Bogong moths (Agrotis infusa) can rely on the stars of the night sky to orient their migrations of distances up to 1,000 km. This navigational mechanism is likely supported by a suite of directionally tuned neurons distributed in the optic lobe, central complex, and lateral accessory lobes of the Bogong brain. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

The Australian Bogong moth (Agrotis infusa) is a small noctuid moth that undertakes annual, nocturnal migrations of up to 1000km to escape the summer heat of its breeding grounds. The moths travel to cool alpine caves, where they enter a dormant state (aestivation) before returning to reproduce and die. During migration, their brains integrate magnetic and visual cues to guide their flight direction. While the Bogong moth's neurobiology is increasingly understood, its visual system has remained unexplored. Here, we describe the morphology, ultrastructure, optics, and visual opsins of the Bogong moth's compound eyes and ocelli. Using light and electron microscopy, micro-computed tomography, in situ hybridization, and spectral absorbance measurements, we show that the compound eyes are typical superposition eyes with a tiered rhabdom, similar to other noctuid moths. The ocelli are small but structurally complex, featuring a two-tiered retina with spectrally distinct receptor cells and a lens forming a focused image on the ocellar retina. At the molecular level, the Bogong moth expresses three canonical opsins (UV, blue, and long-wavelength) and an additional red-shifted long-wavelength opsin, suggesting enhanced sensitivity to long-wavelength light. These opsins exhibit distinct expression patterns across the compound eyes, indicating functionally distinct dorsal and ventral eye hemispheres. Overall, the Bogong moth's visual system displays multiple adaptations to nocturnal vision. These features, likely shared across noctuid moths, may have contributed to the evolution of the exceptional navigational abilities during long-distance migrations in dim light that define the Bogong moth, but which are also widespread across noctuid moths.

Despite their tiny size, lepidopterans accomplish some of the most extraordinary migrations on Earth. Monarch butterflies and bogong moths, for example, travel vast distances to find the same seasonal sheltering sites year after year, and remarkably do so without any prior experience. How do these delicate creatures navigate so precisely across large and changing landscapes? Scientists have spent decades unraveling this mystery, revealing that lepidopterans possess a sophisticated suite of navigational tools that rival those of much larger animals. Lepidopteran compass systems rely on celestial cues like the sun, stars, and polarized light, as well as the Earth's magnetic field. Diurnal monarchs and nocturnal bogong moths have become model species for understanding how insects combine skylight and magnetic compasses to find their way. Recent discoveries have shed light on the neural circuits and genetic blueprints that power these compasses. In this review, we provide an overview of the navigational toolkit employed by lepidopteran migrants, dive into their mechanisms, and highlight future directions needed to fully decode the secrets of insect long-distance navigation.

The relevance of goal directed movement for insect pest control.

Bogong moths (Agrotis infusa) are native to Australia. Each year, the nocturnal insects migrate ∼1000 km from locations including southern Queensland, northern and western New South Wales, eastern South Australia and Victoria to the alpine areas of southeastern Australia at elevations above 1850 m, where they aestivate – the summer equivalent of hibernation – in isolated caves. They then return to their native territory the following year to reproduce and die. During their long-distance migrations, which can take up to a month, the insects are guided by the Earth's magnetic field and the night sky to the caves. Eric Warrant has studied these remarkable insects over the last 15 years, investigating the senses that allow them to follow the navigational cues that guide their exceptional journey. He tells Journal of Experimental Biology about these extraordinary creatures, how they are exquisitely adapted to their migration and their cultural significance to the First Nations people of Australia.

Stochastic wind-driven migration likely maintains panmixia in the endangered bogong moth, Agrotis infusa

Each spring, billions of Bogong moths escape hot conditions across southeast Australia by migrating up to 1,000 km to a place that they have never previously visited—a limited number of cool caves in the Australian Alps, historically used for aestivating over summer1,2. At the beginning of autumn, the same individuals make a return migration to their breeding grounds to reproduce and die. Here we show that Bogong moths use the starry night sky as a compass to distinguish between specific geographical directions, thereby navigating in their inherited migratory direction towards their distant goal. By tethering spring and autumn migratory moths in a flight simulator3–5, we found that, under naturalistic moonless night skies and in a nulled geomagnetic field (disabling the moth’s known magnetic sense4), moths flew in their seasonally appropriate migratory directions. Visual interneurons in different regions of the moth’s brain responded specifically to rotations of the night sky and were tuned to a common sky orientation, firing maximally when the moth was headed southwards. Our results suggest that Bogong moths use stellar cues and the Earth’s magnetic field to create a robust compass system for long-distance nocturnal navigation towards a specific destination.

Abstract The bogong moth, Agrotis infusa, an endemic noctuid moth of Australia, is known for its extensive long‐distance movement and summer aestivation in the Australian Alps. Recent studies have focused on moth activity in the Alps, but there are limited data for other regions. This study aims to build on the current understanding of bogong moth movement and breeding patterns using unpublished historical data across eastern Australia. We analysed historical data from moth traps in Victoria, New South Wales (NSW) and South Australia (SA) from the 1960s to early 1990s. The study employed the HYSPLIT model for trajectory analysis of moth flight paths and DARABUG2 for phenological modelling. We examined moth catches across different seasons to infer movement patterns, breeding sources and over‐summering activity. Our findings question several long‐standing assumptions about the spatial ecology of the bogong moth. The trajectory analysis suggests that many aspects of A. infusa movement can be explained via dynamic migration, without fully relying on inherent navigation abilities. Important breeding areas may be beyond the self‐mulching clays of NSW and southern Queensland and include far western NSW, south and central SA and southern Victoria. Substantial moth activity during summer in many traps suggests alternative over‐summering strategies including local breeding or even aestivation in areas other than the Alps. Furthermore, the autumn and winter data imply return migrations from diverse source areas and potential local breeding, expanding the understanding of the moth's life cycle beyond a univoltine pattern. In conclusion, the bogong moth appears to exhibit a more complex and adaptable migration and breeding strategy than previously understood, utilising a range of habitats across eastern Australia for breeding and possibly aestivation. This underscores the need for a revised understanding of bogong moth ecology, which is crucial for its conservation and management, especially considering its recent classification as ‘Endangered’ on the IUCN Red List.

The Bogong moth Agrotis infusa is well known for its remarkable annual round-trip migration from its breeding grounds across eastern and southern Australia to its aestivation sites in the Australian Alps, to which it provides an important annual influx of nutrients. Over recent years, we have benefited from a growing understanding of the navigational abilities of the Bogong moth. Meanwhile, the population of Bogong moths has been shrinking. Recently, the ecologically and culturally important Bogong moth was listed as endangered by the IUCN Red List, and the establishment of a program for long-term monitoring of its population has been identified as critical for its conservation. Here, we present the results of two years of monitoring of the Bogong moth population in the Australian Alps using recently developed methods for automated wildlife-camera monitoring of flying insects, named Camfi. While in the Alps, some moths emerge from the caves in the evening to undertake seemingly random flights, filling the air with densities in the dozens per cubic metre. The purpose of these flights is unknown, but they may serve an important role in Bogong moth navigation. We found that these evening flights occur throughout summer and are modulated by daily weather factors. We present a simple heuristic model of the arrival to and departure from aestivation sites by Bogong moths, and confirm results obtained from fox-scat surveys which found that aestivating Bogong moths occupy higher elevations as the summer progresses. Moreover, by placing cameras along two elevational transects below the summit of Mt. Kosciuszko, we found that evening flights were not random, but were systematically oriented in directions relative to the azimuth of the summit of the mountain. Finally, we present the first recorded observations of the impact of bushfire smoke on aestivating Bogong moths - a dramatic reduction in the size of a cluster of aestivating Bogong moths during the fire, and evidence of a large departure from the fire-affected area the day after the fire. Our results highlight the challenges of monitoring Bogong moths in the wild and support the continued use of automated camera-based methods for that purpose.

Endangered Bogong moths (Agrotis infusa) forage from local flowers after annual mass migration to alpine sites

The impact of elevated aestivation temperatures on the behaviour of bogong moths (Agrotis infusa)

Context Migratory populations of bogong moths in Australia are in decline. Numbers decreased after European settlement in the 1800s, and were stable before declining again from about 1980. Numerous hypothesised drivers for the decline have been postulated, and Caughley’s declining population paradigm provides a systematic approach to diagnosing which of these are important, and hence the knowledge to guide recovery actions. Aims This paper aims to assess which of the hypothesised drivers remain as candidate hypotheses for further investigation. Methods Within the context of known bogong moth life history and the timing of observed declines, hypothesised drivers of the two decline phases were assessed with respect to their potential impact on larval recruitment and adult survival during migration and aestivation. Key results Changes in vegetation composition and availability arising from the spread of pastoralism stand out as a likely driver of the early decline, with the herbivorous moth larva facing competition with introduced livestock, feral herbivores, and increased densities of native macropods. Many of the numerous postulated drivers of the most recent decline (e.g. changes in rainfall, rising temperatures in aestivation sites, increasing fire frequency) appear to have little support to be retained. Postulated drivers that remain as working hypotheses include increasing soil temperatures, increased cropping areas, and changed cropping practices and area. The effect of some drivers, such as artificial light pollution, is unclear and may warrant further investigation. Conclusions Inference on the drivers of bogong moth population decline is wanting. Implications Designed experiments are needed.

Context Globally, insectivorous bats are important moderators of insect populations, including agricultural pests. However, in human-modified environments, changes to insect diversity and abundance may have detrimental impacts on bat populations. The southern bent-wing bat (SBWB; Miniopterus orianae bassanii), is a critically endangered, cave-dwelling bat with a restricted distribution across south-eastern Australia, an area now dominated by agricultural land uses. Understanding SBWB diet may highlight the role of bats in influencing insect populations in surrounding agricultural land, while simultaneously providing crucial data for conservation management of this critically endangered species. Aim To investigate the SBWB’s diet using arthropod DNA metabarcoding of scats and guano collected from seven caves across the species’ range. Methods We collected scats from bat roosts and from guano piles on cave floors during late summer and early autumn of 2019. We used PCR to amplify two short, overlapping arthropod mtDNA cytochrome oxidase subunit 1 barcodes and sequenced these using the Illumina MiSeq to identify arthropod diet species. Key results Moths (order Lepidoptera) were the most prevalent insect identified in all samples and from all sites. Many of the 67 moth species identified were associated with agricultural land use (e.g. pasture webworm (Hednota pedionoma) and armyworm (Persectania dyscrita)), and several, including the bogong moth (Agrotis infusa), are migratory, suggesting the SBWB’s diet changes seasonally. Conclusion By describing the diet of the SBWB, we have fulfilled one recommendation of the national recovery plan for the species. The SBWB preys predominantly on moths, and its diet has likely been impacted by the increase in agricultural land use across its range. Further research is required to understand its foraging habitat requirements. Implications Our findings suggest the SBWB may play a role in controlling populations of moth species considered to be agricultural pests. The wide variety of moths consumed by SBWBs could afford the species some resilience to landscape changes affecting moth assemblages. The methodological framework developed here could be applied to investigate how land-use changes may contribute to bat population declines, but also how insectivorous bats may provide important ecosystem services by controlling pest insect species in modified landscapes.

The Bogong moth Agrotis infusa (Boisduval) is a migratory noctuid moth from south-eastern Australia which annually migrates thousands of kilometres for a period of aestivation in boulder-piles, caves and crevices on the highest mountain peaks of the Australian Alps. The same aestivation sites are used each year, and over time a highly organic deposit made predominately of preserved insect chiton and plant matter has accumulated at many of them. Examples of these sediments were characterised using a range of standard methods to ascertain the organic content, the carbon and nitrogen components, the lipids (oils and waxes) concentration and the acidity of each deposit. The deposits were found to be high in organic matter with a relatively high C:N ratio, low in lipids, and highly acidic. The acidity and amount of organic matter in these deposits are above threshold levels for classification as peat. The high concentration of insect remains, their taphonomic importance and the ecological context warrant the naming of sediments at Bogong moth aestivation sites as “insect derived peat” or “moth peat”.

The Bogong moth Agrotis infusa is well known for its remarkable long‐distance migration – a return journey from the plains of southeast Australia to the Australian Alps – as well as for its cultural significance for Indigenous Australians. Each spring, as many as four billion moths are estimated to arrive in the Australian Alps to aestivate in cool mountain caves and in boulder fields, bringing with them a massive annual influx of energy and nutrients critical for the health of the alpine ecosystem. However, a massive decline in moths present at their aestivation sites has occurred over the past 3 years, with only a few individuals present where hundreds of thousands could earlier be found. In order to understand the possible sources of decline, we analysed historical records of Bogong moth numbers at aestivation sites in the Australian Alps, including observations on Mt. Gingera (NSW) in the early 1950s, observations from 1980 onwards in the Snowy Mountains (NSW) and an almost‐unbroken series of observations each summer over the past 53 years in three caves at different elevations on Mt. Buffalo (Victoria). This analysis shows that moth numbers were probably steady from 1951 until about 1980, fluctuated and slowly fell from then until 2016 and dramatically crashed in 2017. In the Murray–Darling Basin, the main winter breeding ground of Bogong moths, changes in farming practices, such as increasing land clearing for crops (which has removed around a quarter of a billion moths annually from the mountains compared to pre‐European levels), has probably driven some of the decline in Bogong moth numbers observed from 1980 to 2016. The impact of insecticide remains unclear and is in urgent need of further study. Even though we found little evidence that increasing global temperatures per se are responsible for the Bogong moth decline, the Australian climate has nonetheless become drier and warmer over past decades, possibly hampering the survival of immature stages in the breeding areas and confining adult aestivation to gradually higher elevations. The crash in moth numbers from 2017 is most likely due to the recent severe drought in the moth's breeding grounds.

Insects form an important source of food for many people around the world, but little is known of the deep-time history of insect harvesting from the archaeological record. In Australia, early settler writings from the 1830s to mid-1800s reported congregations of Aboriginal groups from multiple clans and language groups taking advantage of the annual migration of Bogong moths (Agrotis infusa) in and near the Australian Alps, the continent’s highest mountain range. The moths were targeted as a food item for their large numbers and high fat contents. Within 30 years of initial colonial contact, however, the Bogong moth festivals had ceased until their recent revival. No reliable archaeological evidence of Bogong moth exploitation or processing has ever been discovered, signalling a major gap in the archaeological history of Aboriginal groups. 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.

Moth wings are densely covered by wing scales that are assumed to specifically function to camouflage nocturnally active species during day time. Generally, moth wing scales are built according to the basic lepidopteran Bauplan, where the upper lamina consists of an array of parallel ridges and the lower lamina is a thin plane. The lower lamina hence acts as a thin film reflector having distinct reflectance spectra that can make the owner colorful and thus conspicuous for predators. Most moth species therefore load the scales’ upper lamina with variable amounts of melanin so that dull, brownish color patterns result. We investigated whether scale pigmentation in this manner indeed provides moths with camouflage by comparing the reflectance spectra of the wings and scales of the Australian Bogong moth (Agrotis infusa) with those of objects in their natural environment. The similarity of the spectra underscores the effective camouflaging strategies of this moth species.

Every year, millions of Australian Bogong moths (Agrotis infusa) complete an astonishing journey: In Spring, they migrate over 1,000 km from their breeding grounds to the alpine regions of the Snowy Mountains, where they endure the hot summer in the cool climate of alpine caves. In autumn, the moths return to their breeding grounds, where they mate, lay eggs and die. These moths can use visual cues in combination with the geomagnetic field to guide their flight, but how these cues are processed and integrated into the brain to drive migratory behavior is unknown. To generate an access point for functional studies, we provide a detailed description of the Bogong moth's brain. Based on immunohistochemical stainings against synapsin and serotonin (5HT), we describe the overall layout as well as the fine structure of all major neuropils, including the regions that have previously been implicated in compass-based navigation. The resulting average brain atlas consists of 3D reconstructions of 25 separate neuropils, comprising the most detailed account of a moth brain to date. Our results show that the Bogong moth brain follows the typical lepidopteran ground pattern, with no major specializations that can be attributed to their spectacular migratory lifestyle. These findings suggest that migratory behavior does not require widespread modifications of brain structure, but might be achievable via small adjustments of neural circuitry in key brain areas. Locating these subtle changes will be a challenging task for the future, for which our study provides an essential anatomical framework.

BackgroundThe Mountain Pygmy-possum (Burramys parvus) is a critically endangered marsupial, endemic to alpine regions of southern Australia. We investigated the diet of a recently discovered population of the possum in northern Kosciuszko National Park, NSW, Australia. This new population occurs at elevations well below the once-presumed lower elevation limit of 1,600 m.Goals and MethodsFaecal material was analysed to determine if dietary composition differed between individuals in the newly discovered northern population and those in the higher elevation southern population, and to examine how diet was influenced by rainfall in the southern population and seasonal changes in resource availability in the northern population.Results and DiscussionThe diet of B. parvus in the northern population comprised of arthropods, fruits and seeds. Results indicate the diet of both populations shares most of the same invertebrate orders and plant species. However, in the absence of preferred food types available to the southern population, individuals of the northern population opportunistically consumed different species that were similar to those preferred by individuals in higher altitude populations. Differing rainfall amounts had a significant effect on diet, with years of below average rainfall having a greater percentage composition and diversity of invertebrates. Seasonal variation was also recorded, with the northern population increasing the diversity of invertebrates in their diet during the Autumn months when Bogong Moths (Agrotis infusa) were absent from those sites, raising questions about the possum’s dependence on the speciesConclusionsMeasurable effects of rainfall amount and seasonal variation on the dietary composition suggest that predicted climatic variability will have a significant impact on its diet, potentially impacting its future survival. Findings suggest that it is likely that B. parvus is not restricted by dietary requirements to its current pattern of distribution. This new understanding needs to be considered when formulating future conservation strategies for this critically endangered species.

Context Climate change is causing changes to seasonal food resources, with critical health and survival impacts for many species. The endangered Burramys parvus (mountain pygmy-possum) predominantly consumes Agrotis infusa (Bogong moth), a long-distance seasonal migrant. Aims We aimed to examine direct and indirect climate-related influences on B. parvus food resources so as to assess the susceptibility of the species to climate change. Methods We analysed a long-term (17-year) data record of B. parvus faecal samples from sites across a climate gradient, in relation to plant-growth indices derived from climate data. We also modelled the population dynamics of A. infusa against climate variables and in relation to the probability of consumption by B. parvus. Key Results The diet of B. parvus was highly variable among sites and years and there were strong seasonal patterns for predominant food resources (A. infusa, other local arthropods, Podocarpus sp. and other local seeds). Seasonal patterns generally diminished with an increasing elevation, which may be due to resource availability or complex interactions with food preferences. Growth conditions across spatially far removed A. infusa breeding grounds influenced their abundance recorded in the Alps in spring, which was reflected in B. parvus diet. Conclusions Strong seasonal and climatic influences on dominant food resources suggest that B. parvus may be susceptible to climate change. Selective foraging for the lipid-rich A. infusa and Podocarpus sp. seed suggests that there may be important health and survival benefits for B. parvus. Implications Given the dependence on cooler, higher-elevation aestivation sites, A. infusa may have reduced survival in a warmer world. Climate change across the vast migratory route of A. infusa is likely to further affect survival and availability for consumption by B. parvus. Predicted increases in fire frequency and severity may reduce availability of the fire-sensitive Podocarpus sp. The health and survival of B. parvus may be compromised as a result of reduced availability of A. infusa and Podocarpus seed and a greater dependence on angiosperm plants (seeds and nectar) and local arthropods because of the consequent change in dietary lipid composition. Integrated predictive modelling of A. infusa and B. parvus population dynamics under future climate-change scenarios is recommended.