Ecological services of insects

Some amazing facts about creepy-crawlers, based on Schowalter & Withgott (2001) and Losey and Vaughan (2006).

Traditional approaches to insects today remain to the ‘us against them’ techniques of pest control we were using back then. Insects are viewed as unconditionally threatening forces, yet we need them for global survival. The human society directly depends on a healthy and productive natural environment that contains diverse plant and animal species. Usually insects contribute up to 87% of species diversity of a given ecosystem. In the UK alone, there are over 20,000 recorded species of insects. There are five major ecosystem services provided by insects:
(1) Decomposers. By recycling of dung, dead wood material (e.g. fallen tree trunks or foliage) or carcasses of dead animals (e.g., burying beetles, see on the Figure), insects stimulate and accelerate breakdown of organic materials by such organisms as soil mites, fungi and bacteria, enhancing soil fertility, reducing potential spread of diseases, and increasing site utility. Borrowing insects mix organic and inorganic material, increasing soil porosity and water-holding capacity.

(2) Herbivores. Insects eating plants can cause substantial damage during their outbreaks. Yet it is known that most plants can compensate for being eaten, and usually the weaker trees/plants are eliminated. Besides, insects also produce very large amount of nutrient-rich material (insect frass, molts, bodies and partially eaten foliage) that falls as litter. Nutrients that leach from this litter stimulate turnover of organic material in the soil and enhance its health.
(3) Food source. Many birds feed their chicks with insects, which constitute a significant and compulsory part of their protein diet. Major freshwater fisheries, especially those of salmonoids, are supported largely or entirely by aquatic insects.
(4) Dispersal agents. Insects disperse seeds, transmit pathogenic agents, and even transport other invertebrates from place to place (the phenomenon known as phoresy). Ants are amongst the most important seed dispersers.
(5) Pollinators. Many plants depend on insects as pollinators of their flowers, and pollinators can be a limiting resource for them.