Unknown grub care help

E

ExtoCooler

L1
Hi everyone! I need some help with the new grub I bought. The site and seller tell me that it's a dynastes tityus but the other people I showed pictures of believe it to be a Goliathus grub. I'm also worried about them not eating and the black spots forming on their stomach and back. I'm wondering what the best kind of enclosure would be for it and how to feed the grub, since there's not a lot of guidance online for them. Should I use a heat mat to warm up the enclosure to a good temperature? How do I prepare the food and help the bug eat and which foods to supply it with.

Please help me!

IMG_20220221_104152.jpg

 
Unbelievable,

you got a bargain, maybe- Goliath grubs take very different care than virtually every other beetle grub,

That looks like a healthy L2, if you don't know already, the grubs do not eat substrate, they eat protein, and need more attention

than substrate eaters. I feed mine high protein koi pellets, which I moisten, use coco fiber for substrate, they need kept clean, 

temps in the mid 70's.  There are online articles, and there's Youtube as well, maybe someone here will send you some links to 

some good online information.

 
kevink said:
That looks like a healthy L2
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I think it's an L3 larva, but otherwise agree with everything kevink said. Goliathus that is already this far into the development, assuming healthy, is a huge bargain, as you essentially got to skip most (I estimate ~70%) of the feeding/cleaning interval. I am not sure what the tiny black dots are though. In case it is some kind of an infection, I think it would be prudent to record its mass every other week or so to make sure it is growing/maintaining its mass (unless it is getting yellower and getting closer to the end of the L3 stage and slowly reducing in its mass, which is also fine).

Also it blows my mind how large the spiracles are on G.g or G.r L3 larvae every time I see them.

 
I think the spots are an infection from a new substrate type, when I set up the enclosure I used the substrate the larvae came packed with and mixed it in with the other substrate I used but it wasn't a lot of substrate. Right now I'm struggling with them not eating and maintaining the temperature high enough. I've been told conflicting information about the heat mats so I'm trying to use a small space heater to warm up the room. It's very cold here in Massachusetts.

 
It's tough to get a heat pad just right, I have a couple sizes of reptile pads..for some reason- at any rate, they just were too warm, even with using

bath towels as a buffer, maybe a pad for warming plants would work, or something with a thermostat. I think mid 70's is the recommendation.

I use a space heater to oscillate near my containers, I've got 3 grubs, if I had a larger operation, it would take some rethinking. If you don't already

have one, a digital  thermometer works great, they're cheap and fun to play with.

 
For insects, heating the entire room is the most practical way of maintaining the ideal temperature.  For most species, it's best to keep the temperature at approximately 75 F (24 C), if possible.  Somewhat lower than that is ok, but try to avoid going much below 70 F (21 C).  Heating pads are intended more for use with reptiles, which have a better ability to regulate their temperature than insects do.  If supplemental heating is needed for keeping an insect room within the optimal range, I recommend using a Vornado space heater such as model AVH2.  These heaters are more expensive than most, but are much safer to run for extended periods since unlike earlier generation space heaters, they have no glowing heating element, and have built-in shut down protection in the event of a malfunction, or if they accidentally get knocked over.

 
ExtoCooler said:
Should I keep the substrate warm too or is it fine being colder for the larvae?
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Between 70-80 F, and preferably as close to 75 F as you can maintain.  If kept much below 70 F for extended periods of time, this can lead to metabolic issues, eventually leading to a failure of the larvae to develop any further.  Also, if too cool (or too warm), the larvae won't feed properly.

Regarding those small black spots - they're melanin deposits, which form in response to contact with something that has caused skin irritation.  Generally, this is a result of a nutrient overload in the substrate, caused by a lack of substrate change on a frequent enough schedule.  Overfeeding can very rapidly lead to fouling of the substrate, so best to be conservative about how much food is offered at a time.  Never offer more than a larva will eat in about 24 hours.  Any food that is not eaten after that amount of time will likely be ignored, as it will have become moldy.

These numerous, small spots are a completely different condition from the "black mole disease" that sometimes (rather rarely) occurs in beetle larvae, which is caused by infection with a coccidian parasite.  This disease typically causes a small number of quite large spots, rather than a large number of tiny spots.  Black mole disease is ultimately fatal, but the far more common condition that produces numerous small spots, caused by poor substrate sanitation, generally does not affect the health of larvae to the extent that they fail to grow and develop into adult beetles, especially if steps are taken to maintain good substrate sanitation for the remainder of the larval stage.

 
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ExtoCooler said:
I've left the larvae alone for a few days, and he's still not eating. I don't think he's molting so I'm not sure what to do.
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Please give details on - 

temperature
substrate moisture level
size of the container
type of food 

- and I will try to determine what the problem might be.

Also - is the larva mostly staying at the bottom of the container, or is it wandering around at the top?

 
The moisture level is at the right amount, it sticks together when I bunch it up, the temperature has been between 73 and 77 Fahrenheit for the room and enclosure, the food is koi pellets with 40% protein and 4% fat, and the enclosure is an 11" x 8" x 7" enclosure with substrate filled about a third of the way up.

 
ExtoCooler said:
The moisture level is at the right amount, it sticks together when I bunch it up, the temperature has been between 73 and 77 Fahrenheit for the room and enclosure, the food is koi pellets with 40% protein and 4% fat, and the enclosure is an 11" x 8" x 7" enclosure with substrate filled about a third of the way up.
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The Larvae also burrows a lot, he's mostly in the substrate whenever I check on him

 
ExtoCooler said:
...the enclosure is an 11" x 8" x 7" enclosure with substrate filled about a third of the way up.
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That's much too large a rearing enclosure for a Goliathus larva.  Instead, place the larva in a 16 oz container, such as this deli container, or similar (you'll need to make some ventilation holes in the lid, of course, and also secure it tightly with rubber bands to keep the larva from pushing it open) - 

PK16SC-4.jpg


This species prefers confined spaces, and likes to be in contact with a solid wall as much as possible; in a larger, more open space, they don't feel secure.  Also, larger containers make it more difficult for them to find the food.

 
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make sure and moisten your koi pellets, the larva would probably never encounter a dried food material in the wild, and make sure your air vents are big enough for good

air flow, without letting the substrate dry out.

My grubs are a bit bigger, but I've got them in containers with a  4.5" x 7" footprint, and 3 or 4 cups of substrate, only about 3" deep, and they do seem

to gravitate towards one side or end and stay near the bottom as well. I made a youtube video showing my little operation, it's called

"goliathus goliatus grub care"

 
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