Spider messy family relationship: this is the smell of mother!

27 / October 2023

They are all family members, so they eat each other.

warning, there are pictures of spiders in this article.

people often say "love is deep". The efforts made by animal mothers for their children are always touching. But there is a form of giving that is creepy. That is the phenomenon of matriphagy, in which mothers let their children eat themselves.

Stegodyphusspp. Dome spiders are common spiders that live mainly in the Old World. They make a living by netting insects on branches and bushes. They are famous for eating their mothers.

the scientific name S. lineatus

Photo Source: commons.wikimedia

for example, the whole reproductive process of S. sarasinorum, which lives in India, is as follows: the female spiders lay 350-550 eggs, make a spherical oocyst out of silk and wrap them up. The female spiders guard the oocysts on the web for 4 or 5 weeks, during which time she does not hunt or eat at all.

after the little spider hatches, the mother of the spider will tear the oocysts and let the children climb out. Although she has been hungry for several weeks, she can still spit food out of her stomach and feed the little spider for two to three weeks. Then, the little spider climbs to the mother, sucks the mother's body fluid, and eats the mother into an empty shell within 3-4 hours.

although the spider mother is very sacrificial, she is not polite to her husband at all. Researchers on the web of female spiders, found a lot of male spiders' empty shells, they came to find a mate, but became a delicious meal for female spiders. This is another common cannibalism among spiders: wives eat husbands.

the scientific name S. sarasinorum

photographer: Prathamesh Ghadekar

male spider is a victim, but he also has a ferocious and violent side. Another kind of dome spider, S. lineatus, the male spider finds a female spider with an oocyst and steals it away. Then mate with the female spider and give birth to a second nest of eggs. According to one study, nearly 1/3 of the eggs lost by female spiders are caused by males.

the act of killing children and seizing mothers is quite common in the animal world, as well as in vertebrates. For female spiders, if the child is gone, the nutrients and time invested in the child (an average of 18.5 days) will be wasted. So it's not surprising that spider mothers protect their children ferociously.

but after "accepting" the fact that the child has disappeared, the best choice for her is to kill her son for a second child and ensure the continuation of her genes. Because the previous child lost some of its nutrition, her second fetus will have fewer eggs.

S. lineatus's baby spiders are lying next to their "suicidal" mothers

photographers: Jorge Almeida

S. lineatus also ate his mother when he was a child. So the family relationship of the spider forms a closed loop of "rock scissors and paper". The child kills the mother, the mother kills the father, the father kills the child. It can be said that this is no longer tragic or tragic, but almost absurd.

there are many animals that can eat their mothers besides tarantulas. For example, a hunting spider in Australia, the scientific name Diaea ergandros. A kind of insect (Q ú) worm (commonly known as "clamp worm") with the scientific name Anechura harmandi, and so on.

eating mothers sounds crazy, but it's actually evolutionarily logical. The mother of some animals can only reproduce once in her life, and she can only invest all her reproductive resources in this fetus. Her body is also a kind of resource and should not be wasted. If you can sacrifice yourself to improve the survival rate of future generations, such behavior will be preferred by natural selection.

Resources:

Schneider, J.M. And Lubin, Y. Infanticide by males in a spider with suicidal maternal care, Stegodyphus lineatus (Ersidae).

Deshmukh, Ujjwala Shivaji