Spurr wasp trap
The Spurr wasp trap was designed primarily as a method of surveying Vespula wasps, and is made from a 1.25-litre plastic soft-drink bottle (with the bottom cut off), a 0.8-litre plastic screw-top jar (with an 80-mm diameter hole in the lid and six 10-mm diameter holes in the side), and a specially moulded plastic funnel with a 10-mm opening in the apex. The soft-drink bottle is glued to the lid of the jar, and the plastic funnel inserted through the hole in the lid so it protrudes into the soft-drink bottle. Bait (e.g., sardine catfood) is placed in the bottom of the jar, and the jar screwed into its lid (attached to the soft-drink bottle). The trap is normally hung on low branches by a short cord tied around the neck of the soft-drink bottle. Wasps enter the jar through the holes in the side, collect a piece of bait, and fly upwards through the funnel into the soft-drink bottle, where most become trapped
At the peak of the season in areas with high wasp numbers, more than 1000 wasps per trap per day may be caught in this way. Traps should be re-baited daily or at most every second or third day because if the bait is not removed by wasps, it deteriorates in that time.
Spurr wasp traps also catch a range of other insects, especially flies, bees, wasps, and moths. Bait type can be changed to suit a different group of insects, although specimens tend to become caught in the bait itself if liquid bait is used. One disadvantage of the Spurr wasp trap for general surveillance purposes is that it can be fiddly getting the sample of live insects out of the drink bottle (especially if it contains dozens of live and very angry wasps). Anaesthetising the insects by placing the trap in a plastic bag to which CO2 is added saves a lot of time, but requires carrying a small gas cylinder.