We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM–QCF (frequency modulated – quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.

The purpose of this study was to evaluate the impact of moonlight on the swarming activity of bats at an abandoned mine in southern Sweden. The mine serves as a hibernaculum for six species of insectivorous bats. Swarming activity at one of the mine entrances was measured on 12 nights between 1 August and 8 September 2000, by electronically counting the number of bats passing through an opening (about 30×40 cm) leading to a mine tunnel. The number of bat passes outside the mine was also counted, using a bat detector. Most bats were males, as confirmed by mist-netting outside the mine. Low frequency vocalizations, indicating territorial interactions, were heard frequently. The number of bats entering the mine was closely correlated with the number of bats flying outside, and neither was affected by moonlight. We conclude that the insectivorous bats at high latitudes may not have been exposed to significant nocturnal predator pressure, leading to the evolution of lunar phobia, as have many tropical bats.

We studied the influence of moonlight upon the foraging activity pattern of the fruit bat Cynopterus sphinx. We observed the bats when foraging on the fruits of Calophyllum inophyllum and on the leaves of Mimusops elengi and Cassia fistula for 31, 27 and 28 days, respectively at the botanical garden in the Madurai Kamaraj University campus. The number of feeding bouts was recorded every hour between 18:00 and 05:00. A feeding bout involves a bat landing on the tree and collecting a part (or whole) of the fruit or a leaf. The total number of feeding bouts was negatively correlated with per cent moonlight each night. The number of feeding bouts decreased during the waxing phases of the moon. During the period of new moon the mean number of feeding bouts was significantly higher compared to the periods of other phases. During the first quarter and the last quarter phases, feeding occurred more during the dark part of the night, especially when the bats foraged upon M. elengi and C. fistula. While cloud cover enhanced the foraging activity, lightning and thunder suppressed it. Our study indicates that moonlight influences the foraging activity of C. sphinx.

Nightly catches of Scirpophaga nivella (F.) in light traps in rice plots in West Bengal, India, showed two discrete peaks of abundance in each trap-year corresponding to congenial weather and abundance of summer (mid-March-mid-June) and autumn (mid-July-mid-November) rice plants. Estimated generation times showed many overlapping generations in each trap a year. Variations in summer catches were significantly correlated (P < 0.01–0.05) with maximum temperature and minimum relative humidity of the day, and minimum temperature and wind speed of the night; whereas those in autumn catches were significantly associated with maximum temperature and minimum relative humidity of the night (P < 0.01–0.05). Autumn crops had more infestations, and sustained greater larval density than summer ones. Females were twice as heavy as males (2.1:1) and adults were heavier in October than in May. Catches of immature and mature females were consistently maximum at full moon and new moon, respectively.