Techniques for preparing micro-slides of thrips
A - SLIDE PREPARATION FOR ROUTINE IDENTIFICATIONS
The following method, using a water-soluble mountant, such as Hoyers or CMC10 (from Masters Co. Inc. 890 Lively Blvd. Wood Dale, IL 60191, (630) 238-9292, firstname.lastname@example.org). This method is rapid and thus relatively inexpensive.
1. Remove the specimens from the collecting fluid into clean 70% alcohol and attempt to open the wings and straighten the antennae using micro-pins (see below).
2. Place a drop of Hoyers Mountant or CMC10 Mountant onto a cover slip (13mm circle, No. 1). Place a thrips into this drop, ventral side uppermost, and gently lower a slide onto the drop. Invert the slide as soon as the mountant has spread sufficiently.
3. Place immediately into an oven, or onto a hot-plate, at about 40-50°C. Leave for a few hours before attempting to study. Alternatively warm over a spirit lamp.
4. When the mountant is dry, ring with nail varnish and label appropriately (see below).
B - SLIDE PREPARATION FOR ARCHIVING AND TAXONOMIC STUDY
To reveal fine details of body sculpture and minute setae, specimens need to be macerated gently. A few specimens may be prepared without maceration to preserve the natural colouration.
Specimens can be manipulated with fine micro-pins, mounted in sealing wax on match sticks. A simple lifting tool can be made from a small loop of fine wire. The best dishes are 'excavated glass blocks', 15mm high, 40mm square with an excavation of about 5ml volume.
Maceration removes body contents by soaking specimens in a weak NaOH solution. Treatment overnight in about 2% solution seems optimum, but black specimens require longer (even several days). Maceration of thrips should always be carried out at room temperature, in contrast to techniques used for preparation of aphid and coccid specimens.
1. Place thrips into clean water in an excavated block; it is best if the specimens float with their wings on the surface. Leave for 1 hour.
2. Add to the water an equal volume of 5% NaOH solution and leave overnight.
3. Transfer the specimens from NaOH solution to water for a few hours, using a needle or wire loop. Then transfer the specimens into 60% ethanol for storage or further treatment.
4. Replace the 60% alcohol with 70% alcohol and leave for about 1 hour.
5. Replace with 80% alcohol and leave for 20 minutes.
6. Replace with 95% alcohol and leave for 10 minutes.
7. Replace with absolute alcohol and leave for 5 minutes.
8. Replace with fresh absolute alcohol and leave for another 5 minutes.
9. Transfer to clove oil and leave until fully clear.
Prepare a small mounting block by fixing to the centre of a microscope slide a 2 mm deep layer of 25 mm square card, and cover this with plastic tape to provide a clean, surface.
1. Place a clean 13 mm diameter cover slip onto the mounting block; put a drop of Canada Balsam onto the centre of the cover slip and into this place one thrips specimen ventral side uppermost.
2. Spread the legs and wings, and straighten the antennae by pressing on the basal segments with a fine needle.
3. Invert a clean microscope slide and lower it firmly but gently onto the specimen in balsam on the cover slip. As soon as the surfaces touch, re-invert the slide with the coverslip adhering. Sometimes it helps to place a small drop of balsam in
the centre of the slide before touching the balsam on the cover slip.
4. Place the slide onto a hot-plate at once, at about 50°C, to drive off the xylene as quickly as possible. Dry the slides in an oven at about 50°C.
With the head of the thrips directed toward you, the right hand label should indicate the host plant, followed by the country (in capital letters) and then the locality and date, with collector's name (and code number). The left hand label should indicate the sex, morph and genus and species names of the thrips.