Patterns in the spatial and temporal use of Texas milkweeds (Asclepiadaceae) by the monarch butterfly (Danaus plexippus L.) during fall, 1996

摘要

In an attempt to better understand the fall migration of D. plexippus through Texas, the spatial and temporal distribution of milkweeds (Ascelpiadaceae) and immature monarchs were monitored along an 800 km transect. Important monarch host plants were found to be distributed unequally along the transect. Breeding monarchs were present at least one month before the main body of migrants appeared. The distribution of eggs and larvae did not spatially follow the distribution of milkweeds. Some milkweedspecies and locations were used more than others. Possible explanations for the distribution patterns observed include the circumscribed nature of the fall migratory pathway and the foraging efficiency of the polygyne version of the imported fire ant.