Parent body length: Male 64.4mm / Female 42.3mm(A), 43.0mm(B)
Number of eggs laid: 7 eggs from A female / 6 eggs, 17 of L1 larvae, 26 of L2 larvae from B female
Incubation period of eggs: Approximately 1 month
Substrate used for laying: LB Flake Soil (substrate fermented twice)
Survival rate from hatching to L2: Approximately 85%
Substrate used for larvae: LB Flake Soil (substrate fermented twice with Kinshi)
Amount of flake soil used per larva: Male 15L (4 gallons) / Female 3.8L (1 gallon)
Larval period: Approximately 5-12 months
Pupal period: 20-50 days
Inactive periods: 2-5 months
Maturity period: 1-2 months after inactive periods
Life span of adult: 10-16 months (can live longer if not paired)
✅ Eggs:
The eggs of Dorcus titanus yasuokai typically hatch within about a month.
✅ Larvae:
The larval period for Dorcus titanus yasuokai is generally known to be around 6–14 months.
I raised my larvae using my own LB Flake Soil, and each larva consumed 15L (4 gallons) for each male / 3.8L (1 gallon) for each female.
Male
▪ Egg to L1: 160ml (5.5oz) x 1.5
▪ L2: 350ml (12oz) x 1.5
▪ Early L3: 1000ml (34oz) x 1.5
▪ Mid to late L3: (2800ml (95oz) x 3 rounds) x 1.5
Female
▪ Egg to L1: 160ml (5.5oz) x 1.5
▪ L2: 350ml (12oz) x 1.5
▪ Early L3: (1000ml (34oz) x 2 rounds) x 1.5
📌 The reason for multiplying by 1.5 is that the substrate needs to be compacted.
A 1000ml bottle holds about 1500ml worth of compressed substrate.
As for weight, the heaviest male reached 67g, and the largest female reached 15g.
7/23/2024
2 Months After Hatching
11/03/2024
6 Months After Hatching
12/24/2024
8 Months After Hatching
✅ Pupa:
The pupal period ranged from a minimum of 21 days to a maximum of 53 days.
The heaviest male pupa weighed in at 41g, while the heaviest female reached 9g. This represents roughly a 30-40% reduction from their final larval weights.
03/28/2025
Male Pupae
11/03/2024
Female Pupae
02/17/2025
Male Pupa
11/03/2024
Female Pupa
✅ Adult:
Out of the 14 male Dorcus titanus yasuokai that have emerged so far, 10 have successfully eclosed at over 90mm, and the remaining 4 are all over 80mm. Considering the relatively small size of the parent, these are very promising results.
The largest male reached 96.5mm, while the largest female measured 50mm.
There’s definitely potential to aim for 100mm+ in the next generation.
Father (Left)LBDTY F2 - 2 (Middle)
LBDTY F2 - 1 (Right)
LBDTY F2 - 1 ♂ (Left)
96.11mm
LBDTY F2 - 2 ♂ (Right)
95.18mm
LBDTY F2 - 3 ♂
94.1mm
📌 Shortly after eclosion, he lost two legs and two tarsi within the first two weeks.
This condition is believed to be a type of eclosion failure caused by the leg joints not being fully hardened at the time of emergence.
Notably, his pupal period was unusually short, only 32 days compared to the other males, which likely contributed to the issue.
He survived for about two months, from March 22 to June 3.
LBDTY F2 - 4 ♂
03/22/2025
📌 The most promising larva, weighing in at 67g, the heaviest of the male, was found dead inside the pupal chamber.
There were no external injuries or foul odor, so suffocation is suspected as the cause of death.
LBDTY F2 - 5 ♂ (Left)
96.50mm
LBDTY F2 - 6 ♂ (Right)
93.15mm
LBDTY F2 - 7 ♂ (Left)
91.47mm
LBDTY F2 - 8 ♂ (Right)
90.61mm
\LBDTY F2 - 9 ♂ (Left)
90.46mm
LBDTY F2 - 10 ♂ (Right)
88.21mm
📌 Both No.9 and No.10 emerged with a wing malfunction where the elytra do not fully close.
However, since the hindwings were successfully retracted, they will be fine.
LBDTY F2 - 11 ♂ (Left)
91.23mm
📌 He has a misaligned Head-Thorax.
A properly hatched beetle has its head, thorax, and abdomen in a straight line.
Occasionally, during emergence, the head may become stuck in an angled position and harden.
This is rare, but seems to occur mainly in Dorcus species.
LBDTY F2 - 12 ♂ (Right)
90.99mm 
LBDTY F2 - 13 ♂
06/08/2025
📌 The larva’s weight had been steadily dropping from 20g, and the final recorded weight was just 13g, It successfully constructed a pupal chamber on May 30, but unfortunately, it was found dead inside the chamber on June 8.
LBDTY F2 - 14 ♂
88.70mm
🔥 No. 15, 16, and 17 were raised using a layered substrate half Kinshi and half LB Flake Soil during their 4th and 5th substrate changes.
While each larva showed different preferences between the two layers, the results were noticeably poorer compared to those raised solely on LB Flake Soil, likely due to the introduction of Kinshi too late in their development.
Death in pupa state
📌 During the process of transferring the pupa into an artificial pupal chamber, an issue occurred where body fluid burst out.
I applied hemostatic powder, and he survived for about two weeks, but ultimately, it was unable to emerge.
LBDTY F2 - 16 ♂ (Left)
80.50mm
LBDTY F2 - 17 ♂ (Right)
77.34mm
📌 An issue occurred where the elytra did not fully close.
✅ Numbers 15, 16, and 17 were switched to kinshi rearing from mid-3rd instar, but unlike those raised on LB flake soil, the results were not as good.
Possible factors could be that the kinshi used was nutritionally inferior compared to LB flake soil, or that the switch to kinshi was made too late.
For the next generation, I plan to use kinshi supplemented with appropriate additives and switch them during the 1st–2nd instar stage to see how the results turn out.
