Cross-fostering

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Cross-fostering is a technique used in animal husbandry, animal science, genetic and nature versus nurture studies, and conservation, whereby offspring are removed from their biological parents at birth and raised by surrogates, typically of a different species, hence 'cross.' This can also occasionally occur in nature.

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Animal husbandry

Cross-fostering young animals is usually done to equalize litter size. Individual animals born in large litters are faced with much more competition for resources, such as breast milk, food and space, than individuals born in smaller litters. Herd managers will typically move some individuals from a large litter to a smaller litter where they will be raised by a non-biological parent. This is typically done in pig farming because litters with up to 15 piglets are common. A sow with a large litter may have difficulty producing enough milk for all piglets, or the sow may not have enough functional teats to feed all piglets simultaneously. When this occurs, smaller or weaker piglets are at risk of starving to death. Herd managers will often transfer some piglets from a large litter to another lactating sow which either has a smaller litter or has had her own biological piglets recently weaned. Herd managers will typically try to equalize litters by number and also weight of individuals. [1] When done successfully, cross-fostering reduces piglet mortality. [2]

In research

Cross-fostering can be used to study the impact of postnatal environment on genetic-linked diseases as well as on behavioural pattern. In behavioral studies, if cross-fostered offspring show a behavioral trait similar to their biological parents and dissimilar from their foster parents, a behavior can be shown to have a genetic basis. Similarly, if the offspring develops traits dissimilar to their biological parents and similar to their foster parents environmental factors are shown to be dominant. In many cases there is a blend of the two, which shows both genes and environment play a part.

In animal studies, genetically hypertensive offspring reared by normotensive dams have been shown to have lower blood pressure compared to the controls.[ citation needed ] This shows that hypertensive genotype could be modified by the changes of the postnatal environment. Besides this, hyperkinetic animals reared by a normal dam have been shown to have lower locomotor activity compared to its controls.[ citation needed ]

In one experiment, siblicide was shown to be somehow related to parental care. When non-obligate siblicidal blue-footed boobies were swapped with obligate siblicidal masked booby chicks, it was found that the blue-footed chicks exhibited more siblicidal behavior. [3]

In a small study, cross-fostering tammar wallabies at the average age of 67 days postpartum to mothers that had 100 days old pouch young resulted in significantly heavier fostered young at 100 days old. Analysis of maternal milk composition found higher concentrations of lipid after pouch young is transferred into their host mother. [4]

In selective livestock breeding cross-fostering can be used to combine desirable genetic qualities such as weight, fat distribution or appearance with environmentally influenced ones such as temperament.

In humans, studies of children in foster care have shown that alcoholism is both genetic and environmental: early onset alcoholism can be linked to biological parentage, whereas adult onset alcoholism is often influenced by the alcohol abuse by foster parents.

In conservation

Cross fostering has been used in conservation biology such as the rearing of black robin chicks by other species. In this instance the species was so close to extinction, with literally a handful of surviving individuals and a single mother, there was little chance of raising many offspring. In this case a related species were used to raise the eggs, with their own eggs being replaced by conservation workers with those of the robin. In this case imprinting is one of the concerns, as species raised in a different environment may not be able to recognize their own species. In a world first, the Adelaide Zoo successfully cross-fostered a baby tree kangaroo, whose mother was killed when it was five weeks old, with a surrogate rock-wallaby mother. The Zoo had a successful cross-fostering program between wallaby species, but this is the first time it was tried with a tree kangaroo and wallaby. [5]

In nature

The ranges of these galahs overlap with a related species, leading to natural cross fostering. Galahs flying motion blur.jpg
The ranges of these galahs overlap with a related species, leading to natural cross fostering.

Cross fostering may occasionally occur in natural situations. In Australia, the closely related species from the cockatoo family, Eolophus roseicapilla (the galah) and Cacatua leadbeateri (the pink cockatoo), have overlapping ranges, and compete for nesting holes. However, two pairs of birds may share the same nest for a time, as they do not become aggressive until several eggs have been laid and incubation begins. When they do, the pink cockatoos are always the victors, evicting the galahs in what is termed interference competition. They are not consciously aware that some of the eggs in the nest were laid by the other bird however, and thus raise offspring of both species. These natural experiments have been used by Australian ornithologists Graeme Chapman and Ian Rowley to investigate the relative importance of genes and environment. [6] For example, they discovered that the galah chicks gave normal begging calls and alarm calls, but their contact calls (used to maintain social cohesion) were more like those of the pink cockatoos with which they lived.

Such natural instances of cross fostering can also lead to hybridization between species that would not normally breed. A case of this is offered by the Galapagos finches. Two species of the genus Geospiza , the medium ground-finch (Geospiza fortis) and the common cactus-finch (Geospiza scandens) occasionally hybridize. The birds' songs are a barrier to interbreeding, but sometimes young birds will not learn their own species song, e.g. if their father dies and they are nesting near another species. Another situation where birds can imprint on the wrong song is when one species takes over the nest of another but fails to remove all of its eggs. [7] Cross fostered young can then hybridize with their foster parents' species, allowing gene flow between the two populations. Hybrids experience reduced fitness, however, so the two species can remain separate. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Hybrid (biology)</span> Offspring of cross-species reproduction

In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents such as in blending inheritance, but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.

<span class="mw-page-title-main">Behavioral ecology</span> Study of the evolutionary basis for animal behavior due to ecological pressures

Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for animal behavior due to ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined four questions to address when studying animal behaviors: What are the proximate causes, ontogeny, survival value, and phylogeny of a behavior?

<span class="mw-page-title-main">Galah</span> Type of cockatoo

The galah, less commonly known as the pink and grey cockatoo or rose-breasted cockatoo, is an Australian species of cockatoo and the only member of the genus Eolophus. The galah is adapted to a wide variety of modified and unmodified habitats and is one of Australia's most abundant and widespread bird species. The species is endemic to mainland Australia. It was introduced to Tasmania, where it is now widespread, in the mid-19th century and much more recently to New Zealand.

<span class="mw-page-title-main">Helpers at the nest</span>

Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes remain in association with their parents and help them raise subsequent broods or litters, instead of dispersing and beginning to reproduce themselves. This phenomenon was first studied in birds where it occurs most frequently, but it is also known in animals from many different groups including mammals and insects. It is a simple form of co-operative breeding. The effects of helpers usually amount to a net benefit, however, benefits are not uniformly distributed by all helpers nor across all species that exhibit this behaviour. There are multiple proposed explanations for the behaviour, but its variability and broad taxonomic occurrences result in simultaneously plausible theories.

<span class="mw-page-title-main">Brood parasitism</span> Animal reliance on other individuals to raise its young

Brood parasitism is a subclass of parasitism and phenomenon and behavioural pattern of animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, usually using egg mimicry, with eggs that resemble the host's. The strategy involves a form of aggressive mimicry called Kirbyan mimicry.

<span class="mw-page-title-main">Blue-footed booby</span> Species of bird

The blue-footed booby is a marine bird native to subtropical and tropical regions of the eastern Pacific Ocean. It is one of six species of the genus Sula – known as boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait and a product of their diet. Males display their feet in an elaborate mating ritual by lifting them up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm (35 in) long with a wingspan up to 1.5 m (5 ft).

F1 hybrid (also known as filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where the term F1 crossbreed may be used. The term is sometimes written with a subscript, as F1 hybrid. Subsequent generations are called F2, F3, etc.

Parent–offspring conflict (POC) is an expression coined in 1974 by Robert Trivers. It is used to describe the evolutionary conflict arising from differences in optimal parental investment (PI) in an offspring from the standpoint of the parent and the offspring. PI is any investment by the parent in an individual offspring that decreases the parent's ability to invest in other offspring, while the selected offspring's chance of surviving increases.

<span class="mw-page-title-main">Alloparenting</span> Parenting not done by the birth parents

Alloparenting is a term for any form of parental care provided by an individual towards young that are not its own direct offspring. These are often called "non-descendant" young, even though grandchildren can be among them. Among humans, alloparenting is often performed by a child's grandparents and older siblings. Individuals providing this care are called by the neutral term "alloparent".

<span class="mw-page-title-main">Siberian jay</span> Species of bird

The Siberian jay is a small jay with a widespread distribution within the coniferous forests in North Eurasia. It has grey-brown plumage with a darker brown crown and a paler throat. It is rusty-red in a panel near the wing-bend, on the undertail coverts and on the sides of the tail. The sexes are similar. Although its habitat is being fragmented, it is a common bird with a very wide range so the International Union for Conservation of Nature has assessed its conservation status as being of "least concern".

<span class="mw-page-title-main">Nazca booby</span> Species of bird

The Nazca booby is a large seabird of the booby family, Sulidae, native to the eastern Pacific. First described by Walter Rothschild in 1902, it was long considered a subspecies of the masked booby until recognised as distinct genetically and behaviorally in 2002. It has a typical sulid body shape, with a long pointed orange-yellow bill, long neck, aerodynamic body, long slender wings and pointed tail. The adult is bright white with black and white wings, a black tail and a dark face mask.

<span class="mw-page-title-main">Siblicide</span> Killing of an infant individual by its siblings

Siblicide is the killing of an infant individual by its close relatives. It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds.

Monogamous pairing in animals refers to the natural history of mating systems in which species pair bond to raise offspring. This is associated, usually implicitly, with sexual monogamy.

<span class="mw-page-title-main">Japanese quail</span> Species of bird

The Japanese quail, also known as the coturnix quail, is a species of Old World quail found in East Asia. First considered a subspecies of the common quail, it is now considered as a separate species. The Japanese quail has played an active role in the lives of humanity since the 12th century, and continues to play major roles in industry and scientific research. Where it is found, the species is abundant across most of its range. Currently, there are a few true breeding mutations of the Japanese quail. The varieties currently found in the United States include Pharaoh, Italian, Manchurian, Tibetan, Rosetta, along with the following mutations: sex-linked brown, fee, roux, silver, andalusian, blue/blau, white winged pied, progressive pied, albino, calico, sparkly, as well as non-color mutations such as celadon.

<span class="mw-page-title-main">Mangrove finch</span> Species of bird

The mangrove finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is endemic to the Galápagos Islands. It was found on the islands of Fernandina and Isabela, but recent surveys have failed to record the species on Fernandina. It has been classified as critically endangered by BirdLife International, with an estimated population of 20–40 mature individuals in 2021, located in two large mangroves on Isabela. A study has shown that the two small populations remaining on Isabela Island have begun undergoing speciation and that one or both populations will eventually become extinct due to a lack of interbreeding.

<span class="mw-page-title-main">Savaging</span> In ethology, aggressive behaviour displayed by the mother towards the offspring

Savaging is a term used in the study of ethology that refers to aggressive behaviour displayed by the mother towards the offspring. Aggressive behaviour includes being rough with, injuring, biting, attacking, crushing and killing of the offspring. While savaging behaviour has been seen in multiple species, it is predominantly demonstrated in domestic pigs. As the definition of savaging is so broad, research on the prevalence of savaging behaviour varies with reports of little savaging of offspring to savaging of offspring up to the 20th percentile. Prevalence of aggressive, non-fatal savaging is greater in gilts, or females who have not yet previously farrowed, as piglet-focused aggression is more frequent in young animals than sows, adult females who have previously given birth. Occurrence of savaging demonstrated by sows is greater if the sow has previously savaged her offspring either as a gilt or sow. Savaging behaviour usually occurs during the first two days after parturition. Prevalence of savaging is similar among first and second farrowing cycles. Savaging behaviour has a significant impact on both agricultural economy and animal welfare which is why it is currently a subject of interest in the pig industry.

<span class="mw-page-title-main">Seabird breeding behavior</span>

The term seabird is used for many families of birds in several orders that spend the majority of their lives at sea. Seabirds make up some, if not all, of the families in the following orders: Procellariiformes, Sphenisciformes, Pelecaniformes, and Charadriiformes. Many seabirds remain at sea for several consecutive years at a time, without ever seeing land. Breeding is the central purpose for seabirds to visit land. The breeding period is usually extremely protracted in many seabirds and may last over a year in some of the larger albatrosses; this is in stark contrast with passerine birds. Seabirds nest in single or mixed-species colonies of varying densities, mainly on offshore islands devoid of terrestrial predators. However, seabirds exhibit many unusual breeding behaviors during all stages of the reproductive cycle that are not extensively reported outside of the primary scientific literature.

A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents. Ornaments are used in displays to attract mates, which may lead to the evolutionary process known as sexual selection. An animal may shake, lengthen, or spread out its ornament in order to get the attention of the opposite sex, which will in turn choose the most attractive one with which to mate. Ornaments are most often observed in males, and choosing an extravagantly ornamented male benefits females as the genes that produce the ornament will be passed on to her offspring, increasing their own reproductive fitness. As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop known as a Fisherian runaway. These structures serve as cues to animal sexual behaviour, that is, they are sensory signals that affect mating responses. Therefore, ornamental traits are often selected by mate choice.

<span class="mw-page-title-main">Begging in animals</span>

Begging in animals is when an animal solicits being given resources by another animal. This is usually a young animal soliciting food from their parents, brood hosts or other adults. However, the resource is sometimes non-food related or may be solicited by adult animals. Begging behavior is most widely studied in birds, however, mammals, amphibians, and invertebrates perform begging displays. Generally in food solicitation, begging behavior is instinctive, although in some instances it is learned.

Animals, including siblings, compete for resources such as food, territory, and potential mating partners. In animal sibling rivalry, individuals compete for parental care or limited resources, which can sometimes result in siblicide, the killing of siblings. Sibling rivalry occurs in many different forms. Siblings may compete for resources in a prenatal and/or post-birth environment. The degree of rivalry varies, ranging from a low level of violence in non-aggressive to the killing of kin in siblicide.

References

  1. Cross Foster at Medical Dictionary
  2. The Impact of Cross-Fostering on Swine Production Archived 2011-07-28 at the Wayback Machine
  3. Loughweed, Lynn W. (1999). "Parent Blue-footed Boobies Suppress Siblicidal Behavior of Offspring". Behavioral Ecology and Sociobiology. 45 (1): 11–18. doi:10.1007/s002650050535.
  4. Waite, Rosemary; Giraud, Andrew; Old, Julie; Howlett, Meegan; Shaw, Geoffrey; Nicholas, Kevin; Familari, Mary (2005). "Cross-fostering inMacropus eugenii leads to increased weight but not accelerated gastrointestinal maturation". Journal of Experimental Zoology Part A: Comparative Experimental Biology. 303A (5): 331–344. doi:10.1002/jez.a.174. ISSN   1548-8969.
  5. VIDEO: Baby tree kangaroo fostered by rock wallaby, Australian Geographic, 19 June 2015
  6. Rowley, I. & G. Chapman (1986) Cross-fostering, imprinting, and learning in two sympatric species of cockatoos. Behaviour 96: 1-16
  7. Interview with Peter and Rosemary Grant, in Campbell, Neil; Jane B. Reece (2002). Biology. San Francisco: Benjamin Cummings. p.  1247 p. ISBN   978-0-8053-6624-2.
  8. Mogbo, T. C.; Okeke, T. E.; Okeke, J. J.; Nwosu, M. C.; Ibemenuga, K. N. (2013). "Cross Fostering In Animals as a Tool for Conservation". Journal of Renewable Agriculture. 1 (7): 123–125.

Primary sources