Harbingers of Spring

Written by CTP Student, Alex Blomfield

To me nothing represents the joy of spring-time like butterflies. With spring approaching I am looking forward to my second field-season studying the pearl-bordered fritillary butterfly. The pearl-bordered fritillary gets it’s Latin name, Boloria euphrosyne, from the Greek goddess Euphrosyne, who represents joy. It is indeed a fitting name for this butterfly which is the earliest of the fritillary family to emerge in the spring.

The pearl-bordered fritillary favours early-successional habitats, such as those created by coppicing. It’s habit of following the course of woodsmen and colonising newly created woodland clearings, earnt it the colloquial name of ‘Woodman’s Friend.’ Sadly, changing agricultural practice and declines in traditional land management have seen many populations die out as suitable habitat has been lost.

This butterfly is now one of Britain’s rarest and only persists in fragments of semi-natural habitat, but historical Lepidoptera collections bare evidence to their once widespread distribution. Historical collections provide a valuable resource for research and can be used to help us understand current populations better. As part of my project I’ve been comparing historical fritillary specimens from Tullie House Museum and the Natural History Museum database to current populations in north-Lancashire and south-Cumbria.

I’m using wing morphology to infer changes in butterfly mobility in response to habitat fragmentation. Population mobility is an important consideration in conservation; dispersal determines species’ survival in fragmented landscapes, and influences processes such as local adaptation, community dynamics and population genetic structure. My initial analysis shows differences in several morphological traits, including thorax volume and wing size, between current and historical specimens. This suggests that dispersal capacity may have changed over time and my fieldwork this year will building upon these results.