Anything from a shoebox to a large glass tank can be used for an enclosure. I'd recommend a minimum of a one gallon container for a breeding group of any species an inch or longer, smaller species can usually be comfortably housed in something half as large. Generally you want an enclosure a bit more wide than it is deep.
The enclosure should be very well ventilated, lid and cross ventilation is best in a plastic container, in a glass tank a screen lid or no lid at all should be fine. If you don't use a lid, make sure the cage decorations aren't too close to the rim of the enclosure, to prevent any escapees. Eleodes generally can't climb smooth surfaces, but can and will climb decor to get out if possible.
For substrate, you can use coconut fiber, sphagnum peat, sand, a mix of them, etc., some species are content to breed and lay in a coconut fiber or peat based substrate, others require a 50/50 mixture with sand, or a completely sand based substrate to induce oviposition. A mixture of native habitat information and trial and error is generally needed to tell which of these substrates each species is comfortable with, most don't really care except when it comes to oviposition.
Extra materials such as rotten wood, compost, and leaf litter are generally unnecessary substrate components, but will be eaten if offered.
Substrate should be at least one or two inches deep, 4-6 inches minimum if you're going to attempt communal pupation.
As for humidity, being desert beetles, the adults dislike high humidity, and like most of the enclosure dry, though some humidity should be present for the larvae.
If you're planning on removing large larvae from the breeding enclosure to pupate them in isolation, (which we'll discuss later), then just keep two thirds or three quarters of the substrate bone dry, the remainder of the substrate moist. A horizontal humidity gradient is best in this situation.
If you want to attempt communal rearing, in which larvae are not isolated for pupation, you'll need a substrate 4-6 inches deep at the minimum, with the bottom 2-3 inches of the substrate kept humid, the upper layers kept dry. To achieve this vertical humidity gradient, periodically pull back the top layers of substrate of one half of the enclosure, mist the area heavily, then cover it back up and repeat on the other side. This type of humidity gradient will increase the air humidity in the enclosure, even if the top few inches of substrate feel bone dry, so very high airflow is important for the survival of the adults.
Diet:
Dog/cat/chick feed works best as the staple diet, with fruits and veggies being nibbled on by some species.
A food bowl is recommended to prevent grain mite outbreaks, which can prove harmful to these beetles. Grain mites thrive best when food touches the substrate, and thus excess food, especially food that's been dragged out of the bowl, should be removed every few days.
Many species will also nibble on decaying hardwood leaf litter, though I have yet to find a species that absolutely requires it in their diet, or to induce oviposition. However, it can be helpful to have in a large enclosure, (if adults don't often drag food out of the bowl), so you know hatchling larvae will have something to eat.
Temperature:
Room temps are fine for most species, but temps at a minimum of 75F° seem to best to induce optimal breeding. Temperatures above 80F° can be harmful to pupae in my experience, and prolonged temps at 90F° or above can even be harmful to adults and larvae of some species.
Breeding/Life cycle:
Adults normally live 1-3 years, depending on the species, though some can go on for at least 5. They can be sensitive to overcrowding though, so in larger colonies, many won't make it past the two year mark. Each CB female lays at least a couple dozen eggs soon after maturing, and then again the following year, usually in Spring/Summer, (northern species/localities may need a winter diapause for consecutive batches of eggs each year). The eggs take about 1-2 weeks to hatch, exact rates vary species to species, and the resulting larvae are tiny and agile, thus they often go unnoticed until they molt a few more times.
Larvae can take anywhere from 4-8 months to reach maturity, all depending on species, ambient temperatures, food availability, etc., after which they seek humid, stable substrate to burrow into and make their pupal cells. Like most desert Tenebrionid larvae, pupal cells are constructed by pushing substrate away from themselves until they clear a little room in the dirt. They do not reinforce their pupal cell walls with frass or spit like Scarabaeoid beetles do, so they must build their cells in at least somewhat humid, compressed substrate, otherwise the walls can collapse and kill the pupae within.
When the larvae reach maturity, (they'll be a little longer than the adults they came from), unless you are going with a communal pupation setup as described in the Housing section, you will need to isolate them and place them deli cups filled with an inch or two of moist, compressed substrate, (2 oz cups work great for species under an inch, something at least twice as large will be needed for bigger species though). With any luck, they will burrow down and create a pupal cell near the bottom.
The larvae of some larger Eleodes species like acuticauda, armata, spinipes, etc., oddly seem to be quite picky about the humidity of their pupal environments, and for these species a communal pupation setup as outlined in the Housing section might not be a good choice, and survival rates can be low. Ideally you want the pupation substrate for these larger species to be just humid enough to hold it's shape, and that's it. Light, periodic misting and good airflow will help maintain this humidity level. Even if kept perfectly, the survival rate for pre-pupal larvae and pupae of these species can be very low.
Sometimes in a large colony, larvae will attempt to pupate in the moist areas of the enclosure, and through the burrowing actions of their brethren, get pushed up to the surface. These "pre-pupal" larvae are easy to tell apart from other larvae, as they are immobile, and normally curl up into a J shape. They should be removed ASAP and moved to deli cups with a thin, smooth layer of moist coconut fiber. Sometimes they will pupate successfully in these conditions, other times they die, but it's better than leaving them in the main colony, where they will certainly be eaten. Keep the pre-pupal larvae and pupae moist, but never spray them directly, as contact with water droplets seems to kill them.
After a week or two of staying in the pre-pupal position, the larvae will molt into pupae. Pupae take around 2-3 weeks to finish development, after which they molt into soft, teneral adults. Assuming you've gone with the isolation pupation technique, once you notice your pupae have turned into adults, or after they claw their way to the surface from their pupal cells, (whichever comes first), you should move them ASAP to well ventilated deli cups with bone dry substrate, mist one small area for moisture, and give them a small amount of food. If the adults stay in their humid pupal setups too long, they will die. (This isn't as much of a problem in communal pupation setups, as they'll just claw their way up to the drier areas of the enclosure, however if they're still very soft and teneral, they can be damaged by their tankmates). You have to move them very gently though, because they are still soft, and their elytra can easily be dented and deformed permanently at this stage.
Keep the new adults in isolation for 1-2 weeks, take care not to let the cup dry out completely. Once they have finished hardening up, they can safely be handled, and put back in the main colony. Then the cycle begins anew.
Species accounts:
Eleodes (Blapylis) clavicornis
Like most members of this subgenus, adults enjoy burrowing. This species can be reared on plain coconut fiber or some equivalent, but does best when at least 50% of the substrate is sand. Pupal survival rate is rather low, and oddly the sex ratio is highly skewed towards males.
Eleodes (Blapylis) wakelandi
A small species that breeds readily on most substrates. Survival rate of pupae is average.
Eleodes (Blapylis) sp. "Idaho"
A widespread, unidentified species in southwestern Idaho. Easy to breed, not too picky about their substrate. Pupal survival rate is pretty high.
Eleodes (Cratidus) osculans
Apparently common in Southern California. This species is very easy to breed, though requires at least 50% of the substrate to be fine sand to induce consistent oviposition. Survival rate of pupae is very high, this species does well with a communal pupation setup. Adults are very messy eaters and leave food everywhere.
Eleodes (Eleodes) acuticauda
This large species seems to prefer, if not require a sandy mix for breeding, (at least 50/50, if not just pure sand), and the pre-pupal larvae and pupae are very sensitive to excess humidity. Survival rates of pre-pupae and pupae are generally rather low, though thankfully adults do seem to lay lots of eggs.
Eleodes (Eleodes) armata
This species isn't too picky about what substrate they'll oviposit into, however pre-pupal larvae and pupae are quite sensitive to excess humidity. Survival rates of those stages can be quite low, though adults seem prolific.
Eleodes (Eleodes) hispilabris
One of the easiest Eleodes species to breed, hispilabris is prolific, hardy, and the pupal survival rates are very high. Not at all picky about substrate type. Makes a decent occasional feeder.
Eleodes (Eleodes) obscura
This is a very bulky species, adults are easy to keep alive and have been bred successfully by a few keepers. Females seem to prefer at least a partially sandy substrate to oviposit in, and lay LOTS of eggs. Larvae seem easy to rear at first, but larger larvae prefer to be housed separately, and can cannibalize quite heavily in the later instars. Additionally, large larvae of northern strains seem to need a diapause to develop properly, and probably pupate in the spring. Even with the proper seasonal cues given, the pupal survival rate can be quite low as well, perhaps they are finicky about the humidity in their pupal cells (like several other large Eleodes species).
Eleodes (Eleodes) spinipes macrura
Eleodes (Eleodes) spinipes ventricosus
A massive species, captive stock is over a decade old, and has become significantly easier to rear over multiple generations in captivity. Adults are very prolific and not too picky about what substrate they'll oviposit in, pre-pupal larvae and pupae are sensitive to excess humidity though, and thus survival rates can be relatively low.
Eleodes (Eleodes) suturalis
Adults are not picky about their oviposition substrate. Apparently quite easy to rear, often confused with the similar E.acuta.
Eleodes (Eleodes) tenuipes
Adults of this large species aren't picky whatsoever about their oviposition substrate. Unfortunately pre-pupal larvae and pupae seem to have a poor survival rate in captivity, they likely are sensitive to excess humidity in their pupal cells.
Eleodes (Melaneleodes) rileyi
One of the smaller species in the genus, adults are quite prolific, not picky about oviposition substrate. Larvae are unusually long and thin in comparison to other Eleodes larvae. Pupal survival rates aren't too low, conditions needed for pupation similar to other similarly sized Eleodes.
Eleodes (Melaneleodes) tricostata
Adults aren't picky about what substrate they'll lay eggs in. Larvae should always have access to moist substrate, as they are especially sensitive to drying out for Eleodes. The CB adults of this species may require seasonal cues to induce breeding.
Eleodes (Metablapyis) nigrina
Adults aren't picky about oviposition substrate, females only seem to lay a few dozen eggs each though, rather than the hundreds other Eleodes species can produce. Larvae tend to stay in the humid areas of the enclosure and don't like dryness that much, but are otherwise quite hardy and fast growing. Pupal survival rates are high.
A massive species, recently entered captive culture. Significantly easier to rear than the below subspecies, with pre-pupal larvae and pupae not being overly sensitive to high humidity in their pupal cells. Adults seem to prefer at least some sand in their oviposition substrate, and are quite prolific.
Eleodes (Eleodes) spinipes ventricosus
A massive species, captive stock is over a decade old, and has become significantly easier to rear over multiple generations in captivity. Adults are very prolific and not too picky about what substrate they'll oviposit in, pre-pupal larvae and pupae are sensitive to excess humidity though, and thus survival rates can be relatively low.
Eleodes (Eleodes) suturalis
Adults are not picky about their oviposition substrate. Apparently quite easy to rear, often confused with the similar E.acuta.
Eleodes (Eleodes) tenuipes
Adults of this large species aren't picky whatsoever about their oviposition substrate. Unfortunately pre-pupal larvae and pupae seem to have a poor survival rate in captivity, they likely are sensitive to excess humidity in their pupal cells.
Eleodes (Melaneleodes) rileyi
One of the smaller species in the genus, adults are quite prolific, not picky about oviposition substrate. Larvae are unusually long and thin in comparison to other Eleodes larvae. Pupal survival rates aren't too low, conditions needed for pupation similar to other similarly sized Eleodes.
Eleodes (Melaneleodes) tricostata
Adults aren't picky about what substrate they'll lay eggs in. Larvae should always have access to moist substrate, as they are especially sensitive to drying out for Eleodes. The CB adults of this species may require seasonal cues to induce breeding.
Eleodes (Metablapyis) nigrina
Adults aren't picky about oviposition substrate, females only seem to lay a few dozen eggs each though, rather than the hundreds other Eleodes species can produce. Larvae tend to stay in the humid areas of the enclosure and don't like dryness that much, but are otherwise quite hardy and fast growing. Pupal survival rates are high.
Eleodes (Omegelodes) debilis
This subgenus is monotypic funnily enough! E.debilis lay very large eggs compared to their size, at least in comparison to other Eleodes spp., and seem to prefer a coco fiber or coco fiber and sand mix for oviposition (plain sand doesn't work well). Oddly I was unable to ever get their eggs to hatch, and I'm not sure why. So the difficulty of rearing larvae to adulthood remains unknown.
Eleodes (Promus) goryi
The adults don't appear particularly picky about their oviposition substrate, but a 50/50 sand and coconut fiber mix works well. Larvae are unusually dark for Eleodes. Larval and pupal survival rates are quite high.
Eleodes (Promus) subnites
This species is not picky about oviposition medium, and is a great beginner's species. Larval and pupal survival rates are high.
Eleodes (Pseudeleodes) longipilosa
Adults are rather fragile, and apparently quite picky about their substrate. Coconut fiber is not acceptable, they likely need a 100% sand substrate or at least near 100% sand... Captive larvae have yet to be produced. I have observed one wild larva, it was quite hairy, like the adults.
Eleodes (Pseudeleodes) tribulus
Adults aren't that picky about their oviposition substrate, though they appreciate a 50/50 sand and coconut fiber mix. Adults spend a lot of time underground. They aren't incredibly prolific, however this species is fast growing, easy to pupate, and pupal survival rates are very high, so colonies can grow quickly. Teneral adults are at unusually low risk for being damaged by cagemates, due to their long hairs and secretive underground lifestyles keeping other individuals at bay.
Eleodes (Xysta) longicollis
Adults aren't picky about oviposition substrate. A good beginner's species, they are hardy, the larval and pupal survival rates are very high, and they grow fast, (larvae mature in 4-5 months under optimal conditions).
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Overall Eleodes can be a rewarding genus to breed, and there are many out there that haven't been bred yet! I hope this caresheet proves useful to those who wish to breed these iconic desert insects!
I've worked with most of the species mentioned myself, but big thanks to Isaac Fox, Joshua Campos, Erin Munkacsy, and the works of Orin McMonigle for information on the species I have not yet worked with.
If you have species specific rearing information on species not listed here or species listed that have little info, such as substrate preferences, humidity preferences, larval and pupal survival rates, etc., feel free to contact me and I can add them to the species accounts list.
This subgenus is monotypic funnily enough! E.debilis lay very large eggs compared to their size, at least in comparison to other Eleodes spp., and seem to prefer a coco fiber or coco fiber and sand mix for oviposition (plain sand doesn't work well). Oddly I was unable to ever get their eggs to hatch, and I'm not sure why. So the difficulty of rearing larvae to adulthood remains unknown.
Eleodes (Promus) goryi
The adults don't appear particularly picky about their oviposition substrate, but a 50/50 sand and coconut fiber mix works well. Larvae are unusually dark for Eleodes. Larval and pupal survival rates are quite high.
Eleodes (Promus) subnites
This species is not picky about oviposition medium, and is a great beginner's species. Larval and pupal survival rates are high.
Eleodes (Pseudeleodes) longipilosa
Adults are rather fragile, and apparently quite picky about their substrate. Coconut fiber is not acceptable, they likely need a 100% sand substrate or at least near 100% sand... Captive larvae have yet to be produced. I have observed one wild larva, it was quite hairy, like the adults.
Eleodes (Pseudeleodes) tribulus
Adults aren't that picky about their oviposition substrate, though they appreciate a 50/50 sand and coconut fiber mix. Adults spend a lot of time underground. They aren't incredibly prolific, however this species is fast growing, easy to pupate, and pupal survival rates are very high, so colonies can grow quickly. Teneral adults are at unusually low risk for being damaged by cagemates, due to their long hairs and secretive underground lifestyles keeping other individuals at bay.
Eleodes (Xysta) longicollis
Adults aren't picky about oviposition substrate. A good beginner's species, they are hardy, the larval and pupal survival rates are very high, and they grow fast, (larvae mature in 4-5 months under optimal conditions).
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Overall Eleodes can be a rewarding genus to breed, and there are many out there that haven't been bred yet! I hope this caresheet proves useful to those who wish to breed these iconic desert insects!
I've worked with most of the species mentioned myself, but big thanks to Isaac Fox, Joshua Campos, Erin Munkacsy, and the works of Orin McMonigle for information on the species I have not yet worked with.
If you have species specific rearing information on species not listed here or species listed that have little info, such as substrate preferences, humidity preferences, larval and pupal survival rates, etc., feel free to contact me and I can add them to the species accounts list.
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