Posted: Feb 23, 2012 6:22 pm
Agrippina wrote:Here's a question for Lion, why did God make these animals in this way:
Screwed over by nature.
I have some even better examples than that Aggie.
For example, quite a few Hemiptera have dispensed with the usual etiquette of mating. Instead of coupling genitalia, males in these species simply drive their copulatory organs through the body wall of the female. The familiar Beg Bug, Cimex lectularius, is one member of the Hemiptera that engages in this behaviour. Females have even evolved 'bulls eye' structures on the body to guide the male's aim. Another member of the Hemiptera, Xylochloris maculipennis, takes this a stage further. Not only do males drive their armour-piercing genitalia through the female's body wall to inseminate her, males will also invite other males to mate with them, in order to decommission the rivals' genitalia. Two other species of Hemiptera, namely Hesperocimex cochimiensis and Hesperocimex sonorensis exhibit an even more bizarre ferature. These two species are blood-sucking parasites, that live off the same bird species, and are thus direct competitors. If a male H. cochimiensis inseminates a female H. sonorensis, the female's body responds with a massive and lethal immune reaction, probably similar in form to a cytokine storm. Consequently, H. cochimiensis may use sex as a biological weapon, with which to kill off the rival species and destroy its mating chances.
It's not just Hemiptera either. Recently, a species of spider was discovered in Israel, that uses the same method, known as hypodermic insemination. Because of the trauma inflicted upon the female during mating, the species was named Harpactea sadistica.Other spiders prevent other males from inseminating a female, courtesy of bits of their copulatory organs breaking off and forming a plug in the female's genital opening.
Then you have Anglerfishes. These solve the problem of paternity in an interesting way. The male latches on to the female, and becomes a sort of semi-parasite. After he has attached to the female, his bloodstream connects with hers, and, as a result of the influence of female hormones, the male then starts to atrophy. First he loses his digestive system, then he start to lose his eyes, then he loses his brain, and ends his days as nothing more than a testicle sac, subject to female hormonal control. Trouble is, all that effort can end up being wasted, because in some species of Anglerfish, the female can support multiple male semi-parasites.
Returning to insects, there's an entire Order, known as the Strepsiptera, whose species have a singularly wacky life cycle. These insects are parasites, or, more correctly, the adult females are parasites. The males are free-flying, with a full complement of the usual insect anatomical parts, namely eyes, legs, wings, etc. The females, on the other hand, have abandoned all of this. Female Strepsiptera have no eyes, legs, wings, and even more weirdly, have no functioning external genitalia. Female Strepsiptera are, in effect, nothing more than a bag with a mouth at one end and an anus at the other. Males hunt down these unprepossessing partners to mate with them, which is achieved by the male rupturing the body cavity between the head and prothorax, which leads to a brood canal. In effect, female Strepsiptera have lost the usual female opening, and instead, offer up a sort of substitute vagina located where the back of the neck would be in humans.
As if this failed to be weird enough, the eggs hatch inside the female, and the first instar larvae spend their lives swimming around in her haemocoel (insects have an open circulatory system, with their organs bathed in a fluid called haemolymph, which performs the service of blood for these creatures). Once the larvae reach the second instar, they emerge from the female in possibly the strangest birth procedure known, again exiting her body through the substitute vagina, then have to find a host of their own in order to continue their lives. If they fail to do this before their limited energy reserves run out, they die. Successful larvae then spend time living as parasites inside their host, until it's time to pupate. Females emerge from the pupal case looking like the larvae, whilst males emerge with purportedly "normal" adult insect features. However, the male's lot is not a happy one. Not only does he have to find a mate, which means finding another host insect with a female in residence, but he has a limited amount of time to achieve this end. He has about five hours of energy reserves, and no functioning mouthparts with which to replenish them. Whether he's mated or not, at the end of five hours, he grinds to a halt and dies.
Meanwhile, how about this for a nice piece of hijacking? In Lake Tanganyika, there exist four species of Cichlid fish belonging to the Genus Ophthalmotilapia, of which O. ventralis is a popular aquarium fish. These fish are mouthbrooders, protecting their young inside the mouth of the female. However, the parents can sometimes find their reproductive efforts totally wasted. The reason? A catfish species, Synodontis multipunctata, performs a sort of reproductive burglary of the female's mouth. While the Cichlids are spawning, the catfish dash over the spawning site, and drop their own eggs in amongst those of the Cichlids, in an act of hit-and-run mating that takes place in less than a second, and which sees the catfish performing a sort of 'carpet bombing' of the Cichlids' spawning site with catfish eggs. The Cichlids pick up the catfish eggs with their own, and incubate them. The catfish eggs hatch first, developing faster than the Cichlids' own eggs, and when the catfish fry have hatched and are ready to eat, they dine on the Cichlids' eggs and fry whilst inside the female Cichlid's mouth. The female Cichlid continues caring for these freeloaders until they are too big to fit inside the female's mouth, whereupon they make their way into the world, protected by dorsal and pectoral fin spines that make them an unpalatable mouthful for any other fish foolish enough to try and eat them.
Oh, and how about the Green Spoonworm, Bonellia viridis, a species of marine flatworm? This one is particularly interesting. Larvae are planktonic, and sexually undifferentiated. The sexual fate of the adult worms, however, is dependent upon, of all things, a green pigment in existing adult females. This pigment, Bonellin, also serves as a defence against predation, and is a powerful paralysing agent that incapacitates would be predators very quickly. But as well as defending the adult females against predation, it determines the fate of future generations of Spoonworm larvae.
If a larva descends to the ocean floor, without encountering an existing female, that larva becomes a female. If, however, a larva descends to the ocean floor, and prior to reaching full adulthood, encounters an existing female, then the green Bonellin pigment has a masculinising effect upon the developing larva, switching its destiny to that of a male. The developing male larva is then either swallowed by the female or absorbed through the outer integument. Swallowed males are passed untouched by the digestive tract into the female's reproductive system, where they spend the rest of their lives as captive providers of sperm for the female. Males absorbed through the outer integument similarly wind up in the female genital sac. Males also lose the ability to feed independently, becoming in effect another body part of the female.
Of course, none of this is a problem for evolution, which simply allows whatever works to develop, without any regard for our sensibilities, or that of any other sentient entity. But any "creator" responsible for this lot must have a truly diseased imagination.
