''Ostrinia furnacalis'' is a species of
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 ...
in the family
Crambidae
The Crambidae are the grass moth family of lepidopterans. They are variable in appearance, the nominal subfamily Crambinae (grass moths) taking up closely folded postures on grass stems where they are inconspicuous, while other subfamilies includ ...
, the grass moths. It was
described by
Achille Guenée
Achille Guenée (sometimes M.A. Guenée; 1 January 1809 – 30 December 1880) was a French lawyer and entomologist.
Biography
Achille Guenée was born in Chartres and died in Châteaudun.
He was educated in Chartres, where he showed a very earl ...
in 1854 and is known by the common name Asian corn borer since this species is found in Asia and feeds mainly on corn crop. The moth is found from
China to
Australia, including in Java, Sulawesi, the Philippines, Borneo, New Guinea, the Solomon Islands, and Micronesia. The Asian corn borer is part of the
species complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
, ''Ostrinia'', in which members are difficult to distinguish based on appearance. Other ''Ostrinia'' such as ''
O. orientalis'', ''
O. scapulalis'', ''
O. zealis'', and ''
O. zaguliaevi'' can occur with ''O. furnacalis'', and the taxa can be hard to tell apart.
This moth exhibits unique acoustic
mimicry of a predator by mirroring the
echolocation calls of bats in order to temporarily paralyze female moths and make it easier to mate. It is also well known as being an
agricultural pest
A pest is any animal or plant harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environ ...
on several crops in the western Pacific region of Asia, especially on
corn.
The Asian corn borer is second only to maize
downy mildew
Downy mildew refers to any of several types of oomycete microbes that are obligate parasites of plants. Downy mildews exclusively belong to the Peronosporaceae family. In commercial agriculture, they are a particular problem for growers of cruc ...
as the most prevalent corn pest .
There is currently extensive research on eradicating this pest from corn crop in Asia, including the use of
biological agent
A biological agent (also called bio-agent, biological threat agent, biological warfare agent, biological weapon, or bioweapon) is a bacterium, virus, protozoan, parasite, fungus, or toxin that can be used purposefully as a weapon in bioterroris ...
s and
toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849 ...
s.
Geographic range and habitat
The Asian corn borer is most commonly found throughout
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
and
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...
. More specifically, it is located in China, the Philippines, Indonesia, Taiwan, Malaysia, Thailand, Sri Lanka, India, Bangladesh, Japan, Korea, Vietnam, Lao, Myanmar, and Cambodia.
There are also a limited number in the Solomon Islands, Africa, and parts of Australia.
The Asian corn borer thrives in
tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
regions because in these countries there is continuous farming of its host crop through the year.
Food resources
While the main food source for the Asian corn borer is
corn, it also consumes and destroys bell pepper, cotton, hops,
millet, pearl millet, foxtail millet, sugarcane,
sorghum, and ginger. In addition, it can be found on a number of wild plants, as well, such as wormwoods,
Job's tears
Job's tears (''Coix lacryma-jobi)'', also known as Adlay or Adlay millet, is a tall grain-bearing perennial tropical plant of the family Poaceae (grass family). It is native to Southeast Asia and introduced to Northern China and India in remote ...
, knotweeds, wild sugarcane,
Johnson grass
Johnson grass or Johnsongrass, ''Sorghum halepense'', is a plant in the grass family, Poaceae, native to Asia and northern Africa. The plant has been introduced to all continents except Antarctica, and most larger islands and archipelagos. It re ...
, and
para grass
''Brachiaria mutica'' (''Urochloa mutica'') is a species of grass known by the common names para grass, buffalo grass, Mauritius signal grass, pasto pare, malojilla, gramalote, parana, Carib grass, and Scotch grass.Stone, Katharine R. 2010''Uroch ...
.
Larvae and pupae
The larvae work their way through the host plant (typically maize), by beginning to feed on the underside, or
whorl, of the leaves. Younger
instars
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 ass ...
typically feed on the tassel of the plant, and then move on to feed in the ear. There they feed on the silk and
kernel
Kernel may refer to:
Computing
* Kernel (operating system), the central component of most operating systems
* Kernel (image processing), a matrix used for image convolution
* Compute kernel, in GPGPU programming
* Kernel method, in machine learn ...
s of the corn plant. Later instar stages begin to make their way into the plant by feeding on
stalks. This allows them to be able to form
pupae
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 their ...
within the stems of the plant.
Additionally, if the food supply of the current plant is limited, the larvae create
silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the ...
that serves as a connection between plants so that they can travel from plant to plant. They are then transported by the wind through a process known as
ballooning Ballooning may refer to:
* Hot air ballooning
* Balloon (aeronautics)
* Ballooning (spider)
* Ballooning degeneration, a disease
* Memory ballooning
See also
* Balloon (disambiguation)
A balloon is a flexible container for (partially or fully) co ...
, where the strands catch the wind in order to transport the larvae. They also use existing silk strand connections to other plants as trails where they can hope to find a better food source that can also serve them as a location for pupation.
Life cycle
Eggs
The eggs of the Asian corn borer are found grouped at the base of and under the leaves of corn plants in masses of 25 to 50 eggs.
They appear scaly and are laid in overlapping groups, resembling roof tiles and fish scales.
The eggs are approximately half a millimeter long and white, turning black before emergence, which occurs 3 to 10 days after
incubation.
Larvae
The Asian corn borer goes through 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 ...
stages while in the
larval phase.
The first-instar larva is pinkish with dark spots and a dark head. The late instar larva is yellow brown with dark spots and reaches up to 2.9 centimeters in length.
Pupa
After 3 to 4 weeks, the
caterpillar larvae transform into
pupae
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 their ...
for 6 to 9 days in a
cocoon in the soil or stem of the plant, before becoming
moths.
Adult
The adult moths have distinct color pattern for each sex which makes them easy to identify. The females are pale yellow or tan with darker wavy bands across their wings. Females also tend to be larger than males with a wingspan of 20–30 mm. Meanwhile, males are darker with a tapering
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
and similar bands across their wings and tend to be slightly smaller in size than the females.
The adult moths live for 10 to 24 days. During this lifetime, female moths can lay up to 1500 eggs.
Parasites
Natural enemies of the moth include several parasites such as the
tachinid
The Tachinidae are a large and variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. Over 1,300 species have been described in North America alone. Insects in this family ...
fly ''Lydella grisescens'', the
braconid
The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...
wasp ''Macrocentrus cingulum'', and the
ichneumon wasp ''Eriborus terebrans''. It is also susceptible to the
entomopathogenic fungi
An entomopathogenic fungus is a fungus that can kill or seriously disable insects.
Typical life cycle
These fungi usually attach to the external body surface of insects in the form of microscopic spores (usually asexual, mitosporic spores also ...
''
Beauveria bassiana'' and ''Nosema furnacalis''. Additionally, the Asian corn borer has the potential to develop the insect disease
muscardine
Muscardine is a disease of insects. It is caused by many species of entomopathogenic fungus. Many muscardines are known for affecting silkworms.Singh, T. ''Principles And Techniques Of Silkworm Seed Production''. Discovery Publishing House. 2004. ...
.
Mating
Mimicry
During
courtship
Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
, the male Asian corn borer produces an ultrasound call by rubbing scales on its wings against scales on its
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
. This
ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...
call acoustically mimics that of the bat
echolocation call.
The males take advantage of this predator cue in order to seduce a mate via sensory trapping, which are signals that mimic those of a predator in order to exploit the adaptive, neural responses of signal receivers.
The female responds to this signal by becoming motionless, making it easier for males to mate since they are not effective at
copulating. This predator cue behavior is exhibited in several other species including
Goodeinae
Goodeinae is a subfamily of splitfins from Mexico, part of the family Goodeidae. They are small fish which mostly live in fresh water, especially around Mesa Central, west of Mexico City. Members of the subfamily are also found in brackish water ...
fish,
swordtail characins, and
water mites.
Pheromones
This species has a
pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
communication system used during mating. The females contain an extruding sex pheromone gland which releases the pheromone, composed of tetradecanl acetate (14Ac), (''E'')-12-tetradecenyl acetate (''E''12–14Ac) and (''Z'')-12-tetradecenyl acetate (''Z''12–14Ac).
This gland is composed of thick cell layers and is located between abdominal segments in the moth. In response to the female pheromones, males typically extrude
hair-pencil
Hair-pencils and coremata are pheromone signaling structures present in lepidopteran males. Males use hair-pencils in courtship behaviors with females. The pheromones they excrete serve as both aphrodisiacs and tranquilizers to females as well as r ...
s, or pheromone signaling structures, prior to copulation, making it easier for the male to mate.
Offspring ratios
This species has been known to have a skewed
sex ratio
The sex ratio (or gender ratio) is usually defined as the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. Many species d ...
occurring at a low frequency. The skewed ratio is caused by a parasitic bacterial infection, ''
Wolbachia
''Wolbachia'' is a genus of intracellular bacteria that infects mainly arthropod species, including a high proportion of insects, and also some nematodes. It is one of the most common parasitic microbes, and is possibly the most common reproducti ...
'', that feminizes the male offspring.
Many female moths produce mostly female
offspring
In biology, offspring are the young creation of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more general way. This ca ...
, and some broods are entirely female. This is supported by evidence that the antibiotic application of
tetracycline
Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis.
Common side effects in ...
, an agent that kills ''Wolbachia'', produces all-male offspring broods. Additionally, the female-biased sex ratio can be maternally inherited. While the skewed ratios have only been observed in three populations in
Japan, this phenomenon is not unheard of. In other taxa such as wasps and various crustaceans, infection with ''Wolbachia'' can skew sex ratios.
Physiology
Flight
The adult moths are known for being strong,
nocturnal fliers, and can fly up to several miles in a single night. Reasons for these long flights are speculated to be because of mating, since there is a negative correlation between flight duration and egg production. Lower humidity conditions inhibit the flight ability of the adult.
Antenna
The Asian corn borer has important
receptor
Receptor may refer to:
* Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse
*Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a ...
s on their
antennae that enable the moth to detect
olfactory cues for mate attraction and
oviposition. Males show strong activity of their antennae to the chemicals released by females.
Each antenna on both sexes also has six types of
sensilla. These include chemical receptors, mechanical receptors, temperature receptors, and hygroreceptors.
Diapause
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 ...
is the delayed development of an insect due to unfavorable environmental conditions. ''Ostrinia furnacalis'' is known to typically diapause over winter months. During diapause, it has been observed that the oxygen levels of the moth are relatively stable and remain at a high level. However, this is not the case with
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
levels. Though glycerol levels are low in October and November, they markedly increase during December and January. In other words, glycerol levels, which are associated with survival rates, increase with increasing temperature. This is considered a form of cold weather resistance for the moth.
Human interaction
Agriculture
This insect can cause devastating losses in a
corn field. In the
Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
losses of 20 to 80% have been reported. In
Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...
it has reached 95%, and in the
Marianas, 100%.
The moth
larva
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.
...
does most of the damage by feeding on almost all parts of the plant. It destroys the fruit when it bores into the ear to feed on the silk and
kernel
Kernel may refer to:
Computing
* Kernel (operating system), the central component of most operating systems
* Kernel (image processing), a matrix used for image convolution
* Compute kernel, in GPGPU programming
* Kernel method, in machine learn ...
s, and the stem when it creates a cocoon for
pupation
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 ...
. It also invades the tassels, where it feeds on pollen.
Control
Biological control
One method used to control the moth in
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
is the wasp ''Trichogramma ostriniae'', a native
parasitoid of the moth's eggs. This method of
biological pest control has shown varied success.
[Shelton, A]
''Trichogramma ostriniae''
Biological Control: A Guide to Natural Enemies in North America. Department of Entomology, College of Agriculture and Life Sciences, Cornell University. Several other species have been used as well including ''Trichogramma dendrolimi'', ''Trichogramma chilonalis'' in Guam, although it has been less effective, and ''Trichogramma evanescens'' in the Philippines. The earwig, ''
Euborellia annulata'', is also used for biological control of this pest.
Some bacteria that inhabit the gut of
entomopathogenic nematode
Entomopathogenic nematodes (EPN) are a group of nematodes (thread worms), that cause death to insects. The term ''entomopathogenic'' has a Greek origin, with ''entomon'', meaning ''insect'', and ''pathogenic'', which means ''causing disease''. Th ...
s, specifically ''
Xenorhabdus
''Xenorhabdus'' is a genus of motile, gram-negative bacteria from the family of the Morganellaceae. All the species of the genus are only known to live in symbiosis with soil entomopathogenic nematodes from the genus '' Steinernema''.
Although n ...
'' and ''
Photorhabdus'', have the pathogenic potential to kill ''Ostrinia furnacalis'' within 48 hours.
Another method used to control the spread of this pest is to detassel the corn. This reduces the larval populations that feed on the tassels.
Toxins
Like the
European corn borer
The European corn borer (''Ostrinia nubilalis''), also known as the European corn worm or European high-flyer, is a moth of the family Crambidae which includes other grass moths. It is a pest of grain, particularly maize (''Zea mays''). The in ...
, this moth is susceptible to
Bt corn, a crop which has been
genetically modified
Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including ...
to produce
Bt toxin
Delta endotoxins (δ-endotoxins) are pore-forming toxins produced by ''Bacillus thuringiensis'' species of bacteria. They are useful for their insecticidal action and are the primary toxin produced by Bt maize/corn. During spore formation th ...
that harms the moth. This corn has been introduced to the
Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
, where it has been monitored to gather data on its relationship with the moth. It has been successful, producing higher yields than conventional corn breeds.
Bt cotton
Bt cotton is a genetically modified pest resistant plant cotton variety, which produces an insecticide to combat bollworm.
Description
Strains of the bacterium '' Bacillus thuringiensis'' produce over 200 different Bt toxins, each harmful to ...
has also had some success in
China.
[Tan, S. Y., et al. (2011)]
"Comparative susceptibility of ''Ostrinia furnacalis'', ''Ostrinia nubialis'', and ''Diatraea saccharalis'' (Lepidoptera: Crambidae) to ''Bacillus thuringiensis'' Cry1 toxins"
Faculty Publications: Department of Entomology, University of Nebraska, Lincoln. Paper 332. Another method of controlling the pest in cotton crops is to intercrop with corn, growing some corn plants in the cotton field. The moth
overwinters
Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activ ...
in corn plants instead of the
cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor pe ...
plants in order to relieve the cotton plants of their moth loads. Bt-based pesticides are available, and conventional chemical
pesticides are used. Corn breeding is continuing in the search for varieties resistant to the moth.
References
{{Taxonbar, from=Q13972012
Pyraustinae
Agricultural pest insects
Moths described in 1854
Moths of Japan
Insect pests of millets