Care Sheet - Mars Rhinoceros Beetle (Megasoma mars)
Written by: Richard’s Inverts
An adult male Mars Rhinoceros Beetle (Megasoma mars)
Common Name: Mars Rhinoceros Beetle
Scientific Name: Megasoma mars
Distribution: North and South America
Etymology:
[Mega-soma] meaning “large-body” in Ancient Greek
[mars] named after the Roman god of war
World Record Size:
Wild – ### mm
Captive Breeding – 133.7 mm (2023)
Egg to adult: 12-36 months
Adult lifespan: 3-6 months (up to 12 months in exceptional cases)
Pupal stage duration: 2-3 months
Maturation time of fresh adults: 2 months
Egg incubation duration: 1 month
Rearing temperature: Room temperature (18-25°C)
Distribution data of extant Megasoma species:
Megasoma mars – Brazil, Colombia, Equador, Guyana, Peru, Venezuela
Megasoma actaeon – Brazil, French Guyana, Guyana, Suriname, Venezuela
Megasoma anubis – Argentina, Brazil, Paraguay
Megsaoma cedrosa – Mexico
Megsaoma elephas – Belize, Colombia, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, Panama, Venezuela
Megsaoma gyas – Brazil
Megsaoma janus – Argentina, Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru, Venezuela
Megsaoma joergenseni – Argentina, Paraguay
Megsaoma lecontei – Mexico
Megsaoma pachecoi– Mexico
Megsaoma punctulatus – USA
Megsaoma rex – Bolivia, Paraguay, Peru
Megsaoma sleeperi – USA
Megsaoma theristes – Mexico
Megsaoma vogti – Mexico, USA
A large male of Mars Rhino Beetle (Megasoma mars) compared to a medium sized Hercules Rhinoceros Beetle (Dynastes hercules ssp. hercules).
Species Description:
The Mars Rhino Beetle, (Megasoma mars) is the largest species in the Megasoma genus of rhino beetles. The genus name – Megasoma – literally translates to “mega=big” + “soma=body” when translated from Ancient Greek which aptly fits the large, bulky characteristics of this group of beetles. Species in the Megasoma genus can be split into two distinct groups: one group which are covered in microscopic hairs all over such as Megasoma elephas, and the other being smooth and without hairs like most regular beetle species. Megasoma mars belongs to the latter non-hairy group within the Megasoma genus.
The larvae of Megasoma can grow to significant sizes, and a closely related species called Megasoma rex currently holds the world record for the heaviest insect in the world. A captive bred larva back in 2013 reached a whopping 228 grams before pupation, which is 3x heavier than the insect which holds the title of second place (Giant Tree Weta).
Like other species in the Megasoma genus, the body of Megasoma mars is incredibly wide and large in mass which is unrivalled by any other Rhino Beetle genus. Even the longest beetle species in the world – Dynastes hercules – looks average sized in comparison to the wide Megasoma species due to their bulk.
Although Megasoma mars does not have any distinct subspecies, many of the species in this genus look very similar and have a distribution range all over Central American and South America. I have listed the 15 different species along with their distribution above.
The ventral view of the Mars Rhinoceros Beetle (Megasoma mars)
Food for Beetle Larvae:
As with most stag beetle species (Dynastinae 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.
Unlike with stag beetle larvae, a portion of the substrate for rhino beetle larvae can be replaced with decayed leaves of the same tree species if there is a shortage of decayed wood. I recommend that the ratio of leaves should not exceed the ratio of 1:4 (20% : 80%) of leaves to wood respectively.
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 Megasoma mars:
How to make a breeding box:
Prepare a 50 L box and fill it 70% full with substrate.
Compress the substrate down as hard as you can (use your hands to press it from above).
Lightly fill up to 70% of the container again 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 Megasoma mars 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. Megasoma mars can be reared on either wood/flake soil. At the L3 stage, the larvae should be kept in a container that is a minimum of 5000 ml in size.
Pupal stage:
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. Their pupal period is about 1 month, after which they emerge into an adult beetle.
