This Week in Anting: Black Lighting

Had the black light on almost every night this week and saw lots of Acorn Ant activity. 

 

Hundreds of males to at least three species showed up at the black light between the hours of 9:00pm and 10:30pm. They probably fly all night but I don't need to stay out that late.

I've come to learn that identifying queens in this genus should never be done at a glance because there are some oddities I've never seen before.

So in the video this is what I was calling Temnothorax longispinosus. The problem is online images of queens of the species show them as totally black! None of this yellow spots on the gaster or bands of color. The legs are correct though. At a glance without any magnification this ant looked totally black to m.

 Now compare that to this queen. This is most likely Temnothorax ambiguus, and there were a lot of these running around in the video. They were very much different than the larger black species in the photo above. The trouble is though now that I have them in test tube setups these two look identical to one another! So I either have two species with very similar looking queens or some of the colonies to one species were just dehydrated (perhaps nesting somewhere with a small entrance hole requiring queens to slim down to leave the nest?)...

This is a Temnothorax curvispinosus queen. It is basically what all of my queens now look like besides a slight detail.

 The name "curvispinosus" refers to their curved spines. Those little thorns you see on rear part of the thorax on Temnothorax ants. 

  The name T. ambiguus refers to how difficult they are to tell apart from T. curvispinosus. The one main difference is that their spines are not curved at all.

Some Uncommon Ants In My Yard

While trying to photograph Aphaenogaster dispersing Trillium seeds I chanced upon a few unexpected surprises. The only colony I was able to find actively foraging happened to be in an old stump, a former Norway Maple we had had cut down many years ago. To set the scene properly this was in the shade of an Eastern Redbud Tree and the stump is now used as a perch for a Mason Bee box as well as a stone dish we use as a bird's bath. Naturally we flush out the water every day or so to keep the mosquito larva down and the stump has been getting soaked for many years. The result seems to be idea for a surprising amount of ant diversity.

The stump is absolutely teaming with decomposing arthropods. Here an Acorn Ant, Temnothorax curvispinosus, has found one. Small soft bodied creatures such as this, especially ones smaller than the ants themselves make excellent ant food. It's likely several colonies of Acorn Ants are also nesting within the log.

Here a Strumigenys pergandei has also caught something, I believe it's a spring tail. These ants are rarely seen because the only nest in shaded places that are "cold and damp." Cold refers to when they nest in soil, usually under a rotting log. Generally the soil will be cool to the touch, even in summer. They hunt and forage in rotting wood and leaf litter, often where decomposing insects and arthropods are abundant enough to have turned much of the dead plant matter into soil. Supposedly the yellowish structure on their waist segments, as well as the petal-like structures on their head and body are to help camouflage them from prey items.

This is an awful shot of a Proceratium silaceum but they were there too. Even more cryptic than Pyramica, they have a front facing stinger on the end of their gaster (abdomen) so they can sting prey that's in front of them, in tight closed spaces, as opposed to having to turn around. They're worth a google image search to get the idea.

It's nice knowing these uncommon ants can still be found in my yard, because this is the first time in several years that I've seen either in my yard. Now I know where to look!

Some Early Myrmecochory Action

I so rarely get to see my specimens of Twinleaf, Jeffersonia diphylla, all flowering at once, let alone be pollinated by one another to see the seedpods. Normally the pods don't grow bigger than a nickle and shrivel up with nonviable seed inside. Today though I came across a fairly large seedpod. I reached down to see if it was soft enough to harvest and the darn thing broke right off the stem on me. Worst of all, the seeds weren't ready yet.... Waste not, want not.

Twinleaf disperses its seeds with aid of ants. Normally the seeds are rock hard and brown very much like unpopped popcorn. These had their little bit of elaiosome formed but the seeds were soft and green, like peas or green beans. The ants didn't seem to mind this and carried them off all the same. 

The elaiosome is what's treasured by the ants but with the seeds still soft it's likely they'll be eaten too. This is just as well though. I doubt they would have grown in this early state anyway. 

The ants here are Aphaenogaster rudis, which is actually a complex of several species. DNA analysis to count the number of chromosomes is required for a true species ID but overall they're the same. The species names are more or less scientific codes instead of Latin names, so the blanket term A. rudis works fine. They're all commonly found in woodlands across North America, they all nesting in soil and sometimes rotten wood in contact to the soil. They all form colonies with populations ranging from 2,000 - 12,000 ants. Nests are small and move around on occasion, making them ideal seed dispersers, along with their size.

Ideally the seeds would be rock hard and either discarded in the nest, or hauled out to the waste or midden pile where it would be buried in dead insects and other discarded seed husks anyway. Often plant seeds like this require two winters to germinate, where it's more likely the colony of ants has moved on, and or the garbage heap has decomposed into plant fertilizer. Some plants such as Trilliums emit a terrible odor when they germinate which likely helps encourage the ant colony to move along. 

The ants find nourishment everywhere they can, even among the seedpod itself. If the ants didn't come along to clean out the seeds, rodents, birds, and wasps would have. Rodents and birds love eating the seeds. Wasps go for the elaiosome just like the ants, but are unlikely candidates for seed dispersal. They may drop them on the surface for birds and rodents to find, or bury them too deep within the earth, or the seed could end up within the dead branch of a tree.

One plant that was right on time was the Woodland Poppy, Stylophorum diphyllum. The same idea of seed dispersal applies, however I can't get it out of my head how much the elaiosome to this plant resembles ant brood. It just looks like clusters of eggs and larva, which ants are more than happy to eat, especially if it doesn't belong to them.

The seeds, being ripe, are rock hard and firmly attached to the elaiosome packet. I have trouble removing it and I'm a human! It's unlikely the ants will be able to chew them into dust or "ant bread" so they'll be discarded within the nest and in a few years I'll likely have a patch of woodland poppy growing here.

Where this strategy of seed dispersal can go wrong though is when the wrong sort of ant finds the seed. This is an Acorn Ant known as Temnothorax curvispinosus. They're adorably tiny, with small colonies of ~200 workers that all fit right inside a hollow acorn, hollow plant stems, or dead plant matter. Not only do they nest in the wrong sort medium for starting seeds, but also the workers are too small to carry the seeds off. They're more likely to just recruit more workers from the colony and deal with the elaiosome where they found it, and the seed is simply left where it was beneath the parent plant. 

As a disclaimer I will admit all of these photos were staged to a point. You'll notice I just opened the seedpods and spilled them on a stepping stone where an Aphaenogaster rudis colony happens to nest. I just don't have the time to wait for this to happen naturally in my yard, but trust me it does. There are plenty of Woodland Poppy plants with open seedpods on them right now that have spilled their seeds in the garden. I typically find Tapinoma sessile and Crematogaster cerasi stealing the elaiosome from the seeds where they fell and don't disperse them. The occasional Aphaenogaster forager does find a few though and bring them back to the colony. Since they've been self seeding in my yard for the past three years now I've been finding Woodland Poppies coming up in places where ant colonies tend to nest, and or have been dragged away from the parent plant a short ways at least. Sometimes the ant carrying the seed home gives up or gets disturbed by a spider or something. 

Turkey Corn, Dicentra eximia, will likely be the next plant who's seeds do this to ripen in my garden... sadly I missed my chance with Hepatica this year, but they seem okay about germinating where they fall anyhow. So though a plant uses this strategy to disperse its seeds, it's not always required for success, simply a way to give them a leg up.

Early Ant Activity

Ant Chat Episode 31: Some Spring Flying Ants

This is basically a rundown of the species I've found flying here in my yard. I'm thrilled to report I've lost count as to how many ant species are found in my yard. Counting ant species is a slightly better way of measuring biodiversity in an area than say beetles, moths, and butterflies. Counting everything of course is probably best, but ant colonies are for the most part stationary, rather than just passing through.

Stenamma is the most recent genus found outside. I honestly didn't think they occurred in New Jersey, let alone my yard. Workers are really small and, I think, easy to mistake for Temnothroax as I have been apparently doing all my life. After the Stenamma queen I find what I thought was a Leptothorax species but after doing some research I find those are most common on the west coast, so that's likely a Temnothorax, or less likely, a Formicoxenus.  

Alex Wild tells me that North American species of Stenamma have a narrower section of the petiole as it comes off the mesosoma, see here. I should probably qualify this as one of those "most of the time it's true" statements. Just glancing over some of the Ant Web specimens I found a Temnothorax or two with the same trait. For the most part though, Temnothorax have don't have this smooth poll-like portion of the petiole; I'd say over all the majority have this section as an angular section. Stenamma seem to have smaller eyes which are also flatter to the head, while most Temnothorax seem to have larger eyes that dome outward somewhat. Again though there is a Stenamma or two that have very Temnothorax-like eyes. I'm not even going to throw Formicoxenus and Leptothorax into the mix but you get this idea, identifying something can be a pain in the ass.

While I have the genus down for that queen, I don't have the species. Stenamma have cryptic nests underground where I've read they are almost certainly predators of small arthropods.

Also above I found a Camponotus castaneus queen starting out. I'd already found a queen to this species behind work. Finding a new queen trying to start her colony in my yard is very rewarding. I made the decision to not catch her because the current adult colony that's out there really isn't doing so hot this year. They may be coming to the end of their colonies natural lifespan and I think it's important to allow some queens to get away. As another example there are some parts of my yard that I just don't look for ants and otherwise never disturb.

Trillium Colors and Design

Trillium grandiflorum

In an earlier post I questioned when the peak bloom phase is for Trillium grandiflorum. I said it's a choice between all the flowers being white, or when they fade to purple. What I didn't consider is the line in between.

Trillium grandiflorum

Trillium grandiflorum

There's something to be said for when both are seen next to one another. I think the vibrancy of the younger whites is exemplified by the contrasting older pink, magentas, and purples.

 

Trillium luteum

Trillium luteum

Trillium luteum is another species I have in abundance blooming now. The flower doesn't make any dramatic color change other than to grow even more yellow and less green.

A Tapinoma sessile and Nylanderia flavipes foraging on a Trillium simile flower.

Later in the year the Trilliums will be going to seed and I'll be relishing the ant elaiosome action their seeds attract. For now though the Trilliums offer another dimension to the forest floor for ants to scout  and occasionally steal a taste of nectar. 

Temnothorax species walking on Trillium luteum leaf.

Temnothorax species exiting Trillium grandiflorum flower.

Ant Chat Episode 27: Ants and Wildflowers

A pairing of spring wildflowers and the ants I find around them. Even before planting all these wildflowers I already had a lot of ant diversity. So with this video I'm basically documenting the wildflowers I've planted around certain ant colonies and in the future I'll be noting any interest if at all.

I also open up one of my honey bee hives that didn't survive the winter and see what's lurking about. I am certain they died of starvation and not CCD.