Feeding over the 24-h cycle: dietary flexibility of cathemeral collared lemurs (<Emphasis Type="Italic">Eulemur collaris</Emphasis>)

Animals show specific morphological, physiological and behavioural adaptations to diurnal or nocturnal activity. Cathemeral species, i.e. animals with activities distributed over the 24-h period, have to compromise between these specific adaptations. The driving evolutionary forces and the proximate costs and benefits of cathemerality are still poorly understood. Our goal was to evaluate the role of predator avoidance, food availability and diet quality in shaping cathemeral activity of arboreal mammals using a lemur species as an example. For this, two groups of collared lemurs, Eulemur collaris, were studied for 14 months in the littoral forest of southeastern Madagascar. Data on feeding behaviour were collected during all-day and all-night follows by direct observation. A phenological transect containing 78 plant species was established and monitored every 2 weeks to evaluate food availability during the study period. Characteristics of food items and animal nutritional intake were determined via biochemical analyses. The ratio of diurnal to nocturnal feeding was used as response variable in the analyses. The effects of abiotic environmental variables were removed statistically before the analyses of the biotic variables. We found that diurnal feeding lasted longer during the hot–wet season (December–February), whereas nocturnal feeding peaked during the hot–dry and cool–wet seasons (March–August). Although the lemurs foraged mostly in lower forest strata during daylight and used emergent trees preferably at night, the variables which measured animal exposure to birds of prey failed to predict the variation of the ratio of diurnal/nocturnal feeding. Ripe fruit availability and fiber intake are the two variables which best predicted the annual variation of the lemur diurnality. The data indicate that feeding over the whole 24-h cycle is advantageous during lean periods when animals have a fibre-rich, low-quality diet.     

Ultrastructural and chemical characterization of egg surface of honeybee worker and queen-laid eggs

Summary. Worker policing in honeybees predicts the evolution of a mechanism to discriminate between queenand worker-born eggs. Although it has been postulated that this discrimination is based on an egg recognition pheromone, neither the chemistry nor the glandular source were elucidated. To verify whether egg discrimination might be based on structural differences, we compared the ultrastructure surface of queen-laid diploid and haploid eggs to that of worker-laid eggs using SEM. Only small differences between the different types of eggs were found. Thus, at least based on the fine structure of the egg surface, queen eggs are indistinguishable from worker-laid eggs.To explore the chemosensory hypothesis for egg discrimination, we conducted a detailed comparative chemical analysis of the different egg types. The coating of all egg types was dominated by linear alkanes, but queen eggs, diploid and haploid, differed from those of workers on two accounts: 1. The diversity of compounds found on queenlaid eggs was much greater than found on worker-laid eggs, mainly due to the number of hydrocarbons. 2. Acetates of some fatty alcohols, alkenes and especially monomethylalkanes were characteristic to queen eggs. The origin of the two latter substances and the acetates is still unknown. Whether these compounds constitute the signal that enables police workers to discriminate between queen- and workerborn eggs remains to be investigated.     

Adapting bridge infrastructure to climate change: institutionalizing resilience in intergovernmental transportation planning processes in the Northeastern USA

Multi-level governance networks provide both opportunities and challenges to mainstream climate change adaptation due to their routine decision-making and coordination processes. This paper explores institutionalizing resilience and adaptation to climate change in the intergovernmental transportation planning processes that address bridge infrastructure in the Northeastern United States (USA), specifically in Vermont and Maine. The research presented here relies on nine interviews with policy-makers and planners, a survey of transportation project prioritization criteria, development of a longitudinal bridge funding database, and its integration with publicly available geospatial data. It presents a novel spatial analysis methodology, a modified version of which could be adopted by transportation agencies for prioritizing scarce adaptation funds. Although transportation agencies are undertaking a variety of mitigation activities to address business-as-usual needs, climate change adaptation and resilience efforts remain underprioritized. Adaptation is a global concern, but impacts vary dramatically between regions and require localized solutions. Bridges and culverts, which are especially vulnerable to climate-induced flooding impacts, have complex maintenance and design processes and are subject to convoluted adaptation planning procedures. Critical gaps in resources and knowledge are barriers to improved adaptation planning. Restructuring the transportation project prioritization procedures used by planning organizations to explicitly include adaptation may provide a novel strategy to institutionalize resilience in transportation. These procedures must be considered in the context of the intergovernmental networks that exist to support transportation infrastructure. Although these networks will likely vary across countries, the approaches introduced here to study and address transportation infrastructure adaptation may be applied to many settings.