First record of Thaumasia Perty, 1833 nursery web spider (Araneae: Pisauridae) preying upon Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae) in the Neotropical region

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  First record of Thaumasia Perty, 1833 nursery web spider (Araneae: Pisauridae) preying upon Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae) in the Neotropical region Abstract Thaumasia Perty, 1833 are opportunistic spiders that inhabit the Neotropical region. This study reports a spider of the genus Thaumasia preying upon Polistes canadensis (Linnaeus, 1758) in semiarid region of Brazil. A spider of the genus Thaumasia was observed moving rapidly from the fountain's water surface to capture an individual of P. canadensis . After successfully capturing the wasp, Thaumasia sp. was observed partially perched on the wall of the fountain, with the prey still on the water surface and trapped by its chelicerae. The pedipalps and chelicerae of Thaumasia sp. manipulated the head of P. canadensis , which stopped moving shortly after being captured, probably because of the action of the spider's venom. The study records a wasp in the diet of Thaumasia based on the ca...

Hue’s in the trap? Effects of colour, time of day, and weather on the use of pitfall traps for invertebrate surveys

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Hue’s in the trap? Effects of colour, time of day, and weather on the use of pitfall traps for invertebrate surveys

Abstract

Introduction

Conservation of terrestrial invertebrates fundamentally depends on robust data. Pitfall trapping is a time- and cost-efficient method that provides valuable information.

Aims/methods

There is limited research on how pitfall trap colour influences catch, although colour is known to be important for other trap types, including pan traps. Here, we use data from 2,897 trapping days in grassland, parkland, farmland and woodland habitats to explore effects of pitfall trap colour (blue/orange/green) on catch abundance (number of invertebrate individuals caught), diversity (Shannon’s index), and community composition. We also assess how trap catch is influenced by trapping period (daytime vs. nighttime) and weather (precipitation and temperature).

Results

Catch abundance and diversity was higher in green traps than blue or orange traps overall and in grassland or parkland, whereas there was no effect of trap colour in farmland and woodland. For specific orders, catch abundance was significantly higher in green traps for Araneae, Coleoptera and Isopoda, but higher in orange traps for Hymenoptera in parkland and farmland, and higher in blue traps for Stylommatophora and Coleoptera in woodland. There was a significant time of day * colour interaction: green traps yielded higher catch abundance and diversity than blue or orange traps for day and night trapping, whereas orange traps yielded higher catch abundance and diversity than blue traps for night trapping only. As expected, catch abundance and diversity was higher in warmer temperatures, while precipitation had taxa-specific effects on catch abundance (Stylommatophora = positive; Isopoda = negative).

Discussion

There are opportunities to optimise protocols for specific habitats and taxa.

Implications for insect conservation

Based on the results of this study, which has considered four sites (each covering a single habitat: grassland, farmland, parkland, woodland) across two years, we suggest that conservationists using pitfall traps for a census of invertebrate communities should use green traps if selecting a single colour, or a combination of colours. For more focused projects, we offer taxon- and habitat-specific recommendations that are achievable without additional resource demands.

Goodenough, A.E., Baker, H.L., Otitolaye, F. et al. Hue’s in the trap? Effects of colour, time of day, and weather on the use of pitfall traps for invertebrate surveys. J Insect Conserv 30, 14 (2026). https://doi.org/10.1007/s10841-026-00748-1