For my specialist study in the UK I am studying the food preference of Lasius niger by feeding them 3 cotton buds soaked in different solutions (sugar+water, salt+water, and just water). So far, I have found that they prefer the salt solution over the suger solution and I am wondering whether this is possible as Lasius niger are knwon to prefer sweet foods over others. I believe the food preference is seasonal and is related to colony needs (althought my colony does not have a queen).
Your ant feeding experiments sound interesting. We contacted an expert on the salt preference of ants, Dr. Michael Kaspari, to help us with this question. Here is what Mike had to say:
It is indeed possible. A diet rich in plant exudates like nectar is typically poor in sodium, the Na in NaCl, or table salt. We have found that ants that are more herbivorous are likely to take advantage of NaCl baits, especially if those baits are presented to ecosystems that are far from an ocean source of sodium. Check out KASPARI, M., YANOVIAK, S. & DUDLEY, R. 2008. On the biogeography of salt limitation: a study of ant communities. Proceedings of the National Academy of Science USA, 105: 17848-17851."
Mike also suggested Googling "ants" and "salt" to find other relevant resources.
Best of luck with your research!
Mike Kaspari (guest expert), Corrie Moreau & the AntAsk Team