Year: 2015
Type: dataset
Abstract: Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated sun compass to navigate south during their spectacular fall migration.Recent experiments show that the circadian clocks that provide time compensation for the sun compass mechanism reside in the antennae and not in the brain.This surprising finding poses a novel clock-compass connection that may apply widely to insects. Annual migratory cycleThe yearly migration of eastern North American monarch butterflies ( Fig. 1) is the longest repetitive migration among insects.During the fall migration, millions of butterflies from the eastern United States and southern Canada make the yearly journey to overwinter in roosts in a small area in central Mexico, with some traveling distances of 4000 km (2500 mi).Fig. 1 Migrating monarchs in flight.(Photo by Dennis Curtin) Migrating monarchs are in reproductive diapause, a condition in which the butterflies suspend mating behavior and exhibit arrested reproductive development.Migrants also have increased cold tolerance and abdominal fat stores, exhibit a marked increase in longevity, and display a strong urge to fly south.Reproductive arrest persists at the overwintering site until the early spring, when the butterflies reproduce and fly northward to lay fertilized eggs on newly emerged milkweed plants (the obligate food source of the larvae) in the southern United States.Another two generations of reproductively competent, short-lived spring and summer butterflies appear to follow the progressive emergence of milkweed northward to repopulate the range of the eastern population of monarch butterflies.In the fall, decreasing day length and other environmental events trigger the migratory generation and, once again, the long journey south commences.Time-compensated sun compass: a major navigational tool
Source: AccessScience
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2562992447