Thrips are minute, slender insects belonging to the order Thysanoptera, characterized by their narrow, fringed wings (meaning “fringe-wing”). Approximately 7,700 species have been described, typically measuring about one millimeter in length. While many species feed on fungi or are beneficial predators, a small subset acts as agricultural and garden pests. These plant-feeding thrips use asymmetrical mouthparts to puncture plant cells and suck out the contents, causing damage to commercial crops. Understanding their diverse habitats is key to managing populations, as their location shifts based on life stage, climate, and host plants.
Geographic Distribution and Climate Needs
Thrips are found across nearly every continent, from arctic areas to the tropics. However, the majority of species, and certainly the most economically significant pest species, thrive in warmer, temperate, and tropical regions. Temperature is a primary factor influencing their development, with warmer conditions leading to faster life cycles and increased generations per year. The geographic range of many pest species expands when temperatures become more conducive to their growth.
Thrips frequently seek out specific microclimates that offer protection and stable conditions. High humidity is often needed for their survival, particularly for the delicate larval stages. This preference explains their prevalence in sheltered locations like greenhouses, where temperatures are stable and moisture levels can be high. Thrips are weak fliers, but their fringed wings allow them to catch air currents, enabling long-distance dispersal to new areas.
Specific Plant Host Environments
The primary habitat of adult and feeding larval thrips is the host plant itself, where they actively feed on tender, developing tissues. They are typically found in concealed parts of the plant, which offers protection from predators and environmental extremes. Flowers are a highly preferred environment, with thrips often hiding deep within the petals or the base of the flower structure to feed on pollen and plant cells. This feeding can lead to streaked or discolored petals and cause flower buds to become deformed or fail to open entirely.
Beyond flowers, thrips also target young, succulent growth, including newly emerging leaves, terminal buds, and developing fruits. They use their rasping-sucking mouthparts to damage plant cells, resulting in the characteristic silvery or bleached scarring on the foliage. The damage on young tissue can cause the leaves to become distorted or curled as they expand. Different species exhibit varying host preferences; some, like the onion thrips (Thrips tabaci), have a broad host range that includes vegetables like onions and cabbage. Other species, such as the western flower thrips (Frankliniella occidentalis), are notorious for infesting a wide variety of ornamental and vegetable crops globally.
Off-Host Locations and Lifecycle Habitats
While the adult and feeding larval stages reside on the plants, other developmental stages require habitats away from the main foliage. The lifecycle of many thrips species includes non-feeding, resting stages known as the prepupa and pupa. These stages often occur in the soil or in sheltered areas near the base of the host plant. The larvae of many pest species drop to the ground to complete this transformation, seeking refuge in the top layer of soil or within leaf litter and plant debris.
Soil and ground cover provide a protective environment for these pupating thrips before emerging as winged adults. Other species, such as the greenhouse thrips, may pupate openly on the underside of leaves or in crevices on the plant. Additionally, adults and eggs can use bark crevices, galls, or the sheltered spaces between overlapping leaves as temporary off-host locations for protection or oviposition. These off-host locations are a significant part of the thrips’ habitat, making sanitation and soil management important considerations in their control.