November 2004

The Dutch Large Copper

Hester Soomers

The Dutch subspecies of the Large Copper (Lycaena dispar batava) is a characteristic marshland butterfly, and is restricted to the Netherlands. Management of the few sites remaining is crucial for the survival of this unique, and now endangered species. A computer model was developed to predict changes in number and distribution of the species over the next 100 years. Combination of measures, such as the construction of corridors, habitat enlargement and reintroduction will enlarge the distribution area. This will not, however, be sufficient for improving its chance of survival, according to the simulation model. This can only be achieved by reducing the mortality of eggs and caterpillars, and a carefully timed mowing regime.

Looking for special species

Kars Veling

In order to get an accurate picture of the distribution of a butterfly species, each observation is of great significance. This article emphasises how important a zero observation is. However, it is only valid when certain criteria are met. The species must have been looked for in its characteristic habitat, during the flight period, in good weather and enough time should have been spent looking for it, depending on the species in question. A manual will be issued to help field workers.

New and lost butterflies

Chris van Swaay

In The Netherlands, Maculinea alcon only occurred on the foodplant Gentiana pneumonanthe. In 1942, when the butterfly was found in the coastal dunes on Gentiana cruciata, it was described as a new subspecies Maculinea alcon arenaria. International research during the last decades revealed that in many European countries, the Maculinea species using Gentiana cruciata as a foodplant should be considered as Maculinea rebeli. This opened the possibility that the Dutch subspecies of the coastal dunes was in fact a subspecies of M. rebeli, so adding a new species to the list of Dutch butterflies. However, the European project MACMAN has shown that there is in fact no genetic difference between M. alcon and M. rebeli, so all of these butterflies are M. alcon.
On the other hand, it recently became clear that the European Wood Whites were in fact two species: L sinapis and L reali. Research in the collections of Dutch Wood Whites showed that L reali was only present at one location in the south of Limburg between 1951 and 1958. After this period, only a few vagrants have been seen. Since 1992, L sinapis has established itself near Maastricht, and all recent Wood Whites belong to this species.

Giving attention to woodland edges

Vivian Siebering

Dutch Butterfly Conservation is giving extra attention to woodland edges by issuing a booklet ‘Woodland edge management for butterflies and other invertebrates', written especially for nature wardens. Emphasis is placed on the transition zone where brambles, bushes and herbaceous plants can attract butterflies and other insects. The Ilex Hairstreak (Satyrium ilicis) is chosen as an example of what sort of information the book gives. To encourage more wardens to turn abrupt woodland edges into appropriate habitats for these insect species, Dutch Butterfly Conservation has also organised workshops of which excursions form an important part.