Brown Recluse and Black Widow Spiders

Spiders and insects belong to the phylum Arthropoda and have similar characteristics, including segmented appendages (legs), segmented bodies that are divided into two or three fairly distinct regions, and hard exoskeletons. Although similarities exist, these arthropods are not in the same group or class. Insects are in the class Insecta, and spiders are in the class Arachnida.

There are a number of criteria used to place spiders and insects in separate groups. However, the most obvious rule is the number of legs. Insects have three pairs of legs, and spiders have four pairs. Spiders also have only two body segments, the cephlothorax (combination of head and thorax) and the abdomen, while insects have three segments—head, thorax, and abdomen. Spiders are found in a variety of habitats where they catch and eat many small animals, with insects making up the major portion of their diets.

If you mention spiders, people might have several initial thoughts and reactions. Some might think of the large circular webs they see during the summer and fall seasons. However, some spiders never build a web and use speed (wolf spiders) or stealth (crab spiders) to catch their prey.

Other people may think of the venomous nature of spiders. While it is true that all spiders have jaws, called chelicera, and venom glands, the vast majority of spiders do not have venom that is toxic to humans. Two spiders capable of injecting toxic venom are the brown recluse and the black widow. This publication deals with the biology and control of these two spiders around homes and landscapes in Mississippi.

Download the PDF for the full publication, which includes images of these spiders.

Publication 2154 (POD-01-26)

Revised by Jerome Goddard, PhD, Extension Professor, and Blake Layton, PhD, Extension Professor (retired), Agricultural Science and Plant Protection. Originally written by James H. Jarratt, PhD, Extension Entomologist (retired), and Jerome Goddard (then at the Mississippi Department of Health).