Dramatic decline of northern bat in Sweden over 30 years.

We monitored northern bat (Keyserling & Blasius, 1839) acoustically along a 27 km road transect at weekly intervals in 1988, 1989 and 1990, and again in 2016 and 2017. The methodology of data collection and the transect were the same throughout, except that the insect-attracting mercury-vapour street-lights along parts of the road were replaced by sodium lights between the two survey periods. Counts along sections of the transect with and without street-lights were analysed separately.

The bat-bird-bug battle: daily flight activity of insects and their predators over a rice field revealed by high-resolution Scheimpflug Lidar.

We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g.

Age of enlightenment: long-term effects of outdoor aesthetic lights on bats in churches.

We surveyed 110 country churches in south-western Sweden for presence of brown long-eared bats in summer 2016 by visual inspection and/or evening emergence counts. Each church was also classified according to the presence and amount of aesthetic directional lights (flood-lights) aimed on its walls and tower from the outside. Sixty-one of the churches had previously been surveyed by one of us (J.

Bats adjust their mouth gape to zoom their biosonar field of view.

Active sensing, where sensory acquisition is actively modulated, is an inherent component of almost all sensory systems. Echolocating bats are a prime example of active sensing. They can rapidly adjust many of their biosonar parameters to optimize sensory acquisition.

Vision complements echolocation in an aerial-hawking bat.

The northern bat Eptesicus nilssonii normally hunts flying insects in the air using frequency-modulated echolocation calls. It is also known to detect and catch visually conspicuous prey (white moths) hovering low among grass stalks. To overcome the problem with acoustic clutter from the grass, which interferes with target echo detection, the bats make use of visual cues in addition to those of echolocation.

Evasive response to ultrasound by the crepuscular butterfly Manataria maculata.

The crepuscular nymphalid butterfly Manataria maculata was studied in Monteverde cloud forest, Costa Rica, during the dry season reproductive diapause. M. maculata has ears in the form of Vogel's organs located near the base of the forewings.

Feeding activity of the northern bat Eptesicus nilssoni during pregnancy and lactation.

Female northern bats emerged at dusk to feed when aerial insect density was 0.1 m or higher. A model suggests that this is the threshold level above which foraging may be energetically profitable.