Efficiency and Kill Rates

Historically wasp traps have been gauged by the number of wasps that they kill. As a measure this has now been shown to be a red herring. Why? Well, to explain, we need to compare a low efficiency wasp trap with a high efficiency wasp trap. Let’s imagine that the low efficiency wasp trap is about 10% efficient. What does that mean? Well, it means that the trap will kill one out of every nine wasps that it catches. Let’s also for arguments sake, say that each wasp that feeds and escapes from a trap brings back 9 wasps from its nest. The first wasp that enters the low efficiency wasp trap might be one of the unlucky 10% and is killed. [ 1 dead wasp – 0 wasps in vicinity ]. The next wasp that comes along statistically should survive and so will return to its nest to bring back 9 wasps so that 10 wasps now visit the trap. Of these 10 wasps 1 will die because the trap is 10% efficient [ 2 dead wasps – 9 wasps in vicinity ]. The 9 wasps each go back to the nest and bring back a further 9 wasps each meaning that in total 90 wasps now visit the trap. Of these 9 will die leaving 81 wasps to escape. [ 11 dead wasps – 81 in vicinity ]. The 81 escaping wasps return to their nests and each bring back 9 wasps making a total of 810 wasps coming to visit the wasp trap. Of these 81 will be killed leaving 729 in the vicinity of the trap. The low efficiency wasp trap has killed 92 wasps – a very impressive total! However, the low efficiency wasp trap has also attracted 729 wasps that were never there in the first place! Contrast what happens with the high efficiency wasp trap. The first wasp that comes along is killed [ 1 dead wasp – 0 wasps in vicinity]. The next wasp that comes along is also killed. [ 2 dead wasps – 0 wasps in vicinity ]. What? That’s it? Only 2 measely wasps to be wasp free? The video clip below demonstrates the principle. Obviously in nature the numbers don’t work in such an orderly fashion but the principle is the same. The thing to remember though is that whilst a high efficiency wasp trap might kill 100% of the wasps that it catches, that does not mean the trap will be effective. Effectiveness depends on a number of factors including the use of appropraite bait and setting the trap in the correct position to intercept wasps and to interrupt wasps when they are already swarm feeding.

Head to Head Studies

Some people use head to head studies to evaluate wasp traps. What this means is taking two traps and placing them literally side by side within a matter of inches of each other to see which trap kills most wasps. Where such tests are conducted between a low efficiency wasp trap and a high efficiency wasp trap then it is fully expected that the low efficiency wasp trap will catch and kill far more wasps than the high efficiency wasp trap (which may not even catch a single wasp under these test conditions). This is simply because scouting wasps escaping from the low efficiency wasp trap navigate back to the exact location of the low efficiency wasp trap so ignoring the high efficiency wasp trap. (This is programmed swarm feeding). Meanwhile, the odd scout which enters the high efficiency wasp trap is killed and cannot communicate the location of the high efficiency wasp trap back to its nest so the high efficiency wasp trap looks as though it doesn’t work. All the while the low efficiency trap is teaming with lots of wasps swarming in its vicinity.

Wasp Persistence Studies

If the purpose of a wasp trap is to protect an area from wasps, then the measure that should be used to gauge how successful a trap is should surely be the number of wasps persisting in the vicinity of the trap? This is the measure that WaspBane uses to gauge wasp trap efficiency. In field studies, the WaspBane wasp trap was tested against the dome trap for wasp persistence. Great care was taken to ensure that the testing was performed to remove bias. An empty open grass field was selected which had no naturally occuring food sources for a distance of at least 50 metres from the test site measured by the distance to the nearest hedgerow. There was no pre-existing wasp problem and no wasps were found in the test site. Two test locations were set up roughly 50 metres apart. A WaspBane wasp trap was set up in the first location according to instructions using a 50/50 mix of lager and water and 150g of honey. A dome trap was set up in the second location using proprietary bait purchased with the dome trap. The traps were set at 8.00am on the first day. For the next 14 days each of the traps were observed at about 2.30pm and the number of wasps within 2m of their vicinity counted and recorded. At 8.00am on the 15th day, the location of the traps was swapped such that the WaspBane wasp trap was moved to location 2 and the dome trap moved to location 1. As before, the number of wasps persisting within a 2m the vicinity of each trap was counted at about 2.30pm for the next 7 days. At 8.00am on the 22nd day, the locations of the traps was reversed again and counts taked for the next 7 days giving results for a total of 28 days. The location of the traps was swapped to remove any bias that might have resulted from wasp flight paths to and from nests in the surrounding areas. Each trap was inspected each morning and the dome trap was rebaited 6 times. The method is shown in the video animation below:

The results speak for themselves. The graph in the animation above shows how many wasps were found persisting in the vicinity of each trap. It is important to remember that there were no wasps in the vicinity of the traps prior to the start of the test. When the traps were swapped between locations the WaspBane was trap successfully eliminated the wasps persisting in the area of the dome trap. The dome trap on the other hand attracted wasps to each location that it was placed in. The dead wasps in each trap were not counted but it was clearly evident that the dome trap killed far more wasps than the WaspBane wasp trap. The wasp persistence counts taken from each day were tallied for each trap and the average taken. The WaspBane wasp trap had 97.5% fewer wasps in its vicinity compared to the dome trap.