For animals in the wild, survival depends on being able to detect and respond rapidly to danger by switching from risky (e.g. conspicuous courtship) to survival-oriented behaviors. Very little is known about the hormonal or neuroendocrine mechanisms that control the rapid switch in behavioral state that occurs when an animal detects threats or other stressors. Prior studies with rough-skinned newts (Taricha granulosa), an amphibian model, found that stress-induced suppression of male sexual behaviors (amplectic clasping) involves corticosterone (CORT) and that this steroid hormone uses a novel membrane receptor and modulates the responsiveness of medullary neurons in clasp-controlling neural circuits. We provide evidence that this rapid suppression of male sex behaviors, when induced by either acute stress or CORT administration, involves activation of endocannabinoids signaling in the hindbrain. In a series of behavioral studies, administration of a cannabinoid antagonist, AM281, blocked the suppressive effects of exposure to acute stress or an injection of CORT on the performance of clasping behaviors in sexually active males. Similarly, in electrophysiological studies, prior treatment with AM281 blocked CORT-induced suppression of spontaneous neuronal activity and sensory responsiveness of hindbrain neurons in clasp-controlling neural circuits. These data suggest that, in response to acute stress, elevated CORT concentration increases endocannabinoid signaling in the hindbrain and alters sexual behaviors by modulating the excitability of medullary circuits.

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The threatened skinks Oligosoma grande and O. otagense currently exist in small, fragmented populations inhabiting rock outcrops among subalpine tussock grassland in southern New Zealand. This habitat is disappearing as farm production increases. Population numbers in three prime sites on Emerald Creek are low in absolute terms (11?56 individuals of each species; 15?78/ha). Low numbers and habitat fragmentation place populations at demographic and genetic risk. Emergence of both species from outcrops is highly weather-dependent, being negatively correlated with cloud cover and positively correlated with vapour pressure deficit and either air or rock temperature. Although higher numbers of both species emerge in warm, dry and sunny weather, O. grande is more likely than O. otagense to be seen in marginal conditions. Many animals showed site fidelity but some moved between outcrops; maximum distances between sightings were 139 m for O. grande and 79 m for O. otagense. Pair bonding may occur in O. otagense. We recommend that annual censuses with moderate-low confidence intervals be carried out at a range of sites, that future surveys and censuses consider weather variables explicitly, and that the effects of habitat degradation and habitat enhancement on dispersal between outcrops be investigated.

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