White bloom on males of the tribe Gromphadorhini

[Gromphadorhini]

I have been engaged in Gromphadorhini species for quite some time and throughout the whole time, and I observe in all cultures without exception a whitish coating on the tergites of the male abdomen. I noticed that it appears only in mature males, who are very active and exhibit pronounced sexual behavior. Males that do not exhibit this behavior have no plaque. What do you think it could be?

 

[All About Arthropods]

The only speculation I had ever heard is that it may be some sort of a sunblock analogous to what is used by things like Blue Death Feigning Beetles. Knowing that it only appears in mature, sexually-active males might reduce the likelihood that this is true though.

 

[Gromphadorhini]

The only speculation I had ever heard is that it may be some sort of a sunblock analogous to what is used by things like Blue Death Feigning Beetles. Knowing that it only appears in mature, sexually-active males reduces the likelihood that this is true though.

No, apparently not that. Beetles are daytime, and cockroaches are nocturnal; they just don't need such protection. In addition, this happens only in males, females are always clean and shiny. I assume that this is due precisely to the libido of males. There is an assumption that this substance has an attractive smell for females. It would be very good to examine the chemical composition of this substance, as well as the abdominal pleura for any glands there. Only who would do this? 

 

[Hisserdude]

For some reason I always thought it was some sort of fungus, and that's why the symbiotic mites were beneficial in keeping it in check, it may be something they exude to attract females though, who knows... 

 

[Axolotl]

I've had this flare up from time to time in several of my hisser colonies, though most often on G. oblongonota. I see it rarely, yet with enough regularity for me to also think it's related to a biochemical/bacterial/fungal imbalance. It seems to show up overnight and only affects a few individuals at a time. Perhaps the individuals mite count drops enough that the fungus can flourish? 

All of my hisser colonies have mites, so I'm not sure what triggers the white bloom. Maybe a mite die-off? I've long suspected that the white coating may be a fungus, though a benign one that doesn't seem to readily transfer between individuals. When I see it, it's usually on a single adult in the colony (though thinking back, it does seem males are far more prone to it).

I've successfully removed/eradicated it from my colonies by treating the affected individuals with a 20% vinegar/80%water solution. Vinegar has corrosive properties when it comes to exoskeletons, so I use it with care. I spritz it on a paper towel, wipe all of the white off with the paper towel and quarantine the individual. I repeat the treatment once a week for 4-8 weeks. Once it's gone, I maintain quarantine for any additional 2-3 weeks to ensure it's gone. During that final quarantine period I perform "mite transplants" from others in the colony using a kubuki brush to transfer the mites from one roach to another. The treatment is tedious and requires many quarantine enclosures as I keep the affected individuals separate from each other, but it does work. 

I've also quarantined affected individuals without the vinegar treatment or mite transplant, and they usually die within a few months. 

I've also noticed that some colonies are more prone to it. For example, I had a hybrid G. oblongonota colony where it showed up every few months, but my new non-hybrid G. oblongonota show no signs of the white stuff. 

I'm very curious as to what it is. Perhaps someone with a high quality microscope and a biology background could investigate?

 

[All About Arthropods]

No, apparently not that. Beetles are daytime, and cockroaches are nocturnal; they just don't need such protection. In addition, this happens only in males, females are always clean and shiny. I assume that this is due precisely to the libido of males. There is an assumption that this substance has an attractive smell for females. It would be very good to examine the chemical composition of this substance, as well as the abdominal pleura for any glands there. Only who would do this? 

Or maybe it was simply thought of as a desiccation buffer, I forget. Either way, the other theories mentioned here are much more valid. 

Exactly. LOL People can't even manage to figure out their taxonomy, let alone the even finer nuances of their beings.