mantid sight

[chocolatecolubrid]

Hi everyone. Just been wondering about how mantids see. I had assumed that the little black dots in their eyes that follow you everywhere were actually that - their eyes - but now that I'm getting more into macro photography I can see that their eyes seem to have a compound texture, like a fly. So do they see as a fly does, by gathering detail from each of their compound segments, or do they have a different visual structure?

 

[Stuart89]

Mantids have 5 eyes, 3 that look straight ahead on its forehead, and the 2 on each side of the head. Given that they have a pupil, I personally dont think they see like a fly would do, but more like we do, seeing where it looks (pupils pointing). And I think that what looks like a flies eye is a simplistic way for the pupil to move around the eye. Whereas we use muscles and ligaments to move our eyes, they dont have any muscles so they need another method.

Would be interested in any detailed and complex replies from people who know exactly how it works!

 

[Christian]

The black dot is no pupil, but a pseudopupil. As the name implies, it has nothing to do with vertebrate pupils, but is just the area on the compound eye where the ommatidia don't reflect light, that is the ommatidia facing perpendicularly to the observer. As every other insect, mantids have compound eyes. The ocelli count 3 in mantids and have another function (orientation, polarized light?).

 

[darkspeed]

The black dot is no pupil, but a pseudopupil. As the name implies, it has nothing to do with vertebrate pupils, but is just the area on the compound eye where the ommatidia don't reflect light, that is the ommatidia facing perpendicularly to the observer. As every other insect, mantids have compound eyes. The ocelli count 3 in mantids and have another function (orientation, polarized light?).

If you have a scientific mind this will give a good read. It goes into great depth on mantis vision, but is highly technical.

http://books.google.com/books?id=DpQtuB-EV...fUENoFYqa--IGBM

It almost word for word describes the pseudopupil the way Christian did. However it needs to be pointed out that pseudopupils are not limited to just mantids but to all compound eyes, including those of other invertibrates such as crustaceans.

I didnt see any reference to the ocelli in regards to vision in mantids in that particulat text, but further research uncovered the following...

http://en.wikipedia.org/wiki/Ocellus

Interestingly enough, there has been thorough research into the function of ocelli as circadian entrainers... i.e. sensors that tell the mantis when it is light and dark... while the research has not been mantis specific, it is of current interest among several in this forum as to the affect of circadian rhythim on mantis health and breedng. My investigations have led me to some worthwhile information. It was found that most insects, when subjected to constant periods of whatever light cycle produced the most activity (light for day active insects, and dark for nocturnal insects) ther level of activty remained almost constant with the level of light, and for some insects abnormal periods of light or dark resulted in dramatically shortened mating periods. Furthermore, in some insects, when the ocelli were destroyed or covered up the test subjects resulted in gradual loss of natural rythim, whereas covering the compound eyes and leaving the ocelli intact had little effect. In other insects the results were exactly opposite. Meanwhile if test subjects had both compound eyes and the ocelli covered or destroyed, their rhytihm stabilized at 12/12 active / inactive, unaffected by light conditions in the subjects environment.

 

[Rick]

^^ I have a copy of that book and it is very technical.

 

[spawn]

I just got started into reading the page about occluded compound eyes and then google told me my "preview" was over. F google. :angry:

 

[FitzWallace]

Thanks for asking the question! And for the answer! I've always wanted to know, but never got around to asking.

 

[FitzWallace]

That is one expensive book! Those that have it or have read it - worth the $? While I'm no entomologist, I do have a scientific-type interest.

 

[FitzWallace]

Didn't mean to hijack the thread - started a new one called Good mantis books?

 

[Christian]

As Rick pointed out, the book is very technical and intended for entomologists. However, if you are familiar with the terminology it is a fantastic book to read, summarizing up almost all knowledge on this group at that time. Although there are some taxonomic deficiencies in some of the chapters (e.g. the repeated use of Tenodera aridifolia sinensis instead of T. sinensis) and some important work by Europeans had been ommitted, it is a highly recommended book. Don't expect too much about tropical species, though. Most scientific work covered in this book was carried out on T. sinensis and other introduced species in N-America. The chapter on defensive mechanisms by Edmunds & Brunner is maybe the most interesting one for hobbyists.

 

[chocolatecolubrid]

Thank you all for replying and answering my question! That text you posted was extremely interesting, so I may have to look into getting that book :lol: