A Neotropical Savanna

John Bennett reported in December that the algarrobo tree was preparing for the dry season by changing to brown dry season leaves which he assumed had fewer stomata and therefore would lose less water than the green leaves. Here are the brown leaves.

He’s been keeping an eye out on this tree for us, and I thought I’d pass along to you his report.

Ok… time to update on the algarrobo garment renewal…

Here is the algarrobo with its new set of green chemistry labs, ready to process winter mineral carrying fluids from the ground and continue reaching out to the sun.

Nice tree, isn’t it?

Here is a closer look at the chlorophyll labs, and… what is that brown thing amidst the leaves?

Let’s take a a closer look…

Looks like some nectar sucking poisonous flying bugs have set up residence among the new foliage. A closer look at the creatures shows them peeking out their residence’s aperture. Wonder what they make of the camera flash?

Before getting entranced with the wasps, I’ll pipe in here with a reminder from John’s first report and also a couple of other observations.

In his first report, John told us that the scientific name of the tree is Hymenaea courbaril. and that it is in the family Fabaceae, subfamily Caesalpiniodieae.

Fabaceae is the bean family, which means the tree has compound, alternate leaves. If you need a refresher, there’s a pretty complete description of the bean family in the post on macano, The Living Fence. In the case of the algarrobo, the compound leaves consist of two leaflets. The subfamily is the one with the large frilly flowers, such as the Flamboyant tree.

The genus name, Hymenaea, is named for Hymen, the god of marriage. It refers to the leaflets, which occur in pairs (Botanary). The species name, curbaril, is one of the common names for the wood of this tree (Vozzo).

The tree that has just now put out green leaves will flower starting in March and continuing through July. The fruits will ripen the following year, between February and May (Carrasquilla). If you go back to John’s first image, the one with the brown leaves, and click on it to enlarge it, you will see a large kidney-bean shape in the tree. That’s last year’s fruit, due to ripen any day now.

Here’s what John has to say about the tree and its fruit:

It is an extraordinary tree, in many respects; and the fruit is one of the richest food sources you can find. Some people don’t like the smell, or taste, but I was brought up with it. When you open one of the pods, take the dry fleshy pits out and take a good sniff of the inside of the pod… I find it wonderful. But I don’t care for Roquefort or such.

So it’s about time we started watching for the fruit at the local markets, yes? And see for ourselves if we like it, yes?

Meantime, about those wasps…

There is a great variety of them in Panamá; big, small, mean, docile, with all sort of dwellings, but I have never read anything about them. For example, take a look at another bug aerodrome…

These critters always build their entrance atrium looking south.

And look at these guys… they build into walls and such, and are always curious about who is around their den… A while back I witnessed a war between these critters and ants.

Take a look at this aerial combat, between two varieties of bees…

Anyone who knows anything about the wasps or bees around here is welcome to speak up. These are fascinating abodes.

Last June, I saw a couple of galls on one of our very attractive trees, one in the myrtle family, called Myrcia splendens – the “splendid myrtle.” Galls, you may remember, are plant growths that have been stimulated by an insect. The growth serves as both home and food for the insect’s developing larvae.

After submitting an image of one of the galls to What’s that Bug? and learning that no one there knew what kind of gall it was (and they still don’t, as of today), I did a little searching on the internet and continued to come up fairly empty-handed. Last year’s galls were twig galls, or appeared to be so from the way they were attached to the tree.

Now there’s another type of gall on this tree – a leaf gall, which is a more common type of gall than a twig gall.

If you click on the image to enlarge it, you’ll see the leaf and how the growth appears to tuck into it. The leaf itself is producing this growth, of course, but it looks like the gall is just snuggling up to the leaf. You may be able to tell, also, that most of the leaves in this image are new – they’re a light green compared to the older leaves, which are dark green. Also, young flower buds can be seen here and there. This timing of the appearance of the galls brings home a statement from wikipedia on galls:

In order to form galls, the insects must seize the time when plant cell division occurs quickly: the growing season, usually spring in temperate climates, but which is extended in the tropics.

The insect naturally wants its home and food to grow rapidly, so here in Panama, anyway, this insect has chosen to settle on the splendid myrtle just as it’s putting out new leaves and flower buds.

Practically the only material I can find on galls and plants in the myrtle family is the observation that there are lots of them. In Australia, half the galls found have been on plants from the family Myrtaceae (Mo Bot Garden).

Worldwide, though, galls may be more likely to occur under certain ecological conditions than with specific plant associations. More species of galls are found in nutritionally poor habitats than in richer habitats. They are more likely to be found in association with woody plants that have leaves designed to conserve water than in association with plants without these characteristics (Fernandes et al., 2002). It happens that the splendid myrtle lives in nutrient poor abandoned pasturelands. It also happens that the shiny leaves of the splendid myrtle strike me – subjectively of course – as more likely to be water conservers than water wasters.

That’s about all I’ve been able to dig up. If anyone knows anything at all about galls here in Panama, or Central America, or the entire neotropics, please speak up.

Sunrise (6:49 AM): After watching this plant, the sandpaper plant, Davilla kunthii, for an entire month, I was beginning to wonder whether it would ever bloom. But on the evening of January 29, I saw quite a bit of yellow peeking out of the buds and the next morning at sunrise (6:49 on January 30 here in Potrerillos) when I arrived at the plant, the buds were ready to burst into bloom. A few bees were already hovering around the plant.

As the morning progressed and the flowers opened, it became clear there were two kinds of bees interested in this plant – a large one (circled), and a small bee. (or is it?), below. (The image below, as noted by a correspondent – with an Asian name I can’t translate – is a type of hover fly. I have some other images of the small bee, but they’re not clear enough to post.)

8:00 AM: At least a couple dozen bees were buzzing around. By 8:30 there may have been 50 or more. It was clear that the large bee, at least, was collecting pollen. My only image of this so far is fuzzy, but it’s not hard to see the orange pollen sacs.

8:30 AM: the first few weevils. The weevils are the entire reason I was sitting in the shade comfortably, with my coffee and notebook, watching this sandpaper plant put on its spectacular bloom. I had seen and photographed a weevil swarm last year, and Robin Foster of The Field Museum of Chicago suggested I look at the swarm more closely this year. I’m going to be tracking this plant throughout its blooming period to watch for these weevils.

That they are weevils has been verified by Dr. Henry Stockman who is this January at the Smithsonian Tropical Research Institute here in Panama and kindly looked at my images from last year. He suggested that it is possible that these weevils are eating the pollen – which is a rich protein source. As I watched, I could not see whether they were eating, but they certainly did not seem to be collecting it the way the bees were.
By the time the weevils arrived, some of the petals had already dropped from the flowers. The flowers had gone from opening bud at just before 7 AM to fully open flower, to the commencement of petal-dropping at 8:30 AM. One and a half hours. Astonishing!

9:30 AM: The number of bees was down and the number of weevils was up.

10:30 AM: The petals were seriously dropping off. I could hear the petals landing on the sandpaper-like leaves. They sounded like raindrops. There were even fewer bees, but the weevils were still there.

11:15 AM: Nearly all the petals were gone but several weevils stuck around. When the petals fall off, the cup-like green sepals, which underlie the petals, are left behind with the stamens. The weevils seem unperturbed by the absence of petals and simply crawl around the sepals looking for their pollen meal.

1:30 PM: The sepals were closing in on the stamens. A few weevils were still around, hoping to avoid getting trapped in the sepal jaws, I assume.

4:00 PM: The sepals are completely closed around the stamens. I saw one forlorn weevil crawling around on the sepal surfaces. Some sepals qwew separated enough to show yellow – they’re the ones that were bursting with petals to open the next day.

What a day for a plant! I’m sure Darwin would have loved the show. Remember his study of the “sleeping” leaves of the little machete plant, Erythrina? I wonder what he would have made of the opening and closing jaws of these sepals.

There’s a tree in the gully near our orchard.

Last February, when several plants of the myrtle family (Myrtaceae) were in bloom with their small white flowers and many stamens, this tree, too, was in bloom with its small white flowers and many stamens.

Like the other representatives of the myrtle family, the leaves are simple and opposite, and with my hand lens I can persuade myself that the leaves have small translucent dots, called punctations, like all members of the myrtle family.

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