Large milkweed bug | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hemiptera |
Suborder: | Heteroptera |
Family: | Lygaeidae |
Genus: | Oncopeltus |
Species: | O. fasciatus |
Binomial name | |
Oncopeltus fasciatus | |
Oncopeltus fasciatus, known as the large milkweed bug, is a medium-sized hemipteran (true bug) of the family Lygaeidae. [2] It is distributed throughout North America, from Central America through Mexico and the Caribbean to southern areas in Canada. [2] Costa Rica represents this insect's southern limit. [3] It inhabits disturbed areas, roadsides, and open pastures. [4] Due to this widespread geographic distribution, this insect exhibits varying life history trade-offs depending on the population location, including differences in wing length and other traits based on location. [5] [6]
Adults can range from 11 to 12 mm in length and have a red/orange and black X-shaped pattern on their wings underneath the triangle that is typical to hemipterans. [7] This feature makes the bug easily seen, acting as an aposematic warning to predators of distastefulness. O. fasciatus exhibits Müllerian mimicry and is noxious to predators. The ventral side of the fourth abdominal segment bears a black band in the male and two black spots in the female. Juveniles are born mostly red with black antennae and a few black spots, throughout growth the black spots are developed as well as wing pads. Eggs of this insect are bright orange and easily detectable. [8] [9]
This large milkweed bug is a hemimetabolous insect, meaning it grows in stages called instars and goes through incomplete metamorphosis, exhibiting small changes throughout development such as coloration changes, development of wings and genitalia. O. fasciatus begins as an egg and experiences four nymphal stages over 28–30 days before moulting to adulthood. [10] Females become sexually receptive within a few days of adulthood. Geographic location has a large effect on egg production rate and clutch size, although the intrinsic increase in reproduction depends on to what the individual is acclimated. For example, two close populations (60 km apart) residing on a sharp incline have differing optimal reproduction temperatures, where the cooler (higher) adapted population is at 23 °C and the warmer (lower) population is adapted to 27 °C. Highest clutch size occurs in Puerto Rico, Florida, and Texas populations at 30-50 eggs per clutch. Lowest clutch size was found in California at 25-30 eggs per clutch. Iowa and Maryland (northern populations) exhibited a clutch size in between the two extremes from 25 to 35 eggs per clutch.
In favourable conditions (tropics) reproduction occurs continuously all year round, in less-favourable conditions (temperate zones) reproduction occurs during the warmer months. [11] Reproducing when migrants arrive introduces gene flow between northern and southern populations, this provides an advantage to the midrange populations (variable climates) because females then can ensure genetic variability. The milkweed bug can produce from one to three generations per year depending on climate and geographic location. O. fasciatus exhibits strong selection for survival and will halt reproduction as a trade-off if conditions are not ideal.
Diapause occurs on short days and on cold days in temperate regions and occasionally occurs during dry season in tropical regions. Most populations of the milkweed bug overwinter, usually after migration to their overwintering sites due to environmental triggers such as temperature and photoperiod. [12] However, photoperiod only predicts overwintering in areas where day length affects the maturation of milkweeds. Therefore, no overwintering occurs in tropical regions, as it does not supply an adaptive advantage.
O. fasciatus can be separated into migrators and nonmigrators. Palmer and Dingle [13] showed that northern populations such as the one in Iowa show the greatest tendency for long-distance flight and are highly migratory. Oppositely, southern populations such as those in Puerto Rico show the lowest tendency and are sedentary. [14] Southern populations grow seasonally as migrants first appear in late spring and mid-summer. [15] A migratory syndrome has been described in the northern population, meaning that traits such as wing length, fecundity, developmental time and flight duration are all genetically correlated. Groeters and Dingle [16] suggested that selection is specific to the populations environment due to the small correlations between life-history strategies across geographic ranges. A trade-off between migration and life history traits may be the causation of such a wide geological distribution. Attisano [17] suggested that genetic factors as well as environmental cues trigger migration in some individuals. Since long duration flights decrease with decreasing latitude, temperature is a strong factor influencing the migration. Also, this movement correlates with flowering of milkweeds which provides further evidence that environmental triggers relate to migration. Larger females are thought to allocate resources to migration simply because they have more to spare. Smaller individuals are thought to deploy alternative mechanisms; one being the reabsorption of oocytes for energy. The fact that these insects return to northern environments after migration could be the influence of a genetic predisposition or selected for due to crowding and increased intraspecific competition for resources in the southern areas. [18]
Tropical populations migrate shorter distances than temperate populations because spatial variation of their choice host is much greater, so it is advantageous to seek new plant congregations rather than tolerate the depletion of resources.
O. fasciatus is a specialist herbivore that frequently consumes milkweed seeds. [19] In addition to its plant-based diet, O. fasciatus has been observed feeding on aphids, monarch caterpillar eggs, and larvae, displaying opportunistic behavior. [4] [20]
This bug also feeds on A. nivea , Sarcostemma clausa , Calotropis procera , and Nerium oleander . The southern populations often consume Asclepias curassavica, a tropical milkweed.[ citation needed ] When given sunflower seeds in a laboratory, this bug obtained 90% of their lipids, 50% of their protein and 20% of their carbohydrates, making it an efficient feeder. [19] Toxic compounds in milkweeds are also sequestered, giving this insect its toxicity.
Adults wander during the daytime in search of food since milkweeds live in patches that can vary in size and distance apart from one another. When a follicle is found, they inject saliva into it through their long rostrums, this pre-digests the seed and allows O. fasciatus to suck it up through their anterior pump and pharynx. Often, multiple individuals feed on one follicle, suggesting that a signal is released by feeding individuals that indicates a good food source. It has been shown that adults are more likely to find a food source when another adult is already feeding on it, further supporting the signaling concept. Occasionally, females are seen feeding on shedding exoskeletons from moulting individuals. Rarely, cannibalization is observed in laboratory settings. [21]
Juveniles of O. fasciatus require the seed of milkweed plants for development and growth. Adults can survive on other types of seeds, such as sunflower, watermelon, almond, and cashew, as shown in lab populations. Nymphs live in large groups of about 20 individuals on the plant. [11] Juveniles have a discontinuous, three-part gut that acts similarly to a crop, ventriculus, and ileum, but these are all three parts of the midgut, and there is no connection to the true ileum prior to the adult stage. [19] During the final instar of development, oil accumulates, perhaps to allow for more efficient absorption of nutrients, aid in osmoregulation or to preserve cleanliness of the habitat. It is expelled within 24 hours after the molt to adult, once a patent connection forms between the midgut and ileum. [19]
This insect is often used as a model organism and reared for laboratory experiments due to being easy to rear and handle, short developmental time, few instars, and high fecundity. [22] The phylogenetic placement of O. fasciatus is ideal to use as an outgroup to make comparisons to more derived holometabolous insects, acting as a valuable organism for the study of evolutionary patterns.
The monarch butterfly or simply monarch is a milkweed butterfly in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. It is among the most familiar of North American butterflies and an iconic pollinator, although it is not an especially effective pollinator of milkweeds. Its wings feature an easily recognizable black, orange, and white pattern, with a wingspan of 8.9–10.2 cm (3.5–4.0 in). A Müllerian mimic, the viceroy butterfly, is similar in color and pattern, but is markedly smaller and has an extra black stripe across each hindwing.
The Malabar trogon is a species of bird in the trogon family. It is found in the forests of India and Sri Lanka. In India it is mainly found in the Western Ghats, hill forests of central India and in parts of the Eastern Ghats. They are insectivorous and although not migratory, may move seasonally in response to rain in hill forest regions. Like in other trogons, males and females vary in plumage. The birds utter low guttural calls that can be heard only at close quarters and the birds perch still on a branch under the forest canopy, often facing away from the viewer making them easy to miss despite their colourful plumage.
Elasmucha grisea, common name parent bug, is a species of shield bugs or stink bugs belonging to the family Acanthosomatidae. The term parent bugs includes also the other species of the genus Elasmucha and some species of the family Acanthosomatidae.
Polygonia c-album, the comma, is a food generalist (polyphagous) butterfly species belonging to the family Nymphalidae. The angular notches on the edges of the forewings are characteristic of the genus Polygonia, which is why species in the genus are commonly referred to as anglewing butterflies. Comma butterflies can be identified by their prominent orange and dark brown/black dorsal wings.
Broodstock, or broodfish, are a group of mature individuals used in aquaculture for breeding purposes. Broodstock can be a population of animals maintained in captivity as a source of replacement for, or enhancement of, seed and fry numbers. These are generally kept in ponds or tanks in which environmental conditions such as photoperiod, temperature and pH are controlled. Such populations often undergo conditioning to ensure maximum fry output. Broodstock can also be sourced from wild populations where they are harvested and held in maturation tanks before their seed is collected for grow-out to market size or the juveniles returned to the sea to supplement natural populations. This method, however, is subject to environmental conditions and can be unreliable seasonally, or annually. Broodstock management can improve seed quality and number through enhanced gonadal development and fecundity.
A polyphenic trait is a trait for which multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions. It is therefore a special case of phenotypic plasticity.
Ophryocystis elektroscirrha is an obligate, neogregarine protozoan parasite that infects monarch and queen butterflies. There are no other known hosts. The species was first discovered in Florida, around the late 1960s. Since then, it has been found in every monarch population examined to date, including monarchs sampled in North America, Hawaii, Australia, Cuba, and Central and South America.
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Agrotis ipsilon, the dark sword-grass, black cutworm, greasy cutworm, floodplain cutworm or ipsilon dart, is a small noctuid moth found worldwide. The moth gets its scientific name from black markings on its forewings shaped like the letter "Y" or the Greek letter upsilon. The larvae are known as "cutworms" because they cut plants and other crops. The larvae are serious agricultural pests and feed on nearly all varieties of vegetables and many important grains.
Mythimna unipuncta, the true armyworm moth, white-speck moth, common armyworm, or rice armyworm, is a species of moth in the family Noctuidae. The species was first described by Adrian Hardy Haworth in 1809. Mythimna unipuncta occurs in most of North America south of the Arctic, as well as parts of South America, Europe, Africa, and Asia. Although thought to be Neotropical in origin, it has been introduced elsewhere, and is often regarded as an agricultural pest. They are known as armyworms because the caterpillars move in lines as a massive group, like an army, from field to field, damaging crops.
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Gargaphia solani is a subsocial species of lace bug commonly known as the eggplant lace bug. The species was described by Heidemann in 1914 after it aroused attention a year earlier in the United States as an eggplant pest around Norfolk, Virginia. Fink found that the species became an agricultural pest when eggplant is planted on a large scale.
Phylloxeridae is a small family of plant-parasitic hemipterans closely related to aphids with only 75 described species. This group comprises two subfamilies and 11 genera with one that is fossil. The genus type is Phylloxera. The Phylloxeridae species are usually called phylloxerans or phylloxerids.
Dendroctonus micans, the great spruce bark beetle, is a species of bark beetle native to the coniferous forests of Europe and Asia. The beetles burrow into the bark of spruce trees and lay eggs which develop into larvae that feed on the woody layers under the bark.
Allonemobius fasciatus, commonly known as the striped ground cricket, is an omnivorous species of cricket that belongs to the subfamily Nemobiinae. A. fasciatus is studied in depth in evolutionary biology because of the species's ability to hybridize with another Allonemobius species, A. socius.
Lygaeus kalmii, known as the small milkweed bug or common milkweed bug, is a species of seed bug in the family Lygaeidae. It is found in Central and North America.
The Darth Maul bug, is a species of seed bug found in Asia, Australasia, and Oceania. Its common name is a reference to the Star Wars character Darth Maul, who shares similar markings. It is sometimes referred to as the Milkweed Bug in Australia because it feeds on Milkweed plants, however the Large Milkweed bug refers to a different species - Oncopelltus fasciatus. The two bugs both fall under the family of Lygaeidae and exhibit similar markings and behaviours. Large Milkweed bugs however, are found in North America, unlike the Darth Maul Bug. The distribution of the two bugs, and respective differing taxonomies suggest they are different species.
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