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65-454: Bromopsis erecta (Huds.) Fourr. Bromus erectus , commonly known as erect brome , upright brome or meadow brome , is a dense, course, tufted perennial grass. It can grow to 120 centimetres (47 in). Like many brome grasses the plant is hairy. The specific epithet erectus is Latin , meaning "erect". The diploid number of the grass is 56. Bromus erectus is a perennial, tufted grass with basal tufts of cespitose leaves that

130-443: A century plant can live for 80 years and grow 30 meters tall before flowering and dying. However, most perennials are polycarpic (or iteroparous ), flowering over many seasons in their lifetime. Perennials invest more resources than annuals into roots, crowns, and other structures that allow them to live from one year to the next. They often have a competitive advantage because they can commence their growth and leaf out earlier in

195-940: A photolyase and the other, a protein involved in nucleotide excision repair ). Perennials that are cultivated include: woody plants like fruit trees grown for their edible fruits; shrubs and trees grown as landscaping ornamentals ; herbaceous food crops like asparagus , rhubarb , strawberries ; and subtropical plants not hardy in colder areas such as tomatoes , eggplant , and coleus (which are treated as annuals in colder areas). Perennials also include plants grown for their flowering and other ornamental value including bulbs (like tulips, narcissus, and gladiolus); lawn grass, and other groundcovers , (such as periwinkle and Dichondra ). Each type of plant must be separated differently; for example, plants with fibrous root systems like daylilies, Siberian iris, or grasses can be pried apart with two garden forks inserted back to back, or cut by knives. However, plants such as bearded irises have

260-644: A lot of energy in maternal care. However, male reproductive rate is much less constrained in mammals because only females bear young. A male that dies after one mating season can still produce a large number of offspring if he invests all of his energy in mating with many females. Scientists have hypothesized that natural selection has allowed semelparity to evolve in Dasyuridae and Didelphidae because of certain ecological constraints. Female mammals ancestral to these groups may have shortened their mating period to coincide with peak prey abundance. Because this window

325-401: A result, they are univoltine ), initial food supply is predictably abundant, and larval host plants are abundant and adjacent. Death most commonly occurs by starvation. In the case of the spongy moth, adults do not possess an active digestive system and cannot feed, but can drink moisture. Mating occurs fairly rapidly after adults emerge from their pupal form and, without a way to digest food,

390-470: A root system of rhizomes; these root systems should be planted with the top of the rhizome just above ground level, with leaves from the following year showing. The point of dividing perennials is to increase the amount of a single breed of plant in your garden. In the United States more than 900 million dollars worth of potted herbaceous perennial plants were sold in 2019. Although most of humanity

455-604: A second time. Gracilinanus microtarsus , or the Brazilian gracile opossum, is considered to be partially semelparous because male mortality increases significantly after the mating season, but some males survive to mate again in the next reproductive cycle. The males also exhibit similar physiological degradation, demonstrated in Antechinus and other semelparous marsupials , such as fur loss and increase of infection from parasites. Highly elevated cortisol levels mediate

520-633: A semelparous species that has one litter of four, and then dies. These two species have the same rate of population growth, which suggests that even a tiny fecundity advantage of one additional offspring would favor the evolution of semelparity. This is known as Cole's paradox. In his analysis, Cole assumed that there was no mortality of individuals of the iteroparous species, even seedlings. Twenty years later, Charnov and Schaffer showed that reasonable differences in adult and juvenile mortality yield much more reasonable costs of semelparity, essentially solving Cole's paradox. An even more general demographic model

585-477: A single clutch of eggs in their lifetime and deposit them at one place are clearly semelparous or 'big bang' reproducers. Their entire reproductive effort is committed at one time and they die shortly after oviposition ". Semelparous insects are found in Lepidoptera , Ephemeroptera , Dermaptera , Plecoptera , Strepsiptera , Trichoptera , and Hemiptera . Females of certain families of Lepidoptera, like

650-479: A very few (e.g. Zostera ) occurring in shallow sea water. Herbaceous perennial plants are particularly dominant in conditions too fire-prone for trees and shrubs, e.g., most plants on prairies and steppes are perennials; they are also dominant on tundra too cold for tree growth. Nearly all forest plants are perennials, including trees and shrubs. Perennial plants are usually better long-term competitors, especially under stable, resource-poor conditions. This

715-468: Is nonrhizomatous . The culms grow between 0.6–1.2 m (2 ft 0 in – 3 ft 11 in) in height. The internodes are typically glabrous. The flattened cauline leaves have pubescent or glabrous sheaths. The leaf blades are 10–20 cm (3.9–7.9 in) long and 2–6 mm (0.079–0.236 in) wide. The grass lacks auricles and the ligule is blunt but finely serrated, sometimes with hairy edges. The contracted and ellipsoid panicle

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780-614: Is a biological precept that within its lifetime an organism has a limited amount of energy/resources available to it, and must always partition it among various functions such as collecting food and finding a mate. Of relevance here is the trade-off between fecundity , growth, and survivorship in its life history strategy. These trade-offs come into play in the evolution of iteroparity and semelparity. It has been repeatedly demonstrated that semelparous species produce more offspring in their single fatal reproductive episode than do closely related iteroparous species in any one of theirs. However,

845-499: Is a plant that completes its life cycle in a single season, and is usually semelparous. Perennials live for more than one season and are usually (but not always) iteroparous. Semelparity and iteroparity are not, strictly speaking, alternative strategies, but extremes along a continuum of possible modes of reproduction. Many organisms considered to be semelparous can, under certain conditions, separate their single bout of reproduction into two or more episodes. The word "semelparity"

910-666: Is a very rare strategy in vertebrates. In amphibians , it is known only among some Hyla frogs including the gladiator frog ; in reptiles only a few lizards such as Labord's chameleon of southwestern Madagascar , Sceloporus bicanthalis of the high mountains of Mexico, and some species of Ichnotropis from dry savanna areas of Africa. Among mammals, it exists only in a few didelphid and dasyurid marsupials. Annual plants, including all grain crops and most domestic vegetables, are semelparous. Long-lived semelparous plants include century plant ( agave ), Lobelia telekii , and some species of bamboo . This form of lifestyle

975-441: Is because larvae are morphologically specialized for development within a host's innards and thus are entirely helpless outside of that environment. Females would need to invest a lot of energy in protecting their eggs and hatched offspring. They do this through such behaviours as egg guarding. Mothers that actively defend offspring, for example, risk injury or death by doing so. This is not beneficial in an iteroparous species because

1040-506: Is characterized by multiple reproductive cycles over the course of its lifetime. Iteroparity can be further divided into continuous iteroparity (primates, including humans and chimpanzees) and seasonal iteroparity (birds, dogs, etc.) Some botanists use the parallel terms monocarpy and polycarpy . (See also plietesials .) In truly semelparous species, death after reproduction is part of an overall strategy that includes putting all available resources into maximizing reproduction, at

1105-463: Is consistent with r-selected strategies as many offspring are produced and there is low parental input, as one or both parents die after mating. All of the male's energy is diverting into mating and the immune system is repressed. High levels of corticosteroids are sustained over long periods of time. This triggers immune and inflammatory system failure and gastrointestinal hemorrhage , which eventually leads to death. The term iteroparity comes from

1170-547: Is costly for anadromous salmonids , because their life history requires transition from saltwater to freshwater streams, and long migrations, which can be physiologically taxing. The transition between cold oceanic water to warm freshwater and steep elevation changes in Northern Pacific rivers could explain the evolution of semelparity because it would be extremely difficult to return to the ocean. A noticeable difference between semelparous fish and iteroparous salmonids

1235-783: Is due to the development of larger root systems which can access water and soil nutrients deeper in the soil and to earlier emergence in the spring. Annual plants have an advantage in disturbed environments because of their faster growth and reproduction rates. Each section contains a short list of species related to that topic, these are an example as the true lists would fill several books. Perennials grown for their decorative flowers include very many species and types. Some examples include: The majority of fruit bearing plants are perennial even in temperate climates. Examples include: Many herbs are perennial, including these examples: Many vegetable plants can grow as perennials in tropical climates, but die in cold weather. Examples of some of

1300-447: Is equivalent to a benefit function, while offspring forgone is comparable to a cost function. The reproductive effort of an organism—the proportion of energy that it puts into reproducing, as opposed to growth or survivorship—occurs at the point where the distance between offspring produced and offspring forgone is the greatest. In some situations, the marginal cost of offspring produced decreases over time (each additional offspring

1365-483: Is fed by the re-sowing of the seeds of annual grain crops, (either naturally or by the manual efforts of humans), perennial crops provide numerous benefits. Perennial plants often have deep, extensive root systems which can hold soil to prevent erosion , capture dissolved nitrogen before it can contaminate ground and surface water, and out-compete weeds (reducing the need for herbicides ). These potential benefits of perennials have resulted in new attempts to increase

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1430-438: Is less "expensive" than the average of all previous offspring) and the marginal cost of offspring forgone increases. In these cases, the organism only devotes a portion of its resources to reproduction and uses the rest for growth and survivorship so that it can reproduce again in the future. In other situations, the marginal cost of offspring produced increases while the marginal cost of offspring forgone decreases. When this

1495-498: Is no current universal explanation for the mechanism behind increased male mortality in Dasyuridae. Post-reproductive senescence has also been proposed as an explanation. The grey slender mouse opossum exhibits a semelparous reproductive strategy in both males and females. Males disappear from their endemic area after the reproductive season (February–May). Males found months later (June–August) are of lighter body weight and

1560-435: Is so small, the females of these species exhibit a reproduction pattern where the estrous of all females occurs simultaneously. Selection would then favor aggressive males due to increased competition between males for access to females. Since the mating period is so short, it is more beneficial for males to expend all their energy on mating, even more so if they are unlikely to survive to the next mating season. Reproduction

1625-440: Is that egg size varies between the two types of reproductive strategies. Studies show that egg size is also affected by migration and body size. Egg number, however, shows little variation between semelparous and iteroparous populations or between resident and anadromous populations for females of the same body size. The current hypothesis behind this reason is that iteroparous species reduce the size of their eggs in order to improve

1690-766: Is the case, it is favorable for the organism to reproduce a single time. The individual devotes all of its resources to that one episode of reproduction, then dies as it has not reserved enough resources to meet its own ongoing survival needs. Empirical, quantitative support for this mathematical model is limited. A second set of models examines the possibility that iteroparity is a hedge against unpredictable juvenile survivorship (avoiding putting all one's eggs in one basket). Again, mathematical models have not found empirical support from real-world systems. In fact, many semelparous species live in habitats characterized by high (not low) environmental unpredictability, such as deserts and early successional habitats. The models that have

1755-429: Is too cold or dry. In many parts of the world, seasonality is expressed as wet and dry periods rather than warm and cold periods, and deciduous perennials lose their leaves in the dry season. Some perennial plants are protected from wildfires because they have underground roots that produce adventitious shoots, bulbs, crowns , or stems ; other perennials like trees and shrubs may have thick cork layers that protect

1820-519: Is usually large as well as fatal. A classic example of a semelparous organism is (most) Pacific salmon ( Oncorhynchus spp.), which live for many years in the ocean before swimming to the freshwater stream of its birth, spawning, and dying. Other semelparous animals include many insects, including some species of butterflies, cicadas, and mayflies , many arachnids , and some molluscs such as some species of squid and octopus . Semelparity also occurs in smelt and capelin , but other than bony fish it

1885-767: Is usually upright, rather than nodding, measuring 7–15 cm (2.8–5.9 in) long. The lanceolate spikelets are 1.5–3 cm (0.59–1.18 in) long and have five to twelve flowers. The glumes are acute, with the lower glumes one-nerved and 7–9 mm (0.28–0.35 in) long, and the upper glumes three-nerved and 9–11 mm (0.35–0.43 in) long. The glabrous or slightly scabrous lemmas are prominently nerved and 10–15 mm (0.39–0.59 in) long, with awns 5–6 mm (0.20–0.24 in) long. The anthers are 4–6 mm (0.16–0.24 in) long. B. erectus flowers in June and July. Found on well-drained calcerous soils in disturbed areas, fields, and roadsides, B. erectus

1950-460: Is widespread in Europe, South West Asia, North West Africa, and has been introduced into North America. Perennial Perennials (especially small flowering plants ) that grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as herbaceous perennials . However, depending on

2015-475: The astronomical symbol for the planet Jupiter . Perennial plants can be short-lived (only a few years) or long-lived. They include a wide assortment of plant groups from non-flowering plants like ferns and liverworts to highly diverse flowering plants like orchids , grasses , and woody plants . Plants that flower and fruit only once and then die are termed monocarpic or semelparous ; these species may live for many years before they flower. For example,

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2080-402: The spongy moth of family Erebidae , have reduced mobility or are wingless ( apterous ), so they disperse in the larval stage as opposed to in the adult stage. In iteroparous insects, dispersal mainly occurs in the adult stage. All semelparous Lepidopterans share similar characteristics: larvae only feed in restricted periods of the year because of the nutritional state of their host plants (as

2145-503: The Latin itero , to repeat, and pario , to beget. An example of an iteroparous organism is a human—humans are biologically capable of having offspring many times over the course of their lives. Iteroparous vertebrates include all birds, most reptiles, virtually all mammals, and most fish. Among invertebrates, most mollusca and many insects (for example, mosquitoes and cockroaches) are iteroparous. Most perennial plants are iteroparous. It

2210-505: The adult moths die after about a week. The evolution for semelparity in both sexes has occurred many times in plants, invertebrates, and fish. It is rare in mammals because mammals have obligate maternal care due to internal fertilization and incubation of offspring and nursing young after birth, which requires high maternal survival rate after fertilization and offspring weaning . Also, female mammals have relatively low reproductive rates compared to invertebrates or fish because they invest

2275-446: The advantage of generating larger seedlings that can better compete with other plants. Perennials also produce seeds over many years. An important aspect of cold acclimation is overexpression of DNA repair genes. In Thinopyrum intermedium a perennial relative of common wheat Triticum aestivum , conditions of freezing stress were shown to be associated with large increases in expression of two DNA repair genes (one gene product

2340-510: The dormancy period is over and new growth begins. In climates that are warm all year long, perennials may grow continuously. Annuals which complete their life cycle in one growing season, in contrast with perennials, produce seeds as the next generation and die; the seeds may survive cold or dry periods or germinate soon after dispersal depending on the climate. Some perennials retain their foliage year-round; these are evergreen perennials. Deciduous perennials shed all their leaves part of

2405-553: The exception of the northern quoll ( Dasyurus hallucatus ), which is large. Species with this reproductive strategy include members of the genus Antechinus , Phascogale tapoatafa and Phascogale culura . The males of all three groups exhibit similar characteristics that classify them as semelparous: First, all of the males of each species disappear immediately after the mating season. Also, males that are captured and isolated from others live for 2 to 3 years. If these captured males are allowed to mate, they die immediately after

2470-414: The expense of future life (see § Trade-offs ). In any iteroparous population there will be some individuals who happen to die after their first and before any second reproductive episode, but unless this is part of a syndrome of programmed death after reproduction, this would not be called "semelparity". This distinction is also related to the difference between annual and perennial plants: An annual

2535-406: The female risks dying and not reaching her full reproductive potential by not being able to reproduce in all reproductive periods in her lifetime. Since semelparous insects only live for one reproductive cycle, they can afford to expend energy on maternal care because those offspring are her only offspring. An iteroparous insect does not need to expend energy on the eggs of one mating period because it

2600-458: The following year. This species has been compared to a related species, Marmosa robinsoni , in order to answer what would happen if a female that has reproduced were to survive to the next mating season. M. robinsoni has a monoestrus reproductive cycle, like M. incanus , and females are no longer fertile after 17 months so it is unlikely that females that survive past the drop off in female populations would be able to reproduce

2665-541: The growing season, and can grow taller than annuals. In doing so they can better compete for space and collect more light. Perennials typically grow structures that allow them to adapt to living from one year to the next through a form of vegetative reproduction rather than seeding. These structures include bulbs , tubers , woody crowns, rhizomes , turions , woody stems, or crowns which allows them to survive periods of dormancy over cold or dry seasons; these structures typically store carbohydrates which are used once

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2730-620: The hormones produced due to environmental situations (i.e., seasons), reproduction, and stage of development to begin and halt the ability to grow or flower. There is also a distinction between the ability to grow and the actual task of growth. For example, most trees regain the ability to grow during winter but do not initiate physical growth until the spring and summer months. The start of dormancy can be seen in perennial plants through withering flowers, loss of leaves on trees, and halting of reproduction in both flowering and budding plants. Perennial species may produce relatively large seeds that have

2795-498: The individuals in a 2001 study mostly died from vehicles or predation, researchers found evidence of physiological degradation in males, similar to the physiological degradation in small dasyurids. This includes fur loss, parasite infestations, and weight loss. As the mating period went on, males became increasingly anemic , but the anemia was not due to ulceration or gastrointestinal bleeding. Lack of elevated cortisol levels during mating periods in D. hallucatus means that there

2860-482: The laboratory, and no senile males were found in the wild, suggesting that all males die shortly after mating. Studies on Antechinus stuartii reveal that male mortality is highly correlated to stress and andrenocortical activity. The study measured the corticosteroid concentration in males in the wild, males injected with cortisol, males injected with saline, and females in the wild. While both males and females exhibit high levels of corticosteroid concentration in

2925-403: The males that were injected with saline, strengthening the hypothesis that high, free corticosteroids result in higher mortality in male dasyurids. A similar study on Phascogale calura showed that similar endocrine system changes happen in P. calura as A. stuartii . This supports stress-induced mortality as a characteristic of small dasyurid semelparity. Dasyurus hallucatus ,

2990-414: The marsupial ages, its testicles grow until they reach a peak size and weight at the beginning of the mating season. After the individual mates, the weight and size of the testes and scrotum decrease. They remain small and do not produce spermatozoa later in life, if maintained in a laboratory. The 1966 Woolley study on Antechinus spp. noticed that males were only able to be maintained past mating in

3055-464: The mating season, like those in the wild. Their behaviour also changes drastically before and after the mating season. Before mating, males are extremely aggressive and will fight with other males if placed close together. Males that are captured before they are allowed to mate remain aggressive through the winter months. After the mating season, if allowed to mate, males become extremely lethargic and never regain their aggressiveness even if they survive to

3120-416: The molar teeth are less worn down, suggesting these males belong to a different generation. There is a drop off in the female population, but during the months of July and August, evidence of a gap between generations like the male gap. There is also lower body weight and less molar wear observed in females found after August. This is further supported by the evidence that females that reproduce are not observed

3185-410: The more completely perennial vegetables are: Many aquatic plants are perennial even though many do not have woody tissue. Examples include: Iteroparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it

3250-449: The most carcasses of spawned adults. The dead bodies of the adult salmon decompose and provide nitrogen and phosphorus for algae to grow in the nutrient-poor water. Zooplankton then feed on the algae, and newly hatched salmon feed on the zooplankton. An interesting trait has evolved in semelparous insects, especially in those that have evolved from parasitic ancestors, like in all subsocial and eusocial aculeate Hymenoptera . This

3315-404: The mother's chances of survival, since she invests less energy in gamete formation. Semelparous species do not expect to live past one mating season, so females invest a lot more energy in gamete formation resulting in large eggs. Anadromous salmonids may also have evolved semelparity to boost the nutrition density of the spawning grounds . The most productive Pacific salmon spawning grounds contain

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3380-423: The next mating season. Other changes that occur post-mating include fur degradation and testicular degeneration. During adolescence, male fur is thick and becomes dull and thin after mating, but regains its original condition if the individual manages to survive past the mating season. The fur on the scrotum completely falls off and does not grow back, even if the male survives months after the first mating season. As

3445-418: The northern quoll , is a large dasyurid and exhibits increased male mortality after the mating season. Unlike smaller dasyurids, male die-off in D. hallucatus is not due to endocrine system changes, and there was no observed spermatogenic failure after the mating season ended. If male D. hallucatus survive past their first mating season, they may be able to engage in a second mating season. While

3510-405: The opportunity to reproduce more than once in a lifetime, and possibly with greater care for the development of offspring produced, can offset this strictly numerical benefit. One class of models that tries to explain the differential evolution of semelparity and iteroparity examines the shape of the trade-off between offspring produced and offspring forgone. In economic terms, offspring produced

3575-709: The post-spawning death of semelparous Oncorhynchus Pacific salmon by causing tissue degeneration, suppressing the immune system, and impairing various homeostatic mechanisms. After swimming for such a long distance, salmon expend all of their energy on reproduction. One of the key factors in salmon rapid senescence is that these fish do not feed during reproduction so body weight is extremely reduced. In addition to physiological degradation, Pacific salmon become more lethargic as mating goes on, which makes some individuals more susceptible to predation because they have less energy to avoid predators. This also increases mortality rates of adults post-mating. Traditionally, semelparity

3640-461: The rigours of the local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings, or from divisions. Tomato vines, for example, live several years in their natural tropical/ subtropical habitat but are grown as annuals in temperate regions because their above-ground biomass does not survive

3705-465: The seed yield of perennial species, which could result in the creation of new perennial grain crops. Some examples of new perennial crops being developed are perennial rice and intermediate wheatgrass . A perennial rice developed in 2018, was reported in 2023, to have provided a similar yield to replanted annual rice when evaluated over eight consecutive harvests. Perennial plants dominate many natural ecosystems on land and in fresh water, with only

3770-431: The stems. Herbaceous perennials from temperate and alpine regions of the world can tolerate the cold during winter. Perennial plants may remain dormant for long periods and then recommence growth and reproduction when the environment is more suitable, while most annual plants complete their life cycle during one growing period, and biennials have two growing periods. The meristem of perennial plants communicates with

3835-473: The strongest support from living systems are demographic. In Lamont Cole's classic 1954 paper, he came to the conclusion that: For an annual species, the absolute gain in intrinsic population growth which could be achieved by changing to the perennial reproductive habit would be exactly equivalent to adding one individual to the average litter size. For example, imagine two species—an iteroparous species that has annual litters averaging three offspring each, and

3900-525: The wild, this proves fatal only to males due to females having a higher maximum high affinity corticosteroid binding capacity (MCBC). Thus, free corticosteroid in the plasma of male A. stuartii rises sharply, while it remains constant in females. High levels of free corticosteroid, resulting from mating in wild males and injected cortisol in laboratory males, resulted in stomach ulcers , gastrointestinal bleeding , and liver abscesses , all of which increased mortality. These side-effects were not found in

3965-405: The winter. There is also a class of evergreen perennials which lack woody stems, such as Bergenia which retain a mantle of leaves throughout the year. An intermediate class of plants is known as subshrubs , which retain a vestigial woody structure in winter, e.g. Penstemon . The symbol for a perennial plant, based on Species Plantarum by Linnaeus , is [REDACTED] , which is also

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4030-439: The year. Deciduous perennials include herbaceous and woody plants; herbaceous plants have stems that lack hard, fibrous growth, while woody plants have stems with buds that survive above ground during dormancy. Some perennials are semi-deciduous, meaning they lose some of their leaves in either winter or summer. Deciduous perennials shed their leaves when growing conditions are no longer suitable for photosynthesis, such as when it

4095-411: Was coined by evolutionary biologist Lamont Cole, and comes from the Latin semel ('once, a single time') and pario ('to beget'). This differs from iteroparity in that iteroparous species are able to have multiple reproductive cycles and therefore can mate more than once in their lifetime. Semelparity is also known as "big bang" reproduction, since the single reproductive event of semelparous organisms

4160-414: Was produced by Young. These demographic models have been more successful than the other models when tested with real-world systems. It has been shown that semelparous species have higher expected adult mortality, making it more economical to put all reproductive effort into the first (and therefore final) reproductive episode. Semelparous species of Dasyuridae are typically small and carnivorous, with

4225-581: Was usually defined within the time-frame of a year. Critics of this criterion note that this scale is inappropriate in discussing patterns of insect reproduction because many insects breed more than once within one annual period, but generation times of less than one year. Under the traditional definition, insects are considered semelparous as a consequence of time scale rather than the distribution of reproductive effort over their adult life span. In order to resolve this inconsistency, Fritz, Stamp & Halverson (1982) define semelparous insects as "insects that lay

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