gongylus gongylodes cannibalism

[julian camilo]

hello. sorry for this long intro but it sets the scene for my surprise and the main point of this thread.

im sure if youve read or heard anything about this species then one of the things youve read/heard is probably about it not being as cannibalistic as other (if at all). this attracted me to them somewhat and i kept a small group of 6 a few years ago in a single plastic tank for a while (i moved them to a much bigger netting enclosure when they were closer to adulthood), and while they were often in very close quarters (they would congregate in the area nearest the spotlight at night) sure enough i never had any problem with cannibalism. at times they would both pluck the same fly out of midair and would have a bit of a tug of war but it never "came to blows" as it were. they all reached adulthood intact (i couldnt mate them because i had 5 males and the female took ages to reach adulthood, by which time all the boys had died out).

i took a break from mantids for a few years but recently got a smaller group of gongs (4 smallish ones). i put them in a plastic tank bigger than the one i'd kept the 6 in previously and thought this would do them well for a while. however a few days ago, i woke up to find one had moulted and was very happy, but then realised the one that had moulted was lying next to its old skin, all that was left were the back 4 legs, abdomen and elongated thorax section. the crest/shield section of the thorax was gone, as was the head and front arms. there hung a very fat mantis on the branch directly above the corpse (i say, corpse, what was left was still kicking which was very unsettling, but i put it in the freezer to save it further distress, if thats possible). may i just mention that all the mantids were well fed.

i was kind of disappointed at the gong for having almost tarnished the nice docile repuation i saw gongs as having, but thought it was a one-off. then 2 days ago i was about to go to sleep and check up on them and one of the gongs i suspected was going to moult had, and was perched on a branch. only problem is it was missing front arms, a head and half a thorax, like the previous one. this time it was a different mantis that had comitted cannibalism. i'm now left with two (luckily theyre male and female and on the same instar). but its still really disappointing to think it wasnt a one-off isolated mantis/incident.

so, (if youve got this far by reading all that, have a gold star) what do you guys think is the problem? heat and humidity are pretty much optimal i would say. they were all well fed. it cant have been over territory because ive seen them walk on top and over each other before, as if the other mantis simply wasnt there, and neither cared much. and it was at night, so its not as if they were fighting over basking spots (they wouldnt need to either i dont think). both incidents occured just after the mantis had moulted and so was presumably softer and weaker and more vulnerable, but even so i dont this is an excuse considering the species and the conditions (space, food, etc). so yeh, any ideas? any input would be very appreciated as i dont want this happening to my remaining two obviously.

best wishes

julian camilo

x

 

[Sheldon Johnson]

All i can say about my colony, is that i rarely see canabalism. This Christmas i had my first act of adult canabalism since i started keeping them 2 years ago. An adult female ate a 5th instar male when they were starving because that weeks food didnt hatch, although ive seen them be far more hungry and still not act upon it.

However, gongys are far more likely to canabalise even when there is food around between the 1st 3rd instar, infact i had one batch which displayed more acts oof canabalism as nymphs that any other species i have bred to date.

I cant really figure out the problem, but can you tell me the exact measurements of the tank, type of food, temp and humidity? it might help.

 

[julian camilo]

thanks for your input. im not quite sure what instar they are, but the remaining two are this size:

the female:

the male:

and they ate ones moulting from the previous instar to this one theyre on.

i just measured the container the four (now two) were in and it has these dimensions:

Height 27cm

Depth 19cm

Length 42cm

for food i have been feeding them large bluebottle flies, however i have had alot of problems with the pupa hatching (most of them dont, and the ones that do take a very long time) so ive had to resort to crickets and unhatched waxmoth and bluebottle pupa (i know neither these nor crickets are particularly good form but i had to when the flies let me down. i might get greenbottle maggots like last time, they hatched out much quicker and much more successfuly). maybe this far from ideal food led them to this? because the food theyve had has been mainly very soft and wet, i dunno maybe they were lacking something that is available in exoskeletons, so resorted to each other to get it? this might be very farfetched but im just trying to think of all possibilities.

as for temperature and humidty, i dont have a thermometer or hygrometer inside any of my mantis enclosures as i think ive kind of got the hang of knowing when conditions are about right, though maybe ive got it very wrong this time? the temperature the gongs are at is always very warm, around 40 during the day, maybe down to 30 at night when i switch the lamp off (but they are near a heater, the heaters in our house come on at night). humidity i imagine is very low, but i spray them with a bit of water every other day or every 3 days and they drink it from themselves and wherever else it lands usually, but sometimes they do not seem interested in it.

im not sure what else to mention. maybe its too hot? maybe the food has not been adeqaute? im waiting for some waxmoths to hatch (should be next few days) and some bluebottle pupa (next few days too), in the meantime i have crickets if they get very hungry but i will get some greenbottle maggots and hatch them out soon just in case these bluebottle pupa are dud/dont hatch.

thanks

julian camilo

 

[FieroRumor]

It's possible that the one started molting, and the other saw movement, and just snatched him. YOu know how mantids are sometimes...

 

[julian camilo]

but the thing is, both times the mantids waited til the other one had finished moulting, and THEN attacked. and in any case, it doesnt quite answer the WHY? its really confusing me because i guess i'd expect it from other species but not this one. but thank you for your suggestion. maybe i would do well to remember that they are after all just opportunistic carnivorous insects, and they spotted a weak and vulnerable prey and jumped at the chance

 

[Sheldon Johnson]

First off, dont feed them crickets, you are encouraging them to eat something which is the same colour and roughly same size as a gongy head or body. Also when you get them to adulthood, the females wont lay proper ooths if fed on crickets - too much chittin.

As for your fly situation,there is a simple solution. Get a container, small pot or something and fill it with some soil. Put the maggots in here and they wil bury into it, this will keep them hydrated. The most likely problem you are having with them not hatching (and i would imagine they are very sluggish too even if they do hatch) is that they are being kept too warm. this causes 2 problems, dehdration and increased metabolism. In my experince flies that are kept too warm during incubation tend to come out very sluggish and have much less energy and hatch only about a day earlier, thus resulting in a quick death.

There is one other problem you may have encountered with the flies; if you have gotten them from a tackle shop, they will often put some white poweder on them. Too much of this cause it to harden around the pupae and will stop them from hatching.

Other than this, when it comes to flies you need to develop a cycle. Try getting a load once a week every week, this way you have regular food and know when it should hatch (roughly).

Just remember flying insects are what gongy specialise in and it is best to feed them on them and only on them. I had to use crickets once or twice in my early days when i had problems with flies hatching and it resulted in small badly formed oothecas that never hatched.

 

[julian camilo]

thank you very much for the advice. i did used to have a good fly system a few years ago, and greenbottles (the occasional waxmoth) were the only thing i fed my gongs as i'd heard about this problem they had with crickets. however ive had to resort to them this time round. but thank you for suggesting the soil idea.

i do very much think the heat and dehydration are what stops them hatching, now that i think of it. i put some pupa in the gongs tank so that when they hatched they could be eaten, but these never hatched (im assuming now because it was both way too hot and too dry), whereas some i had in a seperate container, away from heating and lighting, had one fly hatching ok, and one begin to emerge from the pupa but not make it out and die. also what you said about the powder, i did get them from a tackle shop and they did indeed come in this sort of white powder, so this might have something to do with it. i opened a few of the pupa to see if they had developed at all and most of them were pretty well developed, and looked about ready. maybe they couldnt emerge from the pupa because of the powder? although it wasnt too much, they just seemd a bit sprinkled in it. would washing the powder off of the pupa work?

i will deffinitely try the soil idea, thank you very much. also, i keep most of the pupa in the fridge, how long can i keep them here? will they "die" at some point, or even hatch out while still in the fridge? does keeping them in the fridge a long time permanently mess up their development/incubation in some way? sorry for all the questions, im just curious and it'd be useful to know.

thank you very much for your help.

best wishes

julian camilo