Growing Hercules beetles larger than their wild counterparts is the ultimate goal for many enthusiasts. The current record-holder, a staggering 181 mm (~7.1 inches) beetle, was recorded in 2018, smashing the previous record of 171 mm (~6.7 inches) set in 2015. For many, breeding a beetle over 160 mm (6.3 inches) is the gold standard, though even reaching 6 inches can be challenging for beginners.
If you’re dreaming of raising Hercules beetles that will impress fellow enthusiasts, this guide has you covered. I’ve gathered insights from seasoned beetle keepers to help you understand the secrets of breeding bigger beetles. Whether you’re just starting or looking to take your breeding program to the next level, keep reading to unlock the key factors that influence beetle size.
Genetics Are Key
Like dogs and cats, Hercules beetles come in different breeds, each with unique traits. Genetics plays a huge role in determining beetle size, and some breeders have spent years perfecting lines that consistently produce large beetles. One notable example is the HirokA breed by Hirofumi Kawano, which held the record in 2015.
If you’re serious about growing giant beetles, start with a reliable, well-bred line. Here’s why:
Unknown Breeds: While more affordable, these lines are less predictable and may not yield the same results.
Genetics play a big part in the size of beetles. There are different breeds of beetles, just like there are different breeds of cats or dogs. One of the most notable breeds is the HirokA breed by Hirofumi Kawano, who holds the record for longest Hercules beetle in 2015.
Selected Breeds: These beetles come from generations of selective breeding for size and strength.
| Features | Specifically selected breed | Unknown breed/Wild breed |
| Price | Can be very expensive | Cheap |
| Average size | Bigger | Smaller |
| Egg hatch rate | Higher | Lower |
| Overall survivorship | Higher | Lower |
| Genetic variation | Low | High |
Starting Your Own Breeding Line
Even if you start with a known breed, you’ll eventually want to establish your own line. Here’s how to selectively breed for size:
- Select Your Breeders: Choose the largest male and female beetles. Ensure they’re between 1-2 months old for optimal reproduction.
- Track Generations: The first generation is your P (parental) or F0 generation. Their offspring will be the F1 generation.
- Repeat Selective Breeding: Continue selecting the largest individuals from each generation. After 4 generations (F4), you’ll notice a significant size increase.
Inbreeding Risks:
- Low genetic variation can result in shared weaknesses.
- Recessive genetic defects may become more pronounced over generations.
To mitigate these risks, crossbreed your F7 generation with a wild beetle or a beetle from another line. While this may slightly reduce size, it improves genetic diversity and overall fitness.
Feeding for Growth
What your grub eats determines how big it will grow. Nutrition during the larval stage is crucial, as adult beetles don’t grow larger once they emerge.
Grub Diet:
- Rotten Hardwood: The natural diet of grubs, often provided as flake soil.
- Consistency Matters: Stick with the same type of substrate throughout the grub’s growth. Switching brands or types can stress the grub and even cause death.
Tips for Success:
- Supply Chain: Ensure a reliable source for your chosen substrate.
- Food Quality: Some beetle keepers mix protein powders into beetle jelly for added nutrition, which may improve the health of offspring.
Housing for Giant Grubs
The size of your grub’s housing plays a significant role in its eventual size. Simply put, larger housing allows for larger beetles.
Recommended Housing Sizes:
- Male Grubs: Use a 4-8 gallon (20-40 L) container. While a 1-gallon (5 L) container suffices for typical hobbyists, it’s too small if you’re aiming for giants.
- Female Grubs: A 1-gallon (5 L) container is usually adequate.
Individual Housing:
Always house grubs individually to maximize growth. Shared housing often results in smaller adults due to competition for food and space. However, keeping some grubs communally as a backup can prevent loss of your line if male and female growth rates fall out of sync.
Pro Tip: Grubs kept singly in large containers will have more resources to grow larger, while communal housing should only be used strategically.
Final Thoughts
Growing Hercules beetles larger than their wild counterparts is a rewarding but challenging process. By starting with strong genetics, providing optimal nutrition, and ensuring ample space, you’ll be well on your way to breeding record-breaking beetles. Remember, patience is key—it can take years to see significant progress.
