The number and ratio of beetles and other insects trapped in pitfalls could differ depending on different properties of these pitfalls, e.g. the colour, the type of preservative, the cover material used, or whether an escape ladder has been applied.
Backgroundand context
It is customary to use plastic 1⁄2 litre yoghurt jars as cheap pitfalls. These are lightweight, easily obtained and stacked for compact storage and transport. In general these jars are white, but transparent ones occur as well nowadays. It is imaginable nocturnal insects could be put off by the bright reflection of a white jar and are more easily trapped in a transparent or black one. Also, the preservative used, for instance salt water, formaldehyde, ethylene glycol or propylene glycol might attract or deter insects because of their odour. The type of cover used might make a difference as well: it’s possible some insects are attracted to darkened locations to hide, while others may evade it. Lastly, some people apply escape ladders to allow vertebrates to climb out of the trap if they happen to fall in, but some insects might be able to use the same escaping method.
Objectivesand goals
The aim is to quantify the differences in results – if any – of the various kinds of pitfalls in order to be able to interpret and compare results of projects that use different variables. Moreover, advice for best practice can be given.
Methodsand approach
An experimental set-up of pitfalls with different variables close to each other will be put out in the field. It’s important to choose a location not easily disturbed. The trapped insects will be collected, counted and identified to order, family or species level, depending on the group.
Student requirements(e.g. particular courses/interests/skills)
Interest in insects. Keen to do fieldwork and insect identification.
References
Kwan T-S, Park YK, Jung J-K, Lee YG, Park CW. 2022. Effects of preservatives in pitfall traps for collecting arthropods: A comparison of ethylene glycol and five alternative preservatives. Journal of Asia-Pacific Biodiversity. 15: 541-546. 10.1016/j.japb.2022.07.001 https://www.sciencedirect.com/science/article/pii/S2287884X22000723