The color of male males is not only for attracting females

Many creatures have colors that are brilliant and rich in variation than females, and among butterflies, birds and fish can be distinguished by looking at males, but there are many species that can not be distinguished from females. That's why so farSex selectionAlthough it has been explained by, in fact there seems to be another biologically important reason why males should be colorful as well.

IttomboUsedUniversity of California Los AngelesWhat is the reason why it was clarified by the research of?

Details are as below.Why Do Animals, Especially Males, Have So Many Different Colors?

"Since Darwin, biologists at least noticed that there were differences in" secondary sexual traits ", such as vivid colors and large horns, depending on species, Professor Grether said. Darwin said that this diversity is caused by sexual selection. It is the theory that it was able to attract opposite sex so that characteristic traits such as color and horn strongly appear. However, it seems that it can not explain just the reason for the diverse colors of male males.

Professor Gregory Grether and Dr. Christopher Anderson of UCLA's environmental studies and evolutionary biologyHetaerinaSeveral species of genusIttomboIn the survey targeting different species, it was found that the difference in body color was due to distinguish between the same type of male competitor, and another type of males that are not rivals. This result isProceedings of the Royal Society B: Biological SciencesIt is published in the October 28 issue of the magazine.

"It seems that we worked in diversifying colors, cries, chemical signs (odors etc.) in order to eliminate waste of attacking opponents (other species of males) and being attacked in reverse," Professor Grether. "Male of Ittombo of Hetaerina genus proved that the other male who came nearly judged whether it is the same species as her or not depending on the color difference of the feather by seed.In addition, It was also found out that color identification is performed only in areas where the distribution of the two species of ito Tombo is overlapped.This is a process of evolution which has been overlooked academically in the natural world It is one of the most clear demonstrations of '

An Austrian animal behaviorist who was awarded the Nobel Prize in physiology and medicine in 1973Conrad LorenzHe suggested in 1962 that the dramatic color of fish inhabiting coral reefs might be due to culling to avoid fighting the wrong species.

"There seems to be a culling to avoid fighting with the same sex of different species, as there is a culling to avoid crossing with heterosexuals of different species," Professor Grether said. "Lorentz said that there is no advantage in attacking species that tropical fish inhabit nearby but not competitors.This idea never gets adequate attention in the field of evolutionary biology and is overlooked I have done it. "

Dr. Lorenz's idea may not be an accurate explanation of the diversity of tropical fish's body color, but it could be an explanation for body color differences due to species of other living things, Professor Grether says.

"In areas where habitats of multiple species overlap, the ability to distinguish males of a different species from those of the same species is increased, compared to places where habitats do not overlap," said Professor Grether. The researchers colored the male feathers of this species similar to the other species of squirrel in an area where only one species of Ittombo was inhabited, and verified this theory. "Male of Itoto Tombo discriminates whether another male individual is the same species as herself, and this discrimination is made in an area coexisting with several species, and it is hardly done in an area where only one species lives , Which strongly suggests that the discrimination ability of seeds by color occurred as a result of culling by fighting other species. "

"If Lorentz does not need to struggle between the two species, as Lorentz claims about tropical fish, evolution will proceed in a direction that makes the two species more likely to distinguish each other, for example, the difference in color between species is emphasized In addition, the difference in body color will make it easy for female to distinguish male's seeds, "Professor Grether said. Several species of Ito Tombo also found that the color difference appears more vividly in areas where multiple species coexist, compared to areas where only one species inhabits. Professor Grether says, "This can be explained either by avoiding cross-species fighting or by choosing avoiding cross-species breeding."

In the future research, we want to clarify at what rate individuals with species discrimination ability exist and whether those individuals react more competitively to male of the same kind as ours. Professor Grether says heterogenous fighting and its evolutionary impact are scientific issues that have not been fully studied.