Ant biology: October 2011 Archives

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?

Many thanks

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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

I heard of a study wherein ants were sprayed with a chemical that dead ants usually gave off and their nest-mates carried them off as if they were still dead even though they were still alive. Have you heard of this study and if so do you know where I can find it?


Hi Jon,

Thanks for your great question! The story is true. Researchers can capture the smell of a dead ant (or any insect) by dipping it in organic solvents (usually hexane) for a couple of minutes. The solvent can then be applied to another object or individual. The ants perceive this experimentally treated object or individual as dead and dispose it to the colony's dump sites. This behavior makes a lot of sense, because a dead and rotting individual would present a threat to the colony as disease could spread easily.

There are some great studies on this behavior (called necrophoresis):

Blum MS (1970) The Chemical Basis of Insect Sociality. In: Beroza M, editor. Chemicals Controlling Insect Behavior. New York: Academic; pp. 61-94.

Choe DW, Millar JG, Rust MK (2009) Chemical signals associated with life inhibit necrophoresis in Argentine ants. PNAS 106:8251-8255.

Gordon DH (1983) Dependence of necrophoric response to oleic acid on social context in the ant, Pogonomyrmex badius. J Chem Ecol. 9:105-111.

Haskins CP, Haskins EF (1974) Notes on necrophoric behavior in the archaic ant Myrmecia vindex (Formicidae: Myrmeciinae) Psyche 81:258-267.

Howard DF, Tschinkel WR (1976) Aspects of necrophoric behavior in the red imported fire ant, Solenopsis invicta. Behaviour 56:157-180.

Visscher PK (1983) The honey bee way of death: Necrophoric behaviour in Apis mellifera colonies. Anim Behav. 31:1070-1076.

Wilson EO, Durlach NI, Roth LM (1958) Chemical releasers of necrophoric behavior in ants. Psyche 65:108-114.

All the best,
Steffi Kautz & the AntAsk Team

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