Care Sheet - Metallic Stag Beetle (Cyclommatus metallifer)
Written by: Richard’s Inverts
Adult male of a Metallic Stag Beetle “Amethyst” pedigree (Cyclommatus metallifer)
Common Name: Metallic Stag Beetle
Scientific Name: Cyclommatus metallifer
Distribution: Indonesia
Scientific Classification:
Order: Coleoptera
Family: Lucanidae
Genus: Cyclommatus (Parry, 1863)
Species: metallifer (Boisduval, 1835)
World Record Size:
Wild – 100.0 mm
Captive Breeding – 95.8 mm (by 山本耕司, 2004)
Egg to adult: 3-6 months
Adult lifespan: 6 months
Pupal stage duration: 1 month
Maturation time of fresh adults: 1 months
Egg incubation duration: 2 weeks
Rearing temperature: Room temperature (18-25°C)
Distribution data of extant Cyclommatus metallifer subspecies:
Cyclommatus metallifer ssp. aenomicans – Moluccas (Indonesia)
Cyclommatus metallifer ssp. butonensis – Buton Island (Indonesia)
Cyclommatus metallifer ssp. finae – Peleng Island (Indonesia)
Cyclommatus metallifer ssp. isogaii – Sula Archipelago (Indonesia)
Cyclommatus metallifer ssp. metallifer – Sulawesi (Indonesia)
Cyclommatus metallifer ssp. otanii – Moluccas (Indonesia)
Cyclommatus metallifer ssp. sangirensis – Sangir Archipelago (Indonesia)
Adult male of a Metallic Stag Beetle “Gold” pedigree (Cyclommatus metallifer)
Species Description:
The Metallic Stag Beetle, (Cyclommatus metallifer) is a species of stag beetle native to Indonesia. They are known for their extremely large mandibles, and their metallic body that shines in different colours depending on the locaility.
They boast the second longest body out of all the Cyclommatus spp., and major males possess mandibles that are longer than their body. Since they are native to the lowland regions, this species has a relatively stronger resistance to higher temperatures comapred to all the other Cyclommatus spp..
Food for Beetle Larvae:
As with most stag beetle species (Lucanidae family), the larvae will feed on substrate that is mainly composed of decayed wood of trees in the Beech family (Fabaceae family) which include oaks (Quercus spp.), beech, (Fagus spp.) and chestnut, (Castanea spp.). A general beetle substrate guide that covers the different types of substrates for different types of beetles can be found HERE.
To raise large adults, home-made Flake Soil should be used instead of wood collected from nature. Flake Soil is the term used for fresh sawdust that has been decayed under controlled conditions with additional protein sources that results in a uniform, earthy substrate that is rich in nutrients.
To view my tried and tested flake soil recipe with a breakdown of tips and tricks, please click HERE.
Food for Adult Beetles:
Adult beetles can be fed on beetle jelly or most sweet fruits such as bananas, apples, mangos, peaches, melons and watermelons to name a few. Adult females should preferably be given fruits that are higher in protein content such as bananas to aid in their egg production.
Foods to avoid for adult beetles are certain types of sugar-water, and fruits high in acidity such as those in the Citrus genus (oranges, lemons, grapefruits, etc.). Fruits that are high in acidity are said to disrupt the pH balance in the gut of some species, potentially leading to refusal to feed after a certain period of time.
Breeding Cyclommatus metallifer:
How to make a breeding box:
Prepare a 10L box and fill it 50% full with substrate.
Compress the substrate as hard as you can (use your hands to press it from above).
Lay down decayed spawning logs.
Lightly fill up to 70% of the container with substrate.
Place perches on the surface so that the adult beetles can right themselves up if they accidentally flip over.
Place fruits (or beetle jellies) on the surface as well.
Once the breeding box has been completed, place both the male and female Cyclommatus metallifer together in the breeding box. Leave them together for 7-10 days to ensure that they mate properly. Afterwards, the male can be taken out and kept separately if you wish.
If the male is seen attacking the female, it is a likely sign that they are not sexually mature yet. When this hapens, keep them separately in their own enclosures for a few weeks before attempting again.
How to check for eggs/larvae:
The breeding box can be checked for any eggs and larvae 1 month after the female has been introduced into the breeding box. Find a large box and empty out the substrate from the breeding box into it by flipping it over. Carefully break apart and work through the substrate in order to find the eggs and larvae. They are soft and fragile, so please take care to handle them gently when moving the eggs and larvae.
Raising the larvae:
Larvae should ideally be separated and reared individually to prevent the larvae from getting stressed out by each other (and to prevent any risk of cannibalism in more aggressive species). Communal rearing is possible, provided that plenty of space and substrate is given. Cyclommatus metallifer can be reared on either wood/flake soil, or kinshi bottles. At the L3 stage, the larvae should be kept in a container that is a minimum of 800 ml in size.
Pupal stage:
Several months into development, the rate at which they eat will begin to slow down. This is a sign that they are preparing to become a pupa. Cyclommatus metallifer larvae tend to contruct their pupal chambers against the sides of their containers so it is often possible to view their development through the container walls if they are see-through. Their pupal period is about 1 month, after which they emerge into an adult beetle.
From the moment onwards after the larva constructs a pupal cell, it is important to keep disturbance to a minimum. Please refrain from unnecessarily picking the container up or shaking it.
