The Yamato Roach
Periplaneta japonica nymph
This is not my first cockroach species by all means, but it will be the first entry to my Cockroach Journals and for one good reason.
The infamous Periplaneta Genus… a genus which to be honest, I haven’t had much love for because Macau (and sometimes my house) is infested with American cockroaches, Periplaneta americana.
First, I received 10 small nymphs of Periplaneta japonica on the 23rd November 2020, one month ago.
I was always very fearful of jumping into Periplaneta because of their looks, speed, climbing abilities, etc... but after receiving these beauties, I think I was mistaken.
They are super chilled nymphs... they are not bolty at all. I managed to have one nymph staying put on the same place, while i took photos for at least 10 minutes.
One thing that I didn't expect was that these nymphs are poor climbers 🤔 ... it was awkward
Lets hope they remain like this while growing up.
It was a small colony, and I after looking at them, I had already already considering to buy another 20... I like my starter colonies to be 30 individuals at least.
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So one week later, on the 30th November 2020, I received another 16/17 Yamato roach nymphs from the same seller, so, lets hope for a steady growth!
One thing I also noticed is that, although looking similar to red runners (as nymphs), their feeding behavior is not frantic or responsive... they are way too chilled, and then it clicked!
Since they are originally from Japan (freezing winter temps), and because @Hisserdude mentioned something related to diapause so I decided to find out more!
After a quick research, i found these links and papers:
"...all nymphal instars (except for the first one) have an ability to enter diapause"
2 - Flexible life cycle of a cockroach Periplaneta japonica with nymphal diapause
My experience with diapause in ants, is that most species wont feed at all during diapause. I was looking to find out if there was any reference to the feeding behavior in the Yamato roach nymphs during diapause, but unfortunately I couldnt find any so far.
I am wondering if what I am observing is actually the diapause stage?
I have seen them feeding, but again, its just some nibbles and they are done. Their bodies look slender and not the glutton type, even after feeding.
Because of the cold weather front that has hit Macau recently, the temperature drop has made all my roach bins halt their external activity. The room is now at 20C during daytime and dropping at night to 15C.
Most of the roaches are now underground or hiding.
The Yamato Nymphs are congregating in two separate groups under some leaves.
You can take a quick peek as I expose them to the light, on the link down below.
Lovely yellow coloration don't you think?
The colony seems to be doing great !
They are clearly more active at night but anytime of the the day, they congregate in two particular areas, not sure because of pheromones or what, but there is a type of leaf they like to stick to.
One month later after receiving the, as you can see, some are really plump 🥰 some have doubled their size, while others (the smaller nymphs I received) seem to have tripled .
I have been feeding them regularly once a week, some small turtle food pellets and some sweet beetle jelly.
I have also noticed some darkening of their initial coloration, which is really cool. I will try to take more macro photos for you guys soon.
Thank you for reading! Merry Christmas and stay safe!