Insect Glossary

A jar containing substrate colonized with mushroom mycelium such as Pleurotus or Trametes. Used for rearing stag beetle larvae, it tends to produce larger adults than substrate-only methods. Temperature control at 20–25°C is essential.

Fermented broadleaf sawdust used as bedding for beetle keeping. It is used for rearing rhinoceros beetle larvae and setting up stag beetle egg-laying enclosures. Different fermentation stages (primary, secondary, fully matured) serve different purposes.

Decayed wood used by female stag beetles for egg laying. Konara oak and sawtooth oak are commonly used. The log is soaked in water for half a day before being embedded in substrate. Wood hardness preference varies by species.

The process of carefully removing larvae or eggs from the egg-laying log or substrate, typically done 1–2 months after setting up the breeding enclosure. The wood is gently broken apart to avoid injuring larvae, which are then placed in individual containers.

A chamber the larva constructs before pupation by compacting substrate or mycelium into an oval space. If damaged, an artificial pupal chamber can be used as a substitute. Once formed, the container should not be disturbed.

The stage just before a larva pupates. The body becomes wrinkled and the larva stops moving. This phase lasts about 1–2 weeks depending on the species. Vibration or shock during this period can cause eclosion defects.

A condition where wings or body parts fail to expand or harden properly during emergence from the pupal stage. Causes include pupal chamber collapse, temperature fluctuations, vibration, and low humidity. Mild cases are survivable, but severe cases may shorten lifespan.

Breeding successive generations, denoted F1 (first generation), F2 (second generation), etc. As generations progress, inbreeding depression becomes a risk, so periodic introduction of unrelated bloodlines is recommended.

Short for 'Wild,' referring to specimens collected in the field. Also called wild-caught individuals. They usually come with locality and collection data and are valued by breeders for introducing fresh bloodlines.

Short for 'Wild F1,' the first-generation offspring of a wild-caught individual. They carry the direct genetic legacy of wild stock and are considered highly valuable in terms of bloodline.

Short for 'Captive-Bred F1,' the first generation bred in captivity. Generational tracking, along with locality data, is essential information shared among breeders.

A specimen bred in captivity, as opposed to a wild-caught (WD) individual. Captive-bred beetles are accustomed to their environment and easier to handle, but excessive inbreeding may lead to smaller size or deformities.

A jelly-like food for beetles, used as a substitute for tree sap. High-protein jelly is effective for boosting stamina in females before egg laying and large males. The standard size is a 16 g cup.

Maintaining proper temperature in the breeding environment. Most Japanese stag beetles thrive at 20–25°C, while tropical highland species prefer even cooler conditions. Many breeders use wine coolers or air conditioning for temperature control.

A dormant state entered during winter when temperatures drop. Japanese species such as Dorcus hopei and Dorcus rectus hibernate. They are kept with thick substrate at around 10°C and resume activity when spring temperatures rise.

A period after eclosion during which the adult beetle remains still and does not eat. Seen in immature adults, it can last from several weeks to months depending on the species. Forcing activity during this time may shorten the beetle's lifespan.

The growth stage from hatching to adulthood. Larvae grow through instars—first (L1), second (L2), and third (L3, final)—by molting. The larval period is about 10 months for rhinoceros beetles and 1–2 years for Dorcus hopei.

A fully developed individual that has emerged from the pupal stage. The point at which the exoskeleton hardens and the beetle begins to feed is called 'first feeding.' Adult lifespan varies widely by species, from a few months to several years.

Mating a male and female to produce the next generation. Mature individuals are either housed together or paired by hand to confirm mating. After mating, the female is placed in an egg-laying setup to oviposit.

A breeder-assisted mating method where the male is placed on top of the female to encourage copulation. Compared to cohabitation pairing, it reduces the risk of the male attacking the female and allows definitive confirmation of mating.