Eleodes goryi (Solier 1848)
name:
The generic name of Eleodes is from the Greek, meaning "olive-like" describing the beetle's appearance (Tripplehorn, et al., 2009).
The specific epithet honours Hippolyte Louis Gory: French entomologist Hippolyte Louis Gory (27 September 1800 – 26 April 1852) authored
Histoire naturelle et iconographie des insectes coléoptères (1837–1841), volumes 2-4.
Young adult with a bit of sand from the substrate and mature female (right):
Eleodes goryi are a species of darkling beetles found at least in Texas, New Mexico, and Mexico (Blaisdell, 1909 and Triplehorn et al., 2009). Blaisdell offers a detailed morphological description
here.
As with other Eleodes species, E. goryi are flightless with fused elytra and significantly reduced flight wings. Eleodes beetles are able to emit a noxious discharge from the tip of the abdomen to deter predators. (In my own rearing experience, I never witnessed this behaviour, likely because my specimens didn't feel threatened.)
I found five adult Eleodes goryi in my backyard in fall of 2021 and spring / fall of 2022. With my five adults, 3 females and 2 males (based on shape), I decided I wanted to rear these beetles. This short article is about my rearing experience from my initial adults through F2 larvae in summer 2023. I will discuss 1) Adopting Adults, 2) Housing and Care, 3) Life Cycle, and 4) Pupation strategies. Several VIDEOS are included within this discussion.
Adopting Adult Eleodes goryi
I was fortunate to find my initial Eleodes goryi adults in my backyard. In all cases, they were scurrying along the ground and were quite easy to catch with my hands.
Two of the five that I found were carrying Tachinidae sp. eggs:
First of two E. goryi with Tachinidae sp. eggs:
Eleodes goryi after cleaning off Tachinid eggs:
Second of two E. goryi with Tachinid eggs:
E. goryi after removal of eggs:
These beetles' hardened elytra make it easy to remove the eggs using a toothpick. I cleaned off the beetles and added them to my rearing cage.
Housing and Care
I initially kept my beetles with other species of beetles and Orthoptera in a typical rearing cage, a 36"x24"x24 mesh butterfly habitat. However, when I decided I wanted to rear this species, I transferred my five adults to a smaller cage 30"x18"x18" with a substrate dish for rearing larvae.
Underneath the cage is a seedling mat that gently warmed the cage during the colder months.
For substrate, I mixed sand, coconut fibre, and a small amount of organic soil in a tray about 2 inches deep. I placed food on top and added egg carton pieces for hiding places. In this way, the adults could lay eggs in the substrate and I could rear the larvae using the same foods atop the substrate.
The adults were able to hide under the tray edges and use the sticks and paper towel "steps" to climb up onto the tray.
I started with carrot slices and organic romaine lettuce, along with nuts and grains, but later added several other foods.
first cage:
better cages:
FOODS for an Eleodes goryi rearing cage (all vegetables must be organic):
* Carrot slices (a favourite of larvae)
* Zucchini slices (a favourite of larvae)
* Yellow Squash slices
* Eggplant slices
* Sweet potato slices
* Apple slices for adults
* Romaine lettuce leaves (a favourite of larvae)
* Almonds (a favourite of larvae)
* Pecans
* Walnuts
* Rolled oats (whole)
* Fluker's High Calcium Cricket Diet
* Tropical fish flakes
* Dry cat food
* Water dishes with sponges (so the larvae won't drown)
* Nectar sponges (half clear Gatorade, half water, soaked in cellulose sponges)
F2 cage: F1 adults and early F2 larvae:
E. goryi eating rolled oats:
E. goryi eating cricket powder:
E. goryi eating romaine lettuce:
E. goryi eating carrot:
E. goryi, a gentleman and a lady having salad:
E. gori eating apple:
E. goryi (with Cotinis nitida) on nectar sponge:
Note: Per advice from a fellow BugGuider, I added rotting leaves / wood for nutrients needed for these saprophagous beetles.
VIDEO of adult female munching romaine lettuce
VIDEO (closer) of adult female munching romaine lettuce
Vegetable items must be changed every day. Be extra careful when removing each vegetable slice because larvae will often be attached and even burrowed into the vegetable. Gently shake the larvae back onto the substrate and check for any remaining larvae in the vegetable slice. I always put a fresh slice immediately into the space where I have just removed a slice so that the larvae can remain in position and resume eating.
These young larvae were attached to the carrot slice I picked up. I gently put them back on the substrate and covered them with a fresh carrot slice:
The safest way to remove vegetable slices is to keep a holding container for removed slices. Keep the container around while you do other work so you can check it for any still-hidden (burrowed) larvae. Often, ones you didn't see will make their way out of the vegetable where they have burrowed.
Holding container for removed carrot slices:
You will find "munchie dimples" in the vegetable slices and you can see which ones they prefer. Mine loved zucchini, especially the dark green peel, and carrots, and they also enjoyed a variety of other vegetables, such as eggplant, yellow squash, ripe sweet potato, and more. As long as you are using fresh organic vegetables, you can experiment with different types.
Fresh water should be added daily using a small dish with a cellulose sponge to ensure that no one drowns.
Nuts and grains and protein-based foods must be changed out periodically. Larvae especially like almonds.
Life Cycle
EGGS
Females lay eggs in sandy soil. (See VIDEOS below.)
The female beetle digs a small hole only around 5mm deep and then deposits the egg and quickly buries it with substrate.
Eleodes goryi laying egg:
VIDEO: Eleodes goryi laying eggs #1 in sand substrate.
VIDEO: Eleodes goryi laying eggs #2
VIDEO: Eleodes goryi laying eggs #3
Unfortunately, I did not get a photograph of the eggs as I did not want to disturb the substrate. On several occasions, I observed females laying eggs in one of the food dishes of rolled oats and whole grains. You can see this beetle lay the egg and then quickly bury it here:
VIDEO of E. goryi laying egg in food dish.
For proper rearing, I provide the necessary substrate and conditions for eggs to hatch and thrive (see notes in Housing and Care section above).
LARVAE
Smith, Dornburg, and Wheeler (2014) distinguish E. goryi larvae with this: "Eleodes goryi larvae can be separated from the other currently known Eleodes species based on the darkly pigmented eighth and ninth abdominal tergites. It is further distinguished by the pentagonal hypopharyngeal sclerome, lack of a caudal tooth on the pygidium, and the presence of 3–4 ventromedial spines on the protibia." (Detailed description
here.)
Larvae moult through several instars: Smith, Dornburg, and Wheeler detail up to eleventh-instar larvae of various Eleodes species. L. E. Haverfield (1995) notes six to eight instars in the species Eleodes hispilabris connexa.
My larvae began appearing in summer of 2022, but I didn't start intentionally rearing them until December of 2022. My first F1 adults began eclosing in late April, 2023. I think it's likely that both older larvae and some adults overwinter. (Of my five collected adults of unknown ages, two survived through winter, one male and one female.)
E. goryi young larva:
older larva:
VIDEO of young larva burrowing
Moulting:
On rare occasions, I observed older instars wandering to moult, sometimes crawling up the side of the cage. It's best to just leave them alone during this time. Do not assume that wandering larvae are final instars (or prepupal): they can be in any instar. On the few occasions that I observed this behaviour, I noticed that the larvae moulted within a few days, away from the substrate.
wandering larva, in late instar but not final instar:
Eleodes goryi larvae generally moult with relative ease. Here is a later-instar larva moulting:
exuviae:
older larva exuvia:
When in doubt about the instar, it is safest to assume that the larvae are not in final instar and will continue feeding.
Final-instar larvae will measure over 3 cm.
Final-instar larva at 32mm.
Prepupal larvae will appear chubby and, when visible (atop the substrate rather than burrowed), will position themselves on their backs, usually a bit curled:
Prepupal larvae in position to pupate:
PUPAE
The pupal stage for my E. goryi lasted an average of 12 days, with the shortest duration being 10 days and the longest duration being 15 days.
My first F1 pupa pupated on 04.22.2023 and eclosed on 05.07.2023.
This is my first F1 pupa and then the adult on Day 17, two days after eclosing on Day 15:
Pupating
Prepupal larvae after positioning themselves and remaining still (often for many days) will very gradually moult for the final time and pupate.
Prepupal larva in final moult:
Prepupal larva with pupating larva:
Pupating larva:
Pupating larva pushing off exuvia:
Pupae remain fairly flexible during the entire pupal stage. Young pupae are pale white:
Mature pupae exhibit darkening before eclosion:
Pupal SERIES from Day 1 through eclosion:
ADULTS
In my rearing experience, I found that adults eclose an average of 12 days after pupation. They take another two full days to darken and harden. Therefore, the newly eclosed adult must
not be moved or disturbed until Day 3 at the earliest. At that point, you can gently move the adult from the pupal cage to the adult cage.
Eclosing adult with video below:
VIDEO of eclosing adult wiggling to strengthen legs
Eclosing adult darkening the first day (after about 5 hours):
Here is an Eclosion Series from 12:05pm, June 12, 2023 until late afternoon, June 13, 2023. The times are noted on the images:
VIDEO series from this eclosion:
VIDEO Eclosing 1
VIDEO Eclosing 2
VIDEO Eclosing 3
VIDEO Eclosing 4
Pupa ready to eclose at Day 11 and then eclosed at Day 12 and darkened at Day 13:
This is a list of my first ten F1 eclosions with dates:
#1: pupate 04.22.2023, eclose 05.07.2023, 15 days
#2: pupate 04.29.2023, eclose 05.12.2023, 13 days
#3: pupate 05.07.2023, eclose 05.19.2023, 12 days
#4: pupate 05.10.2023, eclose 05.22.2023, 12 days
#5: pupate 05.10.2023, eclose 05.24.2023, 14 days
#6: pupate 05.15.2023, eclose 05.27.2023, 12 days
#7: pupate 05.16.2023, eclose 05.28.2023, 12 days
#8: pupate 05.17.2023, eclose 05.29.2023, 12 days
#9: pupate 05.21.2023, eclose 06.02.2023, 12 days
#10 pupate 05.25.2023, eclose 06.04.2023, 10 days
Adult E. goryi with pupa:
MATING:
From what I observed of E. goryi mating, the male pursues and "jumps" the female, climbing on top and knocking both of them over. Most of the mating I observed was on their sides.
It is likely that there is a mating method to the mating madness, but I am not aware of it. L. E. Haverfield (1995) describes a mating ritual in the species Eleodes hispilabris connexa in which the male entices the female with his palpi, antennae, and tarsi. However, even with the male mounted, the female ultimately determines whether or not mating will occur.
Eleodes goryi mating:
Pupation Strategies and Final Notes
The most difficult part of raising Eleodes is getting your final-instar larvae to pupate. It seems that Eleodes goryi suffer from Peter Pan syndrome and would prefer to remain larvae rather than pupate. I experimented with three methods to see what would work best in inducing these guys to pupate and grow up:
METHOD #1:
Leave mature larvae in larval rearing cage with proper substrate and food (see Housing and Care section above), allowing larvae to burrow and create pupal chambers when ready. One third, and later, one half to most of the substrate is kept very slightly moist to create the consistency necessary for formation of pupal chambers.
METHOD #2:
Place mature and prepupal larvae in individual pupation cups with substrate nearly 2 inches deep and kept very slightly moist to allow for pupation chambers to be formed. Larvae who are still eating stay near the top and then burrow when ready to pupate. Note: after checking the pupal cups each day, I covered them loosely with paper towels.
METHOD #3:
Place mature and prepupal larvae in individual pupation cups with a small amount of substrate, forcing larvae to pupate at the surface. Cover loosely with paper towels. Substrate is kept very slightly moist (in all three methods) with fine mist spraying.
There are some deep dishes and some shallow dishes in the first image below: they will be separated for observation. The second image is of the shallow pupal cups.
Note: these dishes will all be covered loosely with paper towels.
RESULTS:
Method #1: Failure. Only one larva successfully pupated and eclosed.
Method #2: Failure. Only four larvae successfully pupated and eclosed.
Method #3: Success. Twenty-four larvae successfully pupated and eclosed.
Method 1 likely failed because of crowding and disturbance of pupal chambers. Tschinkel and Willson (1971) discuss factors contributing to the inhibition of pupation in crowded environments among Tenebrionidae family beetles.
I recommend using individual pupal cups with shallow substrate, covered lightly with paper towels and kept very lightly misted every other day. This allows the larvae to pupate at the surface, which seemed to work best for the ones I reared. The added bonus to this method is that you can easily observe the full pupation and eclosion processes.
Overall, these beetles are not too difficult to rear but require at least a full year's commitment with daily care. At the time of this writing in September of 2023, I have an F2 generation of larvae who first appeared in early April in my F1 adult cage. I am using the same substrate as before and the same variety of foods. Several of my larvae are late instars, but I have not seen any prepupal larvae as of early September, 2023. I suspect that they will overwinter as late-instar larvae.
F2 larvae found underneath carrot slice in July, 2023:
I encourage others to consider rearing Eleodes and other native Tenebrionidae as they are delightful, interesting, and beautiful beetles. Please feel free to ask me questions and I can try to answer from my limited experience with this species.
References
Blaisdell, F.E. 1909. A monographic revision of the Coleoptera belonging to the Tenebrionide tribe Eleodiini inhabiting the United States, lower California, and adjacent islands. Smithsonian Institution, Washington, DC. Bulletin of the United States National Museum,
Haverfield, L. E. (1965). A Note on the Mating Ritual and Biology of Eleodes hispilabris connexa (Coleoptera: Tenebrionidae). Journal of the Kansas Entomological Society, 38(4), 389–391. http://www.jstor.org/stable/25083475
Smith AD, Dornburg R, Wheeler QD. Larvae of the genus Eleodes (Coleoptera, Tenebrionidae): matrix-based descriptions, cladistic analysis, and key to late instars. Zookeys. 2014 Jun 12;(415):217-68. doi: 10.3897/zookeys.415.5887.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4089825/
Triplehorn, C. A., Thomas, D. B., & Riley, E. G. (2009). The Genus “Eleodes” Eschscholtz (Coleoptera: Tenebrionidae) in Texas. The Coleopterists Bulletin, 63(4), 413–437. http://www.jstor.org/stable/40389465
Tschinkel, W. R., & Willson, C. D. (1971, February). Inhibition of Pupation due to Crowding in Some Tenebrionid Beetles . https://www.bio.fsu.edu/~tschink/publications/1971-0.pdf
Further Reading
Thomas, D. B. (1984). The life history and ecology of the pinacate beetle, Eleodes armatus LeConte (Tenebrionidae). https://cales.arizona.edu/yavapai/anr/hort/byg/archive/TheLifeHistoryandEcologyofthePinacateBeetle.pdf
Triplehorn, C. A. (1971). A New Species of Eleodes from Texas, with Notes on the Subgenus Promus (Coleoptera: Tenebrionidae). The Ohio Journal of Science. v71 n1 (January, 1971), 56-59. https://kb.osu.edu/handle/1811/5592
Triplehorn, C. A., Thomas, D. B., & Riley, E. G. (2009). The Genus “Eleodes” Eschscholtz (Coleoptera: Tenebrionidae) in Texas. The Coleopterists Bulletin, 63(4), 413–437. http://www.jstor.org/stable/40389465
Triplehorn, C. A., Thomas, D. B., & Smith, A. D. (2015). A revision of Eleodes subgenus Eleodes Eschscholtz (Coleoptera: Tenebrionidae). Transactions of the American Entomological Society (1890-), 141(1), 156–196. http://www.jstor.org/stable/43682024
Wright, D. P. (1972, December). Rearing Eleodes suturalis without Diapause. Academic.oup.com. https://academic.oup.com/jee/article-abstract/65/6/1731/2210918
.