Age and seasonal variability of polybrominated diphenyl ethers in free-ranging East Greenland polar bears (Ursus maritimus)

Polybrominated diphenyl ethers (PBDEs) were analysed in adipose tissue from 92 East Greenland polar bears (Ursus maritimus) sampled during 1999-2001. Mean SigmaPBDE concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. Of the 32 analysed PBDE congeners; BDE47, BDE153, BDE99 and BDE100 dominated, and comprised 99.6% of the SigmaPBDE concentration. The SigmaPBDE concentration had a highly significant correlation with SigmaPCB, SigmaCHL, dieldrin, HCB and SigmaHCH concentrations. We found a seasonal pattern of median SigmaPBDE concentration with 1.2 to 1.8 times higher concentrations in March to July than the rest of the year. The seasonal variation also provides a clue to the seasonal exposure, bio-availability, toxic exposure and degradation. We suggest that future geographical PBDE data comparisons may not need corrections for sex or age, but such data sets should be corrected for seasonal variability, using the presented correctional trigonometric regression.     

The three-dimensional structure of 3,3',4,4'-tetrachlorobiphenyl, a dioxin-like polychlorinated biphenyl (PCB)

The crystal structure of PCB 77 (3,3',4,4'-tetrachlorobiphenyl, C(12)H(6)Cl(4)), a dioxin-like PCB congener, is described. The dihedral angle of PCB 77 is 43.94(6) degrees, which is slightly larger than calculated or experimental dihedral angles of biphenyl derivatives in solution but smaller than experimental dihedral angles in the gas phase.     

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in breast milk of first-time Irish mothers: impact of the 2008 dioxin incident in Ireland

The 2008 dioxin incident in Ireland resulted in elevated concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in Irish pork and pork products, due to the consumption of contaminated animal feed by pigs. In order to investigate any resulting impact on the Irish population, these contaminants were measured in pooled breast milk samples from 109 first-time mothers, collected in 2010. A comparison of the results with similar data from 2002 revealed generally lower concentrations of PCDD/Fs and dioxin-like PCBs in the 2010 samples, confirming the declining trend reported by many authors. Contaminant concentration levels for both 2002 and 2010 were generally slightly lower than those reported internationally, with a mean combined PCDD/F and PCB WHO-TEQ of 9.66 pg g⁻¹ fat, for an overall pooled sample of milk from 2010. An apparent slight increase in PCDFs was observed between 2002 and 2010 (from 2.73 pg WHO-TEQ g⁻¹ fat to 3.21 pg WHO-TEQ g⁻¹ fat), with the main contributory congener being 2,3,4,7,8-PentaCDF. While it cannot be totally discounted that the slight increase in 2,3,4,7,8-PentaCDF and in the overall PCDF WHO-TEQ in breast milk could be attributable to consumption of Irish pork during the 2008 incident, we consider that it is more likely that this was due to other factors, including the predominantly urban/industrial sampling locations for the 2010 samples, compared to 2002.     

Satisfaction with fishing and the desire to leave

Predicting who may leave a fishery is an important consideration when designing capacity reduction programs to enhance both ecological and economic sustainability. In this paper, the relationship between satisfaction and the desire to exit a fishery is examined for the Queensland East Coast Trawl fishery. Income from fishing, and changes in income over the last 5 years, were key factors affecting overall satisfaction. Relative income per se was not a significant factor, counter to most satisfaction studies. Continuing a family tradition of fishing and, for one group, pride in being a fisher was found to be significant. Satisfaction with fishing overall and the challenge of fishing were found to be the primary drivers of the desire to stay or leave the fishery. Surprisingly, public perceptions of fishing, trust in management and perceptions of equity in resource allocation did not significantly affect overall satisfaction or the desire to exit the fishery.     

Survival and productivity benefits to social nesting in the sweat bee <Emphasis Type="Italic">Megalopta genalis</Emphasis> (Hymenoptera: Halictidae)

Facultatively solitary and eusocial species allow for direct tests of the benefits of group living. We used the facultatively social sweat bee Megalopta genalis to test several benefits of group living. We surveyed natural nests modified for observation in the field weekly for 5 weeks in 2003. First, we demonstrate that social and solitary nesting are alternative behaviors, rather than different points on one developmental trajectory. Next, we show that solitary nests suffered significantly higher rates of nest failure than did social nests. Nest failure apparently resulted from solitary foundress mortality and subsequent brood orphanage. Social nests had significantly higher productivity, measured as new brood cells provisioned during the study, than did solitary nests. After accounting for nest failures, per capita productivity did not change with group size. Our results support key predictions of Assured Fitness Return models, suggesting such indirect fitness benefits favor eusocial nesting in M. genalis. We compared field collections of natural nests to our observation nest data to show that without accounting for nest failures, M. genalis appear to suffer a per capita productivity decrease with increasing group size. Calculating per capita productivity from collected nests without accounting for the differential probabilities of survival across group sizes leads to an overestimate of solitary nest productivity.     

Variation at local scales need not impede tests for broader scale patterns

Ecologists are not always mindful of the constraints imposed by their scale of observation and sometimes prematurely attempt broad generalisations or become mesmerised by local details depending on their predilections. We specifically chose a character that is known for its local and unpredictable variation (morphology of kelp) to test the effect of scale on our ability to determine spatial patterns. We compared the morphology of Ecklonia radiata between monospecific and mixed stands of canopy-forming algae across temperate Australia (>5,100 km coastal distance) within a hierarchy of several spatial scales. While E. radiata specimens were generally larger in monospecific than in mixed stands, we failed to observe differences in morphology between stands at many sites and locations. Despite substantial local variation, differences between stands became increasingly clear at broader scales. The frequency of inconsistent differences between stands was greatest at local scales (sites separated by kms), intermediate at intermediate scales (locations separated by 100s of kms) and least at regional scales (regions separated by 1,000s of kms). These observations support the idea that large scale patterns can emerge from apparent stochasticity at small scales, and that unaccountable variation at local scales need not impede tests for similar patterns at broader scales. Most ecologists work at scales where complexity tends to be greatest (i.e. local) and is likely to be explained by special and unique events. It is encouraging, therefore, to observe that patterns can emerge from complexity at local scales to provide new opportunities to answer some of the more interesting questions about the relative importance of processes across the vast parts of the worlds coast.Communicated by M.S. Johnson, Crawley     

An oligarchy of nest-site scouts triggers a honeybee swarm’s departure from the hive

Animals that travel in groups must synchronize the timing of their departures to assure cohesion of the group. While most activities in large colonies of social insects have decentralized control, certain activities (e.g., colony migration) can have centralized control, with only a special subset of well-informed individuals making a decision that affects the entire colony. We recently discovered that a small minority of individuals in a honeybee colony—an oligarchy—decides when to trigger the departure of a swarm from its hive. The departure process begins with some bees producing the worker-piping signal (the primer for departure) and is followed by these bees producing the buzz-run signal (the releaser for departure). In this study, we determined the identity of these signalers. We found that a swarm’s nest-site scouts search for potential nest cavities prior to the departure of the swarm from its hive. Furthermore, we found that the predeparture nest-site scouts are the sole producers of the worker-piping signal and that they are the first producers of the buzz-run signal. The control of the departure of a honeybee swarm from its hive shows how a small minority of well-informed individuals in a large social insect colony can make important decisions about when a colony should take action.     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Temporal separation of two fin whale call types across the eastern North Pacific

Fin whales (Balaenoptera physalus) produce a variety of low-frequency, short-duration, frequency-modulated calls. The differences in temporal patterns between two fin whale call types are described from long-term passive acoustic data collected intermittently between 2005 and 2011 at three locations across the eastern North Pacific: the Bering Sea, off Southern California, and in Canal de Ballenas in the northern Gulf of California. Fin whale calls were detected at all sites year-round, during all periods with recordings. At all three locations, 40-Hz calls peaked in June, preceding a peak in 20-Hz calls by 3–5 months. Monitoring both call types may provide a more accurate insight into the seasonal presence of fin whales across the eastern North Pacific than can be obtained from a single call type. The 40-Hz call may be associated with a foraging function, and temporal separation between 40- and 20-Hz calls may indicate the separation between predominately feeding behavior and other social interactions.