Does agonistic dominance imply feeding priority in lemurs? a study inEulemur fulvus mayottensis

We studied agonistic dominance and priority of access to a limited drinking resource in two captive groups of Eulemur fulvus mayottensis.Gender is not systematically related to agonistic dominance or to drinking priority. The dominance hierarchy obtained in the drinking competition test is correlated with the baseline hierarchy in the absence of induced competition, but not with drinking priority. We analyze results within the framework of recent dicussions on female dominance in Malagasy prosimians.     

Does agonistic dominance imply feeding priority in lemurs? a study in Eulemur fulvus mayottensis

We studied agonistic dominance and priority of access to a limited drinking resource in two captive groups of Eulemur fulvus mayottensis.Gender is not systematically related to agonistic dominance or to drinking priority. The dominance hierarchy obtained in the drinking competition test is correlated with the baseline hierarchy in the absence of induced competition, but not with drinking priority. We analyze results within the framework of recent dicussions on female dominance in Malagasy prosimians.     

Does urinary taurine reflect changes in protein metabolism? A study with cycloheximide in rats

Abstract

We have previously reported on the changes in urinary taurine levels in rats following treatment with some hepatotoxic agents and compounds reported to affect protein synthesis. This study follows the time course of the elevation of urinary taurine after treatment of rats with cycloheximide which was maximal 8–12 h alter dosing and was dose related. [³H]-leucine incorporation into proteins was used as an indicator of protein synthesis. There was a significant reduction in [³H]-leucine incorporation into acid precipitable proteins 8 h but not 24 h after dosing. The reduction in incorporation was negatively correlated with the raised levels of both serum and urinary taurine 8 h after dosing. Liver glutathione was raised both 8 and 24 h after dosing rats and liver taurine was significantly reduced at 8 h. It is suggested that measuring urinary taurine in collections made continuously might provide a simple, non-invasive biomarker for monitoring the effects of xenobiotics or other external stimuli on the status of protein synthesis.     

Does illegal hunting affect density and behaviour of African grassland birds? A case study on ostrich (Struthio camelus)

Widespread bushmeat hunting represents one of the major threats to many mammals and birds in Africa. We studied the influence of illegal bushmeat hunting on large grassland birds in the Serengeti National Park (SNP) and adjoining protected areas, by using the ostrich (Struthio camelus) as a case study. First, we documented illegal hunting of both small and large birds by using a questionnaire in the villages on the western and eastern side of the SNP. Second, we studied the effect of illegal hunting on density by driving 4,659 km of transects inside SNP and on the adjacent protected areas, where the data were analysed by DISTANCE sampling. Last, we used flight initiation distance (FID, i.e. the distance between an approaching predator (human) and prey when flight is started), to assess possible impacts on behaviour from illegal hunting. We found that people from the western side of the SNP admitted to hunting both small and large grassland birds, and collect ostrich feathers and eggs. Although the Maasai also hunted small birds, only ostrich feathers and eggs of the large grassland birds were used. Surprisingly, we found no significant differences in densities between the SNP and adjoining partially protected areas, but ostriches had longer FID to an approaching human outside the SNP. Currently illegal hunting does not appear to affect the ostrich population, but given the extensive use of birds for consumption more awareness educational programs accompanied by provision of agricultural incentives within the protected areas are needed.     

Is colorectal cancer a more aggressive disease in young patients? A population-based study from the Czech Republic

IntroductionThe incidence of colorectal cancer in young patients is increasing. The goal of this study was to investigate whether clinicopathological features and survival differed between young, middle-aged and elderly patients.MethodsThe Czech National Cancer Registry was searched to identify all cases of colorectal cancer between 1982 and 2014. Three subgroups of patients were created: young patients, defined as being between 18 and 40 years of age, middle-aged patients, defined as being between 41 and 74 years of age, and elderly patients, defined as being over the age of 75 years.ResultsA total of 192,241 patients diagnosed with colorectal cancer between the years 1982 and 2014 were included in the study. Out of these, 3,287 patients (1.7%) were between 18 and 40 years of age, 134,139 patients (69.8%) were between 41 and 74 years of age and 54,815 patients (28.5%) were 75 years of age or older. The young patients had a higher incidence of mucinous adenocarcinoma and signet ring cell carcinoma, more advanced disease and more rectal tumours than elderly patients. Nonetheless, young patients received treatment more frequently and had better cancer-specific survival than the older patients.ConclusionThe better prognosis in young patients is presumably due to their better physiological reserve and lower incidence of comorbidities. Efforts should be made in younger patients to diagnose early and treat aggressively.     

Do SASS5 scores vary with season in the South African highveld? A case study on the Skeerpoort River,North West province,South Africa

Macroinvertebrate assemblages can vary with season as a result of changing environmental conditions and phenology of individual species. The objective of this study was to determine whether results from the South African Scoring System version 5 (SASS5) are affected by season. The standard SASS5 protocol was used to sample three sites on the Skeerpoort River, South Africa, in autumn, winter and spring 2013, and summer 2014. At each site, stream morphology was characterised and physico-chemical variables were measured. Two-way analysis of variance (ANOVA) was used to compare SASS indices in relation to site and season, and a one-way ANOVA was used to test the effect of season using both current and historical data. Macroinvertebrate assemblage similarity of sites was determined using non-metric multidimensional scaling ordination, followed by analysis of similarity. Whilst macroinvertebrate assemblages differed between seasons and sites, there was no seasonal variation in the values of SASS indices, but they did differ between sites. SASS5 appears to be robust to seasonal variation in macroinvertebrate assemblage and seems suitable for use throughout the year in a perennial river draining the South African highveld region.     

Home range — body mass relations: a field study on African browsing ruminants

Summary Home range data were collected concurrently from four syntopic browsing ruminant species in a conserved savanna ecosystem. Mean home range areas were: giraffe (Giraffa camelopardalis) 282 km²; kudu (Tragelaphus strepsiceros) 21.9 km²; impala (Aepyceros melampus) 5.82 km²; steenbok (Raphicerus campestris) 0.62 km². Home range area (A_hr) scaled on body mass (M) as: A_hr=0.024 M^1.38 (r²=0.99).     

Extending the mirror neuron system model, II: what did I just do? A new role for mirror neurons

A mirror system is active both when an animal executes a class of actions (self-actions) and when it sees another execute an action of that class. Much attention has been given to the possible roles of mirror systems in responding to the actions of others but there has been little attention paid to their role in self-actions. In the companion article (Bonaiuto et al. Biol Cybern 96:9–38, 2007) we presented MNS2, an extension of the Mirror Neuron System model of the monkey mirror system trained to recognize the external appearance of its own actions as a basis for recognizing the actions of other animals when they perform similar actions. Here we further extend the study of the mirror system by introducing the novel hypotheses that a mirror system may additionally help in monitoring the success of a self-action and may also be activated by recognition of one’s own apparent actions as well as efference copy from one’s intended actions. The framework for this computational demonstration is a model of action sequencing, called augmented competitive queuing, in which action choice is based on the desirability of executable actions. We show how this “what did I just do?” function of mirror neurons can contribute to the learning of both executability and desirability which in certain cases supports rapid reorganization of motor programs in the face of disruptions.     

Tree seedlings: how do they establish in spontaneously developed forests? A study from a mountainous area in the Czech Republic

The aim of this study was to find out which tree species can establish in spontaneously developed forests (SDFs) on mesic stands and how many tree seedlings are present there. The influence of different factors was examined and an attempt made to find out if there are some general trends true for groups of species typical for different stages of succession or with different types of distribution. All tree seedlings present in 48 permanent plots were counted (100 m²). The following factors were tested: altitude, slope and exposition, distance from the nearest forest, age and species composition of tree layer, species composition of herb layer, light conditions and soil reaction. The species composition was dependent on altitude and soil reaction. There were surprisingly high numbers of seedlings (in average 145 tree seedlings per 100 m²) and species (in average 5) present in SDFs. Not only species common in the area were found, but also uncommon species were present there, although in low numbers. Nonspecific species are the best colonisers of SDFs, and the anemochorous trees are better colonisers than zoochorous ones. The establishment of different tree species is influenced by different factors. The SDFs most probably shift toward forest with a number of species in the tree layer. The dominant species tend to be spruce and maple, but species typical for early stages of succession will be common in these growths.     

Courtship tactics in garter snakes: how do a male's morphology and behaviour influence his mating success?

The behavioural determinants of male mating success play a pivotal role in sexual selection, but remain poorly known for most kinds of organisms, including most reptiles. In Manitoba, Canada, large numbers of red-sided garter snakes, Thamnophis sirtalis parietalis, court and mate in early spring near communal overwintering dens. To understand how a male's morphology and behaviour might influence his mating success, we videotaped 21 groups of snakes each comprising four males of varying body sizes plus a female. All males engaged in courtship, and mating occurred in all groups. Males with better body condition courted more vigorously and successfully than their smaller rivals did. The males that obtained matings were those that maintained their own cloaca closest to that of the female, aligned most of their body with the female, showed high rates of caudocephalic waving, chin pressing and tail searching, and did not allow other males to insert their body beside the female's. These behavioural differences between ‘winners’ and ‘losers’ were apparent from the beginning of each trial. Thus, male mating success in this ‘scramble’ system is determined not by chaotic, stochastic struggle (as has often been inferred) but instead is strongly linked to male courtship tactics. Energy stores (as evidenced by good body condition) may be critical determinants of mating success in these vigorous courtship episodes.     

Deciding on a new home: how do honeybees agree?

A swarm of honeybees (Apis mellifera) is capable of selecting one nest-site when faced with a choice of several. We adapt classical mathematical models of disease, information and competing beliefs to such decision-making processes. We show that the collective decision may be arrived at without the necessity for any bee to make any comparison between sites.     

Major histocompatibility complex class I diversity in a West African chimpanzee population: implications for HIV research

 Human immunodefiency virus (HIV) poses a major threat to humankind. And though, like humans, chimpanzees are susceptible to HIV infection, they are considered to be resistant to the development of the acquired immune deficiency syndrome (AIDS). Little is known about major histocompatibility complex (MHC) class I diversity in chimpanzee populations and, moreover, whether qualitative aspects of Patr class I molecules may control resistance to AIDS. To address these questions, we assayed MHC class I diversity in a West African chimpanzee population and in some animals from other subspecies of chimpanzee. Application of different techniques allowed the detection of 17 full-length Patr-A, 19 Patr-B, and 10 Patr-C alleles. All Patr-A alleles cluster only into the HLA-A1/A3/A11 family, which supports the idea that chimpanzees have experienced a reduction in their repertoire of A locus alleles. The Patr-B alleles do not cluster in the same lineages as their human equivalents, due to frequent exchange of polymorphic sequence motifs. Furthermore, polymorphic motifs may have been exchanged between Patr-A and Patr-B loci, resulting in convergence. With regard to evolutionary stability, the Patr-C locus is more similar to the Patr-A locus than it is to the Patr-B locus. Despite the relatively low number of animals analyzed, humans and chimpanzees were ascertained as sharing similar degrees of diversity at the contact residues constituting the B and F pockets in the peptide-binding side of MHC class I molecules. Our results indicate that within a small sample of a West African chimpanzee population, a high degree of Patr class I diversity is encountered. This is in agreement with the fact that chimpanzees display more mitochondrial DNA variation than humans. In addition, population analyses demonstrated that particular Patr-B molecules, with the capacity to bind conserved HIV-1 epitopes, are characterized by high gene frequencies. These findings have important implications for evaluating immune responses in HIV vaccine studies and, more importantly, may help in understanding the relative resistance of chimpanzees to AIDS. Received: 8 December 1999 / Accepted: 30 December 1999