The Breeding/Rearing of Prosopocoilus giraffa keisukei (page 4)
- Yasuhiko Kasahara -

4.  A substrate for rearing Lucanid beetles

There are some substrates available for breeding/rearing stag beetles. On this page, I will tell you a substrate recipe for rearing Lucanid beetle larvae, which was originated by H. Kojima, Japan’s leading expert on the breeding/rearing of Lucanid/Dynastine beetles11.

To begin with, what you need are:

  1) Decaying wood mulch (preferably, Fagus sp. or Quercus sp.; no coniferous trees);
  2) Wheat flour;
  3) Natural water (avoid tap water, if possible); and

    * Capacity ratio of each, 1), 2) and 3), respectively: 10 to 1 to 1 (unit: liter)
       The capacity ratio varies among the users of this substrate.

supplies for rearing Prosopocoilus giraffa
Figure 4  A container with lid, a bottle of natural water, wheat flour and wood mulch


  STEP 1: Make mulch completely dry under direct sun or by any other means.
  STEP 2: Mix the mulch with the wheat flour. Then, pour water into it and stir well.
  STEP 3: Keep it at 25 or more degrees C. This makes the substrate well fermented.
  STEP 4: Leave it as it is until the temperature begins to rise. Then, stir it at least once a day
                  until its temperature returns to normal. It may take one or two months.

     * Wheat flour acts as an agent to prompt fermentation which is beneficial to larvae.
        It also is decomposed into nutrition. And when fermentation begins, the substrate
        temperature rises. 

To make wood into mulch, some hobbyists use a home juicer/mixer. Please be aware that you must make the right choice of wood. This is important. If you are unsure of it, you can ask someone who knows it. 

This substrate can be applied to the rearing of rhinoceros beetle larvae if it is further fermented.

5. Tips to attain a maximum-length adult male of this species/variety

1) Ideal rearing environment temperatures are 22-23 degrees C.;
2) Attain a male larva of 60 grams or more in weight;
3) Keep male larvae singly in large containers with good heat conductance
    (e.g. glass bottle with 15 cm or more diameter and 3 liter or more capacity);
4) Keep changing substrates in a three-month interval;
5) Avoid pressing substrate so as not to disturb inside air flow;
6) Keep rearing containers in a dark, well-ventilated place;
7) Keep rearing containers apart; and,
8) Avoid touching rearing containers unless necessary.

6. Acknowledgement

My special thanks are indebted to the following organizations and individuals: ‘The Beetle Ring’ (http://www.naturalworlds.org/beetlering/beetle_sites.htm) by Cameron Campbell, Administrator of ‘Natural Worlds’ (http://www.naturalworlds.org/); ‘The Kanagawa Stag Beetle Club,’ a local chapter of Japan’s largest beetle hobbyist club, ‘The Stag Beetle Fools’ (http://www.mars.dti.ne.jp/~k-sugano/bakamono_web/index2e.html), and its members including Hiroshi Kojima; Benjamin Harink (http://www.beetlebreeding.ch/) for an opportunity of this publication; Petr Malec (http://www.flower-beetles.com/) for advice on difficult-to-breed beetles; my father who has inspired me to pursue this interest; and my mother who has been patient enough for this unusual hobby of mine. 

I can be reached at http://www.geocities.ws/kaytheguru/. Please feel free to visit my beetle website. 

Note: Under the laws of Japan, living Prosopocoilus giraffa are importable to Japan and can be bred/reared there as well.

PS: The following pictures are of a female and male adult of Prosopocoilus giraffa keisukei, captive reared by the author.

Prosopocoilus giraffa keisukei adult female
Figure 6.1  Shown in this picture is a 52 mm long female adult that emerged in September 2003. Captive reared by the author. 

Prosopocoilus giraffa keisukei adult male
Figure 6.2  Shown here is a 103 mm long male adult that emerged on November 16, 2003. Captive reared by the author.


1) Okajima, Shuji, et al., eds. Kabutomushi Kuwagatamushi. Tokyo: GAKKEN, 2001;
  Fujita, Hiroshi, et al., eds. BE-KUWA. No.1-14. Tokyo: MUSHI-SHA, 2001-2005.
  Fujita, Hiroshi, et al., eds. Hajimetekau Kuwagatamushi. Tokyo: MUSHI-SHA, 2002 & 2004. 
2) Fujita, Hiroshi, Nagai, Shinji, et al., eds. BE-KUWA. No.10. Tokyo: MUSHI-SHA, 2004.
3) Fujita, Hiroshi, et al., eds. “Breeders’ Guinness” BE-KUWA. No.9. Tokyo: MUSHI-SHA, 2003.
4) Fujita, Hiroshi, Nagai, Shinji, et al., eds. BE-KUWA. No.10. Tokyo: MUSHI-SHA, 2004.
5) ditto.
6) ditto.
7) ditto.
8) ditto.
9) Ishiyone, Toru., ed. Wonderland Beetles (1). Nara: Nara Ookuwa Center, 2001.
10) Kojima, Hiroshi., ed. Breeding Technique of Lucanid Beetles. Tokyo: MUSHI-SHA, 2000.
11) ditto.


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