Insects

Lady Beetles, Yellowstone Lake; Neal Herbert; September 2016

Spider webs on Swan Lake Flat; Neal Herbert; June 2015

About

Insects provide a vital connection between plants and vertebrates. Without insects, many food chains would collapse. Herbivorous animals, most of which are insects, play a pivotal role as intermediaries in food chains by making the nutrients in plants available to animals that do not eat plants (Waldbauer 2003). During the dry summer months when grizzly bears in YNP are stressed for food, insects become an important part of their diet; Yellowstone grizzly bears are one of the only North American populations that consume insects in noteworthy amounts. Consumption of bees, wasps, and army cutworm moths (Euxoa auxiliaris) increases as higher-quality foods decrease in availability during August and September (Mattson 2002). Insects also regulate vertebrate populations through insect-borne diseases, parasitism, and herbivory competition. For example, ticks may cause significant blood loss, excessive scratching, and disrupt the eating patterns of their vertebrate hosts (Mooring and Samuel 1998).

Insects aid in the crucial process of nutrient cycling by moving soil, consuming carrion, and decomposing organic matter. Insect activity physically modifies the soil profile, improving the habitat for plant growth. Ants and other burrowing insects redistribute soil, bringing mineral-rich components from below and mixing it with organic matter, creating a fertile environment ideal for plant growth. In an area such as the GYE with large populations of large mammals, carrion decomposition is a significant issue. Carrion beetles are especially important in decomposition. Sikes (1994) found more than 50 species of carrion beetle present in the northern range of the GYE that are heavily dependent on ungulate carcasses. (Yellowstone Science)