Moths as food - and as navigators

From a report in Nature:

Ethnographic accounts from around the world have reported the widespread use of insects as food by people. In some cases, such as among the Shoshone and other Great Basin tribes of the U.S., swarms of grasshoppers and crickets were driven into pits and blankets, while among the Paiute the larvae of Pandora moths (Coloradia pandora lindseyi) were smoked out of trees to fall into prepared trenches, where they would be cooked. Across the world, insects could be mass-harvested, often seasonally, offering high nutritional value especially in fat, protein and vitamins...

In Australia, a wide range of insects is known to have been eaten by Aboriginal groups, in particular the larvae (‘witchetty grubs’) of cossid moths (especially Endoxyla leucomochla) in arid and semi-arid areas. Of particular interest to archaeologists and behavioural ecologists has been the seasonal consumption of Bogong moths by mass gatherings of Aboriginal groups in the southern portions of the Eastern Uplands...

Here we report on microscopic remains of ground and cooked Bogong moths on a recently excavated grindstone from Cloggs Cave, in the southern foothills of the Australian Alps. These findings represent the first conclusive archaeological evidence of insect foods in Australia, and, as far as we know, of their remains on stone artefacts in the world. They provide insights into the antiquity of important Aboriginal dietary practices that have until now remained archaeologically invisible.

Details re the process at the link.  I'm not surprised that fat little moths can provide good nutritional value; what to me is more interesting is this part of the report: 

Each spring (September), Bogong moths migrate south over 1000 km from warmer climes. Travelling at night, the moths’ journeys last many days, arriving in the Australian Alps where, over the summer months (late September–March), they lie dormant (aestivate) in the hundreds of thousands among the protected rocky outcrops...

Basically the antipodal counterpart of the migration of Monarchs in the northern hemisphere.  I found more information about that at the Australian Academy of Science:

"In spring, the moths travel from various parts of eastern Australia to the Australian alps, where they inhabit caves. Over the summer they go into a kind of dormancy known as aestivation. This is much like hibernation, however it occurs in some animals over hot and dry periods rather than cold. At the end of the summer, bogong moths take a second long journey and head back home. They then breed and die soon after that. It’s a short but arduous life. The following year’s big migration is taken by the next generation of bogong moths...

The big question is: how do they know where the mountain caves are and how to get there when they have never been there before? Do they somehow inherit the information from their parents?

Professor Eric Warrant and his team have found that the secret to the moth’s navigational skills is an ‘internal compass’ which they use to navigate the Earth’s magnetic field... As bogong moths are night-time travellers, the Moon or the Milky Way are useful points of direction, along with features of the landscape. "

Addendum:  ""I've had them before, they're a bit nutty in flavour or a bit like charred pork fat. It's really high in fat and protein, so it's really quite a superfood... Problems with larvae absorbing arsenic in the soil also meant humans now only eat the moth "opportunistically", Mr Taylor-Grant said."