The bogong moth (''Agrotis infusa'') is a temperate
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
night-flying moth
Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
, notable for its biannual long-distance seasonal
migrations towards and from the
Australian Alps
The Australian Alps is a mountain range in southeast Australia. It comprises an interim Australian bioregion,0042-5184 However, the moth has also been a biovector of arsenic, transporting it from lowland feeding sites over long distances int ...
, similar to the diurnal
monarch butterfly.
During the autumn and winter it is found in southern
Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, established_ ...
, western
New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, western
Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
,
and also in
South
South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...
and
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
.
Adult bogong moths breed and larvae hatch during this period, consuming winter pasture plants during their growth.
During the
spring
Spring(s) may refer to:
Common uses
* Spring (season)
Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...
, the moths migrate south or east and reside in mountains such as
Mount Bogong
Mount Bogong, , located in the Alpine National Park and part of the Victorian Alps of the Great Dividing Range, is the highest mountain in Victoria, Australia, at above sea level.
The Big River separates the massif of the mountain from ...
, where they gregariously
aestivate over the
summer until their return towards breeding grounds again in the autumn.
The moth's name, ''bogong'', is derived from an
Australian Aboriginal language
The Indigenous languages of Australia number in the hundreds, the precise number being quite uncertain, although there is a range of estimates from a minimum of around 250 (using the technical definition of 'language' as non-mutually intellig ...
; the
Dhudhuroa
The Dhudhuroa people (or Duduroa) are an Indigenous Australian people of North-eastern Victoria, in the state of Victoria, Australia. About 2,000 descendants exist in Australia in the early 21st century.
Name
The endonym Dhudhuroa has been analys ...
word ''bugung'' describes the brown colouration of the moth.
It is an icon of Australian wildlife due to its historical role as an important food source and because
Aboriginal peoples
Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...
would come to where the moths spend the summer to feast on them and hold intertribal gatherings.
In recent years, it has invaded major cities like
Canberra
Canberra ( )
is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...
,
Melbourne
Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...
, and
Sydney
Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...
due to strong winds during its spring migration.
Starting around 1980 and accelerating rapidly after 2016, the Bogong Moth population has sharply declined as a result of
increasingly severe droughts, along with increased temperatures in caves used by the moths for
aestivation
Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and ...
, both primarily resulting from
anthropogenic climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
. In December 2021 the bogong moth was added to the
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
as an
Endangered Species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
.
[
]
Taxonomy and etymology
Bogong moths was first described by French lepidopterist
Lepidopterology ()) is a branch of entomology concerning the scientific study of moths and the three superfamilies of butterflies. Someone who studies in this field is a lepidopterist or, archaically, an aurelian.
Origins
Post-Renaissance, t ...
Jean Baptiste Boisduval in 1832, who described the moth as ''Noctua infusa'' from a type specimen from Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
. He described the moth as having blackish-brown hind wings. However, in 1903 British entomologist
Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...
George Hampson
Sir George Francis Hampson, 10th Baronet (14 January 1860 – 15 October 1936) was an English entomologist.
Hampson studied at Charterhouse School and Exeter College, Oxford. He travelled to India to become a tea-planter in the Nilgiri Hills o ...
classified a specimen with white hind wings under this name, alongside another specimen of ''Agrotis spina'' with blackish-brown hind wings. Australian amateur entomologist Alfred Jefferis Turner
Alfred Jefferis Turner (3 October 1861, in Canton – 29 December 1947, in Brisbane, Queensland, Australia) was a pediatrician and noted amateur entomologist. He was the son of missionary Frederick Storrs-Turner. He introduced the use of dip ...
identified ''A. spina'' as a synonym of ''A. infusa'' in 1920. I. F. B. Common, an Australian entomologist, found specimens with both hind wing colours in 1954. Specimens with the white hind wings were only found during specific months in mercury vapour light traps near Canberra
Canberra ( )
is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...
, and he attributed the white hind wing specimens to a seasonal form.
The moth's name, ''bogong'', is derived from the Dhudhuroa word ''bugung'', meaning brown moth. Its presence has contributed to the naming of numerous locations and landmarks. For example, a town, Bogong, in the Australian state of Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
has been named after the moth.[Physical Map of Australia, special advertising feature of Australia.com on pg 16, National Geographic magazine, May 2006, Washington DC] Mount Bogong
Mount Bogong, , located in the Alpine National Park and part of the Victorian Alps of the Great Dividing Range, is the highest mountain in Victoria, Australia, at above sea level.
The Big River separates the massif of the mountain from ...
, located south of the Bogong High Plains
The Bogong High Plains (), part of the Victorian Alps of the Great Dividing Range, are a section of plains located in the Alpine National Park in the Australian state of Victoria and are situated south of Mount Bogong.
In winter this area is ...
, is also named after the moth, with its traditional name, ''Warkwoolowler'', meaning the mountain where Aboriginal people collected the "boo.gong fly". The Taungurung
The Taungurung people, also spelt ''Daung Wurrung'', are an Aboriginal people who are one of the Kulin nations in present-day Victoria, Australia. They consist of nine clans whose traditional language is the Taungurung language.
Their Country ...
name for the bogong moth is ''debera''.
In the Australian state of New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, a series of mountains in the Kosciuszko National Park are named the Bogong Peaks.
Description
Adult bogong moths have an overall dark brown colouration, with a dark stripe interrupted by two light-coloured spots on the wings, distinguishing it from other moths. There are visual differences between the migratory and nonmigratory forms of the moth; migratory moths have brown hind wings while nonmigratory moths have paler hind wings. Bogong moths have a wingspan ranging between 40–50 mm (1.6-2.0 in), and a body length of around 25–35 mm (1-1.4 in). The average weight of an adult bogong moth is 0.326 grams.
Bogong moth eggs are dome–shaped in appearance and are vertically ridged. They are 0.7 mm (0.03 in) in diameter and 0.4 mm (0.02 in) in height.
Caterpillars initially start out with a pale colouration, but as they grow and consume food they become green with pale and dark stripes and spots. Larvae achieve a maximum length of 50 mm (2.0 in).
Distribution and habitat
Bogong moth populations are primarily located across southern Australia, west of the Great Dividing Range. The regions contain populations of nonmigratory and migratory moths of this species, distinguished by their differing seasonal presences in each region. The adult bogong moth lays eggs across New South Wales, southern Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, established_ ...
, and northern parts of Victoria, where larvae hatch and grow until adulthood. During the spring season and subsequent summer aestivation, bogong moths migrate south or east towards the Australian Alps, and can be found in the Australian Capital Territory
The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding townships. ...
and Bogong Mountains. However, bogong moths can also be found in locations as far as Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
and New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
due to strong winds that blow them off their path.
Breeding grounds
Bogong moth eggs and larvae are primarily found in self-mulching soils (soil that mixes itself) and crop pastures, where both wild and agricultural larval food sources are abundant during the autumn and winter
Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultur ...
seasons. The heavy presence of larvae in these pastures can lead to significant crop damage. During the spring
Spring(s) may refer to:
Common uses
* Spring (season)
Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...
and summer seasons, when grasses overtake these pastures, conditions are unfavourable for larval survival since larvae do not consume these plants. This leads to delayed breeding, as bogong moths are multivoltine
Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. The term is most often applied to insects, and is particularly in use in sericulture, where silkworm varieties vary in their voltinism.
...
and so can raise multiple generations. Instead, adult bogong moths migrate in a southerly direction during the summer and aestivate (remain dormant), until conditions are favourable again.
Aestivation sites
During the spring migration
Migration, migratory, or migrate may refer to: Human migration
* Human migration, physical movement by humans from one region to another
** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
, adult bogong moths can be found in their ideal aestivation sites, which generally consist of cool, dark caves and crevices but can include spaces underneath tors and even fallen tree trunks. Stable temperatures and humidity make these locations ideal for bogong moth aestivation. Crevices regulate their environment through wind flow, and caves generally have more regular temperatures and greater humidity. This reduces water loss in bogong moths during their inactivity. While temporary sites can be used in lower elevations, these sites undergo massive population fluctuations and movements throughout their use. Permanent aestivation sites are generally found in higher altitudes of 1500 metres (4920 ft) or above, with the largest, most stable aggregations found on the summits of mountains such as Mt. Gingera.
Life cycle
Adult bogong moths lay up to 2000 eggs in the soil or on plants near the soil after returning from aestivation sites in the autumn migration. Incubation times vary depending on temperature, with eggs hatching after a period of 4–7 days in laboratory conditions. The larvae
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
of bogong moths undergo six instar
An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...
s. Caterpillars grow slowly throughout the first three instars, taking until June to develop over the winter. However, the larvae go through fast growth during the spring, reaching the final instar in late August to September, soon before migration. They are active at night, when they feed on plants within breeding grounds. Larvae undergo pupa
A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...
tion in soil chambers at a depth of 20–150 mm (0.8-7.9 in). Pupation can last between 3–11 weeks depending on the temperature and environment. Pupae are 20 mm (0.8 in) in length and have a shiny, brown appearance. Adults emerge from the soil chambers and shortly after begin migration. Adult bogong moths are active at night, and have different seasonal behaviors. During the spring, bogong moths feed and migrate south, where they aestivate during the summer. Adult bogong moths are not sexually mature yet, and do not actively seek food during this period of dormancy. In autumn, the moths migrate again and return to their breeding grounds, laying eggs and dying.
Image:Agrotis infusa female dorsal.jpg, Female dorsal view
Image:Agrotis infusa female ventral.jpg, Female ventral view
Image:Agrotis infusa male dorsal.jpg, Male dorsal view
Image:Agrotis infusa male ventral.jpg, Male ventral view
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
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
, cabbage
Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...
s, cauliflowers, silver beet, pea
The pea is most commonly the small spherical seed or the seed-pod of the flowering plant species ''Pisum sativum''. Each pod contains several peas, which can be green or yellow. Botanically, pea pods are fruit, since they contain seeds and d ...
s, and potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Unit ...
es 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
''Epacris'' is a genus of about forty species of flowering plants in the family Ericaceae. It was formerly treated in a closely related but separate family Epacridaceae, but the various genera within Epacridaceae including ''Epacris'' have been ...
'', ''Grevillea
''Grevillea'', commonly known as spider flowers, is a genus of about 360 species of evergreen flowering plants in the family Proteaceae. Plants in the genus ''Grevillea'' are shrubs, rarely trees, with the leaves arranged alternately along the b ...
'' and ''Eucalyptus
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...
'' 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 populations of New South Wales do not migrate, and reach sexual maturity at a faster rate than migratory populations.
Social aggregation
During the spring migration, bogong moths gregariously aggregate with densities reaching 17,000 moths per square metre (10.8 square feet) within caves, crevices, and other areas hidden from the sunlight. The lack of light and relatively constant temperature and humidity makes these spots favourable during aestivation. The first moths that arrive occupy the deepest and darkest locations, using their fore tarsi to grip onto the rock faces, and aggregations form around these initial areas, with moths arriving later settling for less ideal areas with more sunlight, higher temperatures, and decreased humidity. To diminish the amount of light that reaches their light-sensitive eyes, later moths push themselves underneath the wings and abdomens of moths that arrived earlier and place their hind legs on top of the moths beneath them. This physical contact and aggregation allow the moths to retain body moisture. When the aestivating moths are disturbed, the moths within the area of disturbance briefly spread out and leave the aggregation, dropping excrement when unsettled before quickly returning to the aggregation and re-positioning themselves.
While the moths mostly remain dormant during aestivation, there are some periods of activity within the aggregation which are correlated to changes in light intensity. During dawn and dusk, portions of the population become active, first crawling around and spreading out, and then flying out of their shelter into the open. While some water drinking has been observed, no evidence of copulation or active foraging has been found during these periods of activity.
Diapause
Facultative
{{wiktionary, facultative
Facultative means "optional" or "discretionary" (antonym '' obligate''), used mainly in biology in phrases such as:
* Facultative (FAC), facultative wetland (FACW), or facultative upland (FACU): wetland indicator statuses ...
diapause
In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press I ...
, an optional period of delayed development in response to environmental conditions, accompanies the biannual migration of the bogong moths. While one generation of moths goes through the two migrations each year, multiple generations are possible in favourable conditions and higher temperatures, as growth across all life stages can occur faster. For example, without the diapause, the bogong moth would normally complete sexual maturation within 50 days. However, this maturation is delayed due to the lack of larval food sources during the summer season. During the summer, hot temperatures occur and grasses, which are an unfavourable diet for bogong moth larvae, overtake pastures and make up the majority of the plants occupying the pastures. Bogong moths avoid this harsh environment by delaying development during the summer so that their eggs do not hatch in a poorly-suited environment; instead, they migrate to cooler, more suitable areas and delay their development during aestivation until the winter season, when they return to the breeding grounds and winter pasture crops begin to grow again. During aestivation, the bogong moths remain dormant for several months, possibly delaying development due to the lower temperatures. The food they consume during the migration is also dedicated to building fat reserves for aestivation rather than development, as bogong moths must consume more food during the autumn migration before maturation and mating. However, in areas with favourable conditions, bogong moths do not have to migrate during the summer.
Ecology
Enemies
Predators
The bogong moth suffers from predation during both its migration and aestivation. During the spring and autumn migrations, several species of birds, mammals, and even fish have been recorded preying on the moth. Little raven
The little raven (''Corvus mellori'') is a species of the family Corvidae that is native to southeastern Australia. An adult individual is about in length, with completely black plumage, beak, and legs; as with all Australian species of ''Corv ...
, currawong
Currawongs are three species of medium-sized passerine birds belonging to the genus ''Strepera'' in the family Artamidae native to Australia. These are the grey currawong (''Strepera versicolor''), pied currawong (''S. graculina''), and black ...
and Richard's pipit
Richard's pipit (''Anthus richardi'') is a medium-sized passerine bird which breeds in open grasslands in the East Palearctic. It is a long-distance migrant moving to open lowlands in the Indian subcontinent and Southeast Asia. It is a rare but ...
congregations form to feast on bogong moths as they travel from aestivation sites during migration. Aboriginal people also travelled to aestivation sites to feast on the dormant moths, and may have searched for these bird congregations to locate these sites. Bats also attack the moths during active flight periods during the dusk, and foxes
Foxes are small to medium-sized, omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull, upright, triangular ears, a pointed, slightly upturned snout, and a long bushy tail (or ''brush'').
Twelve sp ...
, bush rat
The bush rat or Australian bush rat (''Rattus fuscipes'') is a small Australian nocturnal animal. It is an omnivore and one of the most common indigenous species of rat on the continent, found in many heathland areas of Victoria and New South ...
s, and dusky antechinus
The dusky antechinus (''Antechinus swainsonii''), also known as Swainson's antechinus or the dusky marsupial mouse, is a species of small marsupial carnivore, a member of the family Dasyuridae. It is found in Australia.
Taxonomy
The dusky ante ...
have been recorded eating moths. Of the mammals that prey on the bogong moth, the endangered mountain pygmy-possum is the most reliant on bogong moths as a source of food.
Parasites
Two species of mermithid nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
s parasitize the bogong moth during its aestivation: ''Amphimermis bogongae'' and ''Hexamermis cavicola.'' The parasites are transmitted to bogong moths through water; the early instar larval nematodes reside in the debris of the cave floors of common aestivation sites, and crawl up to reach the moths through trickles of water coming down the walls. Bogong moths are infected upon their arrival within the caves once they drink the water. After a few months, the larval nematodes emerge from the moths, which causes the moth to die, and burrow into the cave floor, where they mature and lay eggs over the winter and wait for the next spring migration of the moths. The nematodes are unusual in that they parasitize adult bogong moths instead of the more commonly utilized larval host stage. The nematodes' life cycles demonstrate an adaptation to the migration of the bogong moths, as they are dependent on bogong moths returning to the same aestivation sites.
Biovector of arsenic
Concerns have been raised over the potential role of agriculture in turning the bogong moth into a biovector of arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...
in the Australian Alps. Aggregations of bogong moths in aestivation sites has led to the bioaccumulation of the pollutant in both the surrounding local environment and within predators, particularly in the endangered mountain pygmy possum
The mountain pygmy possum (''Burramys parvus''); also simply known as the burramys, is a small, mouse-sized (weighs ) nocturnal marsupial of Australia found in dense alpine rock screes and boulder fields, mainly southern Victoria and around Moun ...
. However, no conclusive evidence has directly linked agriculture as the source of arsenic in bogong moths.
In 2001, a few months after rainfall had washed out debris consisting of dead moths from within the cave, the complete death of local grasses was seen outside of an aestivation site of the bogong moth. Investigation into the causes of the grass mortality showed that the concentration of arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...
in the surrounding areas was much higher than normal, and the source was determined to be the bogong moths. Since the bogong moths do not feed at their aestivation sites, they had absorbed arsenic from lowland feeding sites as larvae and subsequently transported it over long distances into the mountains. Bioaccumulation, the absorption and accumulation of substances by organisms, occurs with arsenic in bogong moths. While levels within each individual moth are small, the sheer quantity of moths in the area led to a concentration of the pollutant to damaging levels in the environment. The presence of arsenic has also been shown in the feces of mammals such as the mountain pygmy-possum, demonstrating the bioaccumulation of this pollutant in animals. While no source has been determined, concerns have been raised over the possible role of agriculture in the bioaccumulation of arsenic due to its presence in historically and presently-used insecticides. This has led to the discontinued use of insecticides in controlling the bogong moth in urban areas, in favour of less intrusive methods.
Decline in numbers
In the spring and summer seasons of 2017-8 and 2018-9, dramatic drops in numbers of the moths in the Alpine caves have been observed. Millions of the moths have usually lined the walls of these caves over summer, but for the past two seasons there have been none in some caves, according to Professor Eric Warrant of Lund University
, motto = Ad utrumque
, mottoeng = Prepared for both
, established =
, type = Public research university
, budget = SEK 9 billion [Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...]
. He says that the drop in numbers was probably caused by a lack of rainfall due to winter drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...
in their breeding areas and climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
, the lack of rain producing insufficient vegetation to feed the caterpillars. Some caves still harboured thousands of moths, which suggested that the moths "came from different breeding grounds, where one location wasn't as badly affected by the drought as the other. I don't think they will disappear completely, but there's certainly a possibility that they could become locally extinct at their breeding grounds.", Warrant said.
Other biologists and ecologists have pointed to the dramatic effect on animals which feed on the moths, which are an important source of protein for wildlife, including the threatened mountain pygmy possum
The mountain pygmy possum (''Burramys parvus''); also simply known as the burramys, is a small, mouse-sized (weighs ) nocturnal marsupial of Australia found in dense alpine rock screes and boulder fields, mainly southern Victoria and around Moun ...
as well as other insectivorous mammals and birds. "The vulnerability of the Australian Alps to climate change is the worst in the world because we've got these short little mountains so when it gets warmer, there is nowhere for these cold-adapted species to go", according to Euan Ritchie, a wildlife ecologist at Deakin University
Deakin University is a public university in Victoria, Australia. Founded in 1974, the university was named after Alfred Deakin, the second Prime Minister of Australia.
Its main campuses are in Melbourne's Burwood suburb, Geelong Waurn Ponds, ...
.[
]
Interactions with humans
Food source
Bogong moths were historically used as a food source by Aboriginal peoples located in South-eastern Australia. Groups would travel to the area towards the summits of mountains to harvest moths, where they also met with other Aboriginal peoples, fostering inter-tribal relations as people gathered and feasted during these harvests. They would go into the caves and scrape aestivating moths off the walls into nets and dishes using sticks. Once gathered, the moths would be roasted to remove the scales and wings and then either eaten immediately or ground into a paste and made into "moth meat" cakes that would last and could be taken home. The moth was said to have a nice nutty flavour that was most similar to walnut
A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''.
Although culinarily considered a "nut" and used as such, it is not a true ...
s or almonds. The bogong moth is an icon of Australian wildlife due to this historical role as an important food source and as an inter-tribal gathering point in Southeastern Australia.
An excavation of Cloggs Cave, near Buchan
Buchan is an area of north-east Scotland, historically one of the original provinces of the Kingdom of Alba. It is now one of the six committee areas and administrative areas of Aberdeenshire Council, Scotland. These areas were created by th ...
in Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
, revealed microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale be ...
remains of moth on a small grinding stone
Millstones or mill stones are stones used in gristmills, for grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
Millstones come in pairs: a convex stationary base known as the ''bedstone'' and ...
, estimated to be about 2,000 years old. This is the first confirmed evidence of insect food remains discovered on a stone artefact in the whole world. The Gunaikurnai
The Gunaikurnai or Gunai/Kurnai ( ) people, also referred to as the Gunnai or Kurnai, are an Aboriginal Australian nation of south-east Australia. They are the Traditional Custodians of most of present-day Gippsland and much of the southern slop ...
people were one of the peoples who used to travel to the mountains to obtain the high-fat, energy-rich food, and stories of these travels had been passed down in their oral history
Oral history is the collection and study of historical information about individuals, families, important events, or everyday life using audiotapes, videotapes, or transcriptions of planned interviews. These interviews are conducted with people wh ...
. The excavation was done by researchers from Monash University
Monash University () is a public research university based in Melbourne, Victoria, Australia. Named for prominent World War I general Sir John Monash, it was founded in 1958 and is the second oldest university in the state. The university h ...
in collaboration with the traditional owners
Native title is the designation given to the common law doctrine of Aboriginal title in Australia, which is the recognition by Australian law that Indigenous Australians (both Aboriginal Australian and Torres Strait Islander people) have rights ...
, represented by the Gunaikurnai Land and Waters Corporation (GLaWAC).
Pest of crop plants
Bogong moths have had a role in damaging crop plants since winter pastures serve as breeding grounds and larval food sources. Outbreaks of caterpillars have been recorded across New South Wales, with damage primarily done to heavy black soil flats. ''Medicago'' species, wheat, cabbages, cauliflowers, silver beet, peas, and potatoes have been recorded as being attacked by bogong moth larvae.
Control
The bogong moth is a minor and irregular pest of crop plants in Australia. This makes it difficult to predict their pattern and control. Typically, control of this species is not cost-effective. However, if there are heavy damaging outbreaks of the bogong moth, insecticide is applied to the crops that are affected by it.
Migration issues
Millions of bogong moths have been blown off course from their spring migration into major cities like Canberra, Melbourne
Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...
, and Sydney
Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...
due to strong winds, with notable instances of Bogong Moth invasions including the 2000 Olympics in Sydney. The large amount of light and noise present can also attract moths towards cities. Parliament House in Canberra, present in the middle of the Bogong Moth flight path during migrations, was notably susceptible to moths. Light pollution from the building traps them during their flight and encourages the moth to find shelter within crevices, shadows, and sometimes even the insides of the buildings during the light and heat of the day. Efforts have been made to try and drive the moths out by turning off lights, covering attractive corners and pathways indoors, and using insecticides. However, insecticide use has ceased in urban areas due to concerns over environmental consequences.
Conservation status
In December 2021 the bogong moth was added to the IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
as an Endangered Species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
, based on a February 2021 assessment.
References
{{Taxonbar, from=Q285592
Agrotis
Moths of Australia
Agricultural pest insects
Australian Aboriginal culture
Bushfood
Edible insects
Moths of New Zealand
Taxa named by Jean Baptiste Boisduval
Animal migration