Behaviour Food resources Bogong moth larvae subsist on winter pasture crops and wild crop weeds such as cape weeds within bogong moth breeding grounds, primarily depending on annual dicotyledons that grow during the winter. Attacks on a wide variety of cultivated crops have been seen, with plants such as Medicago species, wheat, cabbages, cauliflowers, silver beet, peas, and potatoes all recorded being consumed by bogong moth caterpillars. However, the larvae avoid grasses, which overtake pastures during the summer, making summer unfavourable due to lack of larval food sources. Adult bogong moths feed on the nectar of flowers such as Epacris, Grevillea and Eucalyptus while breeding or migrating, but will not actively feed during aestivation. Migration Bogong moths undergo whole scale long-distance migration biannually, in which they can travel up to 965 km (600 miles). The spring migration begins in early September and occurs from the lowlands of Southern Australia south towards the Australian Alps for purposes of reaching aestivation sites. During the summer, the moths remain in their aestivation sites until autumn, when they migrate back towards the breeding grounds of the lowlands as early as February, but primarily in April. The bogong moth utilizes particular aestivation sites repeatedly throughout migrations, as seen with the development of parasites that depend on the regular arrival and departure of the moths from caves. The population within each aestivation site fluctuates throughout the summer due to moth mortality and the departure and arrival of moths either migrating further south for aestivation or north to return to breeding grounds. However, this differs from changes during migration periods, when the populations rapidly increase with arrival or decrease with departure. Bogong moths are nocturnal migrants, but the exact mechanism for long-distance navigation is not clear. It is possible that they are oriented by light, as seen in the influence of light intensity on activity during aestivation. Additionally, bogong moths may use an internal magnetic compass to aid in navigation, as seen in the similar monarch butterfly. A study published in 2018 concluded that the Bogong moth uses a combination of the Earth's magnetic field and recognizable landmarks to calibrate their route. However, there are also nonmigratory populations; this generally occurs in areas with favourable conditions, where migration to avoid harsh conditions such as seasonal changes in larval food crop abundance is not necessary. Some populations of bogong moths in areas such as Tasmania and in coastal