Tiny wasps, huge diversity – A review of German Pteromalidae with new generic and species records (Hymenoptera: Chalcidoidea)

Abstract

Despite their ecological and economic importance, hymenopteran parasitoids are severely understudied. Even in countries with a long taxonomic history such as Germany, dating back to the 18th century and including prolific figures like Christian Gottfired Nees von Esenbeck and Otto Schmiedeknecht, those species-rich groups are seldom the subject of comprehensive research efforts, leaving their true diversity unknown. This is often due to their small size of a few millimetres on average, leading to difficulties in their identification and examination. The chalcidoid family Pteromalidae is no exception to this neglect. So far, 735 species have been reported from Germany. Estimating the diversity of this group is not possible, but it has to be assumed that many more species are still to be discovered in Germany. With this study, we improve the knowledge on pteromalid diversity and present new records of 17 genera and 41 species, previously unknown to occur in Germany. We also match and describe previously unknown sexes of two species, based on DNA barcode data. The results of this study were generated as part of the German Barcode of Life Project. The newly-recorded species are illustrated and notes on the biology and distribution are given. The ecological significance of Pteromalidae and potential value as indicators for nature conservation efforts are briefly discussed.

DNA metabarcoding and morphological identification reveal similar richness, taxonomic composition and body size patterns among flying insect communities

“…Some of the additional species identified by metabarcoding may be the result of false positives, such as from cross‐contamination, tag jumps or misidentified species, although we took steps to greatly reduce the likelihood of these issues (further discussed in our Methods ). An alternate reason for the additional species is that morphological identification suffers from several known limitations, such as misidentifications (Haase et al, 2006; Haase et al, 2010), inability to resolve certain taxonomic groups to species level (e.g., Sarcophagidae or Pteromalidae; Haas et al, 2021; Meiklejohn et al, 2013), inability to resolve cryptic taxa and difficulties in identifying species solely from body parts or within insect gut contents. Conversely, metabarcoding can resolve taxa that are difficult to identify morphologically (Bucklin et al, 2016) and can identify damaged or consumed species as long as a suitable amount of DNA can be obtained (e.g., Mata et al, 2021; Paula et al, 2016).…”

“…g., Sarcophagidae or Pteromalidae; Haas et al, 2021;Meiklejohn et al, 2013), inability to resolve cryptic taxa and difficulties in identifying species solely from body parts or within insect gut contents. Conversely, metabarcoding can resolve taxa that are difficult to identify morphologically (Bucklin et al, 2016) and can identify damaged or consumed species as long as a suitable amount of DNA can be obtained (e.g., Mata et al, 2021;Paula et al, 2016).…”