Primates follow the 'island rule': implications for interpreting Homo floresiensis

When the diminutive skeleton of Homo floresiensis was found on the Indonesian island of Flores, it was interpreted as an island dwarf, conforming to the 'island rule' that large animals evolve smaller size on islands, but small animals tend to get larger. However, previous studies of the island rule have not included primates, so the extent to which insular primate populations undergo size change was unknown. We use a comparative database of 39 independently derived island endemic primate species and subspecies to demonstrate that primates do conform to the island rule: small-bodied primates tend to get larger on islands, and large-bodied primates get smaller. Furthermore, larger species undergo a proportionally greater reduction in size on islands.     

‘Selfish herds’ of guppies follow complex movement rules,but not when information is limited

Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well understood, and how environmental factors affect the use of these rules even less so. Here, we evaluate the success of different movement rules, by comparing their predictions with the movement seen when shoals of guppies (Poecilia reticulata) form under the threat of predation. We repeated the experiment in a turbid environment to assess how the use of the movement rules changed when visual information is reduced. During a simulated predator attack, guppies in clear water used complex rules that took multiple neighbours into account, forming compact groups. In turbid water, the difference between all rule predictions and fish movement paths increased, particularly for complex rules, and the resulting shoals were more fragmented than in clear water. We conclude that guppies are able to use complex rules to form dense aggregations, but that environmental factors can limit their ability to do so.     

Amphibians do not follow Bergmann's rule

The tendency for organisms to be larger in cooler climates (Bergmann's rule) is widely observed in endotherms, and has been reputed to apply to some ectotherms including amphibians. However, recent reports provide conflicting support for the pattern, questioning whether Bergmann's clines are generally present in amphibians. In this study, we measured 96,996 adult Plethodon from 3974 populations to test for the presence of Bergmann's clines in these salamanders. Only three Plethodon species exhibited a significant negative correlation between body size and temperature consistent with Bergmann's rule, whereas 37 of 40 species did not display a pattern consistent with this prediction. Further, a phylogenetic comparative analysis found no relationship between body size and temperature among species. A meta-analysis combining our data with the available data for other amphibian species revealed no support for Bergmann's rule at the genus (Plethodon), order (Caudata), or class (Amphibia) levels. Our findings strongly suggest that negative thermal body size clines are not common in amphibians, and we conclude that Bergmann's rule is not generally applicable to these taxa. Thus, evolutionary explanations of Bergmann's clines in other tetrapods need not account for unique life-history attributes of amphibians.     

Do mutualistic networks follow power distributions?

Species interactions are central to the structure and dynamics of biological communities. Recently, of particular interest, is the analysis of ecological networks where the number of species to species interactions vary depending on the degree of specialization. For mutualistic networks, species degree has been suggested to follows a power distribution or a truncated power distribution. In this paper, I discuss previously estimated parameters and associated model selection may be unreliable. I use the likelihood approach and compare the results from previous findings and show that the parameter estimates as well as model selection results are indeed very different. Furthermore, the likelihood approach reveals that many mutualistic networks do not follow either power distribution or truncated power distribution.     

Nurse led follow up and conventional medical follow up in management of patients with lung cancer: randomised trial

ObjectiveTo assess the effectiveness of nurse led follow up in the management of patients with lung cancer.DesignRandomised controlled trial.SettingSpecialist cancer hospital and three cancer units in southeastern England.Participants203 patients with lung cancer who had completed their initial treatment and were expected to survive for at least 3 months.InterventionNurse led follow up of outpatients compared with conventional medical follow up.ResultsPatient acceptability of nurse led follow up was high: 75% (203/271) of eligible patients consented to participate. Patients who received the intervention had less severe dyspnoea at 3 months (P=0.03) and had better scores for emotional functioning (P=0.03) and less peripheral neuropathy (P=0.05) at 12 months. Intervention group patients scored significantly better in most satisfaction subscales at 3, 6, and 12 months (P<0.01 for all subscales at 3 months). No significant differences in general practitioners'' overall satisfaction were seen between the two groups. No differences were seen in survival or rates of objective progression, although nurses recorded progression of symptoms sooner than doctors (P=0.01). Intervention patients were more likely to die at home rather than in a hospital or hospice (P=0.04), attended fewer consultations with a hospital doctor during the first 3 months (P=0.004), had fewer radiographs during the first 6 months (P=0.04), and had more radiotherapy within the first 3 months (P=0.01). No other differences were seen between the two groups in terms of the use of resources.ConclusionNurse led follow up was acceptable to lung cancer patients and general practitioners and led to positive outcomes.

What is already known on this topic

Most patients with cancer are routinely seen in outpatient clinics for many years despite lack of evidence of effectivenessDoctors and nurses often fail to detect patients'' emotional distress, and patients have little time to raise concerns

What this study adds

Follow up of patients with lung cancer by clinical nurse specialists is safe, acceptable, and cost effectiveBoth patients and general practitioners were highly satisfied with the nurse led model of follow up     

Does osteoderm growth follow energy minimization principles?

Although the growth and development of tissues and organs of extinct species cannot be directly observed, their fossils can record and preserve evidence of these mechanisms. It is generally accepted that bone architecture is the result of genetically based biomechanical constraints, but what about osteoderms? In this article, the influence of physical constraints on cranial osteoderms growth is assessed. Comparisons among lepidosaurs, synapsids, and archosaurs are performed; according to these analyses, lepidosaur osteoderms growth is predicted to be less energy demanding than that of synapsids and archosaurs. Obtained results also show that, from an energetic viewpoint, ankylosaurid osteoderms growth resembles more that of mammals than the one of reptilians, adding evidence to debate whether dinosaurs were hot or cold blooded. J. Morphol. 275:923–932, 2014. © 2014 Wiley Periodicals, Inc.