Extra instars? Giganticism in mantids?

[JoeCapricorn]

Angel molted to ninth instar last night. Fortune and Meek molted to eighth instar last Thursday. Kit molted to eighth instar over the weekend.

It appears that Angel, Fortune and Meek are all sub-adults. They are also all male in at least the respect that all of them have 8 segmented abdomens and all of them have a similar shaped three pronged protrusion at the end between their cerci. This is strange, since Fortune and Meek are clearly a molt behind Angel, and Angel is much larger than the others, but both have similar sized and shaped wing-buds which are also similar in size and shape to those of sub-adult Hierodula membranacea. I wonder if Fortune and Meek will become adults at L9 and Angel becomes an adult at L10.

I will post pictures comparing Angel with Fortune and Meek. The size difference is dramatic, Angel is about 3.5 inches and Fortune and Meek are both about 2.75 inches - I don't have any photos at the moment, I will wait to either tomorrow or Thursday to take pictures since Angel is still in the process of recovering from his molt last night and I want to give him all the time he needs.

So, now I wonder if Angel is a case of mantis giganticism or Fortune and Meek are cases of mantis dwarfism. I think the former is possible, personally, because I believe Kit has at least two molts to go before she becomes an adult at L10. Her wing buds are about the same size and shape of Angel's wing buds when he was still L8. In the case of Kit, this extra instar is normal, I believe, since she is a female and has a longer development period. However, Angel has displayed several abnormalities with his development. First, he had a molt that was 13 days apart. He has had other molts shorter in time between than the others as well. I think something has caused him to go through an extra molt and may cause him to grow to a rather large size. I don't know how big he will end up becoming, but I estimate a body length of at minimum 4.5 inches.

To truly determine if Angel is the oddity, or if I happen to have a dwarfism oddity in Fortune and Meek, I will have to wait until the adulthood of Baphomet, Jasper, Dio and Nereid. They are L5, L6, L5 and L5 respectively. Another thing I could do is mark down the position of the end of the abdomen and the top of the head on a piece of paper for Kit, Angel, Meek and Fortune. When Jasper, Baphomet, Dio and Nereid molt to where the first four are at right now, I could measure them as well and compare their sizes.

However has anyone had experience of a male, or even female going through an extra molt than usual, or otherwise ended up noticeably larger than their contemporaries? Is the opposite true? Have there been mantises that became adult at a much smaller size than usual?

I have seen several forms of dwarfism with Differential grasshoppers, no particular giganticism but there is a variety of sizes these grasshoppers can become. The two forms of dwarfism I have seen are mainly males or females much smaller than usual and this usually results in twisted, undeveloped wings - one female in particular I kept as a pet until February 2nd of 2002. The other form is basically a grasshopper stuck in sub-adult stage. I have no idea what caused this, but it seemed strangely common last fall - three such grasshoppers were stuck in sub-adult stage all the way through to November! I had seen them around since August, some I may have captured from one location and moved to my yard.

 

[Rick]

I don't keep track of molts usually. All that record keeping would make me go mad. I doubt there were any extra molts from members of the same species. Mantids from the same ooth can grow at very different rates as the picture below demonstrates. I've also seen captive raised mantids that are much smaller than they should be.

From same ooth:

 

[JoeCapricorn]

I keep track of my mantises' molts and post in my "Joe's Mantis Updates" thread, along with a text file that has date of molt and stage molted to. With only 8 mantises it's not that hard and it is quite fun, in fact! It's like each mantis is reborn about 9 or 10 times...

I use this data to predict when the next molts will be and who will be molting. For example, last week and this week had Baphomet, Jasper, Kit, Angel, Fortune and Meek all molt... so that leaves the next molts to Nereid and then Dio.

The next to molt gets extra attention, I clean their cage more often and spray more often. I test them to see if they respond to motile stimuli, and if so then they are fed. Obviously this won't be necessary for a while, but when Nereid gets close to molting I will give him extra special care - always make sure he is on the lid, always make sure his substrate is clean and he has plenty of moisture. Two molts ago he nearly mismolted (he started molting on the bottom. I flipped the container over and he finished molting successfully) and this resulted in twisted antennae, which is better now but still not fully recovered.

So, with all of this data, perhaps I can "discover" some oddities with some of the mantises. Kit is somewhat of an oddity because before 7th instar she looked like a male - while Jasper looked female from 5th instar onward.

And of course there is Angel with his supposed extra stage. Another possibility is that he has inherited some of the genetic traits of his mother, so he is in some ways part female, which resulted in the extra molt.

This actually makes sense in some aspect. Kit, at L8, is slightly smaller than Fortune and Meek at L8. Kit's wing buds are definitely smaller than the others, she has at least 2 molts to go before adulthood - which would be at L10. Angel has been the same way - at L7, he was smaller than the others when they reached L7. His wing buds were small like Kit's at L8 meaning at least two molts to go before adulthood.

Well, I cannot assume for sure that L9 is adulthood for Fortune and Meek and L10 is adulthood for Kit and Angel, but it's my guess.