zoology - Can ants sense food from a long distance?

I recently had ants find and then swarm to a food container that I put down on a desk. I'm curious as to whether an ant would have needed to get lucky (i.e., discovering the food after crawling up the desk) or ants have the ability to sense food from a distance.

I'm skeptical of believing that ants simply scout around until finding food; I'll use this case as an example:

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  My room has had no food or drink in it for weeks, so the area wouldn't be a "hotspot" for ants to be interested in.

  
  


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  I put the mostly empty food container down on my clean desk and turned my lamp off to work on the computer. No more than 2 hours later did I turn my light back on to discover a trail of ants swarming to the container I put down. It happened pretty quickly.

  
  


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  The desk is high, standing on four thin legs. I find it difficult to believe that an ant would crawl up the desk as often as a 2 hour time frame to scout for food, for the message to be passed to the colony so quickly.

  
  

I've been curious about this scenario for a long time. So my question:

Can ants sense food from a long distance? If so, how does it work? If not, how is the phenomena (ants locating food quickly in unlikely places) explained?

Answer

Ants follow odor cues in the wind. A study by Wolf and Wehner (2000) manipulated ant antennae and wind direction to show that ants followed odor plumes on the wind. A more recent study by Buehlmann et al. (2014) showed that desert ants of the genus Cataglyphis cued in on linoleic acid, a so-called necromone (death scent) released by dying insects. Here's a popular article that summarizes the latter study. Chances are good the ants are followed the odor plumes coming from your mostly empty food container.

Literature Cited

Buelhman, C. et al. 2014. Desert ants locate food by combining high sensitivitty to food odors with extensive crosswind runs. Current Biology 24: 960-964.

Wolf, H. and R. Wehner. 2000. Pinpointing food sources: Olfactory and anemotactic orientation in desert ants, Cataglyphis fortis.  Journal of Experimental Biology 203: 857-868.