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largely amphibian Not exactly a doting parent. They find a partner and release as many eggs or sperm as possible. We expect that at least some fertilized eggs will hatch into viable larvae, and that at least some of those larvae will survive to adulthood.
But in one in five amphibian species, one or both parents stick around to care for their offspring, using a surprising variety of strategies.
The best-known amphibian parents are brightly colored amphibians. poison frog, a group of approximately 200 species that appear repeatedly in this article. But their parenting skills may not be as great as once thought, says Jennifer Stinoski, a biologist at the University of Costa Rica. She decided to study this group after spotting them on a field trip as a student of hers many years ago. She said, “I think they get a lot of attention because they are so beautiful. It’s so cute to see them studying.”
So what makes them exemplary amphibian parents? There is much yet to be discovered, but some common principles have emerged.
please stay away from water
Unlike reptiles and the birds that evolved from them, the ancestors of today’s amphibians did not develop eggs with strong, watertight shells. This means that the eggs, like the wriggling, gilled larvae, usually need water to survive.
However, the ponds where many amphibians lay their eggs are full of other animals, many of whom try to supplement their diet by sipping on the eggs. “This must be one of the reasons why so many species have evolved ways to lay their eggs far from the water surface,” said Eva Ringler, a behavioral ecologist at the University of Bern in Switzerland.
recently Article Annual Review of Ecology, Evolution, and Systematics, Ringler, Stynoski and colleagues describe the different locations where amphibians have evolved to lay eggs. Some species build bubble nests to keep their eggs afloat. Others place them on plants above water so that the larvae fall off immediately after hatching. Some people are taking things even further: the amazingly bizarre Surinamese toad (Pipapipa) For example, they store eggs in a special brood pouch on their body.
Keeping eggs out of water is especially common in humid tropics where eggs, larvae, and parents are less likely to dry out. “But amphibian parenting is not limited to the tropics,” Ringler says. “Male midwife frog (alites obstetrician) For example, here in Switzerland they protect their eggs by carrying them between their hind legs. ”
Please cooperate (if necessary)
Depending on the species, amphibian rearing is carried out by the father, mother, or both. Evolved strategies are related to how species reproduce. salamander and newt “These are an interesting group that illustrates this importance,” said evolutionary biologist Balázs Várgy from the University of Debrecen in Hungary, who is studying amphibian parenting styles to understand how amphibians originated. A number of studies have been conducted to compare the
In certain salamanders (the ones thought to behave most like the common ancestor of this entire group), eggs are fertilized outside the body, with the female laying them and the male releasing sperm on them. . In these species, the male does most of the care, which primarily amounts to guarding the eggs from predators. “This makes sense because the female is convinced that he is her father, and the female may be able to escape before fertilization is complete,” Verge says. .
However, in most species of salamanders, like newts, the eggs are fertilized inside the female, albeit somewhat indirectly. The male deposits a package of sperm, which the female picks up at the cloacal opening. In this case, the male often leaves and the female takes care of the offspring. “The parent-offspring relationship is more vague, with the female essentially bonding to the developing larva,” Ringler said. This allows the male to escape to mate with other females. “Therefore, paternal care is very unlikely in species that fertilize internally.”
In poison dart frogs, fertilization occurs outside the female’s body, usually away from the water. This makes a big difference in the evolution of parenting strategies. While it is easy for females to be sure that their chosen partner is the only one who will fertilize their eggs (which can be difficult in crowded ponds), it is easier for males to ensure that their chosen partner is the only one who will fertilize their eggs. It is easier to be sure that your partner is the only one who will fertilize your eggs. The descendants are his.
This may be why coparental relationships evolved in these species. Males are very vocal in defending their territory, and females seek out males with prime land to lay their eggs in relative privacy. Gender plays a different role in care activities, but experiments show that If one parent disappears, the other parent may take over the job..Male with guaranteed paternity Particularly enthusiastic about taking care of eggs They are found within their own territory, but females are more picky.
Some amphibian parents cooperate with other amphibians. In some salamander species, Females care for eggs and young in shared nestsYou probably don’t know which little ones are yours. Additionally, in species such as the African foam nesting tree frog, the female works with multiple males to pump secretions into the foam nest and lay eggs. All males release their sperm into her nest while avoiding the physical skirmishes common with other frogs. In the same nest, these sperm compete to fertilize the egg.
![animal pictures](https://www.popsci.com/uploads/2024/05/09/g-amphibian-parenting-water-land.png?auto=webp&optimize=high&width=100)
keep moving
Some amphibians that lay eggs on land skip the larval stage altogether and emerge from fully formed mothers. However, many hatch larvae, which usually need help finding water. A female frog with marble-shaped nostrils, also known as the shovel-nosed frog (Hemisus marmoratus), They lay their eggs in an underground breeding room. They may then create a slide so that the larvae can later move into the water.
Some frogs carry tadpoles on their backs. “We see great diversity in how different poison dart frogs manage this task,” Ringler says. Some species, such as the bright-thighed poison dart frog (remove the femur) Researching in French Guiana, she transported large numbers of tadpoles to large bodies of water at once. Others include the strawberry poison dart frog (Ufaga Pumilio) One by one, Stinoski carries what he researched in Costa Rica. In a small pool of accumulated watersuch as those that gather between the leaves of bromeliads high up in trees.
Please bring snacks
These small rainwater puddles on plants often contain little or no food. Therefore, some frog parents have evolved to feed their offspring. Female strawberry poison dart frogs regularly visit pools containing their young and lay unfertilized eggs, which are then eaten by the tadpoles. “Research shows that Eggs are essential for offspring survival” Stinoski said. transfer protective poison to the larvae. ” Eggs are not essential for other frog species, but Function as a supplementary food.
Perhaps the most remarkable method of feeding offspring is found in the least-known group of amphibians, the limbless worm-like paper wasps. They spend much of their lives underground, eating bugs and insects. “Like other amphibians, paper wasps support their young in many ways,” says biologist Alex Kupfer of the National Museum of Natural History in Stuttgart, Germany. “But in some species, we discovered something truly unique: females store lipids and sugars in their outer coat layer; excreted as food for children”
As if that wasn’t enough, recent research shows that science is the egg-laying American paper wasp (Siphonops anulatus), mother secrete a milky substance from the cloaca The hatchlings will eat it right away. She appears to do so in response to physical contact and possibly audio signals from her offspring.
![animal pictures](https://www.popsci.com/uploads/2024/05/09/p-caecilian-feeding.jpg?auto=webp&optimize=high&width=100)
Why not invite them?
Perhaps even stranger is the Rio Cauca paper wasp (Typhronectes natans), similar to some salamanders, the eggs are hatch inside the female’s body. In some paper wasps, the young feed on cells or secretions from nutrient-rich structures within the oviduct. Although such an arrangement has not been found in other amphibian groups, many species are viviparous, with live offspring emerging from the reproductive tract. This limits the number of offspring a female can produce, but also increases her chances of survival.
Ringler said this is common in species that live in extremely harsh environments, such as the Alpine salamander, which can be covered in snow for up to 10 months of the year. “So the only viable strategy is to keep the larva inside the body as long as possible and give birth to a fully developed larva.”
Some amphibian species ingest their own offspring. Darwin’s male frog (Rhinoderma darwinii) The eggs are kept in the vocal sac until they hatch. “If you haven’t seen the video about this, please do,” Stinoski says. “He basically spit out a small baby frog”
don’t go extinct
Sadly, a close relative from Chile, Rhinoderma rufumAnimals that spit out tadpoles are endangered and possibly extinct. And two unique Australian frog species whose females harbor tadpoles in their temporarily inert stomachs are now arguably extinct. “Losing a species is always tragic,” says Virge. “But losing such unique behavior is even worse.”
In the face of habitat destruction, climate change, some amphibian parents may be able to help their young survive by keeping them safely indoors, moving them, or providing them with additional food. However, many of these amazingly complex behaviors, and the species that depend on them for survival, are likely highly vulnerable to environmental change.
“Amphibians have different life stages, so they require different habitats and different types of food throughout their lives,” Ringler said, and the loss of even one of these could put amphibians at risk. . “Globally, they are the most blackmailed A group of vertebrates. We need to take better care of them. ”
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