Lawn and Garden Coneheads

Bruce Wenning

The Proturans are not your typical soil dwelling insects. They are in the Order Protura and are blind, slow moving, white colored, tiny (0.6 to 1.5 mm), and have no antennae. They are affectionately referred to as "coneheads" because of their uniquely shaped conical heads.

What makes them unusual is that unlike most insects, proturans� front legs serve as antennae and are full of specialized sensory hairs that aid them in finding food, mates, and suitable habitats. They require dark conditions to exploit substrates such as rotting logs, leaf mold, humus, and soils high in organic matter. Proturans are subterranean and like moist but well drained soils, the same conditions necessary for growing most plants in gardening and lawn care. They are true soil dwellers and are beneficial insects. Proturans hold their specialized front legs outstretched, meticulously tapping and stroking as they feel their way between soil particles, crevices, along plant root channels, and between and within organic compounds. Their front legs are their "eyes".

There are nearly 500 species of proturans worldwide, but only about twenty in North America. These tiny insects are much less numerous than soil mites and springtails, but they are important components of the soil ecosystem. They are common in the soils of deciduous and evergreen forests, meadows, woodlands, organic lawns and gardens. Like other decomposer organisms, such as earthworms, soil mites, springtails, and millipedes, they contribute to soil fertility by feeding on fungal and bacterial infested (decaying) organic compounds. The waste products produced are slowly released as nutrients for plant root uptake. The feeding activities of all soil decomposer organisms help to reduce plant diseasecausing fungi and bacteria.

Adult and immature proturans look alike and utilize the same food sources. The larvae have nine abdominal segments. As they grow (molt) to adults they gain three more abdominal segments, one at each molt.

As they move through the soil (most live in the top six inches) proturans help improve soil structure by mixing soil particles and decaying organic compounds. They also release fecal pellets that stimulate soil microbial activity, which helps to further decompose organic matter. Proturians and many other species of soil invertebrates do the same or similar tasks at different soil depths and moisture and temperature regimes simultaneously, while feeding on different organic compounds at various stages of decay. It is a complex system maintained and enhanced by organic gardening practices.

You can help maintain proturans and other beneficial organisms by avoiding the use of harmful (inorganic) fertilizers and pesticides. Organic fertilizer compounds such as composted manure, leaf mold and processed organic fertilizers will help increase and maintain these beneficial insects in your gardens and lawns. To read more, see "Soil Biology Primer" (Soil and Water Conservation Society), www.swcs.org and "The Ground Crew", the website of Entomology Professor, John Meyer, UNC.

Bruce Wenning is a Horticulturist and Entomologist at The Country Club in Chestnut Hill, Massachusetts and is on the Board of Directors of the Ecological Landscaping Association. This article originally appeared in The Newton TAB in 2006.