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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.

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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:

This comes from Ol Donyo Orok Hill in Southern Kenya (on the border with Tanzania) at an altitude of around 4500 feet.  I found these ants all dead at the entrance of a hole (what I assumed to be their nest).  This was far enough away from any human habitation, farming, or other activity (other than some goat herding) that I ruled out the use of insecticide.  There were a few more dead, spread out of the the space of about 1 square foot, but the attached photo shows the vast majority of them in a small, dense pile.  Some of their exoskeletons were coming apart (especially the tips of the abdomens), but it didn't look like ruptures from predation, rather just decay.

The stem of the plant in the photo is Solanum incanum (Poison/Sodom Apple), which is both indigenous to the area and poisonous to humans and domestic stock, but I doubt that ants would eat something familiar to them which if it was poisonous.  I don't know what species of ant they are, but the closest I can get is some Pachycondyla sp. (though I'm really not sure).

Do you know what may have caused this seemingly sudden mass die-off?

Answer:

Taking a look at Ants of Africa for ants in the genus Pachychondyla, your identification seems in the right ballpark. Are there any experts out there who can tell us more about what kind of ants these are?

As for what has happened, when I've seen similar piles after a couple of events. Most commonly, either the ant colony had a battle with a neighboring colony or there has been some adverse weather that has caused a mass die off.

If the battle was with a neighboring colony of ants, not all the causalities will be torn apart, particularly if the damage was caused by stings or chemical weapons.

Flooding of portions of the nest during heavy rains can also cause big die offs in species that nest underground.

Readers:  Do you have any suggestions why these ants might have died?

Please leave your thoughts in the comments.