Leafhopper & Treehopper (Auchenorrhyncha) key: Methods

The information contained in these pages is based on published work on Australian and New Zealand Auchenorrhyncha by Knight (1973-1987) and others, and on the authors work on the Auchenorrhyncha (Fulgoroidea and Cicadelloidae) of New Zealand and Australia.

Most photographs were taken with an Agfa ePhoto 1680 or a Nikon Coolpix 995 digital camera attached to a microscope, downloaded to a PC and enhanced as necessary using Photoshop, CorelPhotopaint or CorelDraw. Some images were also captured using the reduced dept-of-field software Auto-Montage.

Examination of male genitalia

Examination of male genitalia is an essential requirement for reliable identification to species for leafhoppers and planthoppers.

In order to do this, the apex of the abdomen, or preferably the whole abdomen, is carefully dissected and cleared KOH (Potassium hydroxide, caustic potash) so that it becomes sufficiently transparent to see the internal structures.

*Take great care in using KOH because, even at 10%, it is corrosive and will cause burns if it contacts your skin. Avoid contact with the skin and avoid breathing the vapour.

Dissection of the male genitalia

 (click image to enlarge)
  1. The whole abdomen is removed from the specimen by applying slight pressure with the tip of a pin on the ventre, just between  the thorax and the abdomen. 
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  1. Once removed the abdomen should look more-or-less like the one in the photo to the right (ventral view of abdomen).
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  1. The abdomen is transferred to a test tube containing KOH* (Potassium hydroxide, caustic potash), which is placed in a beaker containing water. The abdomen is warmed for a varying period of time  depending on the size and degree of sclerotisation of the genitalia (generally 20-60 minutes, water in beaker brought to simmering point). 
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  1. This process, known as maceration, removes the muscle and soft connective tissue and leaves the abdomen sufficiently transparent to see the internal structures. Care should be taken not to heat the genitalia for too long since this will result in the genitalia becoming too transparent to see. 
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  1. Once cleared, the genitalia (genital capsule or pygophore and associated structures, see photo) and abdomen are removed from the KOH and washed thoroughly in distilled water to ensure that all traces of the KOH are removed. Abdomen and genitalia are then transferred to 70% ethanol for examination.

    Notes: Individual preferences will dictate whether researchers will separate the pygophore from the rest of the abdomen in order to perform this examination. Some may also wish to dissect the pygophore by detaching the 2 subgenital plates, and pulling out the 2 styles, and the aedeagus from the pygophore. 

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  1. The posterior (anal) aspect of the pygophore will often provide a better view of some structures, especially the aedeagus.

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  1. After examination, the genitalia and abdomen are transferred nto a small rubber-topped plastic tube of glycerine for storage. The pin on which the rest of the specimen is mounted should be passed through the rubber top so that the macerated genitalia and the specimen from which they came are not separated in the collection.
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Alternative to using KOH.

If KOH cannot be used, ethanol (75% solution) could be used instead. However, this means that genitalia would not be cleared. Consequently, pygophore and associated structures would need to be dissected before examination (see Notes under step 5).

With this ethanol method it is possible to bypass steps 1 to 4 (above) by first softening the whole specimen through soaking in warm ethanol, then cutting out the genital capsule from the end of the abdomen, and finally remounting the whole specimen (except genital capsule) on its pin or point.


NZ Hemiptera