Why does a spider mite become established? - briefly
Because they reproduce rapidly, thrive across a broad temperature range, and often lack effective predators on host foliage, spider mites can quickly colonize plants. Their capacity to feed on many plant species further promotes population buildup.
Why does a spider mite become established? - in detail
Spider mites establish populations when their biological and ecological characteristics align with favorable conditions. Their life cycle is exceptionally fast; a single female can produce dozens of offspring within a few days, and many species reproduce without mating (parthenogenesis). This rapid turnover allows colonies to expand quickly after introduction.
Key traits that promote colonisation include:
- High fecundity and short generation time, enabling exponential growth.
- Ability to develop on a broad spectrum of host plants, from ornamental shrubs to agricultural crops.
- Tolerance of a wide temperature range, with optimal development between 20 °C and 30 °C but survival at lower and higher extremes.
- Minimal humidity requirements; some species thrive in dry environments where other arthropods cannot persist.
Dispersal mechanisms further support establishment. Wind currents carry mobile stages (deutonymphs) over long distances. Phytophagous insects, birds, and mammals inadvertently transport mites while feeding or moving among plants. Human activities—trade of seedlings, cuttings, and ornamental foliage—introduce mites to new regions and habitats.
Chemical resistance compounds the problem. Repeated exposure to acaricides selects for individuals with enhanced detoxification enzymes, such as cytochrome P450 monooxygenases and glutathione S‑transferases. Resistant populations survive treatment regimens, maintain reproductive output, and spread to untreated areas.
These factors combine to create a robust invasion potential. Effective management requires monitoring for early detection, strict quarantine of plant material, and integration of non‑chemical controls (e.g., predatory mites, habitat manipulation) to reduce population growth before resistance becomes entrenched.