Black substance on thorax

[Ocelotbren]

I have an adult female Chinese that was wild-caught and brought to me in October.  I don't know how long they typically live when brought inside for the winter but she's lived longer than I expected.

She hasn't been eating the last few days which seemed unusual because she laid an ooth fairly recently, and today I noticed that she has a black substance on her thorax, on the top side.  It seems shiny, like some sort of liquid or gel texture maybe.  I haven't pulled her out to look closer yet, but I'm looking for opinions.

The pictures aren't amazing because I didn't open the enclosure due to there being flies in there, but I think you get the idea.

From what I can see, it reminds me of how the black death is described, but in this case it's not vomit.  She's been eating blue bottle flies only for probably the last month or so.

Could this be a bacterial infection, or is she on her last legs and her body is starting to decompose or something already?  Any thoughts?

Thanks in advance.

 

[Ocelotbren]

Update:

It is likely that she fell since I posted the above because she's only slightly off the ground now, but I am able to get a better picture as a result.

Now it looks like it may not be a substance on her so much as just her exoskeleton itself, and it includes half of her head.  As before, any ideas are appreciated. I am guessing the solution is to put her down since she is probably on the verge of death anyway, but I am still wondering what this is.

Thanks.

 

[CosbyArt]

It is likely that she fell since I posted the above because she's only slightly off the ground now, but I am able to get a better picture as a result.

With the new photo it shows the shine better, color variations, and overall size which makes it appear as dried vomit. Indeed with the black coloration I would be thinking the same. Is there any areas in the habitat that have a dark substance on them? Do you notice a strong odor from her or the habitat?

In your third photo it shows her mouth appears to be free of any vomit/substance. If it is the black death, bacterial infection, mantids always seem to have a black tar substance in and around their mouth (which has a strong odor).

It does not appear to be the discoloring associated with their insides liquefying from decomposing. That looks vastly different, and tends to only appear as they lay dying, or after death.

 

[Ocelotbren]

I don't see any unusual dark marks in the enclosure anywhere, and I don't notice any smell either.  Is it possible that she vomited while hanging at such an angle that it would end up dripping over her head and down her back?  And that she somehow cleaned it all off her mouth?  I'm not sure what else it could be based on what you're saying.

She moved to another spot this morning but appears to be staying low to the ground because she's too weak to get farther up.

 

[CosbyArt]

I don't see any unusual dark marks in the enclosure anywhere, and I don't notice any smell either.  Is it possible that she vomited while hanging at such an angle that it would end up dripping over her head and down her back?  And that she somehow cleaned it all off her mouth?  I'm not sure what else it could be based on what you're saying.

She moved to another spot this morning but appears to be staying low to the ground because she's too weak to get farther up.

She could have, and very possible to do at a correct range of angles.

Judging by the dark "stain" she was climbing vertically (facing upwards) on a surface with a incline (60-70 degree angle) facing her head to the left when she vomited. If it was a thick viscosity vomit it flows slowly, and would stick to her as it flowed. Versus a normal thin viscosity vomit (ate too much) that could produce a much longer "stain" (or simply flowed off her side) and appears as reddish/orange in color.

Indeed the clean mouth is a confusing element, which makes me suspect it is not the black death, but rather she is sick with a similar issue especially if she is getting weaker. When they develop the black death bacterial infection it leads to a black tar like substance which is nearly impossible to remove - especially in their mouth area where it is constantly being replaced.

If she is gets to the point you feel euthanizing her is best, that is your choice to make. The options in the meantime are to offer her water droplets, mushed feeders, and 100% honey all offered from a toothpick, plastic spoon, or such near her mouth and try to get her to eat and recover. For some other possible feeding ideas, see here...

 

[Ocelotbren]

Thanks for the thorough reply @CosbyArt.  Yeah, if it was vomit, it was definitely not normal vomit.  I did watch her poop once yesterday and it was also black.  Not sure if that is considered part of the normal range of colors.

Anyway, I pulled her out this morning and offered water and honey, but she couldn't even hold herself up and would barely move her mandibles in response to the honey and water.  I figured whether the cause was some sickness or just old age, it was time, so I put her in the freezer.  It would be nice to know for sure what happened but I know that's not always possible in this hobby.  I got a bunch of hopefully fertile ooths from her so I have something to look forward to in the spring at least.

By the way, how long into the winter do wild-caught female Chinese mantids typically live if brought in before it gets cold?  This is the first time I've tried it so I didn't have any idea how long she'd live, but making it to February seemed like a good amount of time.

 

[CosbyArt]

@Ocelotbren Your welcome, but it came too late. The color of their frass (poop) can vary but if it is solid, slightly liquid, or diarrhea is more of a indicator.

Sorry to hear she had deteriorated so rapidly and a decision was necessary, it never does get any easier. The only way to know a cause of death (illness) for certain would be to have a local entomologist to test her remains in a lab (i.e. university entomology professor or such).

Great that you have ooths, so hopefully she will live on that way. Best of luck with them.

How long a wild mantid lives indoors can greatly vary on it's age and gender (females live longer). From the mantids I've collected since I started the hobby, a few will only make it to December, most survive to January to February, some make it to March, but April is the longest I've had any live to (and I think that was only once).

Where I live we tend to start getting freezing night temperatures in mid to late November on average. Wild mantids are at least 7-9 months old when it starts freezing, so late February to early March would be the typical 12 month captive lifespan - which not all make it to of course.

I say at least 7 months as I occasionally will see one molt to an adult outdoors in early October, but August to September molts to adulthood is the common time. I have rarely seen mantids alive outside by mid-December, as by then most have died due to freezing temps and lack of feeders. Working backwards on the age, they start hatching in late February to early March depending on the temps each year.

I've seen houseflies and bottle flies in numbers by early to mid-March the typical time insects emerge here, and a mantid ooth hatch as late as June 17 once. Looking at it that way it is disheartening to know all mantids at best die at 10 months old outdoors here. I guess the silver-lining is they have already laid all their ooths by them.

 

[Ocelotbren]

Good to know.  I think our winter weather starts a little earlier here, and I read somewhere that ooths start hatching in Michigan in late May to early June.  I'm in mid-Michigan so I am expecting something around that time this spring.  As you said, it is a short life!

 

[CosbyArt]

Good to know.  I think our winter weather starts a little earlier here, and I read somewhere that ooths start hatching in Michigan in late May to early June.  I'm in mid-Michigan so I am expecting something around that time this spring.  As you said, it is a short life!

Further up north geographically than me, you likely do have a smaller mantid lifespan in the wild. If the May hatch time is right that would put them at October/November range for adults, meaning they likely have just over a month to lay ooths before a earlier winter gets them too.

I'm not sure where your at in Michigan, but looking at a midway point of Mount Pleasant, MI the temps seem to range 10-20F colder than here several times. Looking at the actual temperatures for the same time last year (Jan 29 - March 4 ,2017), my area had 16 days of freezing lows, while Mount Pleasant had 30 days of freezing lows.

Doing some manual searching the last Spring freezing temp was March 23, 2017 for me, and Mount Pleasant was all the way to May 9, 2017. Then the first freezing temp here was October 29, 2017, and Mount Pleasant was October 26, 2017, so that was close on first freeze. Not counting the colder temps leading to those dates (or after) that is still about 47 days difference or over a month and a half.

For mantids that would mean if they have a 10 month lifespan here, they get 8 1/2 months at best there. Judging by the other temps though I would imagine it would be more likely in the 7 - 8 month lifespan range.

 

[Ocelotbren]

I am actually very close to Mount Pleasant, good choice!  That sounds about right too, so yeah they do have quite the short life here.

 

[Serle]

We have a  fairly moderate climate here in the Okanagan (for Canada) , I caught a quite gravid female Religiosa mantis in late  Sept. with frost coming in Oct. I think that would be max. An early hatch would be in late May therefore a life span would be about 5 to 6 months in the wild .  I haven't had any achieve a complete year in captivity yet /.  Tenoderas or Religiosa are our naturalized species here ... S

 

[CosbyArt]

I am actually very close to Mount Pleasant, good choice!  That sounds about right too, so yeah they do have quite the short life here.

I got lucky choosing it then. That they do, and is a good excuse to have more mantids if you need a excuse. At least if you release some of their nymphs/ooths back to keep the population largely unaffected - if not improved.

We have a  fairly moderate climate here in the Okanagan (for Canada) , I caught a quite gravid female Religiosa mantis in late  Sept. with frost coming in Oct. I think that would be max. An early hatch would be in late May therefore a life span would be about 5 to 6 months in the wild .  I haven't had any achieve a complete year in captivity yet /.  Tenoderas or Religiosa are our naturalized species here ... S

Thanks for the details, interesting to hear the mantid lifespans in your area. With that short of a lifespan it would seem a single short warm weather year would wipe them out. Makes me wonder if they have adapted to molt quicker to ensure they have time to lay ooths before winter.

With the mantids you have collected and kept, do those live about 2-3 months longer than the ones left in the wild? That tends to be the average longevity I get, and if you do as well may be a sign of an adapted shorter lifespan.

I have the native Stagmomantis carolina, and naturalized Tenodera sinensis species here. The Mantis religiosa is found about 250 miles north of me, and a species I have not kept yet.

 

[Ocelotbren]

If they do have an adapted shorter lifespan to make sure they get their full life cycle in before winter, that is pretty interesting, especially since cooler temperatures typically slow down their growth and prolong their lives, within reason.  But it would make sense that their lifespan adjusts according to their warm season.

 

[Serle]

I haven't kept any wild caught mantids just what I have hatched so I'm not sure of the difference in lifespans.  Actually we have a fairly hot summer and spring the average temps. are 27 to 35 c lots of 35 plus . Doing some research I found the Dept. of Environment or Agriculture introduced the Mantis Religiosa into our area back in 1938 to help control Grasshoppers . ... S