Thrips are often considered pests for gardens, vegetable patches, and houseplants. Knowing about their lifecycle deal with them better.
Key thrips lifecycle facts
Generations per year – up to 40
Offspring per cycle – 20 to 50
Active during – daytime
Thrips lifespan – 45 days as an adult, not including hibernation
Type of reproduction – sexual (male & female) oviparity (egg-laying)
In exceptional cases, asexual parthenogenesis and live birth
- Read also: thrips damage on plants
Thrips are very small insects that are nearly impossible to see with the naked eye. They start out as rice-like eggs laid in small cuts or wounds in leaves, fruits, or stems of plants.
Lifecycle of thrips
Spring is when thrips start hatching or emerging from hibernation. They reach maturity after two weeks and start reproducing until fall. Thrips damage plants through feeding both in the nymph stage and as adults. Although they usually only live for one or two months, many generations can appear within a single year.
Different stages in the life of a thrips
Adult thrips lay eggs in live plants for them to hatch and give rise to the next generation.
From the moment the egg hatches, up to growing into a full adult that is capable of reproduction, a thrips will go through several stages.
- Nymph or larva (synonyms, but nymph is a more accurate term)
- Prepupa (optional stage depending on the species)
Lifespan of thrips insects
This of course depends on the species of thrips, but the average temperature is a big inflence, too.
- Warm temperatures shorten their lifespan, whereas cool, mild temperatures help them live longer.
- Sometimes winter will interrupt their development. Whatever the stage, the insect can hibernate until spring.
Male and female thrips lifespan
Additionally, adult female thrips live for quite a long time, too: usually around a month and a half, or 45 days. During this time, it lays batches of new eggs every few days if the feeding is good.
- Males live for a much shorter period. Mating reduces their lifespan by half, down to about 30 days!
- A female stores enough sperm from the mating encounter to fertilize eggs for its entire life!
Generations of thrips per year
From egg to adult, only 9 days to 1 month separate one generation from the next.
- For most thrips species, the duration is two weeks.
Eggs, once lain, incubate for 2 to 16 days. They hatch into the first nymph.
Together, all stages from nymph to adult require at least 7 days and at most 15.
- From spring to fall, which usually numbers 8 months, over a dozen generations might appear every year!
- In tropical countries the weather is mild all year round. There may be over 40 generations of thrips!
For farmers and crops, devastation can be significant.
Thrips eggs are lain in soft tissue using an ovipositor. This is a special organ that places the eggs in or on a leaf, stem or flower bud. Unlike other insects like the gall wasp, thrips only very rarely create galls.
In the picture, you can see white dots on the stem of a Stephanotis vine. These are the laying spots for thrips.
Some thrips lay eggs on the surface of the plant, mostly those of the Tubulifera sub-order.
- Learn more about thrips eggs
Nymph stage for thrips
What is a thrips instar?
Like many insects and even snakes, the skin of a thrips won’t grow. Thrips molt as they grow to shed old, tight skins. Each time a thrips molts, it enters a new stage. Each stage is called an “instar”.
For thrips, these stages include both nymph stages and pupa stages.
- Nymph stages occur at the beginning. The shape and characteristics of the thrips remain the same, only the size is different. Most types of thrips have one or two nymph stages.
- Prepupa and pupa stages are when the thrips transforms. For example, wings may appear compared to the previous wingless stage.
Nymph stage is for feeding
Thrips feed and grow during the nymph stages. They travel from one feeding site to another, usually on the same plant.
- Like a mosquito, the nymph bites into a leaf and ingests the contents beneath the skin.
As they go around, nymphs also excrete waste. These tiny black pebbles look like dots strewn across the leaf. Sometimes these contain compounds that try to repel predator insects.
Prepupa and pupa thrips
During these stages, the insect usually stops feeding.
Just like a caterpillar pupates in a cocoon to turn into a butterfly, the thrips nymph evolves into a full adult during the pupa phase.
Where to find thrips prepupa and pupa
Thrips will often travel to the ground to pupate. They hide in leaf debris, soil, and mulch. In fall, this is how most thrips prepare for winter.
- In some cases, such as the ficus thrips, pupa and offspring hide in curled-up leaves.
Through pheromones, females attract males. After mating the female starts laying eggs.
- Females usually only mate once or twice. This provides enough sperm to fertilize all the eggs she might lay.
- Males try to mate several times, and even fight other males for the right to mate with a nearby female.
Often, tiny wings help the thrips get airborn. Thrips aren’t good flyers, but they’re so small that wind easily carries them away to other plants.
Smart tip about the thrips lifecycle
Temperature plays a large part in how fast a thrips will develop. A change from 55°F to 75°F (13 to 23°C) will speed development by 30%! In warm weather, monitor your plants often to catch and control thrips early on!