Behavioural plasticity: an interaction between evolution and experience

Differences in neuronal activity explain differences in memory forming abilities of different populations of Lymnaea stagnalis

The ability to learn and form long-term memory (LTM) can enhance an animal's fitness, for example, by allowing them to remember predators, food sources or conspecific interactions. Here we use the pond snail, Lymnaea stagnalis, to assess whether variability between natural populations (i.e., strains) in memory forming capabilities correlates with electrophysiological properties at the level of a single neuron, RPeD1. RPeD1 is a necessary site of LTM formation of aerial respiratory behaviour following operant conditioning. We used strains from two small, separate permanent ponds (TC1 and TC2). A comparison of the two populations showed that the TC1 strain had enhanced memory forming capabilities. Further, the behavioural phenotype of enhanced memory strain was explained, in part, by differences in the electrophysiology of RPeD1. Compared to RPeD1 from the naive TC2 strain, RPeD1 from the TC1 strain has both a decreased resistance and decreased excitability. Moreover, 24h after a single 0.5h training session, those membrane properties, as well as the firing and bursting rate, decrease further in the TC1 strain but not in the TC2 strain. The initial differences in RPeD1 properties in the TC1 strain coupled with their ability to further change these properties with a single training session suggests that RPeD1 neurons from the TC1 strain are "primed" to rapidly form memory.

Identifying and prioritizing greater sage-grouse nesting and brood-rearing habitat for conservation in human-modified landscapes

Background

Balancing animal conservation and human use of the landscape is an ongoing scientific and practical challenge throughout the world. We investigated reproductive success in female greater sage-grouse (Centrocercus urophasianus) relative to seasonal patterns of resource selection, with the larger goal of developing a spatially-explicit framework for managing human activity and sage-grouse conservation at the landscape level.

Methodology/Principal Findings

We integrated field-observation, Global Positioning Systems telemetry, and statistical modeling to quantify the spatial pattern of occurrence and risk during nesting and brood-rearing. We linked occurrence and risk models to provide spatially-explicit indices of habitat-performance relationships. As part of the analysis, we offer novel biological information on resource selection during egg-laying, incubation, and night. The spatial pattern of occurrence during all reproductive phases was driven largely by selection or avoidance of terrain features and vegetation, with little variation explained by anthropogenic features. Specifically, sage-grouse consistently avoided rough terrain, selected for moderate shrub cover at the patch level (within 90 m²), and selected for mesic habitat in mid and late brood-rearing phases. In contrast, risk of nest and brood failure was structured by proximity to anthropogenic features including natural gas wells and human-created mesic areas, as well as vegetation features such as shrub cover.

Conclusions/Significance

Risk in this and perhaps other human-modified landscapes is a top-down (i.e., human-mediated) process that would most effectively be minimized by developing a better understanding of specific mechanisms (e.g., predator subsidization) driving observed patterns, and using habitat-performance indices such as those developed herein for spatially-explicit guidance of conservation intervention. Working under the hypothesis that industrial activity structures risk by enhancing predator abundance or effectiveness, we offer specific recommendations for maintaining high-performance habitat and reducing low-performance habitat, particularly relative to the nesting phase, by managing key high-risk anthropogenic features such as industrial infrastructure and water developments.