For reliable identification of mantids it is essential that the mantis is well preserved as soon as it has died. Identification of living mantids is extremely difficult. Because of thier diet, once dead, mantids rot quickly so an efficient method of preservation is essential.
Immersion in 70% alcohol is a standard method used by many ecologists; although very effective, it usually destroys much of the colour and should therefore be avoided if possible.
As with most insects, mantids are usually best preserved by drying them; it is important to dry them quickly. Small specimens can be dried without any other treatment, larger specimens may need treating to stop them rotting before they have a chance to dry. Evisceration and stuffing with cotton wool is probably the best method of preservation available to most people.
Another simple alternative is to inject the insect with either 100% alcohol or 40% formalin. Injecting either of these will cause discoloration of green mantids, stuffing often avoids this problem. However, injecting formalin can cause the insect to becom every stiff and it is almost impossible to relax it and reposition the limbs once it has dried. Injecting alcohol is not very successful with large specimens unless they are subsequently dried quickly.
If the mantis is stuffed, care should be taken not to remove the genitalia of the males since the genitalia may be essential for identification. If the genitalia are removed, they should be properly preserved and mounted (see below).
Positioning the legs correctly is very important as the spines on the legs are one of the main features used for identification. The fore legs need to be spread so the spines can easily be inspected.
Preserving male genitalia
Genitalia may be easily removed from fresh specimens or wet preserved material (i.e. in alcohol). Dried specimens will need to be soaked in warm water for 20-60 minutes to allow removal of the genitalia. The following modification of Kaltenbach's (1998) method has proved successful.
The subgenital plate and preceding one or two sternites are detached at one side so the genitalia can be removed, leaving the rest of the abdomen intact (Kaltenbach’s method removed the end of the abdomen). Genitalia are cleared by placing in cold 4M KOH for 1-4 hours (Kaltenbach used warm 10% solution). Muscular tissue is removed with fine forceps. The genitalia should then be washed in water for 2 hours, washed in 90% ethanol for one hour, followed by 100% ethanol for one hour.
Genitalia can be mounted in Euparal on 0.3mm thick plastic sheet and covered with a glass cover slip. They may then be stored with the insect by pinning through the plastic sheet. Alternatively the genitalia may be mounted on a glass slide; however, this means the insect and genitalia must be stored separately.