Locust behavior and city topology: A biodynamic approach for assessing urban flows.

A city's economic growth and the inhabitants' wellbeing are highly affected by its topology and connecting networks, which, in turn, influence movement and flows in the city. Flow relates to how a city is developed, organized, managed, and built. The analysis of flow in cities is challenging but essential. In this study, the fields of urban design and animal science are combined, and a new approach for exploring the relationships between urban topology and physical flow is developed. Specifically, we establish an interdisciplinary methodology to evaluate mobility performance in various urban settings, utilizing experimental observations of the dynamic behavior of natural-biological agents, i.e., locusts, within physical city models. Our novel approach enriches the currently available toolbox by using living organisms as indicators for flow in physical city models. Our findings improve our understanding of the intricate flow interactions in urban settings.

The biomechanics of ultra-stretchable nerves.

When digging in the ground during egg laying the female locust extends her abdomen to 2-3 times of its original length. How the abdominal nervous system accommodates such extreme elongation remains unknown. We characterized and quantified the system's biomechanical response using controlled ex vivo elongation and force measurements. The microstructure of the nerves was studied using histology and high-resolution confocal microscopy. Although the nervous system of sexually mature females demonstrated fully reversible hyper-extensibility of up to 275%, the elongation observed in premature females and males was much more limited. The unique extension dynamics of the different groups were captured by their very different force-displacement curves. Confocal microscopy suggested that elongation is not owing to undulations of the nervous system structure. Thus, the exceptional resistance to deformation and rupture presents the female locust abdominal nervous system as a valuable model for understanding the functionality and pathology related to nerve extension and reversible elongation.

Self body-size perception in an insect.

Animals negotiating complex environments encounter a wide range of obstacles of different shapes and sizes. It is greatly beneficial for the animal to react to such obstacles in a precise, context-specific manner, in order to avoid harm or even simply to minimize energy expenditure. An essential key challenge is, therefore, an estimation of the animal's own physical characteristics, such as body size. A further important aspect of self body-size perception (or SBSP) is the need to update it in accordance with changes in the animal's size and proportions. Despite the major role of SBSP in functional behavior, little is known about if and how it is mediated. Here, we demonstrate that insects are also capable of self perception of body size and that this is a vital factor in allowing them to adjust their behavior following the sudden and dramatic growth associated with periodic molting. We reveal that locusts' SBSP is strongly correlated with their body size. However, we show that the dramatic change in size accompanying adult emergence is not sufficient to create a new and updated SBSP. Rather, this is created and then consolidated only following the individuals' experience and interaction with the physical environment. Behavioral or pharmacological manipulations can both result in maintenance of the old larval SBSP. Our results emphasize the importance of learning and memory-related processes in the development and update of SBSP, and highlight the advantage of insects as good models for a detailed study on the neurobiological and molecular aspects of SBSP.

Omnivory in terrestrial arthropods: mixing plant and prey diets.

Many terrestrial communities include omnivorous arthropods that feed on both prey and plant resources. In this review we first discuss some unique morphological, physiological, and behavioral traits that enable omnivores to exploit such dissimilar foods, and we explore possible evolutionary pathways to omnivory. We then examine possible benefits and costs of omnivory, describe the relationships between omnivory and other high-order complex trophic interactions, and consider the stability level of communities with closed-loop omnivory. Finally, we explore some of the implications of omnivory for crop damage and for biological, chemical, and cultural control practices. We conclude that the growing realization of the ubiquity of omnivory in nature may require a change in our view of the structure and function of ecological systems.