Bottle trap

A bottle trap is a type of baited arboreal insect trap for collecting either prized or harmful frugivorous beetles, especially flower beetles, leaf chafers and longhorn beetles as well as wasps and other unwanted flying insects.
A bottle trap is an insect trap made out of a plastic bottle. Most collectors use bottles of 1.5 or 2 liters to make these traps but smaller bottles are sometimes used as well. There are basically two types:
These bottle traps are made by cutting off the neck of the bottle as well as the complete tapering part of the top. The neck and cap are discarded. For catching wasps only the cap is removed, while leaving the neck in place. The tapering part is placed upside down on top of the rest of the bottle, thereby effectively forming a funnel. This funnel is then fixed to the bottle by piercing both bottle and funnel at two opposing sides. A wire fitted through these holes ensures the funnel solidly fits on the bottle, while the trap can easily be opened when required. After putting the bait in the bottle the trap is placed at the desired location.
Advantages:
Disadvantages:
A side-door bottle trap consists of a capped plastic bottle with a "door" cut into one side, near the top. A simple curve or rectangle shape is cut out, taking care that it stays attached to the bottle on its upside. This plastic flap is then bent upward, effectively forming a rain shield over the entrance. The size of the "door" depends on the type of insects the user intends to trap. After adding some bait the trap is put in its place.
Advantages:
Disadvantages:
Many different types of bait are used. Since this kind of trap is mainly used for beetles that are attracted to (over)ripe fruits, baits with a certain amount of alcohol are usually very effective.
Beetles are commonly baited with banana, optionally with beer, rum and/or sugar, and can also be attracted with a mixture of red wine, vinegar and sugar. Wasps can be drawn into a funnel type bottle trap using syrup, a soft drink or sugar water. Bread soaked with beer will attract cockroaches.
Other fruits are sometimes used, but banana is most common used since it is widely available, normally inexpensive and contains sufficient sugar to start a fermentation process by itself. The different ingredients are usually kept apart and mixed in the trap itself, but some collectors prefer to mix their bait before going into the field.
Bottle traps (like all traps) yield best in places where more of the desired insects are to be expected. For beetles, in general this means high up in trees, especially flowering or fruiting trees. Other places in which traps are often placed with good results include forest borders. Traps placed inside forests usually yield smaller numbers of beetles, but also different species. Traps for luring wasps are usually set up a short distance (several meters) from the place where they are bothersome.
There are various methods used for placing bottle traps:
The first three methods are used most often for collecting beetles, while the latter two are more commonly in use for catching wasps.
Next to the desired beetles, many other insects may find the bait attractive. Sap beetles (a group of small fruit-eating beetles), moths like the large white witch moth, various butterflies, cockroaches, flies, stingless bees, wasps and even small fruit eating bats may enter the bottle traps as bycatch while the collector aims for beetles. Such unwanted animals in the trap may cause the collector several problems: