The effect of light intensity on activity was investigated in a study of captive leaf-eared mice, Phyllotis xanthopygus. This nocturnal mouse lives in rocky outcrops but forages in open areas with little vegetative cover. Primary predators are raptors and canids, all of which are expected to have increased hunting success under higher levels of moonlight. Because of this correlation between light intensity and predation risk, we predicted that increased light intensity during the dark period would result in decreased nocturnal activity. Data were collected continuously for 3 days under varying light intensities and were analyzed using cosinor analysis to estimate parameters describing the activity rhythm (mesor, amplitude, and acrophase). Number of diurnal activity bouts increased after exposure to light intensities similar to full moonlight (3.0 lux). Total activity of mice in middle (1.5 lux) and high (3.0 lux) light treatments was depressed as evinced by significantly lower mesor and amplitude estimates compared with those of mice in control conditions (0.0 lux). The acrophase also was significantly different between the control and the 2 treatment groups.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.