Evolution is a rich and dynamic process. Types respond to pressures in a variety of ways, most of which are restricted to searching for food, avoiding becoming one's food and attracting a friend. To solve the latter is an animal kingdom full of fantastic, bizarre and enchanting adaptations. Displays of bioluminescent Knight Knights can encapsulate all three.
Tombs are special animals. They are not bigger than sesame seed, these crustaceans have shell nuts and often do not get frogs. Like many sea creatures, a number of ostrakodas use bioluminescence to prevent transmission and attract friends. This second use attracted the attention of UC Santa Barbara's Doctor of Medicine Nicholai Hensley in his quest to better understand the interplay between biochemistry and evolutionary change.
In order to create their light displays, the cypridinide ostracts excrete a little mucus injected with the enzyme and the reactants and then float from the glowing balls to repeat the act. The result is a trail of faded ellipses, or the scent that hangs in the water column. And the length of each of these pulses is an important part of the screen. Some are fast as an old-fashioned bulb, says Hensley, while others remain in the water.
In the classical scenario, you would expect to find a clear correlation between how long the lightning and the structure of the enzyme that is responsible for it lasts, said Hensley. "And that's true of some species, but it's not true for all species."
Instead, Hensley and his colleagues found that two mechanisms affect the duration of light pulses. Animals using enzymes with a slower rate of reaction produce longer glows, but also that which consumes a larger amount of reactant that unnecessarily excretes enzymes. Both are played in different combinations across different species.
"That was one of the surprising results we got from our article," Hensley said. Team findings appear in the Royal Society magazine Proceedings B.
This discovery was partly due to the group of animals that Hensley decided to study. Because the ostrakids spit out their light, Hensley could study chemistry separately from the behavior of the animal itself. Contrast it with lightning conductors in which the reaction takes place inside their bodies. As a result, it's under control of the behavior of the animal all the time, explains Todd Oakley, professor of UC Santa Barbara's Department of Ecology, Evolution and Marine Biology, and co-author Hensley. "We can get more in terms of the specifics of chemistry because it's out of the body," he said.
The relationship between these two mechanisms may even influence the development of different species in the future. For example, if one species tends to ever longer impulses, they can get up against the maximum of what the enzyme is capable of. Without the ability to increase enzyme activity, this species can evolve to produce more chemicals per pulse in order to obtain a longer flash.
Hensley is currently exploring how some changes in the enzyme affect his ability to produce light: to work faster, slower or not at all. He also hopes to reconstruct the group's ancestral enzyme and test its function to find out how it differs from those used today by the animals.
At the same time, the team focuses on aspects of the behavior of the ostrakids. For example, they would like to see how many pulse lengths are interested in female ostrakod, compared to aspects such as spacing or direction. Men of some species synchronize their displays when surrounded by other men, creating a charming underwater light show. Hensley plans to take a closer look at this behavior in collaboration with colleagues at the University of Kansas.
"We're just describing how such diversity is, our goal," said Hensley, "and that can give us insight into how it really is."
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Nicholai M. Hensley et al., Phenotypic evolution, which is formed by the simultaneous function of the enzyme in the signals of the bi-luminescent paradoxes of the sea lights, Proceedings of the Royal Society B: Biological Sciences (2019). DOI: 10.1098 / rspb.2018.2621