Phyllium monteithi : sexing

[Insectopia]

In other Phylliums instars start displaying visible differences between the sexes from about their third or fourth instar with females having a more rounded abdomen and males having a more pointed abdomen.
So I was concentrated on this possible difference in abdomen shape in order to tell Phyllium monteithi males and females apart.
Over the last few days our number of Phyllium monteithi 4th instar nymphs jumped from 1 to 4 finally enabling me to compare and most likely to distinguish males and females.
One can in 4th instars clearly see a difference in abdomen shape.
I wouldn’t describe it as more pointed versus more rounded but rather as wider in females and narrower in males.
I assume this to be correct because the 2 instars with narrower abdomens show wing buds whereas the 2 instars with wider abdomen do not.
After taking photos of the new instars, something different caught my attention.
It seems possible, that Phyllium monteithi exhibits in older nymphs an additional and unexpected difference.
All 1st instar nymphs show patches of reddish brown colouration on their legs.
Older nymphs however develop a variation in this pattern.
Until now I thought this colouration pattern simply to be a random variation between nymphs. So I didn’t give it much of a thought.
Now, looking at 2 likely male 4th instar nymphs and 2 likely female 4th instar nymphs, I suspect however that females might be losing their patches earlier.
With only four 4th instar nymphs to compare this remains a mere theory though but a very exciting one.
Please take look at the photo showing my beautiful presumable couple of Phyllium monteithi 4th instars.

Cheers,
Martina

[coleoptra]

Like you said about the width of the abdomen, There's obvious development in the males wing buds compared to fem of the same instar. I really like the markings on the males knee joint ( mid pair of legs ). It adds variety it looks like its all progressing well good job.

[cm7]

This is great information Martina. You are certainly putting a lot of work into them.

My 3rd instar that does have more red also shows wing buds. When I was comparing this to my 2nd instar nymphs neither of them seem to have visible wing buds. The 2nd instar nymphs do however have different amounts of red. One has hardly any red and the other with a great deal.

I will take some more macro images tomorrow and check again to be sure.

Thanks again

[Ethan]

Nice job

how big are the nymphs at this stage?

[Insectopia]

The 4th instar nymphs are about 37mm long.
This is a male.

[kitty.kirst]

Jealous and beautiful.out of 17 diff species I own and study this is one I really really want in my collection!

[cesdamess]

they look amazing well done, I cant wait to get my hands on some!

[cm7]

Here are three macro shots showing colour and wing buds. All 3 have wing buds, although the suspected female has less developed ones (I need to get a better photo of it).

[Insectopia]

Thank you cm7!
Beautiful photos!
From what I know now, I would classify these 3 as 2 males and 1 female.
I expect the females to take one moult more than the males until they do reach adulthood plus there are no rear wings visible in my adult female (if she has some at all, they must be tiny). This explains the less developed wing buds.

[cm7]

It is good that the less red on the legs may show a female. I would hate to have to take a marco of each nymph just to see if they are male or female

I would like to take more photos of the abdomen and compare the 2nd instar nymphs. It is difficult when their abdomen is always curled up.