Horrid King Assassin Bugs dying for no reason?

[Tellorcha]

Hey everyone,

I got 5 horrid king nymphs last months, and already two have died. I am very curious if anyone has any input as to why this would have happened. I was keeping them each in individual tupperware with egg flats and screen glued on the top for lots of ventilation. I read these guys need a bit more humidity than the White Spots, so I sprayed one side of each tupperware about once a week. All 5 were eating well, and one even molted within the first few days I had it. I found the freshly molted one half eaten by a cricket one morning. I am not sure what killed it as it seemed healthy, so I figured the cricket got hungry and preyed on it. Since this incident, I have not left any crickets in their enclosures without my supervision.

I switched the 3 remaining larger nymphs into large ball jars with screen lids (one nymph is tiny, so I left him/her in the tupperware for now). They have sand/coco fiber substrate, and each have a tall piece of cork bark to perch on and molt when necessary. I offer food every couple days and remove corpses. I spray the jars about once a week. All 3 were eating great, and seemed perfectly healthy, until once morning I found one of my two largest nymphs had died as well. This one I have absolutely no idea what could have gone wrong. The only things I can think of is either I over-misted it or perhaps the temps in our apartment fell below 68 over night? We are at the whim of radiators, which usually keep the place around 75 during the day. Our landlords have been known to shut them off for multiple hours in the middle of the night, so I've been keeping a space heater on overnight since the 2nd death. The 2nd, totally unexpected death has made me question whether the first death was due to cricket murder or if it died for some other reason and the cricket just seized the opportunity for a meal.

Any input on what could have caused this? I have read they are generally quite hardy to humidity fluctuation, temperature and etc. I'm pretty bummed to have lost two already, and I'm super paranoid to lose anymore. I have been hunting for these for over a year, and just finally got my hands on some! I'd love to hear any advise or input. Thank you!

 

[BenLeeKing]

When i first got Platymeris I lost 3 cause of me stressing over feeding them after a molt, and they can die if they are bothered too much after a molt even for a day (is what I think), now I kinda ignore the, cause I got so many and they are fine.
Another factor could be humidity(?) My friend keeps his horrida in a tall Tupperware box with little ventilation and it's quite humid in there and they are fine. I've never personally kept horrida, but I would suggest try raising humidity and see where it goes.

 

[chanda]

While any deaths are, of course, disappointing, you should keep in mind that it is normal and expected that some nymphs will not make it. Consider the number of eggs a single mature female may lay. If all of them survived, they would outstrip their food supply. Whereas humans invest heavily in the success of a single or a few offspring, and are able to raise the majority of them successfully to adulthood, most bugs take the opposite approach by dispersing dozens or even hundreds of eggs, and hoping that at least a few survive to adulthood.

I currently have Platymeris biguttatus, Platymeris sp. Mombo, and Psytalla horrida, and I keep all of them pretty much the same. They are in screen-topped glass cages with an inch or two of coconut fiber/sand/topsoil mix for substrate (just something for them to drop eggs on and to help hold in the moisture) and plenty of rough cork bark slabs and tubes arranged vertically for climbing/hiding/hanging underneath to molt. I like to provide multiple loosely-stacked cork slabs (or tubes) so they have somewhere dark they can hide, either inside the tubes or between the slabs.

I mist them once or twice a week. (By "misting" I mean a light misting of the cork slabs, providing water droplets for drinking - plus a heavy spray down the sides of the glass, to soak into the substrate. Not enough to leave puddles or saturate the substrate, but enough to get it at least fairly moist for at least an inch or so down.) They are kept at room temperature (there is a small space heater in the room, just in case it gets chilly at night - or in the summer, when the air conditioner is running). There is also a small humidifier in the room to combat the drying effects of the furnace/air conditioner/space heater, which usually keeps the room humidity somewhere in the 50-60% range - when we remember to refill it. I do keep them communally, both as nymphs and as adults, rather than housing them individually. Surprisingly, cannibalism has been minimal, as long as they are well fed. They also have dermestid beetles in the substrate as a cleaning crew - and supplemental feeders for the nymphs. (These are just those hairy dermestid larvae that frequently show up in cricket bags. I dropped them in with the assassins, and it turns out they breed like crazy and thrive on the assassin bugs "leftovers."

 

[Hisserdude]

I actually think these need LESS humidity than Platymeris, I kept them well ventilated, bone dry, no substrate, their only moisture came from their food. Only had a few premature deaths out of hundreds... All six of my original L1 nymphs made it to adulthood, with one having a molting deformity due to my stupidity in hide choice... I think excess humidity can cause "random" deaths like this, otherwise the mortality rate should be VERY low, (unless you keep every life stage together, in which case you'll see some cannibalism).

 

[Tellorcha]

When i first got Platymeris I lost 3 cause of me stressing over feeding them after a molt, and they can die if they are bothered too much after a molt even for a day (is what I think), now I kinda ignore the, cause I got so many and they are fine.
Another factor could be humidity(?) My friend keeps his horrida in a tall Tupperware box with little ventilation and it's quite humid in there and they are fine. I've never personally kept horrida, but I would suggest try raising humidity and see where it goes.

Thank you for the input. The immediete after-molt feeding could be a possible cause for the first nymph's death, especially considering it molted just a day or two after enduring winter shipping. Hmm. Perhaps I will try raising the humidity, but everything I read either says keep them humid or keep them bone dry. I get so overwhelmed trying to make my own decisions in all the disagreement! I've had most luck keeping my P. biguttatus in bone dry conditions (separating the eggs to keep them humid in a separate tub), so it's my instinct to keep conditions dryer. Maybe I've got to break out of that.

 

[Hisserdude]

P. biguttatus in bone dry conditions (separating the eggs to keep them humid in a separate tub), so it's my instinct to keep conditions dryer.

That's EXACTLY how I kept my Pystalla, I started with six, that six ended up making over 200 offspring, all of which I isolated and reared to L2-3 before selling them off. (To be fair it was a female heavy group of six). They like it pretty dang dry IME... With just food for moisture.

 

[Tellorcha]

While any deaths are, of course, disappointing, you should keep in mind that it is normal and expected that some nymphs will not make it. Consider the number of eggs a single mature female may lay. If all of them survived, they would outstrip their food supply. Whereas humans invest heavily in the success of a single or a few offspring, and are able to raise the majority of them successfully to adulthood, most bugs take the opposite approach by dispersing dozens or even hundreds of eggs, and hoping that at least a few survive to adulthood.

I currently have Platymeris biguttatus, Platymeris sp. Mombo, and Psytalla horrida, and I keep all of them pretty much the same. They are in screen-topped glass cages with an inch or two of coconut fiber/sand/topsoil mix for substrate (just something for them to drop eggs on and to help hold in the moisture) and plenty of rough cork bark slabs and tubes arranged vertically for climbing/hiding/hanging underneath to molt. I like to provide multiple loosely-stacked cork slabs (or tubes) so they have somewhere dark they can hide, either inside the tubes or between the slabs.

I mist them once or twice a week. (By "misting" I mean a light misting of the cork slabs, providing water droplets for drinking - plus a heavy spray down the sides of the glass, to soak into the substrate. Not enough to leave puddles or saturate the substrate, but enough to get it at least fairly moist for at least an inch or so down.) They are kept at room temperature (there is a small space heater in the room, just in case it gets chilly at night - or in the summer, when the air conditioner is running). There is also a small humidifier in the room to combat the drying effects of the furnace/air conditioner/space heater, which usually keeps the room humidity somewhere in the 50-60% range - when we remember to refill it. I do keep them communally, both as nymphs and as adults, rather than housing them individually. Surprisingly, cannibalism has been minimal, as long as they are well fed. They also have dermestid beetles in the substrate as a cleaning crew - and supplemental feeders for the nymphs. (These are just those hairy dermestid larvae that frequently show up in cricket bags. I dropped them in with the assassins, and it turns out they breed like crazy and thrive on the assassin bugs "leftovers."

Thank you for the input! I do agree one of the purposes of insects dispersing many offspring is to account for loss of young; however, I think this should be mostly avoidable in captive conditions. Most death of young among wild inverts is likely due to their extreme vulnerability as larvae, nymphs, etc. to predation and during molt. They shouldn't just drop dead for no reason I don't think, aside from genetic defects. I've had all three of my P. biguttatus make it from small nymph to adult with no issue, and almost never lose young of other insect colonies I have (for reasons that aren't my fault, that is haha).

I appreciate your input regarding the hiding options. The ball jar enclosures, meant for ease of feeding and monitoring during nymph stages, are somewhat open and visible. Perhaps the lack of full-cover hiding places is stressing them out. I'll try replacing the cork bark with an egg flat or toilet paper tubes, and see if they appreciate the added "safety". Thanks for the idea!

I'm curious of your input regarding the humidity. I've heard so many conflicting views on their humidity needs, I feel paralyzed trying to make a decision on the matter. Would you say most of your assassins of all three species make it to adulthood in your current conditions, or do a portion die off consistently as nymphs? Do they grow quickly within a month to 8 weeks, or take several months to reach adulthood? What temperature do you keep them at? I'm not trying to scrutinize your care at all, I'm just curious to compare the outcomes different people experience using different conditions.

 

[Tellorcha]

That's EXACTLY how I kept my Pystalla, I started with six, that six ended up making over 200 offspring, all of which I isolated and reared to L2-3 before selling them off. (To be fair it was a female heavy group of six). They like it pretty dang dry IME... With just food for moisture.

I'm responding to your first post as well as this one. I am inclined to try dryer conditions before opting for more humid conditions, despite the frequency of people vouching for humidity. I can't accurately remember for the first nymph death how humid the tub was when it died, but the second death did occur over night after I had misted. It does make me wary of humidity. You already answered some of my questions that I had posed for Chanda regarding the survival rate of nymphs in the conditions they're kept, but I wonder what temperature you keep yours at? Also, if you don't mind me asking, what was the stupid hide choice? It's great to be able to learn from each others' mistakes!

That is an awesome amount of offspring to have from a colony of 6 individuals! Congrats on all the babies! I am curious for the sake of my P. biguttatus, who have laid many eggs, none of which I've been able to hatch yet. How long do your eggs usually take to hatch, and how frequently do you mist/humidify your eggs? I am certain I have 2 female and 1 male P. biguttatus, and the eggs look like they've plumpened and turned darker red (and have dark caps for a few of them). I have been misting them for almost 2 months though with no hatchlings. For a long while, I was only misting once a week, but for the past 2 weeks I've misted daily. The eggs do seem to have darkened more quickly since I increased misting, but this is yet another factor I've heard so much conflicting opinions on. I'd love to hear your input!

 

[BenLeeKing]

I actually think these need LESS humidity than Platymeris, I kept them well ventilated, bone dry, no substrate, their only moisture came from their food. Only had a few premature deaths out of hundreds... All six of my original L1 nymphs made it to adulthood, with one having a molting deformity due to my stupidity in hide choice... I think excess humidity can cause "random" deaths like this, otherwise the mortality rate should be VERY low, (unless you keep every life stage together, in which case you'll see some cannibalism).

That is very interesting, most people i know just say "keep them more humid and I just accepted that as fact. If I ever get them I'll try keeping them either ways ans see if they prefer one than another

 

[Tellorcha]

That is very interesting, most people i know just say "keep them more humid and I just accepted that as fact. If I ever get them I'll try keeping them either ways ans see if they prefer one than another

That would be a great experiment!

 

[BenLeeKing]

That is an awesome amount of offspring to have from a colony of 6 individuals! Congrats on all the babies! I am curious for the sake of my P. biguttatus, who have laid many eggs, none of which I've been able to hatch yet. How long do your eggs usually take to hatch, and how frequently do you mist/humidify your eggs? I am certain I have 2 female and 1 male P. biguttatus, and the eggs look like they've plumpened and turned darker red (and have dark caps for a few of them). I have been misting them for almost 2 months though with no hatchlings. For a long while, I was only misting once a week, but for the past 2 weeks I've misted daily. The eggs do seem to have darkened more quickly since I increased misting, but this is yet another factor I've heard so much conflicting opinions on. I'd love to hear your input!

In my experience they pop out around a month, but many of of the eggs don't really hatch, some just pop open with no nymphs, some just never hatch. How many eggs did you harvest? when they turn plump and red is when they should be hatching, I guess give it more time to incubate I guess? I do a egg sift once every 3-5 months, and I'm still kinda figuring out the best logistics for hatching.
What I used to do is put them in a box with sub and mist around every day, but I noticed many mold if the box has low ventilation. (many eggs molded, bust still some hatching, forgot specific hatch data, ~20-35% of eggs hatched I think)
Then I switched to cotton ball in a box with where wet the cotton ball in hopes that it can retain and slower release back the moisture so I have to mist less. Sill mold, cause ventilation, so i just decided screw it, have it open to air with no cover. Ended up with also a decent hatch, similar to last time.
This time I just went with open top container, cotton ball, misting and wetting cotton ball directly, so far no mold, and it's been a week, we'll see how this goes.

 

[Tellorcha]

In my experience they pop out around a month, but many of of the eggs don't really hatch, some just pop open with no nymphs, some just never hatch. How many eggs did you harvest? when they turn plump and red is when they should be hatching, I guess give it more time to incubate I guess? I do a egg sift once every 3-5 months, and I'm still kinda figuring out the best logistics for hatching.
What I used to do is put them in a box with sub and mist around every day, but I noticed many mold if the box has low ventilation. (many eggs molded, bust still some hatching, forgot specific hatch data, ~20-35% of eggs hatched I think)
Then I switched to cotton ball in a box with where wet the cotton ball in hopes that it can retain and slower release back the moisture so I have to mist less. Sill mold, cause ventilation, so i just decided screw it, have it open to air with no cover. Ended up with also a decent hatch, similar to last time.
This time I just went with open top container, cotton ball, misting and wetting cotton ball directly, so far no mold, and it's been a week, we'll see how this goes.

This is very helpful, thank you! What temperatures do you keep them around? I have wondered if higher temps would speed the process. I had about 18 eggs in my first harvest, kept in a low ventilation container and all of them molded. I haven't tossed them yet, but I doubt any will survive. My second harvest was around 25 eggs, and they have much more ventilation and are the batch I'm currently monitoring for hatch. There are tons more eggs in the adult enclosure substrate, but I haven't harvested them yet. They're probably dormant due to dryness. Was hoping to hatch some first to hone in on a working technique, but maybe I'll harvest them all this weekend.

The mold is a bummer, glad to hear the top-off approach is working for you so far. Perhaps I'll try a screen or cheese cloth ventilation for my next batch to offer a bit more airflow. I hope you have luck with your next hatch!

 

[Hisserdude]

I'm responding to your first post as well as this one. I am inclined to try dryer conditions before opting for more humid conditions, despite the frequency of people vouching for humidity. I can't accurately remember for the first nymph death how humid the tub was when it died, but the second death did occur over night after I had misted. It does make me wary of humidity. You already answered some of my questions that I had posed for Chanda regarding the survival rate of nymphs in the conditions they're kept, but I wonder what temperature you keep yours at? Also, if you don't mind me asking, what was the stupid hide choice? It's great to be able to learn from each others' mistakes!

That is an awesome amount of offspring to have from a colony of 6 individuals! Congrats on all the babies! I am curious for the sake of my P. biguttatus, who have laid many eggs, none of which I've been able to hatch yet. How long do your eggs usually take to hatch, and how frequently do you mist/humidify your eggs? I am certain I have 2 female and 1 male P. biguttatus, and the eggs look like they've plumpened and turned darker red (and have dark caps for a few of them). I have been misting them for almost 2 months though with no hatchlings. For a long while, I was only misting once a week, but for the past 2 weeks I've misted daily. The eggs do seem to have darkened more quickly since I increased misting, but this is yet another factor I've heard so much conflicting opinions on. I'd love to hear your input!

Yeah, mine definitely seemed to do pretty well when kept dry, and here in the high desert of SW Idaho, the ambient air humidity is abysmal... They were kept at around 74-80F° if I had to guess, with the summer being on the warmer end of that.

Yeah it was a pretty successful first try, I had never kept the common hobby assassin bugs before and was amazed at how prolific they can be, if the eggs are separated and such... I think their eggs only took 1-2 months to hatch, and I kept them consistently humid, (misted them every three days, as much as needed to keep the coconut fiber they were on moist). If your eggs are taking a long time to hatch, and you are keeping them pretty humid, I'd assume the temps were slightly too low, a little bump in temps will probably get them incubating faster.

There are a lot of differing opinions out there on Platymeris/Pystalla care, and people have different thoughts on what a "successful" colony is, a small colony that cannibalizes the majority of offspring or has high die offs but is still self sustaining may be considered normal or successful to some, (since they are SO prolific and not everyone wants hundreds of mouths to feed), I'm just giving my personal experience on breeding this species which I hope you find useful.

 

[BenLeeKing]

This is very helpful, thank you! What temperatures do you keep them around? I have wondered if higher temps would speed the process. I had about 18 eggs in my first harvest, kept in a low ventilation container and all of them molded. I haven't tossed them yet, but I doubt any will survive. My second harvest was around 25 eggs, and they have much more ventilation and are the batch I'm currently monitoring for hatch. There are tons more eggs in the adult enclosure substrate, but I haven't harvested them yet. They're probably dormant due to dryness. Was hoping to hatch some first to hone in on a working technique, but maybe I'll harvest them all this weekend.

The mold is a bummer, glad to hear the top-off approach is working for you so far. Perhaps I'll try a screen or cheese cloth ventilation for my next batch to offer a bit more airflow. I hope you have luck with your next hatch!

Room hovers at at least 70, and now it's about high 70s. I would say as long as adults are ok then it's ok, 70 is should be ideal. (although now I have my mantis heat lamp, and it kinda shines over them, so I'm gonna put them somewhere else)

 

[Hisserdude]

That is very interesting, most people i know just say "keep them more humid and I just accepted that as fact. If I ever get them I'll try keeping them either ways ans see if they prefer one than another

Platymeris can handle humid conditions just fine, but I've heard bad things about keeping Pystalla too humid, and considering mine did fine bone dry, I'm inclined to believe they either prefer dryness, or at the very least do not mind it.

 

[chanda]

I'm curious of your input regarding the humidity. I've heard so many conflicting views on their humidity needs, I feel paralyzed trying to make a decision on the matter. Would you say most of your assassins of all three species make it to adulthood in your current conditions, or do a portion die off consistently as nymphs? Do they grow quickly within a month to 8 weeks, or take several months to reach adulthood? What temperature do you keep them at? I'm not trying to scrutinize your care at all, I'm just curious to compare the outcomes different people experience using different conditions.

The reason I try to moisten the substrate a couple of times a week is for the eggs. When I just had nymphs - before they matured and started laying eggs - I kept them dryer. (I still gave them a misting a couple of times a week, because they will drink water droplets off the glass or off the bark - but I didn't spray down the side of the tank and let it soak into the substrate on that side.)

That said, even though I moisten the sub once or twice a week, the screen tops of the cages allows them to dry out fairly quickly. It may not be totally bone dry, but it certainly isn't wet either. My goal is to have a little moisture in the lower layers of the substrate, but for the top of the substrate to be dry.

As far as mortality rates go, none of my Platymeris sp. Mombo nymphs died on me. All have matured and I'm hoping to be finding eggs any day now. (They may already have them tucked away in the substrate.) I don't remember if I lost any of the Platymeris biguttatus as nymphs or not. I might have lost a couple, but it's been a while so I'm really not sure. Now I have two tanks full of them and they're breeding like crazy. I'm sure there are some losses - probably to cannibalism - but I have too many to keep track of. I have lost a few Psytalla horrida nymphs along the way, but I can't really point to any specific reason why. Because they were always kept communally, I can't rule out cannibalism - or just being disturbed during or immediately after a molt.

 

[Hisserdude]

Also, if you don't mind me asking, what was the stupid hide choice? It's great to be able to learn from each others' mistakes!

Forgot to answer this specific question... When my first six nymphs reached the subadult stage, they kind outgrew the smaller communal enclosure I was keeping them in, so temporarily I housed them each separately so they'd have room to molt. I used eggcrates for all my other individuals, but used a slanted piece of a cardboard box for one subadult... Somehow it lost it's grip while molting to adulthood on the slant, (I think the cardboard was too smooth), and slid downwards to where one of it's front legs were pressed up against the plastic container while it was teneral... This caused that leg to come out all warped.

 

[Tellorcha]

Yeah, mine definitely seemed to do pretty well when kept dry, and here in the high desert of SW Idaho, the ambient air humidity is abysmal... They were kept at around 74-80F° if I had to guess, with the summer being on the warmer end of that.

Yeah it was a pretty successful first try, I had never kept the common hobby assassin bugs before and was amazed at how prolific they can be, if the eggs are separated and such... I think their eggs only took 1-2 months to hatch, and I kept them consistently humid, (misted them every three days, as much as needed to keep the coconut fiber they were on moist). If your eggs are taking a long time to hatch, and you are keeping them pretty humid, I'd assume the temps were slightly too low, a little bump in temps will probably get them incubating faster.

There are a lot of differing opinions out there on Platymeris/Pystalla care, and people have different thoughts on what a "successful" colony is, a small colony that cannibalizes the majority of offspring or has high die offs but is still self sustaining may be considered normal or successful to some, (since they are SO prolific and not everyone wants hundreds of mouths to feed), I'm just giving my personal experience on breeding this species which I hope you find useful.

Reading your experience is very useful. It does sound like your temps are a bit higher than mine, though your misting is pretty similar to what I'm doing now. Perhaps I will keep my space heater on more consistently for a week or two and see what happens.

That's a good point regarding varying opinions on success in a colony. I'm one of the weardos who would welcome hundreds, so I'm aiming for minimal die off. I can understand why many people would consider some die off to be more sustainable though, as it sounds like you could end up with 5 tanks of these things in a couple years. That would be a lot, oh my!

Thanks for your reply about the hide too, good to know what to avoid. My P. biguttatus male actually faced a similar fate as he molted in the shipping tube on his way to me. He has one tiny leg. Not ideal, but he still seems to be thriving lol

 

[Tellorcha]

The reason I try to moisten the substrate a couple of times a week is for the eggs. When I just had nymphs - before they matured and started laying eggs - I kept them dryer. (I still gave them a misting a couple of times a week, because they will drink water droplets off the glass or off the bark - but I didn't spray down the side of the tank and let it soak into the substrate on that side.)

That said, even though I moisten the sub once or twice a week, the screen tops of the cages allows them to dry out fairly quickly. It may not be totally bone dry, but it certainly isn't wet either. My goal is to have a little moisture in the lower layers of the substrate, but for the top of the substrate to be dry.

As far as mortality rates go, none of my Platymeris sp. Mombo nymphs died on me. All have matured and I'm hoping to be finding eggs any day now. (They may already have them tucked away in the substrate.) I don't remember if I lost any of the Platymeris biguttatus as nymphs or not. I might have lost a couple, but it's been a while so I'm really not sure. Now I have two tanks full of them and they're breeding like crazy. I'm sure there are some losses - probably to cannibalism - but I have too many to keep track of. I have lost a few Psytalla horrida nymphs along the way, but I can't really point to any specific reason why. Because they were always kept communally, I can't rule out cannibalism - or just being disturbed during or immediately after a molt.

Thanks for the reply to my questions, and details on your methods. Keeping the lower layers of substrate wet while the top is dry may be the closest to emulating wild conditions, and I could see how that'd make it easier to hatch eggs right in the enclosure with the adults. I was not imagining your conditions accurately from your first post, but this clarifies things quite a bit.

I'm glad to hear your P. biguttatus are breeding well, sounds like your humidity techniques are working well for them. Good luck with finding Mombo eggs too! I have noticed a pattern in this thread and in reading other older ones that the Psytalla seem most prone to dying for unknown reasons. Perhaps they are a slightly more sensitive species. While I may try sticking to dryer conditions first, I did mist pretty lightly whenever I did. If your dudes are all doing well with multiple mistings a week, then I doubt my once a week light misting could be to blame for my nymph loss. Perhaps I'll have to experiment a bit once I (hopefully) have a colony going in the future.

 

[chanda]

If your dudes are all doing well with multiple mistings a week, then I doubt my once a week light misting could be to blame for my nymph loss. Perhaps I'll have to experiment a bit once I (hopefully) have a colony going in the future.

Keep in mind - "multiple" is only one or two mistings a week, depending on how dry it is. When the weather is cold and the furnace is running a lot, it's more likely to be two mistings a week. When the furnace is not running (or when I get lazy) it may be only once a week. It's not like they're getting watered every other day!