Black soldier flies...toxic to mantids?

[ignatz]

I was initially thrilled to have a bumper crop of BSFs this year, and have been experimentally feeding the adults to a few of my more "expendable" species. Thinks were going well but lately I've had some die-offs of H. majuscula. Their abdomens are visibly black, then they fall off their perches and die. Only some of the test group have been affected but it's enough to make me worry, Some have also had the black "cricket pukes" from them. I've quite feeding them out...which is a shame because the biomass from these BSF colonies is incredible...and they're  free, being fed compost.

Any ideas, other people's experiences using BSF adults for mantis food, etc. much appreciated.

 

[Teamonger]

I've been using BSF as a staple feeder for my Chinese Mantises for 2 generations now. Besides the fact they are not overly active and exciting for the mantises and leave extra litter with their hard exoskeletons I've had no problems personally. Almost every time I have had any sort of wave of die outs its almost always after I got desperate and used crickets (which I am never doing again). I have also fed the larva to my mantises with no issues.

Are you breeding/catching them outside? All I can think is as they are breeding in compost perhaps they are getting something on themselves that contains something that is killing the mantises? Bacteria or the like? As far as I recall the adults don't eat so it would have to be transfer rather then diet. My stock is completely farmed and contained indoors with fresh food so that could be the difference.

You are not the first person to write a thread like this so there has to be something to it but I don't think its the flies themselves so I would assume its something in their environment.

 

[CosbyArt]

@ignatz Sounds like the culprit is likely a bacteria infection, and can be passed to other mantids from exposed material (including feeding tongs) and possibly in the air itself.

Bacteria can be caused by excess humidity in substrate, decaying matter such as feeder remains or frass (poop) with high humidity, infected material added to the habitat, and similar things allowing it to thrive. If you see mold in a habitat that is a sign humidity is too high, and bacteria will breed in those conditions.

Affected BSF themselves they should be showing health problems, regardless though it could be in their compost. The matter being broken down normally is due to aerobic bacteria in the compost, while normally harmless can lead to problems if the compost bin material is not turned/rotated properly.

As a precaution you should clean and disinfect the mantid habitats and materials inside it, using hot soapy water, a highly diluted bleach water solution, vinegar, and/or heat. See this post about cleaning/disinfecting. The mantids themselves should be given 100% real honey to help with any infection as well. If it is not bacteria, the only harm done is cleaned habitats and honey treats.

 

[ignatz]

Thanks for all your responses, but several issues stand out:

The only species experiencing die offs are the H. majuscula. We have the opposite problem with humidity  here - I have to struggle to keep it high enough for species from the humid tropics. I keep everything clean. I'm not a complete newbie. Orchids doing fine, as are 15 other species. The larvae are eating all organically grown food waste and some grain, bins are outside. The "infection" has a very rapid onset, one day the animal is feeding, the next it's dead with a blackened abdomen. No time to get them honey or anything else. Other species such as dessicata that got the flies occasionally when they just started to produce are fine. Might be a pathogen that only affects the H. majuscula, or it has become so hot here that a pathogen is being passed on now through the BSFs all the way from larvae to adult, which i find a bit hard to believe, but it's possible.

Going to have to stop being so lazy and do some smears of gut contents on the dead mantises, and stop feeding BSFs for a while. Again, a pity because I've never had feeder colonies that crank so hard.

Also strange that BSFs, which have an all vegetable diet around here, would carry something nasty when the bluebottles and houseflies i get are grown basically on the nastiest stuff imaginable - dead fish, animal products of unknown origin.

Another thing that's odd is that I find that if i handle the adult BSFs for a while, I get a slight allergic reaction to them. a bit of dermatitis, numbness around the lips, etc. That makes me worry that there's something in the bins that is really not good, or that adult BSFs carry some strange proteins around with them...but I've never read anything about this.

I NEVER feed crickets. Learned that lesson a long time ago.

Anyway, will keep you folks updated.

 

[Teamonger]

Yup crickets are just too risky, I have learned my lesson as well unfortunately. 

Very interesting, if you ever find anything out about this I would love to hear it. Its true about the bottle flies being the nastiest things ever so it makes no sense at all that the BSF would be carrying anything they are not. The larva are also boasted as being an end to a lot of hazardous pathogens and the like so yet again its very mysterious. That said pathogens that can affect us are not nearly the same as pathogens that can affect mantises.
http://blacksoldierflyblog.com/2008/06/13/bsf-not-vectors-human-pathogens/

I absolutely love them as a feeder for both my reptiles and mantises so I'm sad you are having such issues with them.

 

[CosbyArt]

@ignatz Very strange and a extremely fast infection of seemingly 24hours to death. Affecting only the H. majuscula species adds a clue, but overall makes it more puzzling. I was not trying to be insulting about the humidity and such, just suggesting a common cause that is often overlooked as it is such a "beginner" problem.

If you a developing a allergic reaction that alone is enough to quit using BSF as feeders anyway. It does make me wonder too if that is a more common issue than known, as they are not a common feeder.

 

[ignatz]

I just had another thought, but in order to test this hypothesis I'd need to do some serious lab work. Being in Albuquerque, land of a million roaches ( in turn supporting an unbelievable number of black widow spiders) they get into the  BSF bins. Depending on what taxonomic school you belong to, roaches and mantids share a common ancestor...and I'm wondering that given all the weird coccidia and other parasites that roaches have that they're not passing on something strange to the BSF larvae, that act as a kind of intermediate host to something nasty. My compound scope is in really bad shape..and being intracellular parasites coccidia are an incredible pain to find - .anybody know of any work that's been done on pathogens that infect mantises, so that I might have a place to start other a standard float and/or smear? This might be worth doing, as I suspect some connection to what I'm experiencing and the black cricket skitters or whatever it is that crickets carry that seem to kill a lot of mantids...

I remember also that roaches have population crashes here when the "monsoon' rains come in the summer - due to conditions being right for the growth of coccidia. it's the only thing that dings their numbers, actually, and maybe the dampness of the bins and the compost create similar conditions...if anybody has any leads on people who are really into insect parasitology, please let me know. Maybe these mantids didn't die in vain...

 

[ignatz]

Hey Teamonger - has your inside setup been described somewhere in full? What do you feed your larvae or do you just start with late stage larvae and let them pupate?

My system starts with compost and soured chicken mash to attract wild adult BSFs...but I haven't figured out how to keep them going in a closed loop during the winter...and won't bother unless i can figure the chain of infection here.

 

[Teamonger]

@ignatz  Yup sure have! However it looks like I need to swap my pictures over to not photobucket finally. I'll try to get to that asap but I have a wedding to go to today so no can do.

I can attest to my first setup working TOO well. I definitely had eggs being lain and massive population explosions. It was pretty darn big however.
The second round is what I'm using now. I have not confirmed matting or eggs yet in that set up but its just starting to get ramped up now after I changed them all over to the new smaller bin.

I feed my colony pretty much exclusively on apples, potatoes, and the occasional squash/pumpkin as its supposed to entice them to lay eggs.



This one probably has a lot of information you really don't need but just incase.

 

[Teamonger]

@ignatz I updated the BSF threads so the pictures are back, just fyi.

And funnily I had a wave of die offs after swapping my mantises to bottle flies so I'm going back to the solider flies. Its like we live in opposite land.

 

[CosbyArt]

@Teamonger Nice, I fixed many of my photos too and glad to see you did the same.

Strange, about the die-offs for you both, neither swap should cause such a reaction. I hope it was minimal and your remaining mantids are healthy.

 

[ignatz]

That's just nuts. But it's been a strange year. I got a bunch of ff colonies from Josh's and they were filled with disgustingness, brought black mold and some bacteria that sours the cultures and makes them smell like all the demons in heck ate beans, beer and cabbage. First year in 20 years of raising them I've ever had any trouble, but I'm really not liking their culture media anymore and will just start making my own when this runs out. The only way we're going to figure out what pathogens if any are at work is to do the lab stuff, which I'd better get moving on. I suspect the extreme heat that's been gripping the SW is partly to blame for a lot of this. One thing about HFs and bluebottles - both have been implicated in spreading botulism to birds, and I'm wondering if the grow medium of the commercial growers contains something nasty that's passing the bacterium to the flies. i'd  Imagine that botulinum toxin would kill more sensitive insects like mantids if high enough concentration...but there would have to be multiple reports of mantis die-offs before this would make real sense. I have bluebottles visiting the bsf bins as well, but their eggs don't make it as the BSF larvae secrete something that inhibits the growth of most other flies...except for a species in the genus Syritta - in the hoverfly family....trying to culture those now as they;re also compost feeders and don't need animal products. By the way, feeding the adult BSFs still to my blue tounged skinks and beardies, and they love them, no ill effects. So, I'm seriously thinking that it's something very species specific...

 

[Teamonger]

@CosbyArt Unfortunately I think the egg I produced did not hatch out very strong stock. I only had about 20 hatch from it and of those I now have a total of 4 left still alive and healthy. Its been a very frustrating and disappointing few months and is working on putting me off Tenoderas completely. I had a lot of random die offs in my first hatch but there were 200 of them so it was easier to handle. I swear that every single time I name a Tenoderas they die within the week its maddening! Doesn't help that I work hard to take awesome care of them then they all up and kick it on me.

@ignatz That sounds about right. Mantises are fragile little things some times. If you do end up doing any of the lab work I would be fascinated/interested to hear the results. 

 

[CosbyArt]

@CosbyArt Unfortunately I think the egg I produced did not hatch out very strong stock. I only had about 20 hatch from it and of those I now have a total of 4 left still alive and healthy. Its been a very frustrating and disappointing few months and is working on putting me off Tenoderas completely. I had a lot of random die offs in my first hatch but there were 200 of them so it was easier to handle. I swear that every single time I name a Tenoderas they die within the week its maddening! Doesn't help that I work hard to take awesome care of them then they all up and kick it on me.

@ignatz That sounds about right. Mantises are fragile little things some times. If you do end up doing any of the lab work I would be fascinated/interested to hear the results. 

I have the same problem, naming a early instar hatched nymph seems to doom it to a early death. My wife refuses to name any now as she says every time she does they die within two weeks.

Sorry to hear you have experienced the dreaded Tenodera nymph hatching problems.

I've had a few weak individual ooths too, with few of those nymphs if any at times surviving to adulthood. To be honest I'm not sure if it related to the mother of the ooth(s), humidity/heat during incubation, or something else; however, thankfully the more ooths that I've hatched over the years the less frequent problems occur that affect nearly all the nymphs.

Sure the species hatches in huge numbers as few survive in nature, but having less than 15% survive to adulthood isn't right. I do know though with my Tenodera ooths it has been a more common issue with captive bred mothers than wild-caught mantid mothers. So I assume it means there is a nutritional need that was not met, producing weak offspring. I like to mix up their feeders for a more natural diet anymore, and it seems to have curbed the weak nymphs too.

If Tenodera is a species you like all I can say is keep at it, as it does get better.

 

[ignatz]

There are several issues that I've already started to notice that I'm wondering are related to inbreeding depression from a lack of new lines being brought in from wild stock. One, all of my mantis populations are very male-heavy. My latest round of G. gogylodes are 90% males. Might be temps or something else, but I've heard of these sorts of problems with other species. Is this hearsay? Maybe given how dangerous it is to be a male has something to do with it, but this high a ratio doesn't really make evolutionary sense unless somebody has a better explanation.

Secondly, no, this low level of survivability of nymphs would not work in nature. We're not even dealing with the high rates of predation experienced by all insects at every life stage. None of these species would be extant if they died spontaneously like they seem to, So, and this probably needs another thread or maybe it;s been covered elsewhere, but it seems to me that the orthodoxy followed by most mantid keepers is going to have to carefully examined for mistakes/and or we have some serious genetic problems here. Could nutrition be a part of this? We feed too few species of feeder insects. Remember that a lot of work has been done with vertebrates - for instance, when I was a kid we fed a lot of goldfish to pisciverous reptiles and other fish, and because goldfish contain high levels of thiaminase, an enzyme that destroys thiamine, the animals died or we had zero breeding success with them. The same thing is happening  with certain Great Lakes game fish due to their eating the introduced menhaden, I'm really starting to wonder now about the inbreeding and feeder issues in particular, In the wild, most mantids would have their pick of literally thousands of prey species....how about the issue of them eating bees, with the pollen loads that they are carrying? All sorts of interesting lipids in pollen, maybe some of them are important in ooth production for some species...who knows?

 

[CosbyArt]

@ignatz Lots of interesting points, and questions that don't seem to be definitely explained currently. I've searched the forum, and various scientific related articles with little relevance to the matters multiple times, even if looking at mantid species in general.

With mantid lifespans of nearly a year and the several generations of testing needed, there does not seem to be anyone standing inline to take on the task of maintaining proper regulated conditions for any reliable results.

I do however like your idea of a new topic for trying to gain insight into the matter from as many keepers as possible. Perhaps with enough observational data some possible theories would postulate.

 

[ignatz]

Hi Thomas, OK, I'll try to start another thread when I get back from fieldwork next week. In the meantime, thoughts, questions, possible lines of inquiry, methods, references, possible contacts for parasitology-oriented entomologists, etc much appreciated. I'm completely uninterested in the commercial side of the great Ponzi scheme that, seemingly at least, is mantis keeping, so maybe a set of empirical questions to answer will keep me motivated.

 

[CosbyArt]

@ignatz Alright sounds good, and hopefully there will be some good responses.

I understand your distaste for the commercial venture, there are many potential problems for even the most honest seller or buyer - let alone one that is less than scrupulous. That is one great thing about the hobby, given the wants/needs of a keeper they can capture their own wild mantids and feeders.

Indeed answering some questions could keep you well motivated and in the hobby for a longtime to come, and hopefully shed new light on matters too.