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Photo#26822
Prionus laticollus mating behavior - Prionus laticollis - male - female

Prionus laticollus mating behavior - Prionus laticollis - Male Female
Frederick, Frederick County, Maryland, USA
June 22, 2005
Size: 6 cm
On June 23 I found a female Prionus laticollus - the largest beetle I have ever seen! I placed her in a temporary wire cage while I fetched my camera, and when I returned the male was clinging to the outside of the cage. I opened the door to the cage and in he ran. The couple proceeded to mate almost immediately. The next morning the floor of the cage was covered with about 30-40 pale yellow eggs, each about 3 mm long. I removed the eggs into another container, and the next morning I found another 30-40 eggs. At that time I released the adults, but kept the eggs on moist soil in a sealed contained. I check the eggs periodically, and just this week I noticed several small larvae crawling around the soil, each slightly longer than the eggs. Any suggestions for rearing these little guys?

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Prionus laticollus mating behavior - Prionus laticollis - male - female Prionus laticollus mating behavior - Prionus laticollis Prionus laticollus mating behavior - Prionus laticollis

Excellent record of procreation!
Well, the common name, Broad-necked Root Borer, suggests a diet of live tree roots, but that's way too much work to provide. Most longhorn larvae will accept substitute diets. Many beetle breeders use dry dogfood, but it needs to be changed daily because it gets moldy. I have seen artificial diet recipies that contain a dozen or more ingredients, including sawdust, brewers yeast and a mold inhibitor. You'll find that, unlike leaf beetle larvae, longhorn larvae don't like company and will bite each other, causing rapid dropoff in population if they are not separated. You may wish to invest in a plastic parts sorter from a hardware or crafts store. No need to ventilate it as the larvae don't need anywhere near the oxygen a vertebrate requires. Also, ventilation holes admit parasitic fly and wasp larvae. Line each cubicle with a small amount of moist rotten wood pulp that's free of wireworms -- another grub enemy, and give them each a small chunk of puppy chow to chew on. Warning: This is time-consuming and discouraging. They could all die before maturity.

An alternative approach would be to dump them all into a big rotating compost bin, hunt down freshly uprooted trees, hack off their roots, toss them into the bin, and give the bin a half-turn to bury the roots in soil. Do this every week or two. One or two might survive. However, this approach would deprive you the opportunity of viewing them readily as they grow.

Good luck. Hope to hear how things turn out!

 
Thanks for the advice!
I like the plastic parts tray suggestion. So far very few larvae have hatched. Based on your post, it sounds like my odds of success would be improved if I start with more larvae. I'll let you know what happens!

 
Lidded
Get a tray with a hinged snap-on lid that will keep moisture in and parasitic flies & wasps out.

 
So, what happened? Any surviv
So, what happened? Any survivors?

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