Thrips of the British Isles

Collecting and preparing thrips

B—Slide preparation for taxonomic research

The objective here is to prepare specimens onto slides with their shape and colour retained in a condition that is as close as possible to the natural, living state but with the body cleared so that surface detail is visible. This ideal is difficult to achieve, and a compromise must be adopted. There are two stages:

1. Maceration to remove body contents
2. Dehydration and mounting onto slides

Most specimens should be macerated to reveal fine details of body sculpture and minute setae. If possible, a few specimens should be prepared for study without maceration in order to preserve their natural colour.

Tools

Specimens can be manipulated or gently massaged with fine micro-pins (available from entomological equipment suppliers), mounted in sealing wax on match sticks or similar fine material acting as shaft-handles. Ideally, use a pair of such pins, one straight but the other with the apex bent. During the maceration and dehydration process, specimens will need to be transferred between different solutions. A simple lifting tool to move specimens from one dish to another can be made from a small loop of fine wire. Alternatively, alcohols and other solutions can be changed in dishes using a fine glass pipette. The most appropriate dishes to use are excavated glass staining blocks-glass blocks 15mm high and 40mm square with a median excavation of about 5ml volume, and with a glass lid to prevent evaporation.

Before trying to slide mount a specimen a mounting block should be prepared. Fix to the centre of a microscope slide a 2mm deep layer of 1 inch square white card. Mark the centre of this with crossed lines, and then cover it securely with plastic tape to provide a clean, shiny surface on which a cover slip can be placed when preparing a slide.