Animals adjust behaviors to balance changes in predation risk against other vital needs. Animals must therefore collect sensory information and use a complex risk-assessment process that estimates risks and weighs costs and benefits entailed in different reactions. Studying this cognitive process is challenging, especially in nature, because it requires inferring sensory abilities and conscious decisions from behavioral reactions. Our goal was to address this empirical challenge by implementing psychophysical principles to field research that explores considerations used by desert isopods (Hemilepistus reaumuri) to assess the risk of scorpions that hunt exclusively from within their burrows. We introduced various combinations of chemical and physical cues to the vicinity of isopod burrows and recorded their detailed reactions on first encountering the cues. The isopods reacted defensively to scorpion odor but only when accompanied with excavated soil or other odors typically found near scorpion burrows. Isopods also reacted defensively to piles of excavated soil without scorpion olfactory cues, suggesting that isopods take precautions even against physical disturbances that do not necessarily reflect predator activity. Simultaneous presence of different cues provoked graded responses, possibly reflecting an additive increase in risk estimation. We conclude that wild isopods use defensive reactions toward environmental signals only when the integrated perceptual information implies an active scorpion burrow or when they lack data to refute this possibility.

Many physical systems respond to slowly changing external force through avalanches spanning broad range of sizes. Some systems crackle even without apparent external force, such as bursts of neuronal activity or charge transfer avalanches in 2D molecular layers. Advanced development of theoretical models describing disorder-induced critical phenomena calls for experiments probing the dynamics upon tuneable disorder. Here we show that isomeric structural transitions in 2D organic self-assembled monolayer (SAM) exhibit critical dynamics with experimentally tuneable disorder. The system consists of field effect transistor coupled through SAM to illuminated semiconducting nanocrystals (NCs). Charges photoinduced in NCs are transferred through SAM to the transistor surface and modulate its conductivity. Avalanches of isomeric structural transitions are revealed by measuring the current noise I(t) of the transistor. Accumulated surface traps charges reduce dipole moments of the molecules, decrease their coupling, and thus decrease the critical disorder of the SAM enabling its tuning during experiments.

Widely accepted major criteria for biodiversity hotspots that deserve conservation include species richness, endemism and threat. Proving that a taxon is endemic to a given area is more difficult, and therefore expensive, with animals than with plants because of the difficulty to prove absence outside the known distribution. Seeking a cost-efficient practical method to show animal endemism while funds necessary for conventional demonstration of endemism are lacking, we argued that when the known distribution of a suspected endemic taxon coincides with an ecogeographically isolated area, e.g. island, its exclusivity to that area is more credible. We selected a model site containing suspected endemics, the 'Arava depression (altitude -400-0 m) between arid southern Israel and southern Jordan. A search of the literature and collections found at least 23 animal taxa endemic to the 'Arava, to the adjacent Dead Sea basin sharing the depression, or to both. We assessed the level of isolation of the 'Arava depression by statistically analysing the geographical distribution of taxa (species or subspecies) of one selected well researched model group, Squamata (lizards and snakes). In northern Israel and Jordan the squamate faunas of the two countries are very similar. In contrast in the south where the 'Arava intervenes, the two faunas greatly differ. The 'Arava both constitutes a partial barrier and is partly isolated. Hence its apparent endemics are likely real endemics, inviting conservation of the area. The more so since the 'Arava is also an arena of much research and education. Our methodology may serve worldwide to identify semi-isolated terrestrial areas for conservation.

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