Raising Dynastes successfully

Dynastes grantii development

 I have been asked repeatedly for the recipe of the wood mulch that I use for beetle larvae that feed on rotting wood. I got this recipe from my friend Bill Kaufman and it really works. Of course you need to prepare it at least 4 weeks ahead of time, so it's late now for Strategus larvae, but still time if you have and egg laying Dynastes female: those eggs take a break till next spring before they'll hatch.

For adults of scarab beetles, I usually use sieved peat moss for egg laying because it is easy to obtain in large amount and normally have success with it. Since peat moss usually carries mites that explode in their numbers very rapidly and cover adults and eggs, I microwave peat moss in a disposable tupperware (plastic bags can also be used) with a lid loosely placed on top; I usually put half-gallon container filled with peat moss in a microwave for about three minutes. After removing the tupperware from the microwave, I place the lid tightly and let the peat moss cool down for several hours. The moisture level is important for egg laying. You want the moisture level to be where peat moss forms a lump when pressed in your hand but easily breaks when poked by a finger. If a clump does not form, moisture level is too low. If a clump does not break easily, there is too much water. This rule of thumb usually applies to other substrate unless you are using very coarse substrate.

For lucanid egg laying, I do not use peat moss. I bury pieces of rotten wood in compost found in tree holes or homemade substrate. Compost is placed first in a container, and it is compressed hard for the first inch on the bottom. Rotten wood pieces are placed after being soak in water for a few hours. More compost is added to fill air space around rotten wood.

For scarab larvae, I usually mix multiple types of substrate. Compost found in deciduous tree holes is great. I also mix some well-rotten wood after braking it. Finally I add substrate I make. It is probably best to use only the homemade substrate if I can make enough of it. (since most dynastines prefer more decayed substrate than most lucanids do, it takes longer to make ideal substrate for scarabs than lucanids). The below are the steps I follow to make the substrate. Substrate that is commercially available in Japan and that generally produces larger beetles than the ones found in wild is made in a similar way. I sometimes use the homemade substrate only for lucanid larvae instead of mixing multiple types of substrate.

Supplies:
Barbeque wood pellet (I get oak from Ace Hardware)
Water
Yeast
Wheat flour
Plastic tub (10 to 20 gallon)
Large spoon or another item to mix substrate
Measuring cup
Bucket or plastic tub

Other items that may be helpful for you

1. Wash barbeque wood pellet by putting it in hot water in a bucket or another container. Rinse a few times. This process will remove most resin used to make the pellet. It is easier if you wash small amount of pellet at a time instead of trying to wash the whole bag of pellet.

2. Dry the washed wood pellet by placing in/on a tub, lid, newspaper, or tarp. If you make it shallow, it drys faster. The pellet becomes sawdust when it is dry. Make sure that it is completely dry before proceeding to the next step.

3. Add 7 to 8% (10% at most) by volume of wheat flour mixed with a couple of spoons of dry yeast into sawdust. It is very important that the container, sawdust, spoon, and your hands are dry during this step; otherwise, flour will make unwanted clumps, which will cause mold or lead to failure in the substrate making. Mix well so that sawdust and flour are mixed evenly.

4. add warm water and stir. Use enough water to get to a consistency that you can form balls of substrate that don't fall apart, but not more. It's moist, not wet.

5. Stir every day for a week, later once a week. Keep above 40 degrees Fahrenheit. White hyphens should run through all of it and the over all color will darken. But if you find black mold, throw it out, it's spoiled.


Important: The first time I tried this, all the males eclosed earlier than the females. This is normal for many insects. But in the confines of the terrarium, they got to the youg females before the females' exoskeleton had time to harden, and the females were killed. To prevent this sad situation, make sure you separate the male pupae (horned) from the females as soon as you can tell them apart. 




Good luck!

 

The Euphoria species of Arizona, USA

Overall, in 2010 the numbers of insects in Arizona seemed rather low compared to for example 2007-2008. The extremely dry summer of 2009 and a general increase in temperatures may be the reasons. Small, short-lived and heterotherm, insects are likely to be sensitive to climatic changes. Many species may also reach the limits of their tolerance in hot and arid Arizona. If it gets any hotter and drier here, they may not survive. But so far we are still hoping that this was a temporary decline in numbers and that many species will rebound. Others may be replaced by even more heat adapted species from Mexico.

But even though collection numbers in terms of species as well as individuals were low, I did succeed to complete my virtual collection of the genus Euphoria in the subfamily of  the Flower Chafers, Cetoniinae this year. These are day-active scarabs that fly extremely well with their hard wing covers (first wing pair) closed. A sneak preview of Bill Warner's yet unpublished Checklist of Arizona Scarabaeoidea confirmed that the ten species below are the ones that I can hope to find.

Euphoria Species of Arizona

 

Since I prepared this table, there has been a revision of the genus Euphoria and some names have been changed: E. fulgida holochloris is now E. monticola .  E. fascifera trapezium is now simply E. fascifera, E. kernii was always spelled like this, E. histrionica is now  E. sonorae

Usually I try to photograph living beetles, but I was also delighted to have access to the beautiful and rather complete collection of Patrick Sullivan in Sierra Vista. The specimens of Euphoria devulsa and E. canescens were photographed in this collection. Even Pat's representative for E. canescens came from Mexico, but Barney Streit told me that E. canescens can be found on Sunflowers along  Duquesne Road,Cochise County, Arizona.


E. kernii, which is so common on Opuntia and Prickly Pear flowers further east (Texas), is found in Arizona in a light and a nearly black morph and seems fairly rare.

E. quadricollis (E. arizonica) female and male

E. quadricollis, synonym E. arizonica, 'is sexually dimorphic, with the females tending to be shiny, broader and much darker than the more gracile, tomentose males. The amount of dark spotting on both sexes is variable, but usually much less in males' (Bill Warner via email). Females seem to be less represented in collections which led to some questions about the identification of the female that I found on a tree stump at Copper Canyon, Cochise Co.The image of the male is of a specimen curated at the collection of the University of Arizona.

Euphoria verticalis

E. verticalis, which used to be in the genus Stephanucha when I collected my first specimen in 2007, apparently flies after both rainy seasons: Eric Eaton caught the first one this year in early April when it was buzzing knee-high along stands of wild flowers in Sabino Canyon. In late September I usually find dozens around Annual Sunflowers at the Santa Cruz River and on Desert  Broom bushes in Molino Basin.

  Euphoria leucographa (sepulcralis rufina)

Every year in late summer,  Desert Broom is also the best place to find Euphoria leucographa, our most common Euphoria. With many other insects, the beetles enjoy the sweet juices oozing from the bark of this bush after generous monsoon rains. In October they also frequent the Desert broom flowers.

Euphoria sonorae (histrionica)

 I collected the similarly patterned, smaller E. sonorae in the Huachucas, from lower Carr Canyon to the very top of Miller Canyon. These beetles bury deeply into the flower disc of Sunflowers. This is so typical for them that they can be recognized immediately by their protruding hind ends.

Euphoria inda

I have encountered E. inda only once, at the research Station in Portal buried in flowers of milk weed and then flying off to the mesquite where I photographed it. B. Streit found it west of Portal in thistle flowers.
About this species, Art Evans has an interesting story to tell in his blog - how a specimen made it all the way to Africa to be described there as a newly discovered genus, until Art found it in the South African Museum in Cape town  and dismantled its cover.

 E. monticola (fulgida holochloris) is a great imitator of Carpenter Bees. Like the bees, it spends a lot of time on the wing without landing. when the beetle is buzzing by at high speed the closed shiny fore-wings give a perfect impression of the bee's heavy, dark body.

 Euphoria monticola (photos D. Danforth)

In July and August, I've seen them in the Chiricahuas and the Canelos in similar forested areas under oaks where the ground was covered in moist leaf litter. The male beetles seem to patrol certain paths and clearings, never flying more than a few feet high, probably in search of females on or in the ground. Females are hardly ever collected

 

Euphoria fascifera trapezium 

 E. fascifera trapezium, which I knew from California, is reported occasionally from our lower desert areas, supposedly associated with pack rat nests. This year it was observed in Tucson in early summer. It seemed to be feeding on fresh Mesquite pods that were bleeding after Mesquite Bug infestation. I finally got hold of one in October when Bruce Mitton collected it for me on blooming Rabbit Bush in his yard in North West Tucson where they regularly breed under his raised planters with lots of composted manure.

The life cycle of this genus is not well described. There seem to be one to two generations per year. The phytophagous larvae have been found in the ground under cow dung and in ant hills. Some adults are reportedly associated with gopher and pack rat nests. Adults feed on pollen, tree-sap, sweet fruit. They have been known to invade bee hives. Rarely, they become pests, damaging young corn or the flowers of roses or mango.

Diplotaxis pumila in Madera Canyon. Another Scarab Mystery

Friday, July 30st. Now the monsoon is getting serious. As I'm driving north on I 19 from Rio Rico towards Tucson, heavy clouds and walls of rain are obscuring the Santa Rita Mountains. Still, it's not yet pouring in Madera Canyon, so I decide to stop for a while. On Madera Canyon Road sand and rocks covering the pavement indicate where the washes have been running the night before.

Harsh Arizona sunshine usually tends to reduce the world to a play of contrasting light and shadows. So I appreciate the way the diffused light brings out the true colors of lush vegetation, reddish soil, white rocks and the occasional insect.

While Desert Broom grows in disturbed areas along the road, knee-high Velvetpod Mimosa (Mimosa dysocarpa) dominates most of the Mesquite grassland of the lower canyon.


Usually the pink flower-stands are disappointingly empty of insects, seeming to leave most of the pollination to the wind. On this rainy afternoon, a green Fig Beetle Cotinus mirabilis is buried deeply in the pink cloud.













Numerous pairs of Stenaspis solitaria are mating - they are all over the Mimosas, Desert Broom, and the Mesquite trees, their larval host plants.



Another little Cerambycid is mating on grass. It's such a narrow-built, small beetle that the bunch grass may well be it's host plant.

Just before the next cloud burst forces me back into my van, I discover many brown little Scarabs on the green parts of the Mimosas. It's Diplotaxis pumila, about 5 mm long and dark brown. Bill Warner tells me later that they are probably not uncommon (in fact, there must have been hundreds within the area around the pay-station of the canyon) but they are rare in collections. If they only come out in weather like last Friday, I know why!

They were feeding on the mimosa leaves, some were mating, and some were producing little yellow spheres - eggs? - excretion of excess fluid? I wished I had paid more attention, because little is known about their life cycle. Scarabs don't usually lay eggs in the open on top of vegetation. But if these guys always do it before thunderstorms, the eggs would be washed down soon and reliably to their destination, the soil and roots under the bushes. Thus, the females could avoid climbing down to the ground where they might drown or be attacked by ants. It seems like an advantageous strategy, but nobody seems to know.Diplotaxis pumila Fall 1909

Dichelonyx truncata in Sedona

At the beginning of June I was visiting my friends Kathleen O'Neil and Peter Tilman in Montezuma Wells. They took me to get reacquainted with the breathtaking beauty of the Red Rocks of Sedona and of the West Fork of Oak Creek Canyon in particular. We arrived just before sunset and the canyon lay already in deep shadow. No better light to best appreciate the deep colors of the landscape.


The trail first crosses the orchards and gardens an old hotel or lodge that burned down long ago. Some walls and chimneys are still standing. An lone fireplace exhibits the great skill of stone masons who used the natural local stone. Left behind ornamental plants make botanists wonder. We found thriving Vinca major, Spirea, Apple and Plum Trees and gorgeous but out of place Blue Iris.

Typical western Pinacate Beetles Eleodes obscurus were doing their head-down acrobatics or were mating everywhere on the sandy path. They looked nearly out of place in these genteel surroundings.


An old cave or mine shaft in the vertical red rock cliff must have served as a root cellar for the lodge. Peter, a geologist and prospector, was taking a closer look when the first beetle landed on his sleeve. Green, small, flighty, it looked at first like a Chrysomelidae. On closer inspection its antennae characterized it as a Scarab. Soon there were more - on my shirt and hat. In fact, I didn't find them on anything else at first.

It was Dichelonyx truncata. Two species of the genus occur in Arizona. Their distribution is very local. In fact, Pat Sullivan's field notes indicated that he found his only specimens also on the West-Fork Trail in Sedona in the seventies.

For any proper bug person everything after this discovery should have been anticlimactic. But I'm also an artist at heart. With two nice beetles in my pocket I could really enjoy the drama of the narrowing sandstone gorge and the great company of my friends.

I loved the contrast of complimentary reds and greens, the deep shadows and the last filtered light, and the delicate columbines, monkey flowers and ferns against the sheer cliffs.


This late in the day, we had the sandy beaches and completely quiet, mirror-still water all to our selves until a bouncy, exuberant Pitbull set another interesting counterpoint.