Mole crickets are subterranean insects, members of the family Gryllotalpidae, recognizable by their stout, cylindrical bodies and large, shovel-like forelimbs adapted for digging. These specialized front legs allow them to move quickly through the soil, mimicking the tunneling action of a mole, which gives them their common name. While their burrowing activity helps aerate the soil, this same behavior causes significant harm to vegetation by severing plant roots and disrupting the soil surface. This destruction, combined with some species’ appetite for roots and shoots, has established them as major agricultural and turf pests worldwide.
Global and Regional Distribution
Mole crickets are found across every continent except Antarctica, with approximately 107 species globally. Their presence spans temperate, subtropical, and tropical regions, but their status as a widespread pest is most notable in areas where non-native species have been introduced. The most damaging species, including the tawny and southern mole crickets, belong to the genus Neoscapteriscus, which originated in South America, primarily in Argentina and Uruguay.
These South American species were inadvertently introduced to the United States around the turn of the 20th century, likely transported in the ballast of ships. They have since spread extensively across the Southern United States, particularly along the Gulf Coast states. The tawny and southern mole crickets are now established from North Carolina westward to Texas, and throughout Florida, with some reports extending their range into Arizona and California. Other pest species originating from South America, like the West Indian mole cricket, have also become established in the West Indies, and Australian turf and pastures also contend with an introduced species, Neoscapteriscus didactylus.
Specific Habitat Preferences
The survival and density of mole cricket populations are influenced by micro-environmental conditions, particularly the soil structure and moisture content. They exhibit a strong preference for light, loose soils, such as sandy loam or other well-drained, friable soils that are easy to tunnel through. This soil type allows them to rapidly create the extensive network of tunnels and galleries they use for foraging and protection.
Moisture is a controlling factor, as mole crickets require moist soil conditions to thrive and for their eggs to successfully develop. However, they actively avoid areas that are excessively dry or fully waterlogged. This preference explains why they colonize environments where water is regularly applied, such as irrigated residential lawns, commercial turf areas, golf course fairways, and vegetable gardens.
The male’s calling song, used to attract females, transmits better through moist soil, signaling a favorable location for egg-laying. Females lay their egg clutches in a chamber dug out of the soil, typically between 5 to 30 centimeters deep, where moisture supports the eggs’ development. Their presence is often most visible in these well-maintained, moist environments where the tunneling activity disrupts the soil just below the surface, creating raised ridges or mounds.
Seasonal Migration and Burrowing
Mole crickets spend the majority of their lives underground, but their depth and movement change significantly throughout the year based on their life stage and environmental conditions. During the spring and early summer, adults emerge from the soil for mating flights, a period of horizontal movement often seen at night when they are attracted to outdoor lights. After mating, females move back into the soil to create egg chambers, typically laying clutches of 25 to 60 eggs.
The newly hatched nymphs remain close to the surface, where they grow and feed actively throughout the summer, creating feeding tunnels known as galleries. This surface activity is most pronounced when the soil is warm and moist, which facilitates both tunneling and feeding on roots and shoots.
As temperatures drop in the fall or during periods of drought, both nymphs and adults exhibit vertical movement, burrowing much deeper into the soil. These deeper tunnels, sometimes extending up to two meters, serve as overwintering sites where the crickets wait out the cold or dry conditions. This ensures their survival until the following spring when warmer, moist conditions draw them back up to the soil surface to begin the life cycle anew. The continuous movement between the surface and deeper soil layers is a direct response to temperature and moisture fluctuations in their immediate habitat.