If I combine all the previous answers, I come to the following hypothesis: larva develops in dungmass - larva pupates - heavy rain soaks remaining dung mass surrounding teneral beetle - drops of liquid dung attach to teneral beetle - liquid dung dries on hardening beetle - beetle emerges with dung spots attached to exoskeleton - beetle gets collected by one of us.

Cheers, Auke

On Wednesday, 11 October 2017, 23:39, Carlos Flechtmann <[log in to unmask]> wrote:

Hi folks

Here in Brazil this is also pretty common on top of Dichotomius and Ontherus species.

I always thought this would just be "dirt".


On 10/11/2017 6:32 PM, JF Mate wrote:
Yes, I have also seen such defects on Copris, Onitis and some aphodines in Spain, usually in wet conditions (Spring). In dry specimens the defects become darker and generally match the colour of the surrounding exoskeleton. I have always assumed it was due to the integument failing to properly sclerotize due to water saturation during emergence.


On 11 Oct 2017 21:19, "Floate, Kevin" <[log in to unmask]> wrote:
Hi All:
My colleague, Wes Watson, has a project with Onthophagus taurus.  A number of the adult beetles he’s recovering are speckled with yellow spots.  Closer examination reveals what appears to be yeast(?) in the spots.  Have others made a similar observations on beetles?  Photos are attached.
Any clue as to what these are?
If you can help Wes out, I know he would appreciate it.  Please contact Wes directly at [log in to unmask]
Kevin Floate, Research Scientist
Insect Biocontrol | Lutte biologique aux insectes
Lethbridge Research Centre | Centre de recherches de Lethbridge
Agriculture and Agri-Food Canada | Agriculture et Agroalimentaire Canada
5403 - 1st Avenue South, P.O. Box 3000 | 5403 - 1ère Avenue Sud, C.P. 3000
Lethbridge, Alberta, CANADA  T1J 4B1
Email | Adresse courriel:  [log in to unmask]
Telephone | Téléphone:  403-317-2242
Facsimile | Télécopieur:  403-382-3156
Teletypewriter | Téléimprimeur:  613-773-2600
Government of Canada | Gouvernement du Canada
Dr. Kevin Floate, Editor-in-Chief

Department of Plant Protection
Av. Brasil, 56
15385-000 - Ilha Solteira - SP
Phone: +55 18 3743-1142
FAX: +55 18 3742-2179
Skype: carlos_flechtmann