How does a spider mite develop? - briefly
Spider mites progress through egg, larva, protonymph, deutonymph, and adult stages, each molt driven by temperature and host plant quality. Development from egg to adult typically takes 5–7 days under optimal warm conditions.
How does a spider mite develop? - in detail
Spider mites undergo a complete metamorphosis that includes four distinct stages: egg, larva, two nymphal instars, and adult.
The female deposits eggs on the underside of leaves, embedding each in a silk sac. An egg hatches in 2–5 days, depending on temperature; at 25 °C the period shortens to about 2 days, while at 15 °C it may extend to 5 days.
The emerging larva possesses six legs and feeds by piercing plant cells with its stylet. After a feeding period of 1–3 days, the larva molts into the first nymphal instar, which has eight legs. This instar molts again after 1–3 days, becoming the second nymphal instar. Both nymphal stages continue feeding and growing, each lasting 1–4 days under optimal conditions.
The final molt produces the adult, which is capable of reproduction. Adult females can lay 30–100 eggs over a lifespan of 5–15 days, again influenced by temperature and host plant quality. At 25 °C, a single female may generate three to four generations within a month, leading to rapid population increases.
Reproduction is primarily arrhenotokous: unfertilized eggs develop into males, while fertilized eggs become females. Under favorable conditions, females may also produce offspring via parthenogenesis, allowing populations to expand even when mates are scarce.
Environmental factors modulate development speed and survival. High humidity (>70 %) accelerates egg hatching but can promote fungal pathogens; low humidity (<30 %) prolongs development and increases mortality. Temperature ranges between 20 °C and 30 °C support the fastest growth, whereas temperatures below 10 °C induce diapause in many species, halting development until conditions improve.
Dispersal occurs through wind‑borne movement of mobile adult females and via silk threads that facilitate ballooning. This enables colonization of new plant parts and neighboring hosts.
In summary, the life cycle proceeds from egg to larva to two nymphal stages and finally to a reproducing adult, with each phase lasting 1–5 days under optimal temperatures. Reproductive capacity, temperature, humidity, and dispersal mechanisms together determine the speed and magnitude of population build‑up.