Spider
Beetles are Scavengers
These very small beetles are scavengers which feed on a wide range of things, including: broken grain, dead insects, bird or animal droppings, and dead animals. They need more moisture than most other stored product-infesting insects, and usually cause only limited damage, mainly to the outer inch or two of grain or whatever else they infest. Several species of these beetles, which look quite a bit different from each other, are worldwide in distribution. Some species have only two larval stages, but most have three. A life cycle, egg-to-egg, may be completed by most spider species in 35 to 90 days under good conditions, but may take as long as nine months. Adults of most species live one to six months, and females lay an average of 100 eggs. Larvae of these beetles will often drill a small hole into wood to pupate, and adults can lay their eggs through rather heavy cloth mesh grain bags. If these beetles are found in grain products, it usually indicates that those materials have been stored at the site for quite a long time, and that there is a source of moisture nearby. These are often a serious pest of museum specimens, especially dry insects which have been stored in boxes which were not sealed very tightly, or did not contain adequate amounts of repellent material. Spider beetles are mainly active at night. Some species cannot fly, but those that can are attracted to lights. Prevention usually involves the standard measures against stored product pests, but good sanitation and rotation of stock will help a lot against these pests. Webbing of larval feeding cells, cocoons, and cast skins can be used to detect and determine the extent of a spider beetle infestation.