Ant Behavior

The rush milkweeds are flowering.


The open flowers attract an array of insects.

For example, tarantula hawks seem to prefer milkweed flowers. In fact, they are one of the chief pollinators of the plant.

No surprise that rover ants also visit.

From the swollen appearance of the metasoma of the upper ant, it looks like the worker ants are feeding on nectar.

Wait, the nectaries aren't open on these buds.

It can be hard to think of something as small as a rover ant as a predator, but they do catch insects like this thrips.

The tarantula hawks, on the other hand, probably aren't in any danger.

 

There's a question for the Consult-Ant this week. (The “Consult-Ant” started on the Leaping from the Box website, where I answered questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)

Question:

I sucked an ant up in a homemade bug vacuum and then transported it over a mile from its home.  Will it survive if I let it go?  Do they have to find their way to their original nest in order to survive?

Anon

Answer:

First of all, can a single ant make it on its own? The answer is no, unless that ant is a queen during certain parts of her life cycle. A single worker ant on its own doesn't have much of a chance of survival.

So, could the ant navigate back to its nest if displaced? Different ants use different cues to navigate when outside the nest. Some ants can use cues from polarized light or the position of the sun. Potentially an ant that uses visual cues might be able to re-orient itself over short distances to find its nest.

On the other hand, some ants rely heavily on chemical trails to move back and forth to their colony. Think of army ants, some of which are blind. In that case, the ant would have to wander around until it accidentally ran across a trail. The likelihood this would happen decreases with distance from the nest.

At the distance of over a mile, the chances the ant will be re-united with its nestmates are non-existent. There's a tiny chance it could join a nearby colony, but it is not likely.

What about a flying insect, like a honey bee? Honey bees would stand a much better chance. They have been shown to be able to fly up to five miles from their hive while foraging. They navigate by visual cues. An experienced forager bee might be able to re-orient from a greater distance than an ant on the ground could.

Please let us know if you have any further questions.

Anyone else have any thoughts?

 

Photograph of ant in a bug sucker by Karen Gibson, used with permission.

2 Comments

When the weather is cold and cloudy, many people dream of sunbathing on a warm, tropical beach. What about ants? Evidence suggests that at least some ants spend time basking in the sun.

See, for example, this video of harvester ants (Pogonomyrmex) sitting in the sun after a rain.

News From Rockcliff Farms blog has photographs of imported fire ants (Solenopsis invicta) sunbathing in large groups during a midwinter warm spell.

Some possible reasons for sunbathing/basking:

  1. Warm up or increase body temperature, particularly in poikilotherms (animals whose internal body temperature varies with the external environmental temperature)
  2. Exposure to ultraviolet light can kill microorganisms, such as bacteria, on the outer surface
  3. Exposure to ultraviolet light in vertebrates induces the production of Vitamin D

 

In his 1995 book Animal Architecture, Juhani Pallasmaa stated wood ants (Formica sp.) use heat captured by basking in the sun to warm their nests.

Kadochová, Frouz, and Roces (2017) recently tested this idea in the laboratory. They found Formica polyctena workers are willing to bask under an artificial heat source, which in this case was an infrared lamp. The authors of the paper didn't find evidence basking workers had a sustained increase in metabolic rate, but did suggest that heat energy absorbed during sun basking can be dissipated enough to increase the temperature inside of the nest. Cool! (yeah, I couldn't resist.)

The authors of the study found certain behavioral castes bask more than others. It would be worth investigating if workers which spend more time with the brood are more likely to bask. The ability to increase the nest temperatures around the brood during cold spells would likely be an advantage.

What do you think?

References:

Kadochová Š, Frouz J, Roces F (2017) Sun Basking in Red Wood Ants Formica polyctena (Hymenoptera, Formicidae): Individual Behaviour and Temperature-Dependent Respiration Rates. PLoS ONE 12(1): e0170570. doi:10.1371/journal.pone.0170570

 

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Pallasmaa, J. 1995. Animal architecture. Helsinki: Museum of Finnish Architecture. 126 p.