For over three decades, the importance of taxon sampling curves for comparative biodiversity studies has been repeatedly stated. However, many entomologists (both within Canada and worldwide) continue to publish studies without standardizing their data to take sampling effort into account. We present a case study to illustrate the importance of such standardization, using the collection of spiders (Araneae) by pitfall traps as model data. Data were analyzed using rarefaction to represent one example of a taxon sampling curve, and by a variety of traditional diversity indices to describe alpha diversity. Raw species richness and single-index diversity measures (Shannon–Wiener, Simpson's, and Fisher's α) provided contradictory results. Rarefied species richness standardized to the number of individuals collected enabled more accurate comparisons of diversity and revealed when sampling was insufficient. Focusing on arthropods occurring in forested ecosystems, we also examined the use of taxon sampling curves in current literature by reviewing 133 published articles from 14 journals. Only 26% of the published articles in our review used a taxon sampling curve, and raw species richness and the Shannon–Wiener index of diversity were the most commonly used estimates. There is clearly a need to modify how alpha diversity is measured and compared for arthropod biodiversity studies. We recommend the abandonment of both raw species richness and single-index measures of diversity, and reiterate the need to use rarefaction or a related technique that allows for meaningful comparisons of species richness while taking into account sampling effort.
Incorporating camera systems into insect traps potentially benefits insect phenology modeling, nonlethal insect monitoring, and research into the automated identification of traps counts. Cameras originally for monitoring mammals were instead adapted to monitor the entrance to pyramid traps designed to capture the plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae). Using released curculios, two new trap designs (v.I and v.II) were field-tested alongside conventional pyramid traps at one site in autumn 2010 and at four sites in autumn 2012. The traps were evaluated on the basis of battery power, ease-of-maintenance, adaptability, required-user-skills, cost (including labor), and accuracy-of-results. The v.II design fully surpassed expectations, except that some trapped curculios were not photographed. In 2012, 13 of the 24 traps recorded every curculio entering the traps during the 18-d study period, and in traps where some curculios were not photographed, over 90% of the omissions could be explained by component failure or external interference with the motion sensor. Significantly more curculios entered the camera traps between 1800 and 0000 hours. When compared with conventional pyramid traps, the v.I traps collected a similar number of curculios. Two observed but not significant trends were that the v.I traps collected twice as many plum curculios as the v.II traps, while at the same time the v.II traps collected more than twice as many photos per plum curculio as the v.I traps. The research demonstrates that low-cost, precise monitoring of field insect populations is feasible without requiring extensive technical expertise.
A modular system for studying the biology of Scolytinae using 3D printed emergence traps is presented. This system consists of traps that can be used for the introduction of beetles into trees as well as for the determination of the number of offspring emerging from trees and branches, and their production of frass and sawdust. Open-source files used for printing these traps have been deposited as supplementary material and can be downloaded for trap production by students of Scolytinae with access to a 3D printer. The cost in material for the production of a single emergence trap on the printer used here is approximately $1.30, with a print time of less than 90 min.
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