Beetlemania
The Care and Keeping of Exotic Beetles
Beetles are some of the most impressive invertebrates on the planet. Of the 350,000 species, many are magnificently coloured, incredibly strong and perform complex behaviours throughout their life cycles. People have kept beetles in captivity for centuries and it continues to be a popular hobby in Japan. In fact, Japan’s rich history of insect-keeping inspired Pokemon, Studio Ghibli and countless seminal poets. Here in the UK and Europe, beetle keeping is yet to gain such widespread popularity but with social media fuelling a new interest in inverts and economic challenges driving new demand for affordable pets, perhaps “the beetles” will be the next big thing.
Martin French and Bugz UK
One hobbyist who has always been well ahead of the curve is invertebrate enthusiast Martin French. He has been keeping and breeding bugs for 30 years, supplying most of the UK’s pet shops with praying mantids for over a decade. Throughout that time he has kept and bred a whole menagerie of bugs and last year founded the BugzUK Parc in Norfolk, an educational facility that showcases over 200 of the world’s most unusual invertebrate species. Martin told Exotics Keeper: “Out of all the invertebrates available, I would say beetles are the least popular to be kept as a pet, their popularity is just starting to take off."
Part of the reason that some of the large, impressive beetles such as rhinoceros beetles (Dynastinae sp.) and stag beetles (Lucanus sp.) are not more popular is that they can take up to seven years to grow into adulthood. This slow-growing process is common in many pet invertebrates. Even popular tarantula species will take several years to reach adulthood. Beetles spend most of their lives underground as a grub, during this time they will feed on nutrients in the soil as they prepare to pupate. “It is hard to get someone enthused about a pet that they probably won’t see for years" added Martin. "Even the species with single season cycles will remain underground for up to seven months and when they do emerge, many of these species are only adult and visible for a few months, and even then, during this time, they will spend a lot of their time underground laying eggs or hiding away.”
Some importers will bring large beetles into the UK as adults. These serve as excellent educational tools, but it is very difficult to age the adult beetle, meaning hobbyists could end up with an animal that is already at the very end of its life. “You can’t predict the availability of these insects” added Martin. “It might be that suddenly someone has some grubs coming through and there are 50 to 60 grubs available, but this is sporadic as there aren’t many people breeding beetles. Adults are imported and if you’re lucky you might get 30 or 40 eggs, but the parents will likely die very quickly, these can then be passed onto other people, but there aren’t currently enough people breeding for commercial sale.”
Whilst the enormous beetles that frequent nature documentaries might not make for ideal pets, some beetles are far more rewarding to keep and are just as beautiful.
Fruit Beetles
Flower chafers (Cetoniinae) are a huge group of around 4000 species belonging to the Scarabaeidae order. Amongst these diurnal pollen feeders are the ‘fruit beetles’ of tropical Africa. Members of this group are, broadly speaking, the best pet beetles and are certainly the most readily available, in fact, the larvae of one species (Pachnoda m. marginata) are commonly sold as live food. Their high calcium and protein content makes them an ideal food source and a pack of ten can be picked up from most pet shops for no more than £4. Inquisitive keepers will have likely experimented by allowing these grubs to pupate and metamorphose into surprisingly colourful beetles. Given the right conditions, this process is relatively easy and is often perceived as little more than a novelty or an interesting experiment for young children. However, the 50+ species of Pachnoda are not the only fruit beetles available to keepers.
Martin continued: “The main appeal of fruit beetles, other than the fact that they are easy to keep, is that they are seasonal – they complete their breeding cycle in less than a year. This means there are more and more species becoming available as more people work with them. Breeders can keep a cycle going to produce new adults each year. Some species get quite large and it is possible to create colour morphs. For example, Mecynorrhina torquata ugandensis come in a variety of colours and it is possible to pair up a brown one with a blue one or a red one to produce interesting colour morphs.”
Most fruit beetles can be kept in reasonably basic conditions. As most fruit beetles are diurnal, the keeper should provide some form of lighting and the enclosure should be well-ventilated to allow airflow. Both elements are reasonably cheap to recreate, and the rest of the beetle’s care is almost free. Fruit beetles require decaying plant matter that is best collected outdoors. Martin added: “The great thing about fruit beetles is that you only really need some plant humus and some old white rotten deciduous wood mixed together and you have a beetle substrate that they can live their entire lives in. They’ll eat that until they become an adult and then go onto fruit or jelly pots. If you go down to your local wood, take the first few inches of deciduous humus and put some old leaves in it they’ll happily live in there.”
“One thing keepers sometimes get wrong is soil density. Beetles tend to like to lay eggs in compacted soil, so it’s generally accepted that the bottom three inches of the substrate are packed down a little harder. This allows the beetle to bury down and create a small cell which protects the egg. If it is in loose soil, it can be moved around and the egg can be crushed.”
Each species will have slightly different requirements. However, most fruit beetles will thrive at room temperature (20-28°C) and around 70% humidity. In some cases, a warmer temperature can prompt the grubs to develop faster and allow the adults to fly easier. “There are some species of fruit beetles which are more difficult to breed because they have more specific requirements to pupate” explains Martin. “For example, Goliathus beetle grubs need more protein, so you need to add things like protein rich dog biscuits into the diet, but this can cause a problem with unwanted mites. They also need specific soil density to be able to form their pupal case. There are quite a few that are complicated, but most fruit beetles are very simple.”
“There really is loads of information out there, so a bit of research should stop anyone from making any mistakes. However, some new hobbyists will use substrate such as coir, not thinking that the grubs eat the substrate that they are in. Coir is okay for keeping the adult beetles on and they probably will lay eggs in there, but if the eggs hatch the grubs will die because there are no nutrients in the coir. If a keeper keeps it simple and takes the right substrate from outside or buys a proprietary mix, the worst situation they might get is little mites that hang onto the beetles’ knees and joints, which can eventually kill them if they are not controlled. They can be easily eradicated with Taurus mites which are another species of mite which will feed on those which are not welcome in the vivarium, and they can be bought over the counter in most reptile shops. So, it’s pretty easy to get rid of a mite problem.”
Unsurprisingly, fruit beetles require a steady amount of fruit to feed on. This is where the bulk of the maintenance is. Fruit can quickly turn mouldy which will eventually attract mites and cause nasty smells in the home. Most keepers now choose to use ‘fruit jellies’ which are nutritious pots of jelly often fed to arboreal geckos. Jelly pots contain natural sugars, are fortified with protein and also provide good hydration which removes the need to add a potentially dangerous water bowl. “Jellies are ideal because they contain everything the beetle needs without the mess” adds Martin. “They can be fixed in one area, are easily replaced and fruit beetles love them.”
Beetle Conservation
Because of the immense diversity of beetles, we know very little about their conservation status. However, the IUCN reports that over 60% of the assessed species are in decline. Whilst it might only be flagship species that are ever assessed in the first place, this worrying trend may be affecting thousands of species of beetles across the world. Most of the impact is attributed to habitat degradation, a problem which is faced by our native stag beetle (Lucanus cervus). “Stag beetles are protected here in the UK” adds Martin. “That means you can’t harvest the grubs and rear them in captivity to be released into the wild, instead, it is important to create deciduous log piles in the garden for their use, and to protect their native habitats. Our native stag beetle can take up to six years to develop and the adults only live for around three to four months. At Bugz UK, we’re setting up beetle log piles to educate visitors as they are not a species that can be displayed.”
“In some parts of the world, such as Japan, the harvesting of adult stag beetles possibly does cause population declines. It is a much more popular hobby over there and the commonly kept beetles tend to be native species, so they are easily collected. In the UK, the exotic beetles that are frequently available are either captive bred or imported in very small numbers.”
Keeping beetles can offer a brilliant introduction to entomology. Whether it’s establishing a colony of fruit beetles to teach young children about life cycles or dedicating seven years tending to a grub as a cultural lesson, bugs can provide an insightful vision of the natural world.
