Strategus Antaeus cannibalistic?

[GelGelada]

I recently went on a trip and I had two cups with multiple eggs inside, four in each because I had no time to run out and get individual cups for my last wave of eggs. I had planned to get them as soon as I got home. No grubs in them already, just eggs. They were meant to be immediately rehoused when I returned, but some of them hatched earlier than my predictions. When I finally got home, there was only three in one and two left in another, though one of the babies appeared to had died of other causes. That baby didn't appear to have eaten and was shriveled up. Nothing could escape... so I'm guessing they're cannibalistic? Or could even fresh babies surrounded by food still feel overcrowded that quickly? They must have been together for barely two days after hatching. I feed them a mix of dead leaf flakes and crushed apple, served as a sort of paste, which has done very well to feed my other Antaeus larva. I saw no note of cannibalism in the handbook for Antaeus... was I just unlucky? I don't think one emerged and crushed the other eggs, but it's possible I suppose... however, I'm skeptical because all of my larva, even my eastern hercules, barely move right now. It's kind of cold in the house. They find their food and just park right at the bottom of their containers where I can see them gorging.

 

[Schledog]

It says in the ultimate guide not to disturb the eggs because they are easily damaged so maybe a larvae could have damaged the eggs or maybe you accidentally damaged the eggs without knowing. But that’s my opinion I haven’t kept this species I was just stating what the guide said while adding something on.

 

[GelGelada]

I want information from people that have hands-on experience with Strategus Antaeus. Not a similar species. Specifically this species.

The "Complete Guide" book that I have is too vague with Strategus Antaeus and has been entirely unhelpful for the time I have been raising this species. There simply isn't enough concise information for them. If it's online, I can't seem to find consistent answers. I don't know if the "Ultimate" guide adds additional information for Strategus Antaeus, but the version I have is but a tiny segment. I have had far better luck with my own experimentation, substrate especially, than anything else, no offense. A big issue I have with the care book is that it states that they will not survive to adulthood in rotten wood but then fails to precisely note what kind of sand they need. I live by a beach. To me, sand is extremely fine. More than "playground" sand but that doesn't compact. To not say what kind of sand is annoying because sand isn't all the same...

Anyway. The eggs seemed healthy and were developing well before I left. They had begun to turn yellow and I could see the babies inside very clearly. If they were damaged, I don't think they would have gotten that far, but I could be wrong. Reason why I disturbed them to begin with is that I would rather risk damage than not be able to observe the eggs, as I was experimenting in different substrates and food, as said in my other threads. Having them individual cups allowed me to have precise dates for when I found them and how they were developing, as the care book also doesn't even say how long it takes for them to mature. Additionally, leaving the female inside her bucket to continue digging would harm them, as I found one crushed egg next to another when I first started looking for eggs a few months ago. Since they only lay about twenty eggs, who knows how many she crushed already while packing the soil that I didn't find.

What I DO want to know is if the grubs are cannibalistic. I'm housing them all separately now, but I want to know. Can someone who has raised the species give me information? Thanks.

 

[PowerHobo]

I can't speak for the species' communal nature, as I've never kept them, but cannibalism or even autocannibalism due to stress is a fairly common trait in most insects with the capacity to do so. This covers a wide swath of occurrences, including uncomfortable temperatures, overcrowding, lack of food, frequent handling (which doesn't sound like the case here since you were away), bad sub/food (for the species), illness, injury, and plenty more.

I know at least some other Strategus spp grow very quickly compared to some other North American scarabs, which could lend to unexpected overcrowding. The unfortunate part is that, as with a lot of larval deaths, even finding the answer to your question on cannibalism, you'll likely never know what really happened here.

Just this year I had two containers with 10 D tityus eggs each experience 100% die off, despite being in the exact same type and batch of containers and using the exact same batch of substrate as four other containers that experienced NO die off (well, 2 deaths, but still). Zero ideas what happened. Never found any mold or anything suspicious.

 

[GelGelada]

Yeah, temperature fluctuation is my primary suspect right now, because it was very warm and then it suddenly got super cold while we were away. The weather is really just doing whatever the it wants right now. Today it's in the mid 70's but a mere two days ago it was below freezing. We don't keep the heat on very high this time of year, but dropping from about 77 to 75 or so doesn't really strike me as a huge drop in a house. Then again, I'm not a teensy larva in moist soil. It might have felt MUCH colder to them than it does to me. Our house is old and our thermostat isn't very accurate and I can't exactly figure out the temperatures in a bunch of small cups right now with the ox beetles. The smallest babies don't have a lot of soil to "cushion" their temperatures in their cups compared to my huge eastern hercules, so that's why I think it may have been too cold and they got shocked?

As for your die-off, I feel you there because I just ran out of my jar of food I made for these guys during the hurricane and I'm kinda worried that they will get shocked from something different. They don't eat much of their substrate so I'm unsure how to keep them well fed with what plants I have here locally. I think moving them to all sand and leaves though would be too much of a shock, since they have been in a mix of oak flake, leaf flakes and sand since birth.

I wasn't aware that they could/would autocannibalize from stress, so thank you for telling me.

 

[AlexW]

Even pentatomids and caterpillars will cannibalize when starving or crowded, and almost all generalist herbivores will eat corpses even if healthy.