I was in Corcovado National Park in Costa Rica where I took this photo (sorry about the quality) of what I think is Camponotus sericeiventris. As you can see, the ant is walking over a sticky, black substance with no apparent problem. The whole trunk of the tree was covered in this substance - is it anything to do with the ants?
Thank you for contacting AntBlog and including an image. We contacted an expert on the ants of Costa Rica, Dr. John T. Longino, to address your question. Here is what Dr. Longino had to say:
"Your ant is indeed Camponotus sericeiventris. I've often seen tree trunks with black, sticky, oozy areas, and ants often seem to be attracted to them. I have always surmised that these are tree infections, a result of wounds and/or pathogens, and that the tree sap is oozing out and evaporating, making a sweet exudate that ants might like. I doubt that the ants are the cause of the exudate.
From the look of your image, the area looks wet but not super sticky. Ants have no problem walking over wet surfaces. Also, if a sticky surface gets a "skin" of moisture or dryness, that would make it easy for an insect to walk over. We might touch a surface and break that thin surface layer, contacting the sticky material below. So a surface that seems sticky to us might not be to an insect.
By the way, I did my graduate work in Corcovado, back in early 1980's, and developed my love of ants there."
John "Jack" Longino (guest expert), Corrie Moreau & the AntAsk Team