We domesticated dogs, sheep, chickens, and even such elusive creatures as bees and parrots, while also forcing wild vegetation such as wheat and corn to grow where we feel comfortable. So we are undoubtedly specialists in domestication, but it looks like we may have competition because we just came across a fish that does the same with shrimp to work on its "farm". This is a species of Stegastes diencaeus that spends most of its days exploring the coral reefs of Central America's Belize coast and feeding on its own algae farms. The fish are very proud of them and chase away all creatures that come too close, except the Mysidium integrum shrimp, which are tasked with fertilizing the crop.
- Stegastes diencaeus aggressively defends the part of the reef where it grows its algae, but the small shrimp are an exception. These take advantage of the caring role of fish, in return they fertilize the crops with their waste, improving the quality of the cultivated algae, and thus the condition of the farmer himself, i.e. Stegastes diencaeus - explains Deakin University ecologist Rohan Brooker. Scientists believe that the relationship of fish and shrimp started with some benefiting from the presence of others without harming them, and then specialized until domesticated shrimp could not function without their fish farmer.
The team uses the example of wolves that have become domesticated by approaching human settlements for scraps, eventually becoming our companions and slowly turning into the dogs we know today. Because the line that defines domestication has not been clearly delineated, some scientists have argued that it requires genetic alterations between wild and domestic animals, as well as sustained multi-generational effects on reproduction and care for domesticated creatures. However, in this case, researchers have good reasons to consider the link between Stegastes diencaeus and Mysidium integrum as domestication.
- The presence of non-shrimp species suggests that the fish are setting up farms for purposes not related to the domestication of shrimp. However, the absence of Mysidium integrum reefs suggests that they rely on a niche created by fish, ie farms, to survive in a predator rich environment. These findings are in line with the hypothetical behavioral processes underlying the domestication through commensalism, they add. This means that the fish do not need shrimp, but the shrimp do need the fish to protect them from predators.