1 INTRODUCTION
The Iranian scorpion fauna is considerably diverse, comprising 68 valid
species belonging to 19 genera and four families, with 60.3% (41
species) endemic to the country (Barahoei et al, 2020). These predatory,
nocturnal arachnids are more frequent in the arid to semi-arid parts of
southern Iran. Scorpionism is an important public health problem in
Iran, and 40,000 to 50,000 cases of scorpion stings are estimated to
occur per year in the country (Dehghani, et al. 2018). However, studies
on Iranian scorpions have been scattered and mostly focused on their
taxonomy and distribution. Recently, some ecological studies have also
been conducted on scorpions in Iran (e.g. Mirshamsi 2013, Gholizadeh et
al. 2016, Motevalli-Haghi et al. 2018, Rafinejad et al. 2020, Kassiri
and Yousefi 2021, Navidpour et al. 2021, Soltan-Alinejad et al. 2021).
Nevertheless, none of these studies tested the pitfall trapping method.
To date, about ten different methods have been used to collect
scorpions, including stone rolling, pitfall trapping, water-pan traps,
using UV light, destroying mud walls, pouring water into scorpion
burrows, excavating channels, using rubber bands, using soaked cloth as
traps, and collecting scorpions by stung patients (Dehghani et al.
2019). Dehghani et al. (2019) evaluated different methods, except
pitfall trapping, for collecting these arthropods in Khuzestan province,
and their results showed that using UV light and turning stones were the
most efficient methods for collecting scorpions at night and during the
day, respectively.
Collecting the largest possible number of specimens of a particular
animal or group of animals can provide a more reliable estimate of
actual species diversity. For this reason, optimization of collection
devices is very important, especially in the case of pitfall trapping,
which is one of the common and widely used methods for collecting
ground-active arthropods (Brown and Matthews 2016).
Pitfall traps are inexpensive, easy to use and efficient, and they
collect large samples suitable for statistical analyses (Spence &
Niemelä, 1994). Pitfall traps operate continuously from installation to
collection (Stašiov, et al. 2021), which can be particularly useful when
studying the numbers and activity of surface-dwelling invertebrates.
Nevertheless, the efficiency of this sampling method for collecting
scorpions and also effects of different pitfall trap designs on the
number and species composition of the captured scorpions have received
little attention hitherto. The aim of our study is to compare the
collection efficiency of different pitfall trap designs to capture the
largest number of species and individuals of scorpions.