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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Matriphagy | 2/3 | https://en.wikipedia.org/wiki/Matriphagy | reference | science, encyclopedia | 2026-05-05T07:15:55.810435+00:00 | kb-cron |
==== Anechura harmandi ==== Anechura harmandi is the only species of earwigs that has been currently documented to exhibit matriphagy. Mothers in this particular species of earwigs have been found to reproduce during colder temperatures. This is mainly for the purpose of avoiding predation and maximizing their offspring's survival, since females are unable to produce a second clutch. Due to the cold temperature, there is a scarcity of available nutrients when the offspring hatch, which is why the offspring end up consuming their mother.
=== Pseudoscorpions ===
==== Paratemnoides nidificator ==== Matriphagy in this species of pseudoscorpions is usually observed during times of food scarcity. After their offspring hatch, mothers exit their nests and wait to be consumed. Offspring follow their mothers out of the nest where they grab onto her legs and proceed to feed through her leg joints, similar to that of Australomisidia ergandros. Females of this species are able to produce more than one clutch of offspring if their first clutch was unsuccessful. Matriphagy in this species has been predicted to prevent cannibalism between siblings as well.
== Evolution == The adaptive value of matriphagy is based on the benefits provided to the offspring and the costs borne by the mother. Functionally analyzing matriphagy in this manner sheds light on why this unusual and extreme form of care has evolved and been selected for.
=== Benefits to offspring === Consuming the mother is a source of nutrition which is important for growth and development. The body mass and opisthosoma length of spiderlings increases after matriphagy compared to before (opisthosoma is the posterior part of the body in spiders, analogous to the abdomen). Additionally, body mass tends to be higher for spiderlings that engage in matriphagy as compared to those that do not. Matriphagy advances molting time. Molting is the growing of a larger exoskeleton and shedding the old one. Advancement of molting time means that the spiders are able to grow at a faster rate. Matriphagous spiderlings tend to experience significantly greater survival rates and fitness compared to non-matriphagous offspring at dispersal. Matriphagous spiderlings hunt larger prey and show much more complete prey consumption than non-matriphagous spiderlings. Matriphagy improves sociality in spiders, primarily by reducing sibling cannibalism.
=== Costs and benefits to the mother === Unlike other milder forms of parental care, matriphagy necessarily costs the mother her life. Nevertheless, matriphagy may serve the mother's reproductive fitness, considering reproductive output, egg sac development, and number of young reared. The key question is whether the mother would produce more surviving offspring by evading matriphagy and reproducing again or by engaging in matriphagy and producing only one clutch.
In the black lace-weaver (Amaurobius ferox) around 80% of females separated prior to matriphagy produce second egg sacs and only approximately 40% of these develop completely (compared to the >90% development of egg sacs in the first brood). Additionally, the number of spiderlings in the second brood tends to be significantly lower than in the first brood. These individuals are also smaller than the spiders in the first brood. Females that successively lay two egg sacs have a lower expected output of dispersing offspring than females that are victims of matriphagy and produce only a single clutch.
== Forms of parental care similar to matriphagy == Matriphagy is one of the most extreme forms of parental care observed in the animal kingdom. However, in some species such as the Funnel-web spider Coelotes terrestris, matriphagy is only observed under certain conditions and extended maternal protection is the main method by which offspring receive care. In other organisms such as the African social velvet spider, Stegodyphus mimosarum and Caecilian amphibians, parental behavior closely related in form and function to matriphagy is used.
=== Extended care in a Funnel-web spider: Coelotes terrestris === The ‘maternal social’ spider, Coelotes terrestris (Funnel-web spider) uses extended maternal care as a reproductive model for its offspring. Upon laying the egg sac, a C. terrestris mother stands guard and incubates the sac for 3 to 4 weeks. She stays with her young from the time of their emergence until dispersal approximately 5 to 6 weeks later. During the offsprings’ development, mothers will provide the spiderlings prey based on their levels of gregariousness.
Protecting the egg sacs from predation and parasites yields a high benefit to cost ratio for the mothers. Fitness of the mother is highly correlated to offspring developmental state—a mother in better condition yields larger young that are better at surviving predation. The presence of the mother also protects the offspring against parasitism. In addition, the mother can keep feeding while guarding her progeny without any weight loss, allowing her to collect sufficient food for both herself and her offspring. Overall, costs of protecting the egg sac are low. Upon separation from egg sacs, 90% of females have the energy sustenance to lay new sacs, although it does induce a time loss of several weeks that could potentially affect reproductive success. In experimental conditions, costs arose if maternal care was not provided, with egg sacs drying out and developing molds, thus illustrating that maternal care is essential for survival. Experimental food-deprived broods reared by the mother induced matriphagy, where 77% of offspring consumed their mother upon birth. This suggests that matriphagy can exist under nutrient-limited conditions, but the costs generally outweigh the benefits when mothers have sufficient access to resources.
=== Parental investment by skin-feeding in Caecilian amphibians ===
Caecilian amphibians are worm-like in appearance, and mothers have thick epithelial skin layers. The skin on a caecilian mother is used for a form of parent-offspring nutrient transfer. In at least two species, Boulengerula taitana and Siphonops annulatus, the young feed on the mother's skin by tearing it off with their teeth. Because these two are not closely related, either this behaviour is more common than currently observed or it evolved independently. The consumed skin then regenerates within a few days.