字幕表 動画を再生する 英語字幕をプリント It’s a dog eat dog world…but just sometimes, if you want to get ahead out in the wild, it pays to work together. When different types of creatures interact with one another in the interest of survival, it’s called a symbiosis, and intentional symbiotic relationships are surprisingly common in nature. Depending on who benefits from the relationship, partnerships can be either mutualistic, commensalistic, or parasitic. Mutualism is when both creatures benefit from being around each other. Like at these remarkable underwater fish spas. Upwelling, nutrient rich waters draw huge numbers and varieties of fish to seamounts and reefs, but not all of them are here for the food. Hammerhead sharks, turtles, and even manta rays make their way to these specific locations for none other than a premium cleaning service. These big fellas drift calmly around the reef, allowing smaller fish like wrasse, surgeonfish and angelfish to pick off parasites and algae, leaving them feeling fresh. The big fish get a luxury exfoliation, and the small fish get a tasty meal, so everyone’s a winner! Of course, there’s always that one friend that asks for just a little too much, and in this case, it’s the manta ray, who times its visits to coincide with the sturgeon fish’s spawning season, to get a free meal of fish eggs along with its wax and polish. Which, frankly, just seems a little bit rude! On the other hand, if only one creature in the partnership benefits, while the other is relatively unaffected, it’s called commensalism. Aphids are tiny insects that feed on plant sap. When they bite into a stem, the sugary liquid surges out under high pressure, in through their mouths and straight out the other end. These back-end secretions are called honeydew, and they are a choice delicacy for their symbiotic companions. Because while the aphids are minding their own aphidy business, ANTS are actively farming them, and creaming off the delicious honeydew. Stroking their antennas over the aphids’ bodies encourages a droplet of honeydew to form, which they can then drink. The ants even move their aphid herds around to more productive areas of the plant, when supplies start to dry up. So, delicious drink for the ant, business as usual for the aphid. Only, it’s not quite as innocuous as it seems. In order to keep their aphid ‘pets’ at home, the ants resort to more aggressive tactics that are definitely not business as usual – ripping off the aphids’ wings, and even drugging them with chemicals from their feet, to make them stay in one place. And since we’ve strayed into such sinister territory, let’s talk about parasitism, the most toxic of symbiotic relationships. In these partnerships, one creature benefits at the expense of another, and while the survival of the parasite depends on the survival of the host, the freeloaders can often cause illness and, eventually, death. There are loads of parasites, from fleas to tapeworms, and even mistletoe. But by far the creepiest out there is the Cordyceps fungus. Cordyceps spores infect insects like this bullet ant, and in true zombie fashion, take over its brain, making it climb high above the forest floor and clamp onto a twig with its mouthparts. Locked in this rictus grip, the fungus has the perfect anchor, and nutrients from the insect’s body, to grow its fruiting body. Once THIS matures, more spores will burst from its tip, and with the wide dispersal that the high vantage point affords, can infect and decimate entire colonies. And what’s even more terrifying is that there are thousands of varieties of Cordyceps fungus, each capable of brainwashing a different insect before consuming it from the inside. So, there you have it. Amazing symbiotic relationships that might not be so amazing for everyone involved. True, you can get ahead by working together, but as with so many things in life, it helps to keep an eye out for yourself as well, or you could end up nothing more than a drugged aphid. If you enjoyed this video, be sure to give us a like, and if you’re new around here, click to subscribe and hit the bell icon to get our Earth Unplugged videos straight into your inbox. We’ll see you next time!