Sometimes, scientists plain run out of ideas. After finding nine other species of cicada-like leafhopper, their discoverer dubbed the next one he found Erythroneura ix, or nine in Roman numerals. Another scientist found so many species of olethreutid moths that he eventually opted for an alphabetical ascension to come up with names, i.e. Eucosma bobana, e. cocana, e. dodana, e. fofana, and so on.
Dating sucks and 41 percent of first marriages end in divorce, but humans have it easy compared to many things that walk, swim, slither, or fly. If you worry about losing your sense of self in a relationship, be grateful you are not an angler fish. “Angler fish” refers broadly to those slightly horrifying aquatic creatures with as much mouth as body, who lure their prey in with wormy or glowing bits of flesh at the end of an antenna-like appendage. When nineteenth century scientists began to catalog the members of the suborder Ceratioidei, which contains such pleasantly named creatures as sea devils, devilfish, and deep-sea anglerfish, all the specimens they could find were female, and scientists had no idea what the males even looked like. They sometimes found fish that seemed to be related, but they were much smaller and lacked the frightening jaws and lure typical of ceratioids, so they were placed into different taxonomic groups. In 1922, almost a full century after the first ceratioid was recorded, an Icelandic biologist discovered a female ceratioid with two of these smaller fish with their faces attached to her body, which he assumed was a mother and her babies in a puzzling configuration. An ichthyologist at the British Museum of Natural History also found a smaller fish attached to a female ceratioid. When he dissected it, it became clear that the smaller fish was not the larger fish’s offspring; it was her mate.
She’ll take care of you.
Scientists soon figured out why the “missing” male ceratioids looked so different. They aren’t built to hunt and devour prey because they don’t hunt. They nourish themselves by attaching to a female. Male angler fish are parasites as much as they are mates. A male ceratioid finds his mate by following species-specific pheromones to a female. The female will guide the males in by flashing her bio-luminescent lure, like a ground crew waving on an airplane with their orange flashlights. Once the male reaches her, he bites into the female’s abdomen and latches on. His body then fuses with hers. They now share a circulatory system, which allows the male to get the nutrients he needs from the female’s blood. Since the male has no further need of eyes for seeing or fins for swimming, those body parts( and others including organs) wither away. The relationship isn’t completely one-sided, though. While the male is taking blood, he also provides sperm when the female is ready to spawn.
Got You Under My Skin
On your next Mediterranean holiday, go for a dive and see if you can spot something that looks like a sausage casing full of green gelatin undulating gracefully in the water. That is a female Bonellia viridis, the green spoon worm. You will know you are looking at a female because only they have the bright green coloration and because the two-millimeter long male Bonellia viridis are more likely to be found inside the female.
The largest penis relative to body size in the animal kingdom belongs to the barnacle at ten times the length of its body. The smallest relative penis belongs to the gorilla. A four hundred pound (or 181 kilogram) adult male gorilla has a penis only two inches (or five centimeters) when erect.
Green spoon worms can determine the sex of other green spoon worms. They begin life as genderless larvae, drifting on the ocean current. If the larva lands on a bit of ocean floor not currently claimed by an adult green spoon worm, it will develop into a female and begin secreting a toxin called bonellin. Bonellin makes the adult green spoon worms green but has an even more dramatic effect on their larvae. If a larva comes in contact with the bonellin toxin, it will turn into a male. The female then sucks the newly made male into her body through her feeding proboscis. He now exists for the sole purpose of providing the female with sperm. It’s a one-way trip for the male, but at least he won’t be alone. A few dozen males may find themselves living in a chamber in the female’s body where they absorb nutrients from the fluid they are bathed in. Like the male anglerfish, male green spoon worms exist to provide sperm, so they only need the organs associated with that task and have few organs otherwise.
Use It and Maybe Lose It
You may think there are no more boring animals in the world than slugs, but mollusk mating is action-packed. Take for instance the mascot of UC Santa Cruz, the banana slug. Like all snails and slugs, banana slugs are hermaphrodites, possessing both male and female sex organs. Things are evenly matched when banana slugs mate—each slug produces eggs and each one has a penis. Their penis can grow to be longer than their body, hence the species name, dolichophallus, or “long penis.” Mating starts off a bit rough, with the slugs striking at each other like snakes and even taking bites out of one another. Then, they arrange themselves head-to-tail, like a yellow yin-yang, and achieve intromission. Mating can last for hours, during which the slugs may exchange sperm and fertilize each other’s eggs equally, or one may fertilize the other. Breaking up can be hard to do, especially when one slug’s penis gets stuck in its partner. If mutual thrashing around can’t dislodge it, the other slug may chew the offending member off. This apophallation (“penis removal” for non-limacologists) renders the slug female, as penises don’t regenerate.
Go, Santa Cruz!
Being female is more resource-demanding than being male, what with having to nourish and support eggs. Most animals have no choice but to accept their assigned role. Flatworms, however, take a proactive approach to avoiding motherhood by trying to stab the other with their penis in an act called “penis fencing.” When two potential mates meet, they rear up, which makes room for them to strike with their two-headed penis on the offense, but defensively leaves their body vulnerable. Penis fencing can last an hour, with the flatworms being stabbed multiple times, until one manages to deposit sperm into the other. The victor swims away, his paternal duties complete. The losing flatworm begins to search for the extra food required for making eggs. Flatworms practice “traumatic insemination” and they are not the only ones. Bedbugs, thorny-headed worms, microscopic roundworms, wheel animalcules, fruit flies, sea slugs, and spiders in the genus Harpactea also prefer to go through their mate’s abdomen rather than through their genital tract.
Firm Handshake
The argonaut, or paper nautilus, is a small octopus found in the open ocean. Argonauts are one of the most sexually dimorphic octopodes, meaning the females are considerably larger than the males, about eight times larger and six hundred times heavier. The females secrete a thin, white, brittle shell, which had been thought for centuries to be for egg storage. More recently, argonauts have been observed using their shells to trap air from the surface so they will be neutrally buoyant at their preferred depth. Like many octopodes, the male argonaut’s third left arm develops into a hectocotylus, the cephalopod version of a penis, which the male can detach for copulation. What makes the argonaut’s hectocotylus different is that, once detached, it can swim over to the female on its own, where it attaches itself inside her pallial cavity (octopus vagina). One mark in the “pro” column for this approach is that the male argonaut can pass on his genetic information while staying a safe distance from the larger female so that he does not become part of her egg-nourishing meal plan. The hectocotylus regenerates, so he who mates and runs away may live to mate another day.
Gender Roles
Males typically benefit from mating as much as possible, in part because they can, while the females, who actually raise the offspring, have to be choosy about their partners. In a cave in Brazil lives a species of tiny louse who did not get the memo. For Neotrogla curvata, females seek out multiple mates and the