Chalcidoidea - unknown mini-wasps: a study in Costa Rica

Chalcidoidea is a large group of poorly known parasitic wasps, of which about 20,000 species have been named. But many more species are known and have not yet been described. Many of the species are parasites of other insects, and may play an important role in controlling their populations. Some chalcidoids are important agents in the control of pest species - biological control. Some other chalcidoids feed on plants; fig trees are pollinated by the fig-wasps. This group of chalcidoids is essential for the production of fruit; the wasp larvae use a small proportion of the fruit to supply food for their own development.

So why are chalcidoids so poorly known?

Their average length is only about 1.5mm which makes them very difficult to collect. Modern sampling methods such as canopy-fogging together with new methods of preservation, have revealed an incredible richness of species with a great variety of form and colour.

One family of Chalcidoidea, Encyrtidae, is the subject of a Natural History Museum investigation in Costa Rica. This is the first comprehensive tropical survey of mini-wasps. Of more than 4000 Encyrtidae species, just 11 have been recorded from Costa Rica. By comparison, Britain with five times the area of Costa Rica, has 200 species. New sampling indicates that there may be as many as 1000 species in Costa Rica. This study will identify and catalogue these species, and develop manuals for their identification. Most species from Costa Rica also occur elsewhere in tropical Central and South America, also known as the Neotropics.


  1. An example a wasp from the genus Secticlava.

  2. Collecting canopy insects using the technique known as "fogging".

  3. Examples of three wasp genera of the Chalcidoidea; Psyllaephagus, Metaphycus and Aenasius.

This project is part of the Faunas and Floras Research Theme.

For further information contact:

Dr John Noyes,
The Natural History Museum,
Cromwell Road, London, SW7 5BD, UK
Tel: +44 (0)207 938 9328 Fax: +44 (0)207 938 8937
E-mail John Noyes

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