Mygalomorph spiders from the Baja California Peninsula with the description of a new species of the trapdoor genus Eucteniza Ausserer (Araneae, Mygalomorphae, Euctenizidae) of Baja California Sur, Mexico

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  Mygalomorph spiders from the Baja California Peninsula with the description of a new species of the trapdoor genus Eucteniza Ausserer (Araneae, Mygalomorphae, Euctenizidae) of Baja California Sur, Mexico Abstract We provide an updated taxonomic checklist of mygalomorph spider species from the Baja California Peninsula (BCP), including new records. In addition, a new species of the trapdoor spider genus Eucteniza Ausserer, 1875 is described from the BCP. Eucteniza candiae sp. nov. is described from a xerophilous scrubland on the west coast of Baja California Sur, Mexico, and is known from a male holotype and a male paratype. This species represents the fourth species of the genus described from the state of Baja California Sur. Consequently, the diversity of Eucteniza in Mexico increases to sixteen known species, representing the highest diversity of the genus in North America. With the description of this new species, the mygalomorph spider fauna of the BCP increases to 17 specie...

To pool or not to pool: Pooled metabarcoding does not affect estimates of prey diversity in spider gut content analysis

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To pool or not to pool: Pooled metabarcoding does not affect estimates of prey diversity in spider gut content analysis

Abstract

  1. Gut content metabarcoding has provided important insights into the food web ecology of spiders, the most dominant terrestrial arthropod predators. In small invertebrates, like spiders, gut content analysis is often performed on whole body DNA extracts of individual predators, from which prey sequences are selectively enriched and sequenced.
  2. Since many spider species are generalist predators, large numbers of samples comprising individual spider specimens must be analysed to recover an exhaustive image of a spider species' prey spectrum, which is costly and time-consuming.
  3. Pooled processing of bulk samples of multiple specimens has been suggested to reduce the necessary workload and cost while still recovering a representative estimate of the prey diversity. However, it is still unclear if pooling approaches lead to bias in recovering the prey spectrum and if the results are comparable with data from individually processed spiders.
  4. Here, we test the effects of metabarcoding pooled spider gut content on the recovered taxonomic diversity and composition of prey. Using a newly adapted primer pair, which efficiently enriches COI barcode sequences of diverse arthropod prey groups while suppressing spider amplification, we test if pooling leads to reduced taxonomic diversity or skewed estimates of prey composition.
  5. Our results show that pooling and individual processing recover highly correlated taxonomic diversity and composition of prey. The only exception are very rare prey items which were less well recovered by pooling. Our results support pooling as a cost-effective and time-efficient approach to recover the diet of generalist predators for population-level studies of spider trophic interactions.
Melcher, A. C., Weber, S., Birkhofer, K., Harms, D., & Krehenwinkel, H. To pool or not to pool: Pooled metabarcoding does not affect estimates of prey diversity in spider gut content analysis. Ecological Entomology. https://doi.org/10.1111/een.13382