The Monophyletic Origin of Delayed Implantation in Carnivores and Its Implications

Lindenfors, Patrik; Dalén, Love; Angerbjörn, Anders

doi:10.1111/j.0014-3820.2003.tb00601.x

Cited by 26 publications

(27 citation statements)

References 21 publications

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“…Whether competition with American mink has contributed to its decline is controversial (Youngman, 1990). Many mustelids exhibit an implantation delay (34% of Mustelidae show embryonic diapause) (Lindenfors, Dalen & Angerbjörn, 2003; Thom, Johnson & Macdonald, 2004). However, data from levels of faecal progestagens and CL development in European mink strongly suggest that there is no implantation delay in this species, as has also been shown for the European polecat ( Mustela putorius ) (Amstislavsky et al , 2009).…”

Section: Discussionmentioning

confidence: 99%

The concept of superfetation: a critical review on a ‘myth’ in mammalian reproduction

et al. 2010

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Superfetation is understood as another conception during an already ongoing pregnancy. This implies the existence of young of different developmental stages within the female reproductive tract during certain periods of pregnancy. Nevertheless, a clear definition of the term as well as distinct criteria to identify the occurrence of superfetation in a species is missing. The variable anatomy of mammalian reproductive tracts seems to make the occurrence of superfetation more or less likely but impedes the simple evaluation of whether it is present or not. Additionally, adequate determination methods are missing or are difficult to apply at the right time. Superfetation or rather superfetation-like pregnancies are reported for numerous species including humans, livestock and rodents. The usual criteria to assume a case of superfetation include the finding of discordantly developed young within the uterus during post mortem or parturition of young after a birth interval shorter than the assumed pregnancy length. Often the occurrence of superfetation is concluded because other explanations of reproductive artifacts are missing. Even severe reproductive pathologies are often confused with superfetation. True superfetation or superfetation as a reproductive strategy may exist in some mammals. In the American mink (Neovison (Mustela) vison) and the European badger (Meles meles) superfetation occurs in combination with embryonic diapause. In the European brown hare (Lepus europaeus), superfetation has long been assumed to exist but evidence is still controversial. Superfetation definitely occurs in certain species of poeciliid and zenarchopterid fish, some of which also exhibit viviparity and maternal care. In mammals, the evolution of such a reproductive mechanism poses many interesting evolutionary, endocrine, microbial and immunological questions that require further investigation. Here we review the scant and at times ancient literature on this poorly understood topic. The different manifestations of superfetation are defined and reliable criteria to detect superfetation are outlined. Also, the differentiation of superfetation into a reproductive strategy or as a disrupted, abnormal reproductive function is discussed. Due to the different discussed functional aspects of superfetation, it is appropriate to establish a more detailed scheme to classify the true natural superfetation cases into superfertilization, superconception and superfetation proper. To date, there is no mammal species known for which superfetation proper in terms of finding discordantly developed fetuses has been conclusively demonstrated to be not only a rare occurence but an evolved reproductive strategy.

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Section: Discussionmentioning

confidence: 99%

The concept of superfetation: a critical review on a ‘myth’ in mammalian reproduction

et al. 2010

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“…The Neotropical otter seems to present facultative delayed implantation, as do other mustelids (Larivière , Lindenfors et al. ). This mechanism is thought to provide the reproductive means to mate during the summer, when there may be greater opportunities for females to choose mates while living in highly seasonal environments (Ferguson et al.…”

Section: Reproductionmentioning

confidence: 97%

The Neotropical otter Lontra longicaudis: a comprehensive update on the current knowledge and conservation status of this semiaquatic carnivore

2017

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1. The Neotropical otter Lontra longicaudis is a widespread semiaquatic carnivore living in a wide variety of environments in both fresh-water and salt-water ecosystems. We summarise the current knowledge on distribution, ecology, behaviour, evolution and conservation status of the species, and highlight the main threats that have been affecting it as well as priority actions for securing its survival. 2. The current geographical range of Lontra longicaudis is discussed, as well as several efforts that have been made to update knowledge of the range. Throughout its known distribution area, the Neotropical otter has high genetic diversity, and recent molecular research suggests that variations in genetic diversity are related to geography. Taxonomic issues regarding the existence of subspecies persist, mainly due to limited sampling in key portions of the species' range. 3. Although the Neotropical otter is widely distributed in Latin America and has flexible behaviour, it is subjected to a variety of threats, which lead this otter to be officially considered Threatened in several countries within its geographical range. 4. The species still faces an uncertain future due to the impact of human activities, thus justifying its classification as Near Threatened in the International Union for Conservation of Nature's Red List. The real level of human-otter conflicts and the impact of modified environments on Neotropical otter populations are still unclear, and must be a priority focus of future studies. 5. There is an urgent need to increase our knowledge on aspects of the Neotropical otter's biology, such as reproduction, generation time, behaviour, physiology, distribution limits, sanitary aspects, evolution and taxonomy. Understanding these topics is vital to ensure the long-term survival of the species, both at the local and at the regional scale, as well as to provide the basis for environmental education actions involving local riverside human communities.

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“…Embryonic diapause is an evolutionary strategy by which there is a reversible arrest in the development of the embryo, almost always at the blastocyst stage of the trajectory of embryonic development. It allows for the uncoupling of fertilization from birth, thereby ensuring that post‐natal development occurs under the most favourable environmental conditions for survival of the offspring (Lindenfors, Dalen, & Angerbjorn, ). It is known to occur in more than 130 species, across six mammalian classes (Fenelon, Banerjee, & Murphy, ).…”

Section: Introductionmentioning

confidence: 99%

Regulation of diapause in carnivores

Fenelon

Lefèvre

Banerjee

et al. 2016

Reprod Domestic Animals

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ContentsEmbryonic diapause is an evolutionary strategy to ensure that offspring are born when maternal and environmental conditions are optimal for survival. In many species of carnivores, obligate embryonic diapause occurs in every gestation. In mustelids, the regulation of diapause and reactivation is influenced by photoperiod, which then acts to regulate the secretion of pituitary prolactin. Prolactin in turn regulates ovarian steroid function. Reciprocal embryo transplant studies indicate that this state of embryonic arrest is conferred by uterine conditions and is presumed to be due to a lack of specific factors necessary for continued development. Studies of global gene expression in the mink (Neovison vison) revealed reduced expression of a cluster of genes that regulate the abundance of polyamines in the uterus during diapause, including the rate-limiting enzyme in polyamine production, ornithine decarboxylase (ODC). In addition, in this species, in vivo inhibition of the conversion of ornithine to the polyamine, putrescine, induces a reversible arrest in embryonic development and an arrest in both trophoblast and inner cell mass proliferation in vitro. Putrescine, at 0.5, 2 and 1,000 μM concentrations induced reactivation of mink embryos in culture, indicated by an increase in embryo volume, observed within five days. Further, prolactin induces ODC1 expression in the uterus, thereby regulating uterine polyamine levels. These results indicate that pituitary prolactin acts on ovarian and uterine targets to terminate embryonic diapause. In summary, our findings suggest that the polyamines, with synthesis under the control of pituitary prolactin, are the uterine factor whose absence is responsible for embryonic diapause in mustelid carnivores.Centre de recherche en reproduction animale, Faculté de médecine vétérinare,

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The Monophyletic Origin of Delayed Implantation in Carnivores and Its Implications

Cited by 26 publications

References 21 publications

The concept of superfetation: a critical review on a ‘myth’ in mammalian reproduction

The concept of superfetation: a critical review on a ‘myth’ in mammalian reproduction

The Neotropical otter Lontra longicaudis: a comprehensive update on the current knowledge and conservation status of this semiaquatic carnivore

Regulation of diapause in carnivores

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