Photo Essay
St. John's Episcopal School Insect Field Trip
On October 16th, 2007, first graders of the St. John's Episcopal School of Odessa, Texas visited the Sibley Nature Center to learn about invertebrates. After an indoor program about the "dangerous" species, the class ventured outside with Sibley director Burr Williams. The students each had a "bugcatcher," a plastic soda bottle that had been modified with a cap and painted with bright colors.
The class went to an old road near the Junior Master Gardeners' complex. This road is several feet below the surrounding pasture and gave some protection from a mildly chilly wind. Conditions were not the best for insects, for with the wind and chill, insects normally are not active. The habitat along the road is mesquite, broomweed, yucca, some native grass, and lots of bare dirt. Dried up stalks of cowpen daisy clustered among some of the mesquite. It had been almost a month since any rain, another factor of possibly finding few insects.
At first, the students found very little as they walked around. After a few minutes they learn to walk slower, or to not walk at all, and look closely at the vegetation. The twenty children found over 40 individual invertebrates in 30 minutes of collecting. Williams photographed the creatures in and on the containers and told the children about their life cycles, behaviors, and adaptations to living in West Texas.
We often do insect surveys at the Sibley Nature Center. Sometimes we only collect insects on one species of plant to try to determine that plant's "associates" - the pollinators, the pests, and the predators that feed on the insects that visit that one species of plant. Other times, we investigate the insects of one habitat, as we did on October 16th. Before digital cameras and computers, we kept written records and collected species in small jars. In 2008, Michael Nickell will begin to create a professional insect collection during student visits to the Center. With the Internet and email access to specialists, we hope to be able to identify the creatures to the species level more often than we have in times past.
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West Texans call this a cucumber beetle. It can be found throughout the growing season on a variety of vegetation, but never in large numbers. They can do damage to just germinating seedlings, but they also carry two bacterial diseases that damage members of the Cucurbit family of plants. Their larval grubs also damage the roots of plants. Since they damage corn, the larvae probably eat grass roots, too.
Stinkbugs, (or shield bugs) normally feed by sucking plant juices. Some are predators on other stinkbugs. This species is often found on green mesquite beans (and surprisingly, some mesquites still had green beans in October 2007, because the frequent rains of the summer had stimulated additional flowering.
There are many species of solitary bees in the landscape of the Llano Estacado. Some only feed on a few species of flowers, others are generalists. All place pollen and an egg in holes in the ground, or in vegetation (the carpenter bee, for example.) After being captured, a number of the insects caught on October 16th investigated their new surroundings calmly.
How in the world did a child see this tiny beetle. It is probably a seed beetle.
Pygmy blue butterflies are the smallest butterflies in North America. They are often found on wild portulaca, white salt heliotrope, and other succulent plants with small flowers. They often feed on tumbleweed as larvae - and this year was a banner year for tumbleweeds. No tumbleweeds were in the collection area, but over 10 acres were choked with tumbleweeds not more than 200 feet away. The children caught a half-dozen on the morning of October 16th.
Several daddy longlegs (harvestmen) were caught as well. Despite the myth that 'they are the most poisonous spider,' they are not spiders, nor are they poisonous. The worldÕs leading authority of harvestmen is James Cokendolpher of Texas Tech. Many species are omnivorous, eating primarily small insects and all kinds of plant material and fungi; some are scavengers of the decays of any dead animal, bird dung and other fecal material. This broad range is quite unusual in arachnids, which are usually pure predators.
Robberflies are common in the mesquite pasture land. Over the years, kids at Sibley have caught over a dozen species. Some species physically are mimics of bumblebees and wasps, but most have this shape.
This robberfly has a white band on its tail.
This species has a skinny tail. Most robberflies patrol a 'beat,' or territory, returning to their same lookout perch after forays after capturing other flying insects.
Many species of beetles are detrivores, cleaning up rotting material, and scat (dung). Some are small, like this fingernail size species - and others are the size of a quarter.
One student brought yucca seeds to Williams, and asked if the holes in some of the seeds were insect created. Williams gathered all of the students and told them about how the yucca moth is the only pollinator of yucca, and the larvae eat less than a tenth of the seeds in exchange. Yucca moths are a classic example of symbiosis.
Chinch bugs can be pests in lawns. They often number in the millions in grassland. One student found an area with several dozen in a square foot, and was able to scoop up several. Grass infected by chinch bugs first turns yellow, then brown, and then die. In the natural landscape their role might be more selective - only affecting one species of grass already affected by competition, drought, or disease.
Over a dozen species of jumping spiders have been found at Sibley. This large 'orange-red' species is the showiest, but it has only been found a few times at Sibley. Jumping spiders possess the best sight among spiders. Females make silken nests on mesquite trunks and cactus pads in places that are protected from the elements.
75 species of grasshoppers (it is estimated) live in West Texas. This and the following species appear to be members of Trimerotropis, which often prefer bare soil areas. This species has two white bands on its folded wings.
This grasshopper species has only one white band on its folded wings. On the Internet there is a field guide to New Mexico grasshoppers, but not to Texas grasshoppers (that we have found) so we utilize it. Grasshoppers can be extremely damaging to crops, so there has been a substantial amount of research done on grasshoppers. There are no popular field guidebooks - the best books for their identification are out of print and cost $400 dollars for a two volume set.
In the fall, paper wasps mate. If a nest is disturbed then, the wasps can be aggressive. While the wasp is nectaring, however, they are usually easy to catch and do not attack when released.
A few saltmarsh caterpillars were found. Normally they are commonly found in June, but this yearıs rain allowed a second generation to be born. They become pretty white moths with brightly colored (orange to yellow) abdomens.
Inspired by the first child to investigate yucca seeds, another student found a tiny seed beetle inside of the yucca pod.
Painted lady butterflies overwinter as adults, emerging on warm days and feeding on tree sap.
A tiny green assassin bug was hidden in a clump of broomweed. It feeds on smaller insects.
A green stinkbug - common on mesquite beans, too, was also found.