why don't leeches attack each other?
402983
First we have to understand why leeches need blood to survive.  Blood is made up of rich proteins and lipids that allow a leech to live quite well.  Second, we need to understand the mechanism by which leeches are attracted to their "prey" Basically, all mammals (both warm and cold blooded) are privy to leech attachment.  It has been widely discussed that the exact attraction of leeches to a mammal involves secretion of pheromones and other biological chemicals that a leech's detectors will recognize.  Since other leeches don't secrete these biological chemicals, they are safe from "attack".
370376
ummm that they kill each other???
848204
Because males of web-weaving spiders must invade a female's web to mate, it's obvious that this can happen. In addition, there are some species that engage in web takeover and web stealing, this often involves eating the host spider or the host's prey.\n\nOne genus of kleptoparasitic spiders, the Argyrodes, routinely live in other spider's webs and steal prey.\n\nhttp://www.amonline.net.au/factsheets/red_spotted.htm\nhttp://www.americanarachnology.org/JoA_free/JoA_v12_n3/arac_12_3_0363.pdf\nhttp://www.cyberoz.net/city/sekine/zukax105.htm\nhttp://www.americanarachnology.org/JoA_Congress/JoA_v30_n2/arac-30-02-238.pdf
964366
the question leads to an assumption that a leech was on your skin, this is a peptide, it should wash off your skin easily, the description on the internet was not suggestive of leeches injecting this in humans, so it should not be in your system, good luck
511978
I think it may have something to do with blood types. My dad and I get bitten all the time, we have A type, yet the flies don't touch my mom, who has type O.
420102
They will repel each other.
642435
It's simply because two negatives repel. But if they are moving in different direction then too they will repel if they are close enough, but it would be hard to notice as they would already be moving away.
210569
Since spiders dont have an internal skeletal structure the nerves are exposed.  When there legs pull together it is there nerves and muscles spasming  \n\nAlso spiders curle up in a ball when scared so if they die while they are curled up than they will stay that way
216384
Yes. They are only 4 feet tall and have 3 eyes. They have red skin and are hostile. They will kill you if you invade their terriorty.
789645
It is a worm, some specie of leeches would suck the blood of larger animals.\nThe link has a picture.
974197
I asked that question, and there is no known mechanism. There is however a mechanism that keeps different species from being able to interbreed.
383307
Marching in a straight line, which is usually the shortest route, seems like a solution to the problem of efficient food transportation. Ants also search for food by walking randomly.\nTo help the ant find its home again it leaves a trail of pheromone as it looks for food. On the way back to the nest, the ant tells the other ants about food by laying down more pheromone, creating a trail with an even stronger scent.\nWhen other ants run into a trail of pheromone, they give up their own search and start following the trail. In this way the ants are not following each other but the pheromone.\n\nAnd about the bumping into...they are on the same path, may not be doing anything, possibly passing food. When they "bump into" you and you think they bite you, believe it or not that "bite" is actually them peeing on you, as their pee is acidic! Ugh!
16480
wow, those are some immature answers. Zebras have stripes for defense tactics. When they huddle together or move together, it is hard for a predator to single out one.
949298
The common garden UK wasp, if it's a female, would win a fight against the Woodlouse spider by stinging the poor spider, rendering it incapacitated.  I say "if it's a female" because only female wasps have stingers.\n\nSome wasp species specialize in using spiders as prey, and various parasitic wasps use spiders or other arachnids as hosts. \n.
565535
...and some insects visit only specific animals. It's known as coevolution - they grew up together over millions of years to the point where some plants can't survive without certain species of insects, and vice versa; and some insects can live only on certain animals (for example, lice).\n\nCoevolution may involve pollination or, as a previously answered, the battle for plants to deter insect feeding by manufacturing secondary metabolites. In this case, insects evolve biochemical pathways to detoxify the feeding deterrents. These interactions eventually become exquisitely complex and, in many cases, exclusive to the species involved. There's alot on the web. Search for coevolution, mutualism, parsitism, symbiosis.
634001
I could not find a case. It is not likely that a panda will attack and during the rare times they have, it was thought that they did so out of irritation rather than for predatory reasons.
174797
Such behavior may seem unreasonable, because a smaller species has more to lose when facing a larger one, in terms of cost/benefit. But in the particular case of breeding birds, they have an added value, namely, the defense of their nests and chicks. Therefore, for them the benefits of attacking a larger predator are greater than the costs. \nThere are some very aggresive and territorial small species, particularly hummingbirds and many tyrannids.\n\nIn the same manner, often the "owner" of a particular territory will win a fight against a larger "outsider". The interpretation is that the smaller but local animal will have greater interest in defending the territory that it already knows and exploits, than the foreign individual who will only give a halfhearted fight.