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Entomology 101

PostPosted: Wed Nov 15, 2006 3:26 pm
by blacknstormy
Image

Ok guys - now I'm going to start force feeding you all some theory along with macro photos :) ;)

I promise it won't hurt ;)

These are Neriids, Family Neriidae, and are often found around rotting fruit/vegetation. They are really quite cool insects, and now you all know how to tell the difference between male and female members of this family :)

PostPosted: Wed Nov 15, 2006 3:58 pm
by Glen
Rel, I think I might have to stick to asking you :lol:

PostPosted: Wed Nov 15, 2006 4:55 pm
by Ladybird
Well Rel, you know I'm always up for some Ento shots!

Maybe for the less 'creepy crawly' nerds we should start with something a bit easier-like the difference between male and female spiders. That is probably the only thing I can remember from Invert Biol at uni :D - that is if I remember correctly!

PostPosted: Wed Nov 15, 2006 5:05 pm
by blacknstormy
Ladybird - spiders are easy :)
Males have boxing gloves, girls don't :) :)

And that is actually the true way you tell the difference between them .... (ripped off the web, but describes the differences well):

Sexual dimorphism (differences) is highly variable among spiders. The primary visible differences between male and female spiders are:

females have larger/bulkier bodies and/or the entire female is much larger than the male.
males generally have enlarged palp ends.

Females are usually larger than the male as the physical demands and accompanying energy requirements to produce webs and broods, are far greater. The male is smaller because once mature, his only function is to mate.

Where males are similar in size to the females, they are generally more slender, with longer legs (Selenopidae, Sparassidae, Pachygnatha, Tetragnathidae). In some cases the male can be one thousandth of the weight of the female (Thomisus, Thomisidae; Nephila,Tetragnathidae; Argiope, Araneidae). In other cases, the male and female are so different that they may even appear to be different species where males of certain species mimic wasps or ants (Salticidae; Gnaphosidae; Seothyra, Eresidae).

2. Copulatory organs

The copulatory organs of the Araneomorpha, or true spiders, have entelegyne features. The male palps are enlarged distally (at the ends) due to a complex copulatory organs or genital bulbs that resemble boxing gloves. Some tiny male spiders have ridiculously large palps relative to their body size. The male and female genital organs are very specific and function on a "lock and key" principle. These organs are used to identify spiders to species level. The female genitalia, the epigyne, is situated ventrally (underside) between the booklung slits on the epigastric furrow. The epigyne is a black, shiny, chitinous, oval to round plate with two openings.

In the primitive spiders, for example Mygalomorpha and haplogyne Araneomorpha, the genitalia have haplogyne features where the female has no epigyne and the males no complex copulatory palps. Instead, the male has a simple bulb that resembles an elongated sting of a scorpion and this is held against the ventral surface of the palp and is not easily visible. Due to the absence of visible genitalia in this group, other characters must be used to determine species.

PostPosted: Wed Nov 15, 2006 5:08 pm
by Ladybird
Well I didn't learn the boxing gloves theory but essentially the principle was the same - females' palps are slender and leg-like whereas males are club-like. Don't remember any of the other differences!

Glad to see I have some memory retention, even if it is relatively minor.

PostPosted: Wed Nov 15, 2006 5:09 pm
by Mr Darcy
Ithought you promised it wouldn't hurt :roll:

PostPosted: Wed Nov 15, 2006 5:11 pm
by blacknstormy
It didn't hurt toooo much though did it????? LOL

PostPosted: Wed Nov 15, 2006 5:25 pm
by CraigVTR
To many big words for me Rel. :oops:
Nice shots though. :)
Craig

PostPosted: Wed Nov 15, 2006 6:59 pm
by Slider
Please explain :shock: :wink:

PostPosted: Wed Nov 15, 2006 7:54 pm
by phillipb
Man !! Talk about diversity in this forum, I've just gone from a thread offering me a cheap mortgage, to some interesting photos by Poon :D , to this thread in just 5 minutes.
Awesome!

As for the insects in this thread, If I had to guess I would have picked wrong, the female looks more like a male to me.

PostPosted: Wed Nov 15, 2006 8:24 pm
by Yi-P
So much said above, only two word I understood, female and sexual.... :lol:

Need to boost up my English skills :P

PostPosted: Wed Nov 15, 2006 8:31 pm
by Manta
"booklung slits on the epigastric furrow"

I love it when you talk dirty Rel!!

PostPosted: Wed Nov 15, 2006 8:44 pm
by phillipb
Yi-P wrote:So much said above, only two word I understood, female and sexual.... :lol:

Need to boost up my English skills :P


Yip, go to Poon's thread, if you understand "female & sexual", you'll have no problems understanding the whole of that thread :P

PostPosted: Wed Nov 15, 2006 9:03 pm
by Oscar
Thanks for the tutorial on spiders Rel. And I can see by your photos that the male Neriids are bigger than the females :lol: :lol: Cheers, Mick :) :) :)

PostPosted: Mon Nov 20, 2006 8:45 pm
by surenj
At first glance I thought they were mosquitoes! :)