J. Judson Wynne, Northern Arizona University
A new species of cave-adapted pseudoscorpion,
Michael Baird, Wikimedia Commons
Does it pay to be a lover or a fighter? The answer can depend upon the situation, of course, but some animals have evolved a greater tendency to war or woo, suggests a study in the latest issue of Nature Communications. Senior author John Fitzpatrick, a lecturer on animal evolution at The University of Manchester, and his colleagues studied over 300 species and found that elephant seals are definitely more fight-prone. "In groups like pinnipeds, in some species, like elephant seals, males are able use their investment in weapons -- in this case extremely large body size -- to keep rival males away from females and there is a trade off between investment in testes and weapons," he explained. "Essentially, the largest pinniped species have the smallest testes, i.e. they are fighters, rather than lovers."
U.S. Fish and Wildlife Service
The walrus is another pinniped that is more brawn and blubber than love machine. Both males and females use up a lot of energy sustaining their big bodies and tusks, which they aren't afraid to use in battles.
Acanthocephala is a group of parasitic worms, according to Fitzpatrick. As if that is not unattractive enough, these worms spend most of their energy in maintaining their body spines and fighting. This is arguably the most un-romantic group of organisms in the animal kingdom.
Dick Daniels, Wikimedia Commons
Male pheasants "invest in both fighting and sex," according to Fitzpatrick. "It is quite costly to invest in everything. You don't get something for nothing in evolution," he said. Nevertheless, there are some animals, like pheasants, which seem to have evolved an even investment in the anatomy and behaviors required to fight and mate. Male pheasants that invest in being large fighters, for example, also develop large testes.
These tiny fish are scrappy, but sexy sometimes too. As for pheasants, male minnows are hard-wired to invest in fighting, often with their strong fins that push waves of water against rivals, but also in procreating. Male minnows often turn bright red or orange to attract females, and then go to a lot of trouble to find the perfect spawning site.
Johan J. Ingles-Le Nobel, Flickr
Male bush crickets have the largest testes compared to body mass of any known species on the planet. Males fight a lot too, though. In China, "cricket fighting" is viewed as a spectator sport on par with bullfighting and cockfighting. Cricket fights are even arranged according to weight class, with human viewers betting on which cricket will win the match.
Moses, Wikimedia Commons
Humans and other primates wind up in the category with crickets and minnows. Our canine teeth and other features can be used in fights, but significant bodily energy often goes into wooing too. As Fitzpatrick said, "Compared with our primate relatives, human males don't exhibit particularly large investment in either weapons (which we measured as the difference between male and female body sizes) or testes size."
Albatross couples romantically dance and spend their entire lives together, devoted to a single, adoring mate. Males will wait for days, sometimes weeks, for their partners to arrive at mating sites.
Jangle1969, Wikimedia Commons
Some snails are hermaphrodites, having both male and female sexual organs, but most still need a partner in order to reproduce. Ronald Chase, a professor of biology at McGill University, found that garden snails court anywhere from 15 minutes to six hours. It's a sexy tease that involves a lot of lip and genital nibbling. Like a natural cupid, one snail then builds up hydraulic pressure that causes the release of a sperm-containing "dart." The result is that these creatures spend a lot of time procreating, as most gardeners have probably figured out.
Lovebirds (birds in the genus Agapornis) aren't always loving around strange birds and humans, but they are completely devoted to their mates. They may spend their days preening, dancing and cuddling. Mating can occur, on and off, for several days at a time during the breeding season. Some lovebirds are endangered in the wild. Black-cheeked lovebirds, for example, are among the most endangered of all African parrot species. "Understanding the ways animals reproduce is important as it helps us understand how species evolve and can prove important for conservation," said Fitzpatrick.
Two new species of so-called pseudoscorpions have been discovered in a cave on the northern rim of the Grand Canyon.
The elusive creatures, which have adapted to their lightless environment by losing their eyes, were discovered in Grand Canyon-Parashant National Monument, which abuts the better-known Grand Canyon National Park.
Unlike true scorpions, these scorpion imposters lack a tail with a venomous stinger. Instead, the arachnids use venom-packed stingers in their pincers to immobilize their prey, study author J. Judson Wynne, an assistant research professor in the Department of Biological Sciences at Northern Arizona University, in Flagstaff, wrote in an email.
The tiny cave where the team discovered the new species — just 250 feet (76 meters) in length — nevertheless supports the highest diversity of cave-adapted arthropods of any known cave in the Grand Canyon-Parashant National Monument, Wynne said. [Creepy Crawlies & Flying Wonders: Incredible Cave Creatures]
The researchers first discovered the two false scorpions during expeditions in a cave along the north rim of the Grand Canyon, between 2005 and 2007. But it took years before the team identified the species as unique.
"Contrary to popular belief, rarely are we in the field, collect an animal and then brandish our grubby field flasks of whiskey to toast a new species discovery," Wynne told Live Science in an email.
To confirm the scorpion lookalikes were a new species, the team had to take them back to a taxonomic specialist, who analyzed all the details of the species and pored over all the existing data on similar species. In this case, the team found that one of the species had a thickened pair of legs and a mound on the pincer, while another had a much deeper pincer than other pseudoscorpions — qualifying each as a distinct species, study co-author Mark Harvey, senior curator at the Western Australian Museum in Perth, said in an email.
The creatures, dubbed Hesperochernes bradybaughii and Tuberochernes cohni, respectively, are about 0.12 inches (3 millimeters) long and feed on tiny invertebrates, including springtails, book lice, mites and possibly cricket nymphs. Many of their prey are just one-fourth the length of a grain of rice.
A new species of cave-adapted pseudoscorpion, J. Judson Wynne, Northern Arizona University
The two species are named after Jeff Bradybaugh, an advocate for cave research and the former superintendent of Grand Canyon-Parashant National Monument, and Theodore Cohn, an entomologist who identified a new genus of cave cricket and passed away in 2013.
The fact that two separate species of pseudoscorpion can live in the cave while competing for the same food source suggests the cave supports a robust food web. The cave is one of the largest roosts of crickets in northern Arizona, and the pseudoscorpion prey feed on the cricket "frass," or poop, as well as the fungus that grows on the poop. The cave is also home to a bizarre, eyeless fungus beetle that feeds on the poop fungus.
At one time, the pseudoscorpions' ancestors lived in the desert environment outside the cave, but they have since adapted to hunting in an environment devoid of light, losing their eyes and gaining an elongated bodies in the process.
In general, pseudoscorpions are odd creatures. Not only are their pincers good for immobilizing prey, they also help the insects hitchhike to new locales.
"They will grasp onto another animal such as birds, mammals and even other insects. They hold on and can be transported long distances," Wynne said.
This allows the insects to travel farther than they ordinarily could, so they can mate and disperse genes farther than they could walking on their own eight legs. These journeys may also take the scorpions to better hunting grounds, although there's no guarantee that the next spot is better than their previous one, Wynne said.
But the pseudoscorpions aren't just freeloaders; they help their animal hosts by devouring parasites such as mites.
The new species were described in the November issue of the Journal of Arachnology.
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