Western Flower Thrips Colony

What is a western flower thrips?

Adult western flower thrips, Frankliniella occidentalis , are about 1 mm in length and are a major pest of greenhouse crops.  The insects cause three types of damage: silvering of leaves and petals (top right), contortion of expanding tissue (lower left), and transmission of impatiens necrotic spot virus (lower right).

Why are we rearing western flower thrips?

The focus of our lab is improving host plant resistance to western flower thrips in floriculture crops.  We are looking for plants that either are not attractive to thrips or plants that reduce insect fitness.  Evaluating plants for resistance requires a large, consistent supply of insects that can be released into cages containing a plant.  One type of cage is shown at right.  

What is the life cycle of a western flower thrips?

The thrips place their eggs inside plant tissue.  The eggs require 3-4 days to hatch.  The photo at right shows the size of the eggs (transparent bean shaped objects) relative to a female thrips.

Thrips which have hatched from eggs are instars.  Instars can be found feeding on plant tissue (leaves, stems, and flowers) in the colony and on greenhouse plants.
Instars then pupate.  During this time the insects develop wings and become adults.  In the greenhouse thrips pupate in the soil. In the colony moist clay rocks are provided for the thrips to pupate on.

Thrips in our colony develop from egg to adult in 13-14 days.

 

How do we rear western flower thrips?

The colony is kept in a growth chamber.  The chamber is set to maintain a temperature of 26 degrees C, relative humidity of 75%, and a 16:8 hour day:night cycle.

Each cage contains bean pods, cut asters, and dilute honey on a sponge for the thrips to feed on.

Fresh food sources are provided to the thrips regularly.  Bean pods and flowers must be left in the colony long enough for eggs to hatch out of the plant material.

Care of the colony focuses on keeping humidity high in the cages without encouraging development of fungal growth.  The goal is to maintain a healthy colony that is high in thrips numbers and free from fungal growth that may impact thrips fitness.  See the daily care protocol sheet for specific instructions.