Ooths outside hatch in fall in So. Cal?

[sidewinder]

An ooth that was maintained in an environment that recieved a consistent ammount of light and still hatched would tend to negate the photoperiod contention, but an otherwise unaccountable failure to hatch under these conditions would support it.Is this fun or not!

PhilinYuma,

I just read this again and am now quite confused. What do you mean by "consistent amount of light"?

Here are my experiments:

1. Take a freshly laid Stagmomantis limbata ootheca and kept it at a temperature warm enough to incubate the eggs (75° F) AND gave it the right kind of light (blue-light) for 18 hours per day. If it hatched in about two months, it would not disprove or prove the photoperiod induced diapause theory. All it would prove is that the S. limbata does not have an obligate diapause.

2. Take a freshly laid S. limbata ootheca and kept it at a temperature warm enough to incubate the eggs (75° F) but keep it in the dark. If it hatched in about two months, that would disprove the photoperiod induced diapause theory. Conversely, if it did not hatch, this experiment in conjunction with a hatch in the experiment above, would prove the photoperiod induced diapause theory.

These experiments would not be hard to undertake. But it would be important to use freshly laid oothecae just to make sure the important segment of the prediapause period was not missed. This segment would be where the environmental cues are evaluated and the diapause "decision" was made.

Clearly these experiments would need to be repeated many times to verify the results. Once photoperiod or temperature was establish as the diapause inducer, experiments could be undertaken to determine thresholds.

Scott

 

[PhilinYuma]

PhilinYuma,I just read this again and am now quite confused. What do you mean by "consistent amount of light"?

Scott

Well, Salamonis, that's an easy one. We have been discussing the fact that outside, a steady decrease in photoperiod up until December 22nd might affect diapause. Perhaps "consistent photoperiod" will make more sense, though a shortening of photoperiod from one day to the next would provide a smaller amount of light and consistent photoperiods would provide a consistent ammount, particularly indoors, where the light would cease as soon as the light was turned off instead of waning slowly as it does in nature.

A seemingly picky but, I think, very important note: One experiment, as you indicate at the end of your post, would not "prove" anything, but merely be consistent with one theory or the other. Your experiments sound fine. Do you have any ooths?

 

[sidewinder]

Well, Salamonis, that's an easy one. We have been discussing the fact that outside, a steady decrease in photoperiod up until December 22nd might affect diapause.

No. That's not what I have been discussing anyway. Photoperiod length is the environmental cue, not the fact that there is a gradual decrease in photoperiod. The facultative pupal diapause of Sarcophaga bullata, the Flesh fly I mentioned in a earlier post in this thread, is an example of this. The 13.5 hour photoperiod is what induced diapause. Decreasing photoperiod would be an illogical environmental cue since the photoperiod would still have to be measured and there would still be a photoperiod threshold that would need to be crossed.

A seemingly picky but, I think, very important note: One experiment, as you indicate at the end of your post, would not "prove" anything, but merely be consistent with one theory or the other. Your experiments sound fine. Do you have any ooths?

Not seemingly. It is picky because clearly I did not mean "absolute fact proved beyond any doubt" since I said the experiments would need to be repeated many times to verify the results. In science the word "proof" is used often and my experiment would provide "proof". Independent experiments would need to be conducted to verify my proof. But it is still proof in the scientific sense of the word.

No, I do not have freshly laid Stagmomantis limbata oothecae at my disposal. Nor I am interested in raising the species or any temperate species for that matter.

Scott

 

[PhilinYuma]

No. That's not what I have been discussing anyway. Photoperiod length is the environmental cue, not the fact that there is a gradual decrease in photoperiod. The facultative pupal diapause of Sarcophaga bullata, the Flesh fly I mentioned in a earlier post in this thread, is an example of this. The 13.5 hour photoperiod is what induced diapause. Decreasing photoperiod would be an illogical environmental cue since the photoperiod would still have to be measured and there would still be a photoperiod threshold that would need to be crossed.Scott

Salamonis:

I clearly misunderstood you. The photoperiod needs to fall below that which obtains when the ooth is laid, is that right? If so, an ooth laid on Dec 3rd (the latest date given by Roberts, so probably close enough), would have an absolute maximum of 19 days before the days started getting longer, even if the trigger were the photoperiod of the shortest day, which seems statistically unlikely. If the trigger period occured on Novenber 5th, though, it would go immediately into diapause. Most stimuli responses seem to be "fuzzy" (as in "fuzzy logic"). There does not appear to be a specific temperature or duration of that temperature that induces or or fails to induce diapause, but the experiment results for S. bullata seem chillingly exact and clinical, and of course, it is quite a leap to infer that mantis physiology should closely aproximate that of flesh flies and silk moths. Still, I don't have a major problem with it as an unsupported possibility.

"Not seemingly. It is picky because clearly I did not mean "absolute fact proved beyond any doubt" since I said the experiments would need to be repeated many times to verify the results. In science the word "proof" is used often and my experiment would provide "proof". Independent experiments would need to be conducted to verify my proof. But it is still proof in the scientific sense of the word."

No, you are wrong on this one, unless there is some "scientific sense" that hasn't found its way into the etymological or scientific dictionaries. Remember the good old null hypothesis? I even tried Webster's NID in the hope that you might be right. No luck, though. When I said "picky", I was trying to be non confrontational (God, it's hard!).

No, I do not have freshly laid Stagmomantis limbata oothecae at my disposal. Nor I am interested in raising the species or any temperate species for that matter.

Then I guess that your experimental models were for the benefit of the rest of us. Of course, if you were to conduct the experiment, and I am sure that you would do so meticulously,you wouldn't have to raise the fry. You could always flush them or feed them to your exotic species.

 

[sidewinder]

Not seemingly. It is picky because clearly I did not mean "absolute fact proved beyond any doubt" since I said the experiments would need to be repeated many times to verify the results. In science the word "proof" is used often and my experiment would provide "proof". Independent experiments would need to be conducted to verify my proof. But it is still proof in the scientific sense of the word.

No, you are wrong on this one, unless there is some "scientific sense" that hasn't found its way into the etymological or scientific dictionaries. I even tried Webster's NID in the hope that you might be right. No luck, though.

PhilinYuma,

This is ridiculous.

Let's look at the first definition of "proof" in the American Heritage Dictionary:

"The evidence or argument that compels the mind to accept an assertion as true."

How about this first definition from Dictionary.com:

"evidence sufficient to establish a thing as true, or to produce belief in its truth."

The experiments I suggested would provide "proof". It may not be good "proof" to some, but it is "proof" none the less. "Proof" is not infallible by definition.

Scott

 

[sidewinder]

I clearly misunderstood you. The photoperiod needs to fall below that which obtains when the ooth is laid, is that right? If so, an ooth laid on Dec 3rd (the latest date given by Roberts, so probably close enough), would have an absolute maximum of 19 days before the days started getting longer, even if the trigger were the photoperiod of the shortest day, which seems statistically unlikely. If the trigger period occured on Novenber 5th, though, it would go immediately into diapause. Most stimuli responses seem to be "fuzzy" (as in "fuzzy logic"). There does not appear to be a specific temperature or duration of that temperature that induces or or fails to induce diapause, but the experiment results for S. bullata seem chillingly exact and clinical, and of course, it is quite a leap to infer that mantis physiology should closely aproximate that of flesh flies and silk moths. Still, I don't have a major problem with it as an unsupported possibility.

PhilinYuma,

Why do you assume the embryo in the ootheca would use the photoperiod of the day they were laid as a basis to calculate an environmental cue? The cue would undoubtedly be a critical day length as seen in Sarcophaga bullata. It may not be as sharp a demarcation though. The fact that the photoperiod was getting shorter would not necessarily be important. The fact that a particular photoperiod threshold was crossed would be. That would indicate the type of winter to expect.

I have no idea what that critical day length would be for any other insect than S. bullata.

I don't know why you consider it quite a leap that mantid physiology would be the similar to other species in the class Insecta in regards to how photoperiod is detected and used as an environmental cue for diapause. Look how similar our physiology is to other species in the class Mammalia.

Scott

 

[Orin]

The reason I suspect photoperiod...

What mechanism do you imagine allows the developing eggs to 'see through' the egg exterior and ootheca and why don't different layers of eggs hatch at different times (or not hatch at all)? Daily seasonal temperature shifts can provide a similar effect but photoperiod would require a specialize organ.

Sometimes trees put out their leaves too early and get frozen, sometimes mantis oothecae hatch too early due to long duration temperature or humidity shifts but not all of them react the same or many extant species would be extinct. The unreliability of weather shifts necessitates that not all oothecae from the same species (or even the same female) will hatch at the same time under the same or very slightly different conditions. For husbandry purposes we look for a general rule rather than the odd exception (some people fall off a ten story building or eat poison and live but those aren't requirements for a human caresheet). In all probability the S. limbata ootheca won't hatch out early.

 

[PhilinYuma]

No, you are wrong on this one, unless there is some "scientific sense" that hasn't found its way into the etymological or scientific dictionaries. I even tried Webster's NID in the hope that you might be right. No luck, though.PhilinYuma,

This is ridiculous.

Scott

Salomonis:

I think that you are right, Salomonis. There is definitely something ridiculous going on here. Have you ever thought of submitting a scientific paper for publication? If so, you may find it difficult to get it published if your experimental data is based on an observed population of one. Scientists always carp about those darned variables. Perhaps we could agree to settle for a "smidgin of proof", or possibly a "prooficle"? I'd go with that.

 

[PhilinYuma]

For husbandry purposes we look for a general rule rather than the odd exception (some people fall off a ten story building or eat poison and live but those aren't requirements for a human caresheet).

Orin:

Do you have one of those human caresheets? It might come in handy.

"In all probability the S. limbata ootheca won't hatch out early."

You're right about that, mate. And if it doesn't, "there'll be something, something to carry on." Damned fine song, (Laura Nero?) even if I don't remember all the words.

 

[sidewinder]

PhilinYuma,

I would not publish a scientific paper with the proof available from two different tests done with two different oothecae. That is why I said "Clearly these experiments would need to be repeated many times to verify the results." A little bit of "proof" is still proof. The simple fact is that the word "proof" does not mean "truth". "Proof" is evidence or authentication.

Scott

 

[sidewinder]

What mechanism do you imagine allows the developing eggs to 'see through' the egg exterior and ootheca and why don't different layers of eggs hatch at different times (or not hatch at all)? Daily seasonal temperature shifts can provide a similar effect but photoperiod would require a specialize organ.

Light can penetrate more than 5mm into soil. Does the proteinaceous material oothecae are made of block light or allow light of the appropriate wavelength through? Other insects that go through a diapause have specialized extraretinal photoreceptors. Why not mantid embryos? Temperature is not reliable, especially in more southern temperate zones.

I am only arguing that photoperiod as an environmental cue makes the most sense since it the most reliable. We won't know which environmental cue, photoperiod or temperature, is actually used to induce diapause in Stagmomantis limbata until someone does those experiments I suggested and does them several times to verify results.

Scott

 

[PhilinYuma]

PhilinYuma,"I would not publish a scientific paper with the proof available from two different tests done with two different oothecae."

Scott

Sounds like a plan, Salomonis! Perhaps this part of the thread is best summed up by a tag from Cervantes' Don Quixote, "the proof of the ooth is in the hatching." I'm not sure if that is exactly right, my Castillian sucks, but he seemed to have a "quotable quote" for nearly everything, and many are stiil current in modern English; things like "quit while you're ahead," "the pot calling the kettle black," and of course, "tilting at windmills." Often though, I abreviate that first one to just the first word.

 

[Orin]

Other insects that go through a diapause have specialized extraretinal photoreceptors. Why not mantid embryos?

Which insects are those and which ones have embryonic photoreceptors?

 

[sidewinder]

Which insects are those and which ones have embryonic photoreceptors?

Any insect that enters diapause based on photoperiod cues taken as an embryo. Specific diapause information is hard to find. But here are a few examples I could find:

Sarcophaga crassipalpis: this species experiences a diapause in the pupal stage that is induced by experiencing short photoperiods during the second half of embryonic development.

Bombyx mori: this species experiences an embryonic diapause if the mother experienced short photoperiods during her embryonic development.

Aedes triseriatus: experiences embryonic diapause induced by photoperiod during its own embryonic stage.

Aedes albopictus: temperate Japan, experiences embryonic diapause induced by photoperiod during its own embryonic stage.

Neodiprion sertifer: experiences embryonic diapause induced by photoperiod during its own embryonic stage.

I am sure I could find more. Actually, I did find many more Aede spp. but decided listing them all would be tedious. The bottom line is that there are many general descriptions of facultative embryonic diapause induced by photoperiod. Talk to an entomologist and you will find this concept ordinary.

Diapause is a well understood event. But, only species that are pests or have other economic impact appear to have their diapause mechanisms studied in detail and published. Hence the dearth of specific information.

Scott

 

[Christian]

I was asked to answer on this topic. To be generous, it was too long and redundant to be read completely. I will try to clarify some points, though, so that future discussions don't repeat futile arguments but have a base.

First of all, you have to distinguish between diapause and quiescence. Diapause is induced before conditions gets worse and, once induced, need a trigger to be finished. Quiescence is an ultimate response to unfavorable conditions, as low temperatures.

In mantids, at least in those species studied in this regard, diapause (whether facultative or not) is induced by photoperiod and fixed by temperature. This is: a decrease in photoperiod induces diapause preparation, but this can be achieved only before a certain embryonic state. That's why early laid ooths sometimes hatch in fall. Diapause is, once induced, fixed by a special embryonic membrane. During diapause, mild days in winter and spring cannot induce a hatch. Only after winter, embryonic develpment is continued and nymphs will hatch in spring. In species with overwintering nymphs, diapause includes a development stop and a low metabolic rate (Empusa).

Quiescence, on the other hand, is induced by unfavorable conditions (e. g. low temps) and ends immidiately as conditions become better. Some populations of Blepharopsis mendica may undergo this kind of hibernation.

However, some species or populations with facultative diapause can overwinter as eggs or as nymphs, depending on the severity of the winter (e. g. Ameles decolor). So, if winter temps get higher, mantids may switch to a larval hibernation state. In fact, overwintering as a nymphs is the more widespread state and occurs almost everywhere south of the 10° C isocline. The spread into more northern habitats required a switch to egg overwintering. Animals, insects in particular, have some well developed adaptive abilities, so warmer winters may not necessarily lead to extinction, but to a change in life history. This change may initially cause some population declines, and, subsequently, a changed species assemblage (rare species may become common and common ones rare), but extinction due to climate changes is a minor threat to mantids (due to a mostly large distribution) - in contrast to some other taxon...

 

[Orin]

I am sure I could find more. Actually, I did find many more Aede spp. but decided listing them all would be tedious. The bottom line is that there are many general descriptions of facultative embryonic diapause induced by photoperiod. Talk to an entomologist and you will find this concept ordinary.

Just because you type a few key words into a search engine doesn't mean what you pull up is relevant. Bombyx diapause is related to day length experienced by the adult moth which has eyes and, if you've ever kept them, the eggs don't hatch without a cold period. I imainge all your other examples are also off track as well.

As for talking to an entomologist, you apparently have no understanding of entomology or you'd realize it's a massive field and entomologists specialize and only those specializing in orthopteroid insects would have anything but very basic knowledge of mantids.

 

[sidewinder]

Just because you type a few key words into a search engine doesn't mean what you pull up is relevant. Bombyx diapause is related to day length experienced by the adult moth which has eyes and, if you've ever kept them, the eggs don't hatch without a cold period. I imainge all your other examples are also off track as well.As for talking to an entomologist, you apparently have no understanding of entomology or you'd realize it's a massive field and entomologists specialize and only those specializing in orthopteroid insects would have anything but very basic knowledge of mantids.

Orin,

Let me quote from page 309 of the Encyclopedia of Insects (Resh and Cardé, 2003). Which, by the way, is a well respected publication and was emphatically recommended to me by an Entomologist acquaintance of mine:

"The best understood hormonal mechanism regulating embryonic diapause is based on the silkworm. In this species diapause intercedes early during embryogenesis, just before segmentation. The development fate of the embryo is determined by the presence or absence of diapause hormone (DH), a neuropeptide secreted by the mother's subesophageal ganglion. In the presence of DH, the ovariole produces eggs that enter diapause, and when the hormone is not present the eggs develop without the interruption of diapause. Whether the mother releases DH is dependent upon the photoperiod she was exposed to as an embryo. Thus, the mother's photoperiodic history dictates whether she will release the DH needed to influence the diapause fate of her progeny."

I will also quote page 166 of Insect Hormones by H. Frederik Nijhout:

"The control of embryonic diapause has been best studied in the Chinese silkworm Bombyx mori. Some races of Bombyx have an obligatory embryonic diapause, and thus have only one generation per year; they are univoltine. The embryos of other races of Bombyx, however, undergo a facultative diapause, and such races can have more than one generation each year. Whether or not an embryo from such a race will enter diapause depends on the photoperiod that its mother experienced while she herself was an embryo."

In regards to the eyes being used to gather photoperiodic information, let me provide a quote from page 308 of the Encyclopedia of Insects (Resh and Cardé, 2003):

"Photoperiodic information is perceived through a receptor in the brain, integrated and stored in the brain, and then translated into endocrine events that control the induction and maintenance of diapause. The location of the photoreceptor responsible for the measurement of daylength has been studied in relatively few insects, but in most of them the compound eyes and ocelli are not the conduit for this information. Surgical destruction of these visual centers or coating the eyes with an opaque paint usually does not interfere with the photoreception involved in the programming of diapause. The photoperiodic signal appears to impinge directly on the brain, but the exact location of these extraretinal photoreceptors has not been elucidated."

Finally, a quote from page 158 of The Insects by Gullan and Cranston:

"Insects can detect day-length or night-length changes (photoperiod stimuli), sometimes with extreme accuracy, through brain photoreceptors rather than compound eye or ocelli. The insect brain also stores the programing for diapause..."

Yes, I have raised Bombyx mori and, if I can recall from experiences 40+ years ago, the ones I raised needed the eggs to be chilled for a while. But clearly that is not always the case based on the information I have provided here. I suspect your information saying the "Bombyx diapause is related to day length experienced by the adult moth which has eyes" is incorrect. What basis do you have for challenging my other examples?

I very well understand that entomology covers an expansive and growing list of species with specialization the most common path taken by those that pursue it. I considered a career as an Entomologist many years ago. But, to your point, insects in the Order Orthoptera are not the only insects that take cues from the photoperiod. They are not the only insects that implement diapause. While the molecular mechanisms of diapause are varied and not well understood, the environmental cues are and I suspect most entomologist have at least a basic understanding of those cues since diapause is covered in even the most basic classroom textbooks. You don't need to be a mantid expert to know that mantids breathe through spiracles.

Scott

 

[sidewinder]

Christian,

Thank you for posting that information.

Scott

 

[Orin]

But, to your point, insects in the Order Orthoptera are not the only insects that take cues from the photoperiod. They are not the only insects that implement diapause. While the molecular mechanisms of diapause are varied and not well understood, the environmental cues are and I suspect most entomologist have at least a basic understanding of those cues since diapause is covered in even the most basic classroom textbooks. You don't need to be a mantid expert to know that mantids breathe through spiracles.Scott

Christian already told you there's no data to support your theory (so did others of course). Your arguement never ceases to die in the face of facts or information.

Orthopteroids are not the same thing as Orthopterans, different levels. Maybe one in a hundred entomologists would know offhand the specifics of Bombyx diapause, maybe not even that many since it's related to a race that probably can't be acquired. Comparing species race specific diapause to the name of a general body part is beyond misleading. There are ten different comments I could respond to but you're way off topic and there's only so much time in the day.

 

[Peter Clausen]

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