Northern Research Station

Title: Synchronous Crepuscular Flight of Female Asian Gypsy Moths: Relationships of Light Intensity and Ambient and Body Temperatures

Author: Charlton, Ralph E.; Carde, Ring T.; Wallner, William E.

Date: 1999

Source: Journal of Insect Behavoir. 12(4): 517-531.

Description: Female gypsy moths (Lymantria dispar) of Asian heritage studied in central Siberia and Germany exhibit a highly synchronous flight at dusk, after light intensity falls to about 2 lux. This critical light intensity sets the timing of flight behaviors independent of ambient temperature. Flight follows several minutes of preflight wing fanning during which females in Germany and those from a laboratory colony (derived from Siberian stock) raised their thoracic temperatures to 32-33?C at ambient temperatures of 19-22?C. Thoracic temperature of females in free flight exceeded the air temperature (19-22?C) by approximately 11-13?C. The duration of wing fanning was strongly dependent on ambient temperature. In Germany, where ambient temperatures at dusk ranged between 21 and 25?C, females wing fanned for only 2.1 +/- 0.2 (SE) min; in the much colder temperatures prevalent at dusk in Bellyk, central Siberia (11-13"C), females spent 11.2 +/- 0.6 min in preflight wing fanning. The majority (+/<80%) of mated and even virgin females initiated flight during the evening of the day they eclosed. However, in Bellyk, a small proportion (12%) of females wing fanned for an extended time but then stopped, whereas others (8%) never wing fanned and, therefore, did not take flight. Females also were capable of flight when disturbed during the daylight hours in Germany where the maximal temperature was high (27-30?C), but not in Siberia, where temperatures peaked at only 17-19?C. However, Siberian females were able to propel themselves off the tree on which they were perched by executing several vigorous wing flicks when approached by the predaceous tettigoniid, Tettigonia caudata.

Keywords: crepuscular flight: migratory flight: temperature effects; light intensity: body temperature; wing loading

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Citation

Charlton, Ralph E.; Carde, Ring T.; Wallner, William E.  1999.  Synchronous Crepuscular Flight of Female Asian Gypsy Moths: Relationships of Light Intensity and Ambient and Body Temperatures.   Journal of Insect Behavoir. 12(4): 517-531..