The Australian Bogong Moth Agrotis infusa: A Long-Distance Nocturnal Navigator

Abstract

The nocturnal Bogong moth (Agrotis infusa) is an iconic and well-known Australian insect that is also a remarkable nocturnal navigator. Like the Monarch butterflies of North America, Bogong moths make a yearly migration over enormous distances, from southern Queensland, western and northwestern New South Wales (NSW) and western Victoria, to the alpine regions of NSW and Victoria. After emerging from their pupae in early spring, adult Bogong moths embark on a long nocturnal journey towards the Australian Alps, a journey that can take many days or even weeks and cover over 1000 km. Once in the Alps (from the end of September), Bogong moths seek out the shelter of selected and isolated high ridge-top caves and rock crevices (typically at elevations above 1800 m). In hundreds of thousands, moths line the interior walls of these cool alpine caves where they “hibernate” over the summer months (referred to as “estivation”). Towards the end of the summer (February and March), the same individuals that arrived months earlier leave the caves and begin their long return trip to their breeding grounds. Once there, moths mate, lay eggs and die. The moths that hatch in the following spring then repeat the migratory cycle afresh. Despite having had no previous experience of the migratory route, these moths find their way to the Alps and locate their estivation caves that are dotted along the high alpine ridges of southeastern Australia. How naïve moths manage this remarkable migratory feat still remains a mystery, although there are many potential sensory cues along the migratory route that moths might rely on during their journey, including visual, olfactory, mechanical and magnetic cues. Here we review our current knowledge of the Bogong moth, including its natural history, its ecology, its cultural importance to the Australian Aborigines and what we understand about the sensory basis of its long-distance nocturnal migration. From this analysis it becomes clear that the Bogong moth represents a new and very promising model organism for understanding the sensory basis of nocturnal migration in insects.

The genetics and epigenetics of animal migration and orientation: birds, butterflies and beyond

“…In the autumn, the same individuals migrate back to the breeding sites to reproduce, and die soon after, leaving their progeny to become the new generation of southward migrants the following spring ( Fig. 4A) Warrant et al, 2016). The opposite flight orientations taken by bogongs and monarchs each autumn and spring in different hemispheres of the Earth, where seasons are reversed, may suggest that similar environmental cues (i.e.…”

The brain of a nocturnal migratory insect, the Australian Bogong moth

“…The Bogong moth is one of the most iconic Australian insect species, well known for its spectacular long‐distance migrations, carried out during the night (Warrant et al, ). Each spring, Bogong moths escape their hot breeding grounds via a 1,000 km long journey to the Australian Alps, where they enter a state of dormancy (“aestivation”) inside cool, high‐altitude caves (Common, ; Warrant et al, ). In early autumn, the moths return to their breeding grounds, mate, lay eggs and die.…”

Aestivation dynamics of bogong moths (Agrotis infusa) in the Australian Alps and predation by wild pigs (Sus scrofa)

“…The annual migration of bogong moths (Agrotis infusa) from the inland plains to the alpine regions of south-eastern Australia is a remarkable natural phenomenon, with many similarities to the monarch butterfly (Danaus plexippuss) migrations in North America (Warrant et al 2016). In behaviours first described in detail by Common (1954), the spring generation of moths migrate from the inland plains to the mountains, where they aestivate gregariously over summer in crevices and caverns at or close to the top of the mountain summits.…”

“…Indeed, when recently describing the aestivation behaviour of bogong moths in the Australian High Country, Warrant et al (2016) relied heavily on the work of Common (1954), who intensively surveyed the coverage of moths on a single rock face within an overhanging shelter near the summit of Mount Gingera in 1951-52 and 1952-53. There is a need to develop an approach for monitoring numbers of bogong moths in the Australian High Country, if long-term changes in moth numbers are to be detectable.…”