Photo Essay
Nature Trail Tour - July, 2008
Take a virtual tour of the Sibley Nature Tour!
[Additional Tours: February, 2006 | April, 2006 | May, 2006 | July, 2006 | August, 2006 | October, 2006 | January, 2007 | February, 2007 | April, 2007 | May, 2007 | June, 2007 | July, 2007 | August, 2007 | September, 2007 | October, 2007 | January, 2008 | December, 2007 | March, 2008]
On July 1st, volunteer Zach Reynolds ventured out along the trail with camera in hand a few minutes after a twenty-four hour rain of an inch and a half. The slow drizzly rain was the first measurable rain since three inches fell in December 2007. The spring wildflowers had long since faded, not one blade of grass was green, and several weeks of over 100-degree temperature had blasted the landscape. The rain was a blessing! Zach discovered something we believe unknown to science (that happened because of the rain!).
Also, please read the related essay.
Click on each image to see a larger version; use your browser's "Back" button to return to this page.
Despite the dryness, the desert willows near the building had been in bloom for a week.
The mesquites still had a few blooms, although most had beans. Some of the beans were still green, some had turned red, and some had turned yellow after being red.
Some of the yucca had yellow leaves. Drought might have affected the plant, or the larvae of the Giant Yucca Skipper or other insects might have damaged the roots.
The winter crop of tasajillo berries had not been completely eaten by the mockingbirds and curved-bill thrashers. Some of the berries had turned brown from rot. Some of the branches of the cactus had died and turned yellow. Flower buds were beginning to appear.
Zach found a wet Reakirt's Blue Butterfly on a mesquite stem. The larvae of Reakirt's butterflies feed on mesquite.
The top of the Reakirt's wings are beautiful, but normally the butterfly rests with its wings closed.
Horsecrippler cactus shrink when it is dry as its moisture is used up. The ribs become closer together and dirt often blows to cover the shrunken cactus. The roots of this one must have been damaged, for it had not swollen with the rain...
...like this one. The fruit is edible, but the tiny glochids (thorns) on it have to be carefully removed. It is rare to find the fruit untouched by the birds, skunks, turtles and other creatures that find them as soon as they ripen.
This year's yucca seedpods had not split open far enough for the seeds to be dispersed by the high winds that accompanied the be beginning of the rain.
Many of the stems of the tasajillo that still had red berries had begun to die.
A whiptail lizard ventured out soon after the rain, seeking prey immobilized by the rain.
A curved-bill thrasher ran across the parking lot, seeking insect prey slowed by the rain, or seeds washed onto the surface.
The thrasher was not happy with Zach's presence!
Immature great-tailed grackles squawked and fussed as they celebrated the end of the rain. Twenty four hours is a long time for a bird to endure being wet.
A western kingbird perched high up in the mesquites, waiting for the flying insects to start moving around.
The mockingbirds also perched high, surveying the changes brought by the rain.
A dragonfly waited for his wings to completely dry.
The red of mesquite beans seemed brighter just after the rain.
If a person chews on a bean this red, it tastes like apple juice - and so does bread made from the flour of the ground up beans.
What in the world is going on here? When Zach brought in this picture, the Sibley staff immediately send him back out to further investigate. The green is cryptogamic soil, but the gelatinous syrup was something new. The beetles were quickly identified as dung beetles, but what were they doing? The butterfly was imbibing the liquid of the syrup. Does the fungal component of the cryptogamic soil sometimes put out the liquid? Some mushrooms have sticky liquid ooze (full of spores) out of them that attracts flies, thereby transporting the spores to new locations. The brown mass in the center was a mystery as well - was it merely soil, an small animal dropping, or yet something else? Tiny Crematogaster ants were also present - but why?
Some of the beetles and some of the ants were busy at the edge of gooey mass, but some beetles were in the middle of the slop.
As Zach watched, more and more Crematogaster ants appeared. They usually feed on aphid honeydew, and even herd the aphids. They also may have a relationship with the caterpillars of some of the "blues" including the Reakirt's blue. Some species of honeydew feeding ants herd the caterpillars to the correct food plant and allow them to overwinter in the ant nest. Notice that one beetle is partially buried in the soil to the left. Zach did not notice any beetles arriving (either on foot, or by flying in).
Several harvester ants appeared, and the Crematogaster ants swarmed around them, as well as beginning clamber on the beetles. In the lower center of the picture a small larvae (possibly of some species of beetle) is visible. All of this action is occurring within an inch of the gooey mass.
One of the beetles created a ball out of the goo. It appears another ball had been partially formed, but look closely at it (it is just above the obvious ball). There appears to be a tiny invertebrate somewhat shaped like a worm curling out of it. Did its presence cause a beetle to stop working on creating that ball? Several ants attended each beetle along the edge of the goo. Those beetles did not seem to be creating balls.
More butterflies appeared and even used the beetles as perches to stand on as they fed on the goo. More and more beetles began making balls. The gooey mass began drying out within 45 minutes of the rain.
A very small green fly with red eyes came to feed on the goo, too.
One of the beetles began to roll one of the balls away from the gooey mass.
The beetles appeared to sink into the mass as they created the balls.
A red rainbug came and remained on the goo for a few minutes. They feed on termites, so was it drinking the liquid? A small fly with the appearance of a housefly (but much smaller) came to the goo, as well.
This beetle rolled its ball over five feet from the original site. It rolled it in a straight line, in and out of the divots created by Zach's shoe.
When it stopped rolling the ball it began digging. The first chunk of dirt was "large" and merely pushed aside. Did the beetle find a small crevice in the soil that it just pushed against to flip it? One ant has come to investigate. A few seeds lay half buried at the top of the picture.
The beetle dug down, pushing dirt aside. Several ants have come to investigate not only the ball, but the beetle, too.
The beetle pushed the soil up and behind it with its legs.
The beetle completely disappeared underground.
The beetle had been digging at an angle, going under the ball, for suddenly the ball rolled and was centered in the disturbed dirt. (The first chunk of soil can be used as a reference to see how far it rolled.)
Within a few minutes the ball was half buried. The beetle was not seen, so how did it engineer the sinking of the ball?
As the ball sank out of site, the ants activity increased. Were they feeding on microorganisms disturbed by the activity of the beetle?
The disturbed soil mound grew higher and higher, until it formed almost a dome of crumbly clods.
An Aphanogaster ant carried an oyster scale by the site of the pulpy mass. Normally the dome shaped scale insect is attached to a woody twig (such as a mesquite). Had the ant pried it loose, or had the rain loosened it?
It took the scale insect to this ant nest, where over a hundred ants were clustered near the entrance to the hole.
Near an auxilary hole of the nest, a winged ant appeared.
More winged ants appeared. The cluster of the ants had been part of the emergence of the winged virgin queens and male ants. Up to 100 winged ants emerge from the nest. The ants will fly some distance where they will join other ants of the same species but from a different nest. There, mating will occur. Because Zach was recording the activity of the beetles, we did not try to record the activities of the ant swarm.
Red harvester ants were also clustered around the entrance to their nest. Normally this species forms a pile of loose soil shaped like half of a volcano on one side of its nest, but the loose soil had all washed away with the rain.
Even when Zach poked at the ants with a stick, they did not deviate from their behavior. Was this species also preparing for the nuptial flight of the winged adults?
A rainbug wandered by. (To learn more about rainbugs visit this photoessay.)
Zach revisited the site of the pulpy cryptogamic soil two days later. It had returned to its normal hard crust, appearing as if someone had poured oil on the dirt.
Not far from the site was one of the dirt piles created by the beetle burying its ball.
The top of the dirt pile had a small hole.
Zach carefully scraped the crumbly dirt away and found a hole underneath. He then dug down to the bottom of the hole and found no evidence of the beetle, or the ball.
Related: Sibley volunteer discovers unknown gelatinous goo on cryptogams that attracts insects