Goliathus goliatus Breeding Log

Last updated: September 16th, 2020

This page is to document the growth and development of the 4 Goliathus goliatus grubs I acquired on July 17th, 2020. These grubs were purchased from Bugs in Cyberspace on July 15th and shipped via USPS Express Priority Mail. All care has been recorded on a spreadsheet and is copied below. In this spreadsheet, I name the grubs sausages because unlike many other large beetle grubs that curl themselves into a “c” shape, these grubs prefer to stretch out and look like sausages in my opinion. The names themselves are irrelevant, though, and it is simply a manifestation of my own bit of foolishness. In addition to the names, be aware that this is the raw data that I recorded each day, and as such, it uses a certain shorthand notation. The first main reference is to “hikari.” This refers to medium-sized pellets of Hikari® Cichlid Gold fish food that were the grubs’ primary food up until September 11, at which point I replaced the medium size with the large Hikari® pellets. This is why the number of pellets fed daily abruptly dropped after this day. In the first week or so, “BIC kibble” is mentioned. This refers to a cup of pellets that was shipped by Bugs in Cyberspace with the grubs. I used that cup of pellets to gradually transition them to the new food, although it may have not been necessary to worry about a gradual transition of food. Also, all reference to substrate means coconut fiber in a soil-like form such as Eco Earth® substrate. These grubs do not require a substrate with nutritional value, so coconut fiber makes for a relatively inert substrate to help limit mold. Other than that, I hope it to be fairly intuitive to interpret, but I will update this section if anyone reaches out in confusion.

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Below are photos of each weighing session and some other general grub photos.

Just after arrival
I had to order a more precise scale to weigh them accurately, so I measured them with a ruler when they first came. Given their ability to stretch and contract, though, I only took this photo for size reference and did not record these measurements in the spreadsheet.
These containers were the first ones I used when they arrived.

Above is a slideshow of weighing Goliathus goliatus 1 “The Messy Sausage” each week. Interestingly enough, between 8/13 to 8/20, she lost about 1.06 grams for no apparent reason, but fortunately, she had regained that weight by 8/27.

Above is the slideshow of Goliathus goliatus 2 “The Bitey Sausage” showing all weekly weighings so far. He was the last to molt to L3 of the bunch (the only one to do so after arriving in my collection), and the first two pictures above show him as an L2.

Grub 2 is also seems to be the only male in the group. Above is a macro picture of the Harold’s Organ, which can only be seen on male cetonine grubs. It is the spot in the middle of the photo that looks similar to the other hair folicles, except that it is devoid of a hair. This article by Beetles as Pets has more information on how to locate it on your own grubs, and this is the source I used to learn how to find it on my grubs as this is my first time keeping large cetonines. (Goliathus sp. are the only large, exotic, cetonine scarab that can be legally owned in the US without a USDA-APHIS licensed containment facility.)

Above is the slideshow of Goliathus goliatus 3 “The Farmyard Sausage” through all weighings so far. This grub has been the easygoing member of the group, and I have not noticed anything unusual in her development. She gets her name, though, because she is the stinkiest of the grubs. Her tank often smells like a farm.

While it is not visible in the slideshow above, this grub, Goliathus goliatus 4 “The Polite Sausage,” has given me the most trouble, despite the nice name. As the spreadsheet mentions, I found her tank was apparently deprived of oxygen by phorid flies laying eggs in the ventilation hole to try and get their larvae to the food pellets I was giving to her. I went to weigh her and found her limp and unresponsive. Thankfully, after cradling her in my hands for about ten minutes, she seemed to miraculously recover and as the spreadsheet shows, she is back to gaining weight at a similar rate to the rest.

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