ISSN:
1432-1351
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Locusta migratoria were tethered on a yaw-torque balance and flown in a wind tunnel of diamond-shaped cross-section. Slowly moving stripes of very low luminance were projected onto the two lower faces of the tunnel and a turning stimulus was generated by reversing the direction of stripe movement on one face relative to the other. It was found that the lower the pattern speed, the higher the luminance required to maintain a torque response. When our results were plotted together with optomotor thresholds taken or inferred from the data of other workers, a threshold curve extending over a luminance range from 10−8 to 1 Lamberts (1 Lambert (L) = 3183 cd/m2), and a pattern speed range from 10−2 to 1 °/s2 °/s could be constructed. An implication of this threshold curve is thatLocusta flying in bright moonlight and as high as 2000 m could, in principle, detect the drift induced by a cross-wind of only 2.5 m/s. However, in the absence of the moon, this sensitivity to drift would be much reduced and it seems to be inadequate to explain some cases of down-wind orientation that have been observed by radar on moonless nights.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00610968
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