 250 WORDS)