How to Care for Adult Beetles

Written by: Richard’s Inverts

This is part 2, of a 4 part care sheet that covers beetle husbandry:

1. Beetle Larva Care Sheet
2. Beetle Adult Care Sheet
3. Beetle Breeding Guide
4. Beetle Egg Laying Guide

*Adult male Chiron Rhinoceros Beetle (Chalcosoma caucasus)*

General Information:

This method is recommended for the care of newly emerged (adult) beetles and raising them for mating or simply for observation as a pet.

Enclosure Setup:

Suitable enclosures for adult beetles can range from something as simple as a sturdy, plastic storage tub, to large, glass vivariums. A naturalistic forest-floor environment can provide both comfort and safety for adult beetles. Firstly, a layer of pesticide-free soil that is several centimetres deep should be added, which helps to retain moisture in the enclosure. Next, a centimetre of fallen leaves or leaf litter should be layered on top of the soil so that the adult beetle can dig under and nestle in when it wishes to rest. Adding branches and tree bark can add structure by creating vertical climbing areas for enrichment.

Temperature:

The adults of most rhinoceros/stag/flower beetles do well in stable, moderate temperatures. An ideal range for the majority of species kept in captivity range between 20-25 °C, but they can tolerate 18-26 °C if the conditions are otherwise stable. It is important to avoid environments that become too cold in winter such as unheated rooms or garages, as well as areas that become excessively hot in the summer. Generally, enclosures should not be placed in direct sunlight, as this can lead to overheating of the enclosure.

Humidity:

Adult beetles obtain all the moisture they need from their food, whether it be beetle jellies or fruit. The substrate inside the enclosure also plays a crucial role in preventing dehydration, as a dry environment can draw moisture away from the beetle’s body. Therefore, the substrate should always remain slightly moist. On the other hand, the substrate should not be kept excessively wet either, as this encourages the proliferation of mites and small flies. Light occasional misting is sufficient in maintaining the appropriate moisture level.

Food:

In the wild, many adult beetles feed on sweet, sticky tree sap. In captivity, this can be substituted for fruit or commercially available beetle jelly. Although beetle jelly can be more expensive, it can provide balanced nutrition and stays fresh for longer compared to natural fruit. If using fruits, sweet varieties such as bananas, apples, and melons are well accepted. Fruits with excessive water content such as watermelon should be avoided if possible, as it can lead to watery excrement that can spoil the substrate faster. Food should be checked frequently and replaced on the first sign of fermentation and spoilage, especially in warmer weather, to avoid pests such as fruit flies.

My recipe for homemade beetle jelly can be found HERE.

Perches and Preventing Flipping:

Adult beetles are much like turtles and often struggle to right themselves up when flipped onto their backs. If they are unable to grip onto anything, beetles can quickly exhaust themselves and die. Providing sticks, bark, and other textured surfaces across the surface of the substrate provides the necessary support needed to recover from a fall. A well-structured enclosure in this sense reduces the risk of accidental death and helps the beetles move around naturally.

Housing Multiple Beetles:

Some species of adult beetles can tolerate cohabitation, while others are territorial. Small, non-horned types of beetles such as most flower beetles (e.g. Pachnoda and Chlorocala) generally tend to be calm and non-territorial. These include species in genera such as Pachnoda and Chlorocala, and these smaller species can be kept communally, provided that there is no overcrowding. However, for large horned beetles such as giant flower beetles (e.g. Mecynorrhina and Goliathus), rhinoceros beetles and stag beetles, males can display territorial aggression and often fight. Therefore, keeping one male per enclosure is generally recommended for these types of beetles (keeping multiple females in the same enclosure is normally okay), but a few can sometimes be kept together in larger enclosures where there is adequate space, multiple hiding places and more than one food source. Nonetheless, when it comes to housing males of large horned species, keeping them individually is always the safest option.