Time Between Molts

[agent A]

I have noticed that in general, as a mantis grows older, time between molts increases. Subadult stage seems longest, maybe it's just that I'm excited to get an adult and it just seems longer, but L3 seems to be where the slowdown starts, L1 and L2 seem to be the shortest instars.

 

[massaman]

maybe its the temperature they seem to slow down when its a lower temperature!

 

[agent A]

maybe its the temperature they seem to slow down when its a lower temperature!

you make a good point! in July I brought them out in 80 degrees, they grew faster with daily exposure to that

 

[idolomantis]

Since they grow bigger they also get more skin to shed..

 

[PhilinYuma]

My goodness, Alex!

First, carefully collected data over time. I was surprised, by the way, to find that this species only passes through six nymphal instars.

Second, sound, testable ideas to account for the data!

Although hormones control an insect's molting cycle, precise times of eclosure are governed by temperature and size, a function of food intake. You may have heard Peter and others say that when raising siblings of a species where the males tend to molt to adult well before the females, they will keep the males in a cooler environmenrtt and feed them less, relative to the females, in order to delay thier becoming adults.

Your figures show that L1, L2, L4, and L5 each take about the same time but that L3 lasts a few days longer and that L6 takes about half as long again as L1-2 and L4-5.

I think that you might well be right about feeding being a factor in the slightly longer time taken in L3. You can easily test it in the next batch by upgrading the size of the food and/or frequency for half of the siblings and leaving the other half unchanged.

The extra time needed for the last instar may, at least in part, reflect the important changes, such as the development of wings and mature sexual organs, that take place during this stage. It would be interesting to see whether or not an increase in food at this stage significantly shortened the time spent in this instar.

One minor procedural point. It is always a good idea to have as homogenous a test group as possible, such as all the siblings from oe ooth. If micake et al simply took longer than Micake's offspring to molt, the fact that you only have the first group representing the latter instars and the second group representing the first three, could cause an experimental error. Since you have taken such careful notes, when the latest batch become adult, examine their data as a separate entity and see if it is any different from your overall findings.

Again, congratulations on your careful work. Very interesting indeed!

 

[Ntsees]

Anyone here ever noticed how after a nymph reaches L3, it starts to grow more slowly? I find it very odd, but I have recorded the times Creobroter gemmatus nymphs spent in different instars.L1-13 days

L2-15 days

L3-17 days

L4-14 days

L5-14 days

L6-20 days

These observations are based on Micake, Mohammed, Misha, and Melinda (I got them at L5), Mellisa and Mr. Nervous, and Micake's babies who are now L3. Why do mantids seem to spend the most time in L3 and then subadult stage? I find it very odd. Is there some kind of developmental milestone they reach at those stages, or is it because I tend to feed them smaller food than they can truely handle at L3 and subadult stage?

It's typical of not only mantids but with other species as well. I once kept crayfish and the newly-hatched molted quite frequently but it gets slower as they mature. But of course, you'll have to take temperature, food, etc. into account as mentioned above.

, and if you noticed, the way we mature is quite fast too. It takes 20 posts (I think) to become the 1st instar but takes more and more posts to reach the higher stages. , hmm, I wonder how many more posts before I can become a full-fledged adult?

 

[kamakiri]

Anyone here ever noticed how after a nymph reaches L3, it starts to grow more slowly? I find it very odd, but I have recorded the times Creobroter gemmatus nymphs spent in different instars.L1-13 days

L2-15 days

L3-17 days

L4-14 days

L5-14 days

L6-20 days

These observations are based on Micake, Mohammed, Misha, and Melinda (I got them at L5), Mellisa and Mr. Nervous, and Micake's babies who are now L3. Why do mantids seem to spend the most time in L3 and then subadult stage? I find it very odd. Is there some kind of developmental milestone they reach at those stages, or is it because I tend to feed them smaller food than they can truely handle at L3 and subadult stage?

Wait a minute. Are you saying that you are gathering the data from two groups: One group that you received at L5 then raised to adult, and a group that was raised from ooth and is currently L3?

If that is the case, I don't see how you are producing data for time at L3, L4, or L5.

And if I'm misunderstanding the above, there is no way your data grouping is tight to the day for every single individual for every single instar and both sexes. No way.

Throw on top of that that there is no data on feeding rates and temps for the different groups, there is absolutely NO WAY that is a responsible set of data to present in such a list. :angry: :angry:

Sadly, this does bastardize and otherwise interesting topic.

 

[PhilinYuma]

Wait a minute. Are you saying that you are gathering the data from two groups: One group that you received at L5 then raised to adult, and a group that was raised from ooth and is currently L3?If that is the case, I don't see how you are producing data for time at L3, L4, or L5.

And if I'm misunderstanding the above, there is no way your data grouping is tight to the day for every single individual for every single instar and both sexes. No way.

Throw on top of that that there is no data on feeding rates and temps for the different groups, there is absolutely NO WAY that is a responsible set of data to present in such a list. :angry: :angry:

Sadly, this does bastardize and otherwise interesting topic.

Grant! This 12 yr old child did what no one else on this forum is doing, collecting and posting data. His numbers, I assume, are averages, to the nearest day, of his data; much the same as Mendel originally presented his (and you may remember that his fellow monks fudged his actual data because they didn't understand outliers).

I mentioned the problem of mixing data from two congruent groups above, but the possible error that it engenders is only significant if Micake and the parental group molted at a different rate from the offspring group. He will be able to check this, of course, when the current group molts to adult, but I don't expect that data will be significantly different, do you?

He presented raw evidence, and asked, as any sixth-grade might, what it might indicate. He did not offer it to support a hypothesis and cannot be judged for the lack of evidence that he did not tie to his findings. His idea that the third instar at any rate, is linked with feeding was a good guess, but it needs investigation with a much larger n.

I was remiss in not suggesting that while altering the amount of food given, he maintain a steady temp, and I have done this sort of thing enough to know better; he hasn't.

Every da on the forum, we get unanswerable questions about "when will my ooth hatch," "how many nymphs will hatch and how many survive," and "what color will they be?" In this case, Alex has given us some straightforward data and asked a sensible question. I think that that puts him well ahead of the curve.

 

[kamakiri]

At 12 years old, I think one is able to understand averages and general scientific methods. But perhaps I can only relate to myself as a 12 year old...

Without accurate data collection and presentation...a sensible question becomes, well, quite ridiculous.

And the data is not 'raw' and as presented would seem to be averaged. How does that happen across different individuals and different conditions?

Would be a very interesting subject if there *is* more data to present...or more sensible data collected.

I guess the bottom line is that I need to hit the ignore button yet one more time.

EDIT:

Upon adding Alex to my ignore list, I noticed that he's actually 13 and turning 14 soon. I'm guessing that's at least 8th grade...as I started my freshman year at 13.

 

[Opivy]

I have noticed that as well Alex, but I've only kept 3 mantids from baby to adult.

And lol - whenever I see the name AgentA drama always follows somehow.

 

[PhilinYuma]

At 12 years old, I think one is able to understand averages and general scientific methods. But perhaps I can only relate to myself as a 12 year old...Without accurate data collection and presentation...a sensible question becomes, well, quite ridiculous.

And the data is not 'raw' and as presented would seem to be averaged. How does that happen across different individuals and different conditions?

Would be a very interesting subject if there *is* more data to present...or more sensible data collected.

I guess the bottom line is that I need to hit the ignore button yet one more time.

EDIT:

Upon adding Alex to my ignore list, I noticed that he's actually 13 and turning 14 soon. I'm guessing that's at least 8th grade...as I started my freshman year at 13.

Grant, my friend, this makes me truly sad.

 

[agent A]

Wait a minute. Are you saying that you are gathering the data from two groups: One group that you received at L5 then raised to adult, and a group that was raised from ooth and is currently L3?If that is the case, I don't see how you are producing data for time at L3, L4, or L5.

And if I'm misunderstanding the above, there is no way your data grouping is tight to the day for every single individual for every single instar and both sexes. No way.

Throw on top of that that there is no data on feeding rates and temps for the different groups, there is absolutely NO WAY that is a responsible set of data to present in such a list. :angry: :angry:

Sadly, this does bastardize and otherwise interesting topic.

look, first nymph of this species I had where L1 and L3, then I got some that were L5, which have reproduced and I now have L3 of this species.

 

[agent A]

Lesson learned! Since you guys seem upset over my records of timing in different instars, I suppose next time if I have a question about why certian things take time and stuff, I should keep out recordings unless they are straightforward, acurate, and complete. I see the problem is I used times from 3 different sets of mantids, one from early 2009 (April to July), one from later 2009 (August to September), and one from November 2009 to January 2010. That's over almost 1 whole year with different individual mantids (not to mention such small amounts like 2 in april and 4 in august-37 hatchlings in November is still a bit low) and the fact that throughout 2009 I got better at keeping mantids (ventilation, heat lamp, advances in feeding, females layed eggs, eggs hatched and large amounts of L1 nymphs molted, not just 1 or 2, only to die in L2)-what I'm trying to say is my recorded times were inacurate because there was no CV. Things were different back when I got Mellisa than now when I have Micake's nymphs. I'm going to be sure next time that if I observed time it took for something, conditions weren't changed in a way that could altar the results. Epiphany experienced! :lol:

 

[PhilinYuma]

Lesson learned! Since you guys seem upset over my records of timing in different instars, I suppose next time if I have a question about why certian things take time and stuff, I should keep out recordings unless they are straightforward, acurate, and complete. I see the problem is I used times from 3 different sets of mantids, one from early 2009 (April to July), one from later 2009 (August to September), and one from November 2009 to January 2010. That's over almost 1 whole year with different individual mantids (not to mention such small amounts like 2 in april and 4 in august-37 hatchlings in November is still a bit low) and the fact that throughout 2009 I got better at keeping mantids (ventilation, heat lamp, advances in feeding, females layed eggs, eggs hatched and large amounts of L1 nymphs molted, not just 1 or 2, only to die in L2)-what I'm trying to say is my recorded times were inacurate because there was no CV. Things were different back when I got Mellisa than now when I have Micake's nymphs. I'm going to be sure next time that if I observed time it took for something, conditions weren't changed in a way that could altar the results. Epiphany experienced! :lol:

My goodness Alex! If this keeps up, we'll have to start calling you Agent B!

I think that the data that you presented was very promising, but for the critics, I suggest that you restrict yr data to Micake's nymphs. For now, try to maintain the same environment, particularly temperature, and keep a record of the nymphs' daily food intake. As you suggest, this is probably a significant factor in their molting. I think that you were wise not to present a hypothesis; let others worry about that, you are doing the real work. When Kamakiri referred to "raw" data, he meant the actual times (in days) that each nymph took to molt. It is a good idea to provide this data together with the averages, so that we can get an idea of the outliers.

Keep up the good work!

 

[agent A]

My goodness Alex! If this keeps up, we'll have to start calling you Agent B!I think that the data that you presented was very promising, but for the critics, I suggest that you restrict yr data to Micake's nymphs. For now, try to maintain the same environment, particularly temperature, and keep a record of the nymphs' daily food intake. As you suggest, this is probably a significant factor in their molting. I think that you were wise not to present a hypothesis; let others worry about that, you are doing the real work. When Kamakiri referred to "raw" data, he meant the actual times (in days) that each nymph took to molt. It is a good idea to provide this data together with the averages, so that we can get an idea of the outliers.

Keep up the good work!

thanks! anyway, why agent B? what does the "B" stand for?

 

[PhilinYuma]

thanks! anyway, why agent B? what does the "B" stand for?

Better.

 

[agent A]

Better.

ahhh! I can't wait t oget another social epiphany!

 

[wangi]

I guess the bottom line is that I need to hit the ignore button yet one more time.

If you have to keep hitting the ignore button...that should be telling you something about yourself.

Agent A, apologise for taking an interest in science this instant!

Things do tend to grow quicker when they are younger. Think of the difference between a newborn and 1 year old human, then think of a 16 year old and a 17 year old - the younger generations do a lot more growing than the older ones. What do you think the reasons and above all advantages behind this are?

 

[agent A]

If you have to keep hitting the ignore button...that should be telling you something about yourself.Agent A, apologise for taking an interest in science this instant!

Things do tend to grow quicker when they are younger. Think of the difference between a newborn and 1 year old human, then think of a 16 year old and a 17 year old - the younger generations do a lot more growing than the older ones. What do you think the reasons and above all advantages behind this are?

good point. I am sencerely sorry for annoying you with a question that had such an obvious (well, an answer that you really don't need multiple opinions about, one you might need multiple opinions about is like "will 20 watt bulb be enough to heat up ghost mantids?", not "why do mantis grow slower as they get older?") answer. next time I will figure it out by myself and if I can't and if it is not a very good question, I will use the PM (epiphany #2!)