Decomposed Leaves with non decomposed oak wood as substrate

[Garin]

Hello beetle breeding experts, another quick question regarding substrate.

I have some friends that have done pretty well raising Megasoma punctulatus. They have gone through a few generations but they also tell me that they have about a 40% die off (60% successful) from the egg to adult. I don't know but I assume that's about normal?

Anyway, they have been using a combination of Oak Leaf Mold with dead Mesquite branches but the Mesquite wood they are able to find is not completely decomposed. It is not the type that crumbles in your bare hands. They take a sledge hammer and smash it up. The mix is about 2/3 oak lead mold and 1/3 smashed up Mesquite branches. I have been reading on this forum that you should only use decomposed wood that crumbles in your bare hands or you must ferment the wood after grinding it up.

Do you think it works for them because the Oak Leaf Mold contains the needed microbes that the non decomposed wood is not providing? They have told me that in the past they used Oak Leaf Mold only but the larvae would die at L3 or so. Thus the non decomposed wood seems to be doing something despite not being decomposed.

Any comments would be appreciated. Shade of Eclipse, you have a lot of knowledge about the microbes and all that stuff so any comment from you would be really appreciated.

I'm new to all this stuff and still don't really understand the decomposed part completely. I also notice that in areas like the desert, there is not much decomposed wood around. So how do the species like Megasoma sleeperi survive if there is very little decomposed wood? There is alot of dead wood from branches, etc but most of it is very dry so it's not the kind that crumbles in your hands.

Thank you again,

Garin

 

[Shade of Eclipse]

Some beetle larvae require wood in their diet and just giving them leaf litter doesn't provide them with the nutrients they require. Mesquite is an aromatic hardwood and won't break down very quickly on its own and until it's decomposed, it usually deters detrivores. Some larvae feed can on non-decomposed wood and have specialized gut microbes that help them do so, but the rhinoceros beetles I've kept have all preferred very broken down wood with a preference towards naturally rotten wood or wood that's been fermented more than once. I've never kept Megasoma punctulatus, so I can't say for sure what's going on, but I have some guesses.

If you mix pulverized wood or sawdust in with a high amount of leaf litter compost, you are basically composting the wood, so the mesquite may be breaking down enough over time that the larvae were able to feed on it. One of the alternative ways of processing sawdust without fermentation is to mix in compost, leaf litter, and a little bit of frass for microbes and then keeping it somewhere warm so that the wood-feeding microbes break down the wood for you. They're probably finding that the larvae are capable of feeding on just the leaf litter for the first couple instars until the wood they've added has been successfully broken down enough for the larvae to feed on it. At that point, the larvae are able to find pieces of sufficiently rotten mesquite to provide them with the nutrients they need for continued development.

In the desert, you can find decomposed wood, but it's usually not on the surface of the soil where it's usually too dry for fungal action. You should look for dead trees instead of dead branches littering the ground. Once you find a dead tree, you'll usually discover that either some of the inside is rotten or the wood near the base and the wood making up the root network is rotten. If you want to find rotten branches, you want to look for places where flash floods would wash dead branches as those places tend retain moisture for longer and the wood has a better chance of being attacked and processed by fungus.

Have they tried rearing them other types of wood or plant matter? Many desert beetles are quite opportunistic and will feed on all sorts of organic matter. Some remain underground for years, tunneling around to feed on bits of buried plant matter, roots, and even feces. Herbivore feces tend to provide a good amount of fiber and organic matter and are one of the primary sources of it in the desert.

 

[Garin]

Thank you Shade of Eclipse for that incredible explanation. I'm not sure what you do for a living but your knowledge of beetle food and feeding habits is amazing.

I do not think they have tried other types of wood or plant matter. They have only tried Palos Verdes for Megasoma sleeperi and Screwbean Mesquite for M punctulatus that were found in their natural habitat. I have heard of other beetle breeders successfully using decomposed oak wood for the M punctulatus.

I agree with your guess that the wood probably is being decomposed by the time the L3 larvae are in need of the nutrients and there are probably some pieces of wood that have decomposed enough by that time.

I have been able to find a few small pieces of wood that have been partly buried in the sand and seem more decayed. I guess they retained a little more moisture because of being protected by the sun.

I also did find some decomposed wood but it appeared that the wood had been burnt, as if someone used it for a camp fire. It crumbled quite easily. I assume the wood that crumbles because it has been burnt is not good because the process was not done properly?

Thank you again for that wealth of information, really interesting. Thank you also for the tips regarding looking in washes and looking at the roots and inside of a dead tree.

 

[Shade of Eclipse]

I studied zoology in college and enjoy learning about the variety of ways life on Earth has adapted to the environments they're found in. I keep a wide variety of animals and try to learn what I can so that I'm able to find better ways to keep them alive and healthy. I work in lab at the university I graduated from and help them maintain their colonies of animals.

Rotten wood tends to burn very well, so it's historically used as fuel to start a fire. Once burnt, wood is no longer useful for rearing larvae since the process of burning transforms the chemical energy stored in chemical bonds into thermal energy. The process turns the fiber, which is a complex sugar, into heat, carbon, and water in the form of steam. A larva would have digested the fiber to produce other forms of chemical energy that it could use. Any protein found in the wood would also undergo similar chemical breakdown and become unusable as well.

If the rotten wood isn't burnt, it's usable if whoever used it for a campfire didn't also pour chemical accelerants on it. I'd probably avoid it just in case. Larvae may also avoid feeding on wood that smells and tastes like it's burnt.

 

[Garin]

Great information, thank you. I'll avoid the possibly burnt wood.

Thanks again for all the helpful information.