The Longest Stag Beetle and Its Captive Breeding and Rearing
By Kay
Getting started
To begin with, what you need are:
1) An imago pair (or several larvae);
2) Containers for breeding or rearing;
3) Food for imagoes;
4) Substrate for breeding or rearing; and
5) Decaying wood logs (length: about 15 cm; diameter: about 10 cm). The logs should be
kept in water for one night, before use.
Instructions
1) Obtain a pair of imagoes (or several larvae) on the following criteria:
a) For choosing wild-caught imagoes, avoid older individuals or the ones with any scar,
injury or missing part; and
b) For choosing captive reared imagoes, avoid individuals of 8 months or older.
2) Oviposition requires some space; e.g. a container with a capacity of about 5 liters or
more. A lid is a must to stop the beetles from escaping. The lid should have tiny air
holes. The breeding container should be placed away from direct sunlight. Get one and
fill it with substrate (Also, see SUBSTRATE FOR REARING LUCANIDAE).
�� Substrate should be put at the bottom of the container, pressed hard, up to 5 cm
high. Next, one or two decaying wood logs should be placed on the top. Then,
another layer of substrate should be added, unpressed, up to a point where the
log(s) is or are almost covered. The female imago dugs holes into the log and
deposits eggs in it. The female imago may also deposit eggs in the substrate
layers. (In this sense, the wood logs are not an absolute must for the oviposition
of this species. If you use the substrate only for its breeding, make sure that
the substrate should be well enough fermented and finely ground.)
�� Then, a mated female imago alone should be put into the container. When you need
to mate a female with a male, hand pairing would be useful. If it does not work,
you can have the male's mandibles fixed by winding them with wire and keep the
pair for a while in the breeding container. Feed them regularly (For food, see 3)).
�� The breeding temperatures should be kept at 20-25 (?) degrees Celsius and
the substrate and the log should be moistened adequately.
A Japanese beetle magazine has reported that its editor himself observed
an imago pair mating on an unidentified tree in a locality at 22 degrees Celsius,
around 900 meters in elevation in Flores Island, Indonesia (Shiokura, 2001).
3) For maintaining imagoes, a pealed banana serves as an ideal food. It is good to place
its pieces or slices on a small tray instead of applying them directly on the substrate.
This prevents them from spoiling faster or avoids an occurrence of fruit flies or mites.
A pealed apple or a peach also serves as a suitable food. There are ready-made 'beetle'
foods (e.g. jelly) available in some countries.
4) See SUBSTRATE FOR REARING LUCANIDAE. A substitute can be garden soil.
However, if you use garden soil or its equivalents, you must put the wood logs in it
since the soil does not serve as a substrate for breeding.
5) Find a fallen decaying wood in your area. Hardwood trees only. Preferably, Fagus sp. or
Quercus sp. Cut it into pieces of about 15 cm in length. Then, keep them under
freshwater for a day. This moistens the log and kills beetle's predator organisms in it.
There are ready-to-use 'beetle' breeding wood logs available in some countries.
Rearing larvae
After one or two months, take the female imago out of the container. (To obtain more eggs, the female imago can be put in another breeding terrarium.) Then, carefully break down the log(s) to see if larvae have already hatched inside. Eggs or larvae may be found in the substrate. If the eggs are found, then keep them carefully in a small container (e.g. plastic cup of 120 cc) until two weeks after their hatch. If the larvae are found, then transfer them singly into plastic or glass bottles/containers of an about 800 ml capacity, which is filled with substrate (See SUBSTRATE FOR REARING LUCANIDAE). The bottle/container must have a lid with tiny air holes. The hole should be covered with thin paper. When you stuff substrate into empty bottles/containers, the substrate should be pressed hard. Some female larvae may undergo emergence in the first bottles/containers without its substrate changed. Meanwhile, male larvae have a greater appetite and take longer time until their emergence. When the substrate in the first bottles/containers is almost eaten up, the larvae need to be transferred singly into the second bottles/containers. For females, use bottles/containers of the same dimensions, but for males, you need to transfer them to larger bottles (e.g. 1,500 ml with at least 15 cm diameter) or to larger containers (e.g. 1.5-3 liters in capacity). Repeat this process, if necessary.
When changing substrates, it is safer to stuff newly fermented substrate first at the bottom of the bottle/container, and then the substrate left over by the larva. The larva can stay the upper substrate if it does not like the new one. If this happens, you can change the layer for a good one. The capacity ratio of the former to the latter is 2-to-1. Also, by so doing, beetle's symbiotic bacteria would grow fast into the new substrate and would promote an ideal feeding environment for better larval growth (Kojima, 2000). From the author's rearing, the duration of larval periods are: Male: 9 or more months; and Female: 4-7 months.
There is one thing that you might have to consider. Under the captive rearing conditions, the female larvae from the same parents tend to emerge (much) earlier than the males. Sometimes, the gap can be over 6 months. Although the imagoes of this species have a rather long life of 6-12 months, this would occasionally make it difficult for a breeder to mate them for the following generation. To avoid this, I would suggest that you should rear at least two different groups of the larvae. For example, the larvae, including several males and females, of the second group should be the ones that hatched 6 months later than those of the first group. This way, at least several male larvae in the first group would emerge around the same time when several females in the second one would. So, you can mate at least several pairs. Note that rearing two or more larvae in one bottle/container is not a good idea for this species.
Larva sexing
For sexing, click here.
Maintaining pupae
After larvae turn noticeably yellowish in color, stop changing substrates. Some time soon, the larvae will make pupation chambers and undergo pupation in them. Often times, you see pupae through the (transparent) bottle/container wall against which their pupation chambers are made. My best advice at this point is patience: do not touch or disturb the rearing bottles/containers, wait until one month after their emergence, and then take the imagoes out carefully. Newly emerged imagoes need 3-4 months for maturity. A sign for their maturity is when they start feeding. The longevity of the imago is 10-12 months after their emergence.
Breeding
The process on Getting started can be repeated.
