The New Forest Cicada – One of the UK’s Most Endangered Insects
The New Forest Cicada is one of the country’s most elusive, and endangered, creatures. Out of the 2000 species of Cicada in the world there is only one in the UK, (this one being native to the UK), and only found in the New Forest (Hampshire). However, there hasn’t been a sighting of the New Forest Cicada in years, with no confirmed sightings this millennia. Being one of the UK’s largest insects at nearly 3cm in length you would be mistaken for thinking it difficult to miss.
In 2013 as a part of ‘The New Forest Cicada Project’, Researchers from the Electronics and Computer Science department at the University of Southampton released an app which uses the phones microphone to detect and record Cicada song. Cicada males have a characteristic, high-pitched sound song which they perform to attract a mate; in fact this song is so high pitched that most human adults struggle to hear it. As The New Forest Cicada is often found high up in trees which makes them difficult to see, their song is usually the best way of detecting them. However, Cicadas only sing in very specific conditions, often when the air is still and the weather warm, generally above 20°C.
From June to September 2013 the app was downloaded 1,500 times and Researchers collected approximately 4,000 reports. Unfortunately none of them detected any Cicadas.
In 2016 the New Forest Cicada Project installed several low cost Cicada detectors around the New Forest. These detectors originated from a larger project which focused on developing low-cost and open-source acoustic tools to aid in biodiversity monitoring, and with a low-low power microprocessor and powerful microphone would be suitable for picking up the Cicada song. 100 of these were placed around the New Forest, but unfortunately again they found no trace of the Cicada.
With the Cicada preferring warmer weather researchers expect them to be found in sunny, south-facing clearings. They require shelter yet need open and unshaded spaces surrounded by tall trees to rest in and shrubs and plants to lay their eggs on. It is thought that the Cicada emerges sometime around the end of May/beginning of July, with the season ending around the end of July which doesn’t give a huge window of opportunity to find these creatures. Cicada eggs are laid during this period which can take between 50 and 125 days to hatch, after which the nymph will burrow beneath the soil where it will spend the first 6 to 10 years of its life, growing and feeding off the sap and roots of various plants. When this time has passed they build a turret like structure out of the soil, thought to give the Cicada an indication of the air temperature to ensure it is warm enough for them to survive, before emerging. Once out of the ground, the Cicada will only survive for that season.
(Bob Linsdell [CC BY 3.0 (https://creativecommons.org/licenses/by/3.0)
So how can we be sure that the New Forest Cicada hasn’t already become extinct? Listed as a ‘Priority’ species under the NERC (Natural Environment and Rural Communities) Act as well as being protected under the Wildlife and Countryside Act, there are several identified threats which could lend themselves to the complete extinction of the New Forest Cicada; these include wetter winters and summers due to Climate Change and the increase of bracken covering the ground and reducing the temperature which is making it too cool for these insects to emerge. Animals and livestock have also been cited as a potential issue, with grazing thought to reduce the habitat and plants in which the Cicada lay their eggs, and general livestock in the area destroying the turrets that the nymphs build underfoot which then leaves them vulnerable to predetors such as ground beetles.
However, Researchers believe that there is no reason as to why the species would have died out. Sightings reach back as early as 1812, but there have been other notable periods where the New Forest Cicada remained undetected such as in the 1940’s and the 1960’s. A study done taking the dates of recording sightings identified a 7-8 year cycle during which it would be unlikely to detect any Cicadas (some sources estimate the cycle as being a 6-10 years), which at the time predicted that the next time the Cicada would be seen or heard would be between 2013 and 2015. However, this period has been and gone with no sightings. Turrets however are believed to have been found, leading researchers to hope that these insects are still out there.
The app is still available to download on both andriod and i-phone and can be found here for anyone who may be planning a trip to the New Forest (or is lucky enough to live there) in the summer. Much more information, including areas of the New Forest which have been dientified as being the most likely candidates for rediscovering the Cicada can be found here in a 2014 report compiled by Buglife.
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