The research, unveiled today, was undertaken by electronic engineers from York University and ecologists from Royal Holloway University in London, to develop a series of new methods to monitor stag beetle numbers.
The team used ginger lures to trap adult beetles and tiny microphones to detect sounds made by their larvae in underground nests, to give an accurate picture of the breeding habits of the beetles. Until now, conservation efforts have been hampered because ecologists lacked a reliable way of monitoring numbers of the beetles – said to be the largest and most spectacular in the UK.
Dr David Chesmore, from the department of electronics at York University, said: "Until now, it has been very difficult to monitor the beetle's distribution without damaging the habitat.
"York's contribution to the project has been on acoustic detection.
"We have discovered not only that the larvae of the stag beetle can be detected using acoustics but the sounds are different from other species likely to feed in the same habitat.
"This means that we will be able to discriminate between the different species and we are developing electronic systems to achieve this.
"Acoustic detection of insects as a sampling method is very under used, but we believe it could have great potential in detecting larvae in the field."
The team discovered ginger was irresistible to adult stag beetles only after testing the attractiveness of many other fruit and vegetables – including bananas, strawberries, tomatoes and cherries – as well as wine and beer.
By using ginger, and designing the traps using heavy-duty plastic, the team was able to produce a very cost-effective method which is vital because most insect monitoring in Britain is done by groups of unfunded amateur recorders.
Using other methods of catching insects, such as light traps or traps baited with food, do not work with adult stag beetles because they are not reliably attracted to light and the species does not eat during the adult phase of its life cycle.
As well as finding a method of monitoring adult numbers, the team also used tiny microphones to pick up the sounds larvae make, as hand-searching is likely to destroy their habitats.
The study was funded by the British Ecological Society, the Forestry Commission, the People's Trust for Endangered Species and the Suffolk Naturalists' Society.