Orthoptera and allied insects of Essex 2002
TIM GARDINER
Centre for Environment & Rural Affairs (CERA), Writtle College, Lordship Road,
Writtle, Chelmsford, CM1 3RR Email: tg@writtle.ac.uk
Change of Recorder
During 2002, Alan Wake handed over the county recording of Orthoptera to the author who works
and studies at Writtle College. Alan was county recorder for over 20 years and has made a massive
contribution to our knowledge of species distributions in Essex. Alan started a survey of the county's
Orthoptera in 1980, which yielded a provisional atlas in the mid-1980s (Wake 1984). This atlas
included 10km maps for all species recorded and a useful key to adult Orthoptera designed by Roger
Payne. Survey work continued throughout the 1980s and early 1990s which ultimately led to the
publication Grasshoppers and Crickets of Essex in 1997 (Wake 1997). This publication included
5km distribution maps for all species recorded in the county and was based on approximately 5000
records. Alan's excellent work in the county, despite moving to Cheltenham in 1991, has given the
author much data to build on.
Whilst he was county recorder, Alan maintained a very well organised paper record of all sightings
sent to him. However, this kind of data is time-consuming to analyse, which has led the author to add
records collected since the 1997 publication into MapMate (a database and mapping programme).
At present, over 1300 post-publication records have been entered into the database. A photocopy of
all records collected by Alan has been made and is stored at Writtle College.
The 2002 Season
The author has been monitoring the abundance of grasshoppers at Joyce Field (TL664067) on the
Writtle College Estate since 2000. These surveys allow the abundance of grasshoppers in different
years to be compared, giving an indication of the effects of weather on Orthoptera. The study site is
unmanaged grassland, dominated by Perennial Rye-grass Lolium perenne and Broad-leaved Dock
Rumex obtusifolius. The monitoring has been conducted by counting the number of adult individuals
of Lesser Marsh Grasshopper Chorthippus albomarginatus and Meadow Grasshopper Chorthippus
parallelus in 10 randomly placed 2x2 metre quadrats in late July and again in August (total of 20
quadrats).
Individuals were recorded in each quadrat by brushing the vegetation with a pole to cause any
grasshoppers present to jump (Richards & Waloff 1954). The 'flushing' of grasshoppers was conducted
in a standardised method, ensuring coverage of the whole quadrat by moving from one edge to the
other sweeping the vegetation in a 180° arc. If a grasshopper jumped out of the quadrat it was still
recorded; however, if a grasshopper leapt into the quadrat from outside it was not counted.
The surveys were conducted under similar hot and sunny weather conditions, and the number of
individuals counted allowed the density per m2 to be calculated for both species in all three years. C
albomarginatus and C. parallelus were most numerous at Joyce Field in 2001 (Pig. 1). Abundance
was particularly low in 2000 for both species. Therefore, 2002 was not a particularly bad season for
grasshoppers when compared to 2000. The total rainfall and sun hours for April to September for all
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Essex Naturalist (New Series) 20 (2003)