Samea multiplicalis | |
---|---|
![]() | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Lepidoptera |
Family: | Crambidae |
Genus: | Samea |
Species: | S. multiplicalis |
Binomial name | |
Samea multiplicalis | |
Synonyms | |
|
Samea multiplicalis, the salvinia stem-borer moth, is an aquatic moth commonly found in freshwater habitats from the southern United States to Argentina, as well as in Australia where it was introduced in 1981. [3] Salvinia stem-borer moths lay their eggs on water plants like Azolla caroliniana (water velvet), Pistia stratiotes (water lettuce), and Salvinia rotundifolia (water fern). [4] Larval feeding on host plants causes plant death, which makes S. multiplicalis a good candidate for biological control of weedy water plants like Salvinia molesta , an invasive water fern in Australia. However, high rates of parasitism in the moth compromise its ability to effectively control water weeds. S. multiplicalis larvae are a pale yellow to green color, and adults develop tan coloration with darker patterning. The lifespan, from egg to the end of adulthood is typically three to four weeks. [5] The species was first described by Achille Guenée in 1854.
Samea multiplicalis was first observed in Brazil in 1854, and has since been documented across the southeastern United States, as far west as Louisiana. This region constitutes its native range. [6] In 1981, the moth was introduced in Australia as a potential method of biological control of the water fern, S. molesta . It is now common throughout Queensland and New South Wales. In Australia, it has been found to thrive in tropical climates, with slower growth and dispersal in more temperate climates. [7]
S. multiplicalis primarily lives on the water plants, Azolla caroliniana (water velvet), Pistia stratiotes (water lettuce), Salvinia rotundifolia (water fern) in their native range, and Salvinia molesta (a water fern) in Australia. These plants grow to form floating mats on the surface of calm or still bodies of water like ponds, lakes, and slow-moving rivers. [8] S. multiplicalis can survive within a temperature range of 11-36 °C, however it survives best around temperatures of 30 °C. [7] It requires warm conditions to survive and develop, however steady temperatures above the low 30s cause populations to crash. Moth populations can survive year round in habitats where food resources and adequate temperatures are sustained through the winter. [9]
In its native habitat, S. multiplicalis prefers the water lettuce P. stratiotes over other aquatic plants for feeding and oviposition, and in its introduced habitat in Australia, it primarily feeds and lays eggs on the water fern Salvinia molesta . P. stratiotes has a rosette of leaves surrounding a short, central stem and a submerged root system. Leaves are covered in short hairs. [9] S. molesta plants in Australia are all clones, meaning they are genetically identical. However, there is some phenotypic variation due to differing temperature and nitrogen availability across its range, which is important due to S. multiplicalis larvae's preference for high-nitrogen food sources. [7]
Caterpillars of the salvinia stem-borer moth feed on several aquatic plants, primarily Azolla caroliniana (water velvet), Pistia stratiotes (water lettuce), Salvinia rotundifolia (water fern), Salvinia molesta (a water fern), and occasionally Eichhornia crassipes (water hyacinth). Feeding by colonies of larvae often leads to intensive damage and plant death after two or three weeks of feeding. Larvae eat by boring into plant stems or feeding externally on leaves. [9]
Often, groups of larvae display cooperative behavior when they feed in groups. They collectively construct a silk canopy over their feeding site while they eat, expanding it as they exhaust their current site and move on to new areas of their host plant. This behavior offers protection from predation, decreasing larval mortality. [4]
Nitrogen is very important nutrient for larval development, especially during the first two instars, so larvae prefer food plants with higher nitrogen content. Higher nitrogen intake correlates with larger larval biomass and faster development, both of which are favored because they decrease larval vulnerability to predation. Additionally, a lack of sufficient nitrogen intake during early development leads to decreased ability to digest and utilize food throughout the rest of the insect's life. [10]
Water lettuce and other aquatic plants tend to have high water content, which dilutes the nitrogen and other nutrients they contain. To account for this, S. muliplicalis has a higher feeding rate than many other Lepidoptera species. When nitrogen levels are especially low, larvae show compensatory feeding behavior, increasing their already high feeding rate and consuming a larger volume in order to make up for the nutrient deficit. This behavior does not usually mitigate the poor quality food, however, and larvae on nitrogen-depleted host plants still experience slower development and decreased digestive efficiency. [9]
Larvae hatch approximately four days after eggs are laid. Larvae have an off-white or pale yellow color during early instars and develop a yellow-green color as they mature. [6] They typically develop through five instars over the course of about two weeks, and male larvae develop faster than females by about two days. In low-nitrogen conditions, larvae require a sixth instar and two or three additional days to develop. [5]
Caterpillars construct a silk cocoon inside of a leaf petiole on their host plant in order to pupate. Pupation lasts between four and ten days, with females developing faster than males. Time spent in this stage of development is not dependent on larval nutrition. [5]
After they emerge from their cocoons, adult salvinia stem-borer moths spend the rest of their three- or four-week life span around their host plants, mating and laying eggs. Female moths lay an average of 150 eggs over the course of several days on the surfaces of host plant leaves or among hairs or leaflet structures. [4] Moths prefer the host plant P. stratiotes for laying eggs due to its structure which provides abundant oviposition surfaces. Moths are not known to oviposit on E. crassipes. Adults are tan with darker markings on both sets of wings and a wingspan of about 20 mm. Adult size is not significantly affected by larval nutrition levels, however insufficient nitrogen during larval development does lead to reduced egg production in female moths. [8]
S. multiplicalis is affected by a number of parasites, most commonly by wasp species of the order Hymenoptera and parasitic flies of the order Diptera, as well as miscrosporidia. Parasitic wasps attack S. multiplicalis larvae during their first instar and pre-pupal wasps emerge during the caterpillars' last instar, killing their hosts. Parasitism rates are fairly high in some populations, which diminishes their effectiveness at controlling weedy host plants. S. multiplicalis larvae are parasitized in both their native and introduced ranges by similar species. Parasitism rates remain steady through spring, summer, and fall and decrease slightly during winter months. [9] [3] [11]
S. molesta is an aquatic plant native to Brazil that is invasive in Australia due to a lack of sufficient herbivory to control the growth of the plant. It has become a common weed in many bodies of water, especially in eastern Australia in Queensland and New South Wales. The water fern grows in expansive mats, potentially crowding out other native aquatic plants and preventing light penetration in water bodies where it grows. [7] Efforts to control S. molesta began in 1980 with the introduction of the salvinia weevil Cyrtobagous salviniae , which is also native to Brazil. S. multiplicalis was introduced the following year in 1981 to aid in the biological control of the weed. [8]
Since their introduction, C. salviniae and S. multiplicalis have had different levels of effectiveness; the weevil has proved more useful than the moth at keeping salvinia populations down through intensive feeding. While C. salviniae and S. multiplicalis both have similar habitat needs, including common host plants, similar nitrogen requirements, and an optimal temperature of 30 °C, S. multiplicalis populations are highly susceptible to parasites and parasitoids, which prevent the colony growth and dispersal that would be required for effective weed control. S. multiplicalis actually has a higher rate of reproduction and dispersal than C. salviniae, but infection prevalence still prevents sufficient levels of feeding to significantly affect S. molesta numbers. [8]
Salvinia molesta, commonly known as giant salvinia, or as kariba weed after it infested a large portion of Lake Kariba between Zimbabwe and Zambia, is an aquatic fern, native to south-eastern Brazil. It is a free-floating plant that does not attach to the soil, but instead remains buoyant on the surface of a body of water. The fronds are 0.5–4 cm long and broad, with a bristly surface caused by the hair-like strands that join at the end to form eggbeater shapes. They are used to provide a waterproof covering. These fronds are produced in pairs also with a third modified root-like frond that hangs in the water. It has been accidentally introduced or escaped to countless lakes throughout the United States, including Caddo Lake in Texas, where the invasive species has done extensive damage, killing off other life.
Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs.
Forage is a plant material eaten by grazing livestock. Historically, the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage.
An instar 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 assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, changes in the number of body segments or head width. After shedding their exoskeleton (moulting), the juvenile arthropods continue in their life cycle until they either pupate or moult again. The instar period of growth is fixed; however, in some insects, like the salvinia stem-borer moth, the number of instars depends on early larval nutrition. Some arthropods can continue to moult after sexual maturity, but the stages between these subsequent moults are generally not called instars.
Salvinia, a genus in the family Salviniaceae, is a floating fern named in honor of Anton Maria Salvini, a 17th-century Italian scientist. Watermoss is a common name for Salvinia. The genus was published in 1754 by Jean-François Séguier, in his description of the plants found round Verona, Plantae Veronenses Twelve species are recognized, at least three of which are believed to be hybrids, in part because their sporangia are found to be empty.
Pistia is a genus of aquatic plants in the arum family, Araceae. It is the sole genus in the tribe Pistieae which reflects its systematic isolation within the family. The single species it comprises, Pistia stratiotes, is often called water cabbage, water lettuce, Nile cabbage, or shellflower. Its native distribution is uncertain but is probably pantropical; it was first discovered from the Nile near Lake Victoria in Africa. It is now present, either naturally or through human introduction, in nearly all tropical and subtropical fresh waterways and is considered an invasive species as well as a mosquito breeding habitat. The genus name is derived from the Greek word πιστός (pistos), meaning "water", and refers to the aquatic nature of the plants. The specific epithet is also derived from a Greek word, στρατιώτης, meaning "soldier", which references the sword-shaped leaves of some plants in the Stratiotes genus.
Spodoptera littoralis, also referred to as the African cotton leafworm or Egyptian cotton leafworm or Mediterranean brocade, is a species of moth in the family Noctuidae. S. littoralis is found widely in Africa, Mediterranean Europe and Middle Eastern countries. It is a highly polyphagous organism that is a pest of many cultivated plants and crops. As a result, this species was assigned the label of A2 quarantine pest by the EPPO and was cautioned as a highly invasive species in the United States. The devastating impacts caused by these pests have led to the development of both biological and chemical control methods. This moth is often confused with Spodoptera litura.
Cyrtobagous salviniae is a species of weevil known as the salvinia weevil. It is used as an agent of biological pest control against the noxious aquatic plant giant salvinia.
Chloridea virescens, commonly known as the tobacco budworm, is a moth of the family Noctuidae found throughout the eastern and southwestern United States along with parts of Central America and South America.
Penicillaria jocosatrix, the mango shoot borer, is a moth of the family Euteliidae first described by Achille Guenée in 1852. It is found from southeast Asia to the Pacific. Records include Borneo, Guam, Hawaii, India, Sri Lanka, Thailand and in Australia, Western Australia, the Northern Territory and Queensland.
Leucinodes orbonalis, the eggplant fruit and shoot borer or brinjal fruit and shoot borer, is a moth species in the genus Leucinodes described by Achille Guenée in 1854. Its native distribution is in the tropical and subtropical parts of Australia and Asia, where it is recorded from Pakistan, Nepal, India, including the Andaman Islands, Sri Lanka, Bangladesh, Myanmar, Laos, Cambodia, Vietnam, Thailand, China, Taiwan, Japan, Malaysia, Singapore, Brunei, the Philippines, and Indonesia (Java). It has also been intercepted from fruit imports in the U.S.A., the Netherlands, Denmark and Great Britain, where it was also reported from the wild. A taxonomic revision of the Leucinodes species of Sub-Saharan Africa concluded that L. orbonalis is currently not present in Africa, and that previous records of this species were misidentifications of previously undescribed species.
Busseola fusca is a species of moth that is also known as the maize stalk borer. It is known from Ethiopia.
Eldana is a genus of moths of the family Pyralidae containing only one species, the African sugar-cane borer, which is commonly found in Equatorial Guinea, Ghana, Mozambique, Sierra Leone and South Africa. Adults have pale brown forewings with two small spots in the centre and light brown hindwings, and they have a wingspan of 35mm. This species is particularly relevant to humans because the larvae are a pest of the Saccharum species as well as several grain crops such as sorghum and maize. Other recorded host plants are cassava, rice and Cyperus species. When attacking these crops, E. saccharina bores into the stems of their host plant, causing severe damage to the crop. This behavior is the origin of the E. saccharrina's common name, the African sugar-cane borer. The African sugar-cane borer is a resilient pest, as it can survive crop burnings. Other methods such as intercropping and parasitic wasps have been employed to prevent further damage to crops.
Adaina primulacea is a moth of the family Pterophoridae. It is known from Taboga Island in the Gulf of Panama, Costa Rica and southern Florida, United States. It is probably widespread throughout the Neotropics, including the West Indies and Central and South America.
Scirpophaga incertulas, the yellow stem borer or rice yellow stem borer, is a species of moth of the family Crambidae. It was described by Francis Walker in 1863. It is found in Afghanistan, Nepal, north-eastern India, Sri Lanka, Bangladesh, Myanmar, Vietnam, Thailand, Malaysia, Singapore, Sumatra, Java, Borneo, Sumba, Sulawesi, the Philippines, Taiwan, China and Japan.
Parapoynx stagnalis, the rice case bearer or rice caseworm, is a species of moth in the family Crambidae. It has a wide distribution and is found in India, Sri Lanka, South-East Asia, South Africa, South America, southern Europe, Russia and Australia.
Salvinia minima is a species of aquatic, floating fern that grows on the surface of still waterways. It is usually referred to as common salvinia or water spangles. Salvinia minima is native to South America, Mesoamerica, and the West Indies and was introduced to the United States in the 1920s–1930s. It is classified as an invasive species internationally and can be detrimental to native ecosystems. This species is similar to but should not be confused with giant salvinia, Salvinia molesta.
Ostrinia furnacalis is a species of moth in the family Crambidae, the grass moths. It was described by Achille Guenée 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, 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.
Chilo partellus, the spotted stalk borer or spotted stem borer, is a moth in the family Crambidae. It was described by Charles Swinhoe in 1885. It is found in India, Pakistan, Iran, Ethiopia, Lesotho, Madagascar, Malawi, South Africa, Sudan, Tanzania, Uganda and on Mayotte.
Cornops aquaticum is a semiaquatic species of grasshopper native to the Neotropics, from southern Mexico south to central Argentina and Uruguay. It feeds and breeds exclusively on members of the aquatic plant family Pontederiaceae, especially water hyacinth, and is being investigated as a possible biological pest control agent for the water hyacinth in countries where that plant is invasive.