Effects of preservatives in pitfall traps for collecting arthropods: A comparison of ethylene glycol and five alternative preservatives

Abstract

Pitfall traps using ethylene glycol as a preservative are widely used to investigate arthropods in forests. However, recently, pitfall traps have been reported to be damaged by wild vertebrates because of the sweetness of ethylene glycol. Therefore, this study compared ethylene glycol with five potential alternative preservatives for the selection of an alternative preservative for use in pitfall traps. Field experiments were conducted at the Namhae Long Term Ecological Research (LTER) site in the southernmost part of South Korea. The five alternative preservatives included salt solution with bleach, which is considered to repel wild animals because of its smell; formalin solution with bleach; salt solution without bleach; formalin solution without bleach; and alcohol solution with a small amount of added glycerin. The number of arthropods collected differed with the type of preservative used; the composition of arthropod assemblages was also different. Among the two alternative preservative solutions expected to repel wild animals, formalin+bleach, and salt water+bleach, the latter was found to be better for arthropod collection.