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On a recent trip to western New York State, we made a cool discovery.

Driving along a quiet country road, we came upon some huge ant mounds.

It's hard to tell how big they were until someone plays spokesmodel.

We found not just one mound, not just two mounds,

but more than twenty of them.

In the photo the size is a bit deceptive because the mounds were up on a bank along the road. However, they were still relatively massive. Most of them were at least two feet tall.

These impressive structures were the nests of the Allegheny mound ant, Formica exsectoides.

Each of the mounds was covered with many active ants. According to the literature, the colonies have multiple queens and split up via fission to form clumps of interconnected mounds.

The mounds are thought to help the ants regulate the temperature inside the nest, which in turn optimizes the development of the young.

Doing some comparisons, it looked like the top of each mound was clear of vegetation and the upper surface was relatively uniform.

This photograph shows a closer view of some ants working on top of the mound.

Lower down, the mound was covered with sparse vegetation and riddled with holes like a sponge. It would be fascinating to know whether these were for drainage, air circulation, or what.

Checking out the lower holes, we found they did serve as entrances and exits. One contained a myrmecophile, although it moved away so fast I couldn't tell if it was a beetle or roach nymph.

The ants were very active. It didn't take long to find a nearby foraging trail.


(This was filmed using a small endoscope attached to laptop, which required two people to run. I need to figure out a way to mount it on some sort of mobile tripod. Any suggestions?)

Compared to a similar-sized foraging trail of our Arizona Pogonomyrmex harvester ants, it was noticeable that these ants weren't carrying anything. Because they are known to feed on insects, as well as gather honeydew, they must process their food in the field. Anyone know more about their foraging behavior?

Even to people who aren't interested in ants, these mounds were such a presence that they inspired awe and curiosity. It would be great to get a chance to study them longer.

Have you ever encountered Allegheny mount ant nests?

Time to knock the cobwebs off this blog with some new posts. Let's start by taking a look at ants tending the aster hopper, Publilia concava.

This species of treehopper is relatively easy to find because the nymphs feed in aggregations on the underside of goldenrod leaves (Solidago altissima).

The relationship between ants and aster hoppers is a mutualism. The ants guard the treehoppers and drive away predators. In this case the ants were Formica sp.

In return, the nymphs supply food for the ants in the form of liquid honeydew. In the center of the photograph the nymph has curled its tubular abdomen to present food to the ant.

The adult female treehoppers lay their eggs in clusters and guard them until they hatch. Then the worker ants take over. In a recent study, Morales and Zink found adult female treehoppers with ants tending them were more likely to lay eggs than untended ones. At one site the researchers discovered egg laying per treehopper actually increases with the number of worker ants nearby.

If you've never watched ants tending aster hoppers, here's a short video. (Unfortunately, the lighting conditions weren't ideal and there was a breeze.).

You might think that the treehopper nymphs, as phloem feeders, would be rather sessile, but the nymphs move around more than you might expect. Morales and Zink suggest that treehoppers may respond to density of conspecifics as well as ants.

In any case, the relationship between aster hoppers and ants is an interesting one.

Have you ever seen aster hoppers tended by ants?

Reference:

Morales MA, Zink AG (2017) Mechanisms of aggregation in an ant-tended treehopper: Attraction to mutualists is balanced by conspecific competition
PLOS ONE 12(7): e0181429. https://doi.org/10.1371/journal.pone.0181429

Morales, 2002. Ant-dependent oviposition in the membracid Publilia concava. Ecological Entomology. 27:  247-250. (download .pdf)

Previous post about the treehopper on thistle, Entylia carinata

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.