Pitfall traps: A review of methods for estimating arthropod abundance

Abstract

Pitfall traps are commonly used in diet studies for insectivorous and omnivorous wildlife. Pitfall trap methodologies and designs vary considerably among studies and investigators. Such variation and lack of standardization limits scientists' abilities to compare their results with others. We conducted a literature review to identify the most common methods used by past investigators who placed pitfall traps for the purpose of quantifying indices of arthropod abundances, and used this information to guide our proposal for standardized pitfall trapping methods. We documented the pitfall-trap methods of 257 studies published between January 1994 and March 2016 in 107 scientific journals. Pitfall-trap methods varied greatly across the time period. We found only minor differences in the pitfall-trap methods most commonly used in different vegetation communities (e.g., preservative was used less frequently for pitfall trap studies in grasslands). Studies published in wildlife journals tended to use pitfall traps of larger diameters than studies published in other disciplines; these studies also had worse rates of methodological reporting than those in entomology journals. We did not detect a decline in negligent reporting over time; !1 key methodological detail was missing from >50% of studies regardless of the decade published. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Calling activity determines male mating success in a territorial frog with parental care

“…In addition, our operational measures related to extrinsic properties might have failed to reliably indicate the theoretical variables related to the male territories. For example, food availability was estimated during a relatively short sampling interval that, although common in the literature, might not have precisely captured invertebrate biomass availability during the entire study period (Hohbein & Conway, 2018). Another possibility is that territory‐related variables are only related to fitness indicators not measured in this study such as hatching success and offspring survival (Howard, 1978).…”

The welfare and ethics of research involving wild animals: A primer

“…For some studies, the collection of samples by killing is almost routine (e.g. collecting voucher specimens for museums: Russo, Ancillotto, Hughes, Galimberti, & Mori, 2017; sampling for many invertebrates: Hohbein & Conway, 2018). At the opposite extreme, there is considerable debate centred on whether it is ethical to ever kill an animal (Hayward et al, 2019).…”

Application of propylene glycol in DNA-based studies of invertebrates

“…The evaporation rate of PG is >500-times lower than for ethanol (Moreau et al 2013). As such a low volatile agent, PG-equipped traps can retain their volumes more or less constant over several weeks to months (Hohbein and Conway 2018). However, long-term UV exposition may decompose PG into water, acetone and 2-propanol (i.e.…”

“…Propylene glycol is a well-established agent in molecular cryobiology, notably used for the cryopreservation of sperms and cell cultures (Bank and Brockbank 1987;Hezavehei et al 2018). For the study of invertebrates, it has been proposed as the chemical of choice in a standardised pitfall trap design for monitoring ground-active arthropod biodiversity (Brown and Matthews 2016;Hohbein and Conway 2018) and is applied as such within the North American National Ecological Observatory Network (NEON;Gibson et al 2012;Hoekman et al 2017) and the carabidologist community (Kotze et al 2011). PGbased pitfall traps were also proposed as a standard and minimally disturbing method to investigate the subterranean fauna of the mesovoid shallow substratum (López and Oromí 2010; emptied every six months).…”