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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Matriphagy | 3/3 | https://en.wikipedia.org/wiki/Matriphagy | reference | science, encyclopedia | 2026-05-05T07:15:55.810435+00:00 | kb-cron |
The Taita African caecilian Boulengerula taitana is an oviparous (egg-laying) caecilian whose skin transforms in brooding females to supply nutrients to growing offspring. The offspring are born with specific dentition that they can use to peel and eat the outer epidermal layer of their mother's skin. Young move around their mother's bodies, using their lower jaws to lift and peel the mother's skin while vigorously pressing their heads against her abdomen. To account for this, the epidermis of brooding females can be up to twice the thickness of non-brooding females. Viviparous (developing in the mother) caecilians on the other hand, have specialized fetal dentition which can be used for scraping lipid-rich secretions and cellular materials from the maternal oviduct lining. The ringed caecilian Siphonops annulatus, an oviparous caecilian, exhibits characteristics similar to viviparous caecilians. Mothers have paler skin tones than non-attending females, suggesting that offspring feed on glandular secretions on the mother's skin—a process that resembles mammalian lactation. This scraping method is different from the peeling actions performed by oviparous caecilians. For both oviparous and viviparous caecilians, delayed investment is a common benefit. Providing nutrition through the skin allows for redirection of nutrients, yielding fewer and larger offspring than caecilians who only provide their offspring with yolk nutrients. Rather than the mother sacrificing herself and solely being used for the offspring's nutrition, caecilian mothers supplement their offspring's growth; they provide enough nutrients for the offspring to survive, but not at the cost of their own life.
=== Gerontophagy in social spiders, Genus Stegodyphus ===
Stegodyphus mothers liquefy their inner organs and maternal tissue into food deposits. The African social velvet spider Stegodyphus mimosarum and the African social spider Stegodyphus dumicola are two social spider species that eat their mothers and other adult females, which is unique since social spiders do not tend to exhibit cannibalistic life history traits. In these specific spiders, deceased females are often found shriveled with shrunken abdomens. Offspring suck nutrients primarily from the dorsal part of the adult female's abdomen, and she may still be alive during this process. This behavior is not quite the same as matriphagy because Stegodyphus spiderlings are perfectly tolerant to other offspring, healthy conspecifics, and members of other species, suggesting that ordinary cannibalism is suppressed. Instead, the parental care exhibited is known as "gerontophagy", or the "consumption of old individuals" (geron = old person, phagy = to feed on). Gerontophagy is the final act of care for the offspring, and some offspring are found larger than others. This implies that some young spiders are already able to feed on prey by themselves and gerontophagy as a source of nutrition is supplemental rather than necessary. Thus, there exists the ‘cannibal's kin-dilemma’, which reveals a form of kin selection in social spiders. In this scenario, kin selection should counteract cannibalism of related individuals in social spiders, but any designated victim should prefer to be eaten by available close relatives.
== Cultural significance == Those who have been exposed to matriphagy may be frightened by such a seemingly strange and bizarre natural behavior, especially since it is mainly observed in already feared organisms. Thus, matriphagy is often posed as perpetuation of a long held fear of arachnids in human society. In contrast, others may look to matriphagy as a leading example of purity, as it represents an instinctive form of altruism. Altruism in this case refers to an "intentional action ultimately for the welfare of others that entails at least the possibility of either no benefit or a loss to the actor," and is a highly popularized and desirable concept in many human cultures. Matriphagy can be viewed as altruism, insofar as participating mothers "sacrifice" their survival for the welfare of their offspring. Although participation in matriphagy is not truly an intentional action, mothers are nevertheless driven by natural selection pressures based on offspring fitness to engage in such behavior. This in turn creates a cycle that perpetuates altruistic matriphagous behavior through generations. Such an example of altruism on a purely biological level differs severely from human standards of altruism, which are influenced by moral virtues such as rationality, trust, and reciprocity.
== List of species that engage in matriphagy ==
=== Spiders === Agelena labyrinthica Amaurobius ferox Cheiracanthium japonicum Seothyra Stegodyphus lineatus Stegodyphus sarasinorum Eresus sandaliatus
=== Earwigs === Anechura harmandi
=== Strepsiptera === The order Strepsiptera is known for hemocoelous vivipary, where the offspring lives in the female's hemocoel and feed on her hemolymph, consuming her from within.
=== Pseudoscorpions === Paratemnoides nidificator
=== Vertebrates === Caecilian
== References ==