Mercury vapour lamps interfere with the bat defence of tympanate moths (Operophtera spp.; Geometridae)

Publication Type:

Journal Article

Authors:

Source:

Animal Behaviour, Elsevier for the Association for the Study of Animal Behaviour in collobaration with the Animal Behavior Society, Volume 55, Issue 1, p.223-226 (1998)

Call Number:

A98SVE01IDUS

URL:

http://www.sciencedirect.com/science/article/pii/S000334729790590X

Keywords:

bats and lighting, Operophtera spp

Abstract:

Bats often forage near streetlamps, where they catch moths in particular. At least two hypotheses may explain the apparent increase in the availability of moths to bats feeding around streetlamps: 1) the moths become concentrated near the light and therefore more profitable to exploit, and 2) the light interferes with the moths’ evasive flight behaviour. The authors tested the second of these hypotheses by exposing flying male winter moths, Operophtera spp., to bursts of ultrasound (26 kHz, 110 dB sound pressure level) from an electronic source. The light from a 125-W mercury vapour lamp had a quantitative effect on the moths’ evasive flight response at close range (within ca 4 m), inhibiting it totally in nearly half (43%, N=125) of the cases. By contrast, moths flying in the surrounding woodland and without interference from the lamp always responded to the sound. Streetlamps of the mercury vapour type (white lamps) thus interfere with the defensive behaviour of moths and presumably increase their vulnerability to echolocating bats. This may have implications for the conservation of both moths and bats.