128 Heath Fritillary in Essex: a review of its status and a report of its second generation
Graph of numbers of second brood Heath Fritillaries at Hockley Woods in 1999
outside of the wood where the more widespread plantains are found. For some West Country
populations which have alternative food plants this may be the case, but the Essex colonies are
dependent on the work of the woodmen to create the suitable new coppiced sections each winter. In
Essex any fritillaries 'going over the top' by flying above the canopy would be destined to an early
demise, confronted by the hostile domains of intensive agriculture and urban developments that
exist in uneasy juxtaposition to Hockley Woods.
These incredible few weeks have tended to pose more questions than answers, in particular concerning
how it may affect the species in future years, especially if this transpires not to be an isolated event.
At their zenith in early September, the second generation numbers were approximately 40% of those
counted in mid-June; how might this affect emergences in June 2000? Presumably any second brood
adults on the Continent utilize a different foodplant such as plantain, otherwise the young larvae in
late summer would perish when the cow-wheat dies off. If the Essex autumn-flying fritillaries were
unsuccessful in engendering offspring we may be entitled to label it as being a 'mistake of Nature',
for they would serve no useful purpose to the species and - if repeated in future years - it might be
detrimental to its survival here. Even in the unlikely event that some larvae did hatch, the probability
is they would suffer a total mortality due to starvation, disease or the effects of cold and damp
weather, particularly bearing in mind they usually have to attain their third instar prior to hibernation.
As the insects were active until very late in the year, the chances of any making it safely through to
the spring of 2000 seem virtually nil.
Monitoring of Heath Fritillaries will go on - indeed, must go on. Events such as this may become the
norm in the warmer world of the 21st Century, and it is detailed recording of the responses of wildlife
which will give the first clues as to what we should expect.
Essex Naturalist (New Series) 17 (2000)