The Breeding/Rearing of Dynastes hercules hercules

By Yasuhiko Kasahara
February 2006

Yasuhiko Kasahara, author of the website Kay's Beetle Breeding Hobby, has written the following article which describes the captive breeding of Dynastes hercules hercules, the world's longest Rhinoceros beetle.  Many thanks to Kasahara for allowing me to present this valuable information on my website.  I am certain that many beetle hobbyists will benefit greatly from the techniques discussed in this presentation.

1. Introduction

To start, I would like to give you a brief history of a rather new fad, beetle rearing, in my country. Year 1986 became a milestone for beetle business in Japan. That year, Hiroshi Kojima, an acquaintance of mine, introduced an article on his success in the breeding of Dorcus hopei binodulosus, the then most popular stag beetle that was sold at rather high prices. By then, because of their high commercial values, they had been over collected here and thus became rather rare in nature. And yet, much of their life cycle had been veiled with mysteries. Kojima’s article shed a light on their life cycle and their breeding/rearing. In the following years, a variety of beetle breeding/rearing articles (substrates, foods, containers, etc.) were developed for the purpose of mass-producing the beetles. Soon, the species were reproduced in a large quantity and the new pet business - beetle breeding/rearing - had begun. Moreover, in 1999, ninety-nine living exotic beetle species became importable to Japan which include Dynastes, Megasoma, Chalcosoma, etc., and more species have been added to the import list from time to time. Over the course of time, some of the species have been reared to a point where they exceed the maximum length that they attain in nature. It is said that there are about 3 million beetle hobbyists in Japan. Now, living beetles from around the world are readily available at supermarkets and pet shops throughout the country. There are even ‘beetle’ shops here1.

My particular concerns are the breeding/rearing of giant beetles, the maximum length of whose males exceeds 100 mm in nature (see the following list: Giant Rhinoceros Beetles). Amongst them, Dynastes hercules hercules is my most favorite. 

Giant Rhinoceros Beetles2:

   1) Dynastes hercules (hercules of Guadeloupe: max. 180 mm?);
   2) Dynastes neptunus (max. 158 mm);
   3) Megasoma mars (max. 140 mm?);
   4) Megasoma elephas (elephas: max. 136 mm?); 
   5) Megasoma actaeon (max. 135 mm?);
   6) Chalcosoma chiron (janssensi of Sumatra Is.: max. 133 mm);
   7) Megasoma janus (janus: max. 120 mm);
   8) Megasoma gyas (gyas of Brazil: max. 116 mm);
   9) Dynastes satanas (Bolivia: max. 115 mm);
  10) Megasoma occidentalis (Mexico: max. 112 mm);
  11) Chalcosoma moellenkampi (Kalimantan Is.: max. 112 mm); and
  12) Chalcosoma atlas (hesperus of Mindanao Is.: max. 108 mm)

The following pages present the breeding/rearing of Dynastes hercules hercules. Discussion on the breeding/rearing follows natural history of the insect, which is thought useful for breeding/rearing. Although the classification of the species may vary among taxonomists, there are 13 varieties3:

   1) hercules Linneaeus, 1758
       (max. 180mm?; Guadeloupe and Dominica);
   2) ecuatorianus Ohaus, 1913
       (max. 165 mm; Colombia, Ecuador, Peru, Brazil and Bolivia);
   3) baudrii Pinchon, 1976
       (max. 100 mm; Martinique);
   4) reidi Chalmeau, 1977
       (max. 105 mm; St. Lucia);
   5) lichyi Lachaum, 1985
       (max. 172 mm; Venezuela, Colombia, Ecuador, Peru and Bolivia);
   6) occidentalis Lachaum, 1985
       (max. 145 mm; Panama, Colombia and Ecuador);
   7) septentrionalis Lachaum, 1985
       (max. 140 mm; Central America);
   8) paschoali Grossi et Arnaud, 1993
       (max. 145 mm; Brazil);
   9) tuxtlaensis Moro'n, 1993
       (max. 110 mm; Mexico);
  10) bleuzeni Silvestre et Dechambre, 1995
       (max. 151 mm; Venezuela);
  11) trinidadensis Chalumeau et Reid, 1995
        (max. 137 mm; Trinidad and Tobago);
  12) morishimai Nagai, 2002
       (max. 120 mm; Bolivia); and
  13) takakuwai Nagai, 2002
       (max. 130 mm; Brazil) 

Ssp. hercules is considered as the longest living rhinoceros beetle in the world. A number of sources say that 180 mm may be the maximum length of a wild-caught male imago (adult) of Guadeloupe. That means, for beetle breeding/rearing enthusiasts, that the male of this subspecies has a potential of growing up to 180 mm long or even longer. Note that, thanks to the collaboration of breeders and hobbyists, some substrates for breeding/rearing Dynastinae were developed and hence, by using them, some breeders/rearers in Japan, both professionals and hobbyists, have reported the rearing of males of this variety from eggs to imagoes of over 150-160 mm in length4 (brief description of a substrate is presented in 4.  A breeding/rearing substrate). The following discussion limits ssp. hercules, first introducing its natural history and then emphasizing its breeding/rearing method to win good results. However, this breeding/rearing method can be applied to many other Dynastinae.

2. Natural history

2.1  Description: Male 46-180? mm including horns; Female 50-80 mm. Dull black on prothorax and yellowish-brown on fore wings. Male's horns have several small teeth along inner edge, and are slightly bent inwardly at tip. Head of a large male reaches to the length of its prothorax and abdomen combined5

2.2  Habitat: Tropical rain forests6

2.3  Range: Ssp. hercules is confined to Guadeloupe and Dominica7.

2.4  Food: The imago saps tree juice and the larva seems to feed on rotten hardwood trees8

2.5  Life cycle: The insect's life cycle is said to be largely unknown in a natural setting9. Under captive rearing (26 degrees C. in summer; 18 degrees C. in winter) using an artificial substrate, however, the author has experienced the following:

  1. Duration of egg incubation: about 1 month
  2. Duration of larval stage:
       Male: 12-18 months (L1: 1 month; L2: 2 months; and L3: 9-15 months); and 
       Female: 12 months (L1: 1 month; L2: 2 months; and L3: 9 months)
  3. Duration of pupal stage: 2-3 months

(continued on next page)


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