Factors contributing to the rarity and threatened status of the Large Copper butterfly (Lycaena dispar batavus).
The Large Copper butterfly, Lycaena dispar, is extinct in Britain and rapidly declining in
the rest of Europe, due predominantly to loss of its wetland habitats. In the Netherlands the
sub-species L. d. batavus is at the edge of its range in Northern Europe and, as with most
marginal butterflies, has more specialised food plant and habitat requirements than the core
populations of L. d. ruti/us.
The aim of this study was to investigate some of the reasons for its continuing rarity,
particularly looking at the reasons for its specialisation on Rumex hydrolapathum in a
fen land habitat, whilst L. d. ruti/us is more generalist and utilises a range of Rumex species.
Laboratory experiments reveal that L. d. batavus has retained its ability to feed on other
Rumex species, without detriment to their overall survival and can utilise these alternative
host plants more efficiently than their natural host plant. This indicates that plant
chemistry is not responsible for their lack of utilisation in the wild. Field experiments have
also shown these potential hosts can support larvae, throughout each of their larval stages,
to maturity within a natural habitat, with no significant differences in survival rates
compared with R. hydrolapathum.
Investigations into adult female oviposition preferences were undertaken. Females showed
a willingness to oviposit on alternative Rumex and expressed no preference for any
particular plant species.
There are plans to re-establish L. dispar into Britain in the near future, dependent upon the
location of a suitable donor population. Allozyme electrophoresis work on L. dispar and
several of its captive colonies, has revealed that the wild Dutch, and one captive
population, have sufficiently high levels of genetic diversity that may enable a reestablishment
programme to go ahead with a captive colony, if necessary.