Journal article Open Access

Morphology and biology of the flower-visiting water scavenger beetle genus Rygmodus (Coleoptera: Hydrophilidae)

Yusuke Minoshima; Matthias Seidel; Jamie R. Wood; Richard A. B. Leschen; Nicole L. Gunter; Martin Fikáček

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  "publisher": "Zenodo", 
  "DOI": "10.5281/zenodo.3251092", 
  "container_title": "Entomological Science", 
  "language": "eng", 
  "title": "Morphology and biology of the flower-visiting water scavenger beetle genus  Rygmodus (Coleoptera: Hydrophilidae)", 
  "issued": {
    "date-parts": [
  "abstract": "<p>Hydrophilidae (water scavenger beetles) is well known as an aquatic beetle family;&nbsp;<br>\nhowever, it contains ca. 1,000 secondarily terrestrial species derived from aquatic&nbsp;<br>\nancestors. The New Zealand endemic genus Rygmodus White is a member of the&nbsp;<br>\nhydrophilid subfamily Cylominae, which is the early-diverging taxon of the largest&nbsp;<br>\nterrestrial lineage (Cylominae + Sphaeridiinae) within the Hydrophilidae. In this paper&nbsp;<br>\nwe demonstrate that Rygmodus beetles are pollen-feeding flower visitors as adults, but<br>\naquatic predators as larvae. Based on analyses of gut contents and a summary of&nbsp;<br>\ncollecting records reported on museum specimen labels, adult Rygmodus beetles are&nbsp;<br>\ngeneralists feeding on pollen of at least 13 plant families. Rygmodus adult mouthparts&nbsp;<br>\ndiffer from those of other (saprophagous) hydrophilid beetles in having the simple&nbsp;<br>\nscoop-like apex and mola with roughly denticulate surface, resembling the morphology&nbsp;<br>\nfound in pollen-feeding staphylinid beetles. Larvae were found along the sides of&nbsp;<br>\nstreams, under stones and in algal mats and water-soaked moss; one collected larval<br>\nspecimens was identified using DNA barcoding of two molecular markers,<br>\nmitochondrial cytochrome oxidase 1 (cox1) and nuclear histone 3 (H3). Larvae of two&nbsp;<br>\nspecies, Rygmodus modestus and Rygmodus sp., are described in detail and illustrated;&nbsp;<br>\nthey closely resemble ambush-type predatory larvae of the hydrophilid tribe&nbsp;<br>\nHydrophilini in the head morphology. Rygmodus is the only known hydrophilid beetle&nbsp;<br>\nwith adults and larvae inhabiting different environments.</p>", 
  "author": [
      "family": "Yusuke Minoshima"
      "family": "Matthias Seidel"
      "family": "Jamie R. Wood"
      "family": "Richard A. B. Leschen"
      "family": "Nicole L. Gunter"
      "family": "Martin Fik\u00e1\u010dek"
  "page": "363-384", 
  "volume": "21", 
  "type": "article-journal", 
  "issue": "4", 
  "id": "3251092"
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