Understanding the habitat requirements of insects and their relatives is the first step in trying to find them. Food, water, shelter and warmth (heat) are the primary requirements for life. Where requirements are all met, species may inhabit that niche and there is a higher probability of finding them there. However, many suitable habitats are also not used for one or more reasons. One reality most entomologists learn early is that often when you want to find even the most common of insects like a cockroach, they are nowhere to be found.
In the largest context, Texas and other parts of the world can be defined on the basis of vegetation and climate as ecological regions (see “Species Diversity and Distribution”) . At a smaller scale (or resolution), habitat patches include elements such as host plants, water edges, cracks and crevices formed by rocks, decomposing plant materials, etc. Habitats of specific insects and their relatives are often very specific and could be called micro-habitats such as those living under bark of trees in a specific stage of stress or decay.
Of the easiest and most predictable collection sites are agricultural fields. There, insects often become abundant because of the production system called a monoculture, where a lot of only one kind of plant is grown. Insects found there are limited to those that feed on the crop and those natural enemies that feed on the pant-feeding insects. Common arthropods found in specific crops are described in educational materials developed by the Texas Cooperative Extension’s entomologists found on http://insects.tamu.edu.
Upon visiting a habitat, your powers of observation will determine your success as a collector. Often, specimens are simply overlooked because many of them are very good at hiding, using cryptic coloration and avoidance behavior. Some caterpillars, for instance, use mimicry and look almost exactly like bird droppings, i.e., orange dog caterpillars – the larval stages of giant swallowtail butterflies, and walking stick insects look like twigs! Still other insects, e.g., “ironclad” beetles, striped armyworm caterpillars, drop to the ground and lay motionless (play ‘possum) when disturbed. Knowing collection equipment and how to use it is the final step to obtaining specimens.