Comparative performance of pitfall, ramp, and tube traps for sampling arthropods in an arid region of southeastern Iran

Abstract

<p> Pitfall traps are widely used for collecting ground-dwelling arthropods, with ramp and tube traps serving as complementary options. This study compares the performance of these three trap types in an arid environment in southeastern Iran. Fieldwork was conducted in spring 2025 across three active orchards in the Sistan region. Six replicates of each trap type (18 total) were deployed along three paired transects. Most adult spiders were identified to the species level, while most other arthropods were identified to the family level. A total of 14,960 individuals representing 12 orders and 52 families were collected. Tube traps captured the most specimens (n = 7,706), outperforming the other trap types across the majority of taxonomic groups, including Isopoda, Coleoptera, and Araneae. Pitfall traps yielded intermediate catches (n = 5,343) and performed comparably to tube traps for several groups, such as Gnaphosidae and Formicidae, while capturing more individuals of Opiliones than the other two trap types combined. Ramp traps collected the fewest individuals (n = 1,911) but captured the highest numbers of Pompilidae and Gryllotalpidae, and, together with pitfall traps, collected several spider species that were under-represented or absent in tube trap samples. Overall, tube traps represent a practical option for sampling epigeal arthropods in arid environments. However, to achieve a more comprehensive community sample and reduce methodological bias, a combination of all three trap types is recommended for biodiversity assessments in desert ecosystems. <br></p>