Kin Selection And Fratricide

[Mime454]

I'm pretty new here. I was wondering why the praying mantids eat their siblings. It would seem that the potential for their siblings to live and spread half their genes would be more beneficial to them than a single meal.

It would only take 2 or more siblings to spread an equivalent amount of their genes. Why is there not a programmed rule in any mantid similar to -> if I am a nymph, I will not eat other nymphs because they are likely to be my relatives. This obviously wouldn't be a conscious thought, but a programmed response like other instances of sibling altruism.

Thoughts?

 

[gripen]

To some extent boxing mantids such as Hestiasula brunneriana communicate with siblings to avoid cannibalism. The bottom line is though a sibling is a good solid meal for an opportunistic predator which may not get another meal for day if not week. Without that meal both nymphs would have starved, instead only one had to die.

 

[agent A]

Only 1 problem I see with cannabalism

Animals eat other stuff to get nutrients they can't produce themselves, like how humans must eat meat for protein their bodies don't make

So if they eat a member of their own species, they really r not getting anything new unless the victim had foreign stuff in its stomach

Not sure how valid my idea is, but it's a good thought

 

[Mime454]

To some extent boxing mantids such as Hestiasula brunneriana communicate with siblings to avoid cannibalism. The bottom line is though a sibling is a good solid meal for an opportunistic predator which may not get another meal for day if not week. Without that meal both nymphs would have starved, instead only one had to die.

This would be more eloquently solved if there were fewer nymph, and more food in the ooth for each one. It doesn't make any sense to make mantids that are just meals.

Do you have any sources for the mantids communicating with siblings? I find that really interesting, but a google search didn't find much.

 

[Mime454]

Only 1 problem I see with cannabalism

Animals eat other stuff to get nutrients they can't produce themselves, like how humans must eat meat for protein their bodies don't make

So if they eat a member of their own species, they really r not getting anything new unless the victim had foreign stuff in its stomach

Not sure how valid my idea is, but it's a good thought

Animals eat for calories. Mantids have calories, it not just for nutrients, or else we could survive on multivitamins alone.

 

[agent A]

Animals eat for calories. Mantids have calories, it not just for nutrients, or else we could survive on multivitamins alone.

i know, but we can't survive solely on calories

 

[Krissim Klaw]

Mantids already have some built in protection. The hunting instinct/desire does not usually kick in till 24-48 hours after hatching. Most also have a strong desire to move and spread out after hatching. I would imagine sibling snacking is only a huge issue when humans try to keep a bunch of mantises in tiny cages.

@Agent A- Killing a sibling you happen upon does not only give you calories. It also takes the competition and a lot of predators will kill their own species not because they are starving but because by doing so means there is less competing for the resources in their territory. There are also the benefits that if you are strong enough to kill your brother it stands to reason you are probably a robust individual with good genetics to pass on.

 

[patrickfraser]

This would be more eloquently solved if there were fewer nymph, and more food in the ooth for each one. It doesn't make any sense to make mantids that are just meals.

Do you have any sources for the mantids communicating with siblings? I find that really interesting, but a google search didn't find much.

Creos do an arm waving move that seems to be a sort of communication when housed together. It's the rowboat....NOT the robot. :lol:

 

[gripen]

This would be more eloquently solved if there were fewer nymph, and more food in the ooth for each one. It doesn't make any sense to make mantids that are just meals.

Do you have any sources for the mantids communicating with siblings? I find that really interesting, but a google search didn't find much.

Most sp. are that way. Only a couple sp. have huge burst hatches and even then as Krissim Klaw said they do not eat until 24-48 hours after hatching.Check this out

 

[PhilinYuma]

I think that many contributors to this somewhat confused thread are mistaking a small enclosure with a natural environment. Chinese mantids, whose ooths produce a large number of progeny, try to migrate almost as soon as the hatch and you will never find an ooth that has been hatched for several days surrounded by a cluster of nymphs as perforce happens if you hatch them in a net cage or, shudder, a 32oz cup..

Members who look for "more elegant" solutions or find that current forms of nymph distribution "make no sense" might wish to reflect on the fact that mantids have been around a lot longer than humans (unless you are a Creationist in which case there is little point n talking with you) and with a little luck, will survive long after.

The question of territorial or con-specific recognition has had some able proponents on this forum, including the late, great Christian. I have seen no scientific evidence, though, that the "waving" that young creo. nymphs among others demonstrate is a recognition signal or territory marking rather than a simple defensive posture. Mantids do not have "territories". they move on when their food source dries up. Perhaps someone here can devise an experiment?

In captivity, it is difficult for a nymph to sequester itself when it molts, and that is when it is most likely to be eaten by a con-specific..

As you know, K.K., I always enjoy your posts. In the case of dominant predators, though, I would suggest that there is little con-specific killing, except when a young male challenges an older one (e.g. lions, tigers, Able and Cain) for mating rights with available females.

To the best of my knowledge, Agent A, hominids, including humans, do not eat their own kind. Cannibalistic tribes eat their enemies for quasi religious reasons and do not dine exclusively, by any means, on human flesh, which, as you may know, is rather bland and tasteless. mammalian predators seldom meat the stomach contents of their prey.

as for your original question, Mime454, remember that whatever the cause of attrition in the wild, be it siblings, predators or starvation, if one male and one female mantis produce two male and two female mantids that can mate at the end of the next season (in the most U.S. mantids only mate once per year), then in a few years, we will be overrun by mantids!

 

[agent A]

To the best of my knowledge, Agent A, hominids, including humans, do not eat their own kind. Cannibalistic tribes eat their enemies for quasi religious reasons and do not dine exclusively, by any means, on human flesh, which, as you may know, is rather bland and tasteless. mammalian predators seldom meat the stomach contents of their prey.

oh, i see

i thought chimps were cannibals? dont they eat enemy chimps' babies?

human flesh has to be heavily seasoned and cooked at low temps to preserve flavor... :tt2:

 

[Krissim Klaw]

As you know, K.K., I always enjoy your posts. In the case of dominant predators, though, I would suggest that there is little con-specific killing, except when a young male challenges an older one (e.g. lions, tigers, Able and Cain) for mating rights with available females.

Sorry, I was being rather lazy with my post and talking about it in the extreme cases that do result in death and not really bothering to go into full detail. I agree, actual killings do tend to be rare although territory/spacial desputes can be more common place generally someone will back down and flee. There tends to be a lot of show even in seemingly viscious attacks. For instance anyone who has seen a dog scuffle, it is so often far more bark than bite and when you pull the two offenders off all you will find is some drool. This of course also makes sense from a survival stand point. While it would be awesome to completely take out your competetor actually locking into a full on battle puts both parties at a great risk unless one or the other is decidedly already weaker. All it can take is one badly placed boken bone or infected bite to really put a damper in the whole living thing.Edit- When it comes to mantises, I did think it was interesting the only time I ever saw a threat display out of any of my euchomenella macrops was between two of my girls. They went at each other a couple of times between the clear side of a cage when I had one out that wandered over to it. They threw their arms wide, arched back and even did some mock strikes. On some level I do feel mantises can recognize other mantises. I'm not sure however I would call their response to such a recognition much different than a threat pose however. Simply recognizing each other may thus be a recognition that the other could be a threat. I feel the message may very well be the same. HEY LOOK AT HOW BIG I AM, HOW TOUGH, HOW DANGEROUS, YOU DON'T WANT TO EAT ME. The species that will throw up such displays and then back down from each other tend to be the same species that don't like eating anything that big. They prefer smaller prey items.

Edit2- I promise this is the last edit. Of course you should take my feelings on mantises with a grain of salt. I am after all convinced they can recognize me from other people.

 

[PhilinYuma]

oh, i see i thought chimps were cannibals? dont they eat enemy chimps' babies? human flesh has to be heavily seasoned and cooked at low temps to preserve flavor... :tt2:

You are right, of course,: chimps, tamarinds and some other primates, though notably not the orang-outang (is hat the U.S. spelling? Too lazy to check!) and gorilla so far as I know. These tend to be "social cannibalism", though, rather than the casual kind of an alligator or mantis eating its young because they happen to be handy.

No need for particularly slow cooking for a human carcass, though. Hang it for a couple of days and then roast it on a spit as you would a pig. Humans devoured by the natives of Polynesia were referred to as "long pig" for good reason.