What is the evolutionary advantage of this?

[wuwu]

i think the shortest would be around 10 minutes, but generally they mate for hours, sometimes overnight.

 

[OGIGA]

Believe it or not, I have been watching almost all night (over 4 hours now). I noticed that the male has been trying to connect, but his abdomen isn't long enough. I'm afraid that if I just leave them as they are so they can do their thing, the female will eat the male. He's the only one I have so if he gets eaten, I want to make sure he at least fertilized something.

 

[critterguy]

Another thought...with vastly different sizes the two sexes of orchid mantis likely eat slightly different foods in the wild which keeps the males from directly competing with the females for food.

 

[Way.Of.The.Mantis]

The male only has to fertilise, not support the life of hundreds of nymphs in an ooth.

 

[OGIGA]

My male hardly ever eats. It's been a little over a week and the last thing he ate was maybe half of a blue bottle.

 

[Villosa]

In some ants, colonies produce males that are less expensive to make. Some species have males that have small heads, small mouth parts, and large eyes for the single purpose of mating and ultimately dying. Males often out number females in this case so that every female will have 3-5 males each to ensure successful matings.

In mantids I suspect this is also true. I've never counted but I wonder what the se.x ratio is in, say, a single orchid mantis ooth. The s.exual dimorphism is basically due to females needing more time to develop into egg laying machines imo and thus need to be extremely large. Males on the other hand are numerous and quick to mature and smaller sized (less waste on resources) to wait for the females to mature.

Oh come on censorship, it's scientific talk here...

 

[Christian]

Hi.

If this to be the most important reason, why isn't it expressed in all species?

The point is: what is the difference between this and other highly dimorphic species and other ones? Every generalistic theory has to answer these questions first. I think I tried to do it.

Regards,

Christian

 

[Asa]

I agree with Christian, you must have a generalistic theory. Though I doubt generalistic is a word.

 

[Villosa]

What works for one may not always work for another. Even slight differences in habitat, food, stresses, and living styles can change the need for dimorphism. The ant genus pheidole has a highly dimorphic caste because minor sisters are small and cannot carry out larger tasks. So more expensive, and larger, sisters are made to help with large tasks and for defending the nest from army ant intruders that seem to favor running raids on pheidole colonies. A genus such as pogonomyrmex lack any serious polymorphism because there really is no need for it yet the two listed above live right next to each other at times. I have not studied mantids as much as I should but there is going to be a specific reason, a very specific reason, why orchids exhibit huge dimorphism that other mantids lack.

Every insect out there is only after one thing, to reproduce and more often than not, they will have very odd and clever ways of being successful. That's why you can't have a general theory that matches for all species of every mantid genus on this planet because you can't expect species from Africa to live the same life as species from Australia or China. Every evolutionary change is to benefit the population because it works, they don't choose to change, it's just smaller males seem to work well for them, so they've become the norm of the species.

 

[Asa]

Actually in ant colonies, it is more often the female that is more abundant. All the reasons I can consider for the dimorphism between the female and male orchid, are listed above. If it is so specific, why are there other rarer mantid species who follow this pattern and have no difference in number of male to female ratio? Quite a deep topic, I like it. Wonderful discussions, Villosa and Christian.

 

[Villosa]

I think you may has misunderstood my previous reply Asa. Yes it is true there are more females in a colony of ants because the cast is made up of sterile females plus the queen. If you were talking about reproductives then that is incorrect, or most of the time it is, as males die (or are extremely exhausted to the point of death) shortly after matings and so by evolutionary standards, if a colony releases 100 females to 80 males then 20 females are wasted which is a big no no in reproduction.

If we go in reverse with lucanus stag beetles, the s.exual dimorphism favors males because of their need to compete with other males for a single tiny female. Females mature faster than the males but are able to dig underground to hide during the day while males, due to their large weapons, cannot. Females are then kept safer than the males, who are buit for toughing it out with one another for the right to mate. The ones usually caught by blacklighting or seen during the day are the males. Which bring me to a interesting segment I saw on video once where a large orange beetle species prefers large females because in the narrator's words "large is beautitful" and this makes me wonder if orchids have something like this going for them too.

Internal server error is stopping me from psoting my last paragraph...why?

 

[Asa]

Interesting, perhaps 'big means better' is 'better' for the orchids. I now understand what you meant by the ants. If the 'big means better' is true, that could lead to a lot of answers that I've been wondering about some of the mantids in India that sometimes have bizarre size differences. However with them, even within the same species, the dimorphism between them varies incredibly.

Some species of roaches also do this. As to the evolutionary advantage of this, I do not believe their is evolution. A prime example of this is the theory that Darwinism is based on 'a little at a time leads to big results'. This is untrue. In a conclusive test based on the islands near I forget which island, some finches were tested on beak size. During a drought there beaks got bigger in order to crack the harder seeds. The scientists hoped to prove that that would mean that in the next few hundred years there would be a whole new race of finches.

Needless to say, after the drought, the finches beaks returned to normal. This cycle kept on going for the next 30 years. At the end of these tests the bird's beak size were exactly the same as when they started.

Somehow there must be some way to prove that the orchids or any species size difference must be based on something more general. Sorry for the long post.