Hunting for a water mite neotype in southern Norway

Hunting for a water mite neotype in southern Norway

Hunting for a water mite neotype in southern Norway

Scientists rediscover lost specimens of water mite in Norway 120 years after they were first described

A stream near the church of Vanse at Lista in southern Norwaythe type locality of Lebertia porosa Thor, 1900.

PHOTO CREDIT: Torbjørn Ekrem

Did you know that scientists can assess natural water quality by monitoring the diversity of aquatic invertebrates? Freshwater insect and arachnid populations are often important indicators of environmental change. This is evident in particularly species-rich groups, such as water mites and biting or non-biting midges, which have great potential for monitoring water quality. The problem is only that they are too difficult and time consuming to identify in routine water quality assessments. This hurdle can be overcome with DNA metabarcoding, but only if a good reference barcode library is available.

Elisabeth Stur of the Norwegian University of Science and Technology (NTNU) University Museum, along with her team, have been doing summer fieldwork for the Water Mites and Midges in southern Norway (Water M&M) project. One of the many goals for this year’s fieldwork was not only to contribute to the reference barcode library, but also to sample the type locality of the water mite Lebertia porosa, described 120 years ago by Sig Thor, a Norwegian priest and acarologist.

The Great Lakes
Phaenopsectra flavipes (Diptera: Chironomidae) with water mite larvae attached. PHOTO CREDIT: Aina Mærk Aspaas, NTNU University Museum

Barcode data indicate that there are at least six cryptic genetic lineages within this species, but it is unknown which of these applies to the nominal species. Since the original type material is lost, re-sampling L. porosa from its type locality is important in designating a neotype that most likely belongs to the species described by Thor in 1900. This way, researchers can stabilize the definition of the L. porosa species name, such that potential new species could be described. This species delineation is part of a MSc. project by Valentina Tyukosova at NTNU: Integrative taxonomy and species delimitation in the Lebertia porosa species complex (Acari, Parasitengona: Hydrachnidia).

The type locality of L. porosa was vaguely described in Thor’s original publication as a “stream near the church of Vanse”. After studying maps of the surrounding area, researchers learned that this church still stands, and were able to locate two nearby streams.

Now they wondered, would these streams still be in good condition 120 years later? As the team of researchers approached what they thought might be the stream in June 2020, they were pleased to see running, clear water under the bridge. Next mystery: could the streams hold a population of L. porosa 120 years after first collection? They found that yes, the waters could, and the water mite populations were bountiful!

The Great Lakes DNA Barcoding Project team

Water mites from the type locality of Lebertia porosa Thor, 1900.
PHOTO CREDIT: Torbjørn Ekrem

Stur and her team are now looking forward to getting these critters under the compound microscope. Using DNA analysis, they hope to identify which barcode clusters they match with, potentially revealing the nominal species of L. porosa. We’re sure that Sig Thor would be thrilled to learn that his identified species is still thriving, 120 years later.

Written by

Katherine Perry

Katherine Perry

Centre for Biodiversity Genomics, Guelph, ON, Canada

July 24, 2020

doi: 10.21083/ibol.v10i1.6243

Don't Miss Out!

Subscribe to the iBOL Barcode Bulletin for updates on DNA barcoding efforts, the iBOL Consortium, and more.

comment on this article

The Barcode Bulletin moderates comments to promote an informed and courteous conversation. Abusive, profane, self-promotional, or incoherent comments will be rejected. 

Resident or invasive species? Environmental DNA can provide reliable answers

Resident or invasive species? Environmental DNA can provide reliable answers

Resident or invasive species? Environmental DNA can provide reliable answers

Environmental DNA can be successfully applied to identify vertebrates in a tropical lake improving our capacity to map and monitor species.
Panoramic view of Bacalar Lake including the 40-m deep Esmeralda sinkhole. PHOTO CREDIT: Manuel Elías-Gutiérrez

Monitoring life within large bodies of water – those species that should and shouldn’t live there – can be very expensive and time consuming. To overcome these limitations, efforts in many temperate regions employ methods that use environmental DNA (eDNA), enabling effective and targeted detection of invasive and resident endangered species.

Our study is the first to demonstrate that eDNA-based monitoring can be successfully applied to target the whole fish community in a tropical freshwater system and its adjacent wetlands.

Between 1980 -1990, eDNA was the term introduced to define particulate DNA and it was used to detect and describe microbial communities in marine sediments and phytoplankton communities in the water column1. However, eDNA is presently defined as the genetic material left behind by eukaryotic organisms in the environment, reflecting a rise in the use of eDNA for the detection of vertebrate and invertebrate species in aquatic systems1. The popularity of using eDNA has increased following the development of next-generation sequencing, advances in quantitative PCR (qPCR), and the growth of DNA barcodes libraries such as the Barcode of Life Data System (BOLD), providing a quicker and more taxonomically comprehensive tool for biodiversity assessments.

 

South end of lake Bacalar with the sinkhole Cenote Azul.
PHOTO CREDIT: Manuel Elías-Gutiérrez

Lake Bacalar is the largest epicontinental habitat in Mexico’s Yucatan Peninsula, and it is renowned for its striking blue color, clarity of the water, and for the world’s largest occurrence of living stromatolites, a calcareous mound built up of layers of lime-secreting cyanobacteria. Due to the presence of sediments derived from karst limestone, it represents the world’s largest fresh groundwater-feed ecosystem. The northern part of Lake Bacalar is connected to a complex system of lagoons and the southern part has an indirect connection to the sea via a wetland system that connects with Hondo River and enters Chetumal Bay. This river has been heavily impacted by the discharge of organic waste and pesticides, by vegetation clearing, and by the introduction of invasive fish such as tilapia and the Amazon sailfin catfish (Pterygoplichthys pardalis) 2-4, first detected in 2013 4. The Amazon sailfin catfish is a serious threat to the fragile stromatolite ecosystem due to its burrowing habits and competition with local fish. The impact of declining water quality and the rise of invasive species on the native fish fauna needs to be carefully monitored in aid of conservation efforts of Lake Bacalar.

A team of researchers from the Instituto Tecnológico de Chetumal and El Colegio de la Frontera Sur sampled eight localities in December 2015, and January and April 2016. After each of 14 sampling events, water and sediment samples were immediately placed on ice before transportation to the lab in Chetumal. To minimize eDNA degradation, we filtered water samples within seven hours of collection. All filters and sediments were stored at -18°C before being transported on ice from Chetumal to the Centre for Biodiversity Genomics in Guelph, Canada, where DNA extraction was undertaken.

 

Water sampling between stromatolites.
PHOTO CREDIT: Miguel Valadez

We sequenced short fragments (<200 bp) of the cytochrome c oxidase I (COI) gene on Ion Torrent PGM or S5 platforms. In total, we recovered eDNA sequences from 75 species of vertebrates including 47 fishes, 15 birds, seven mammals, five reptiles, and one amphibian. Although all species are known from this region, six fish species represent new records for the study area, while two require verification (Vieja fenestrata and Cyprinodon beltrani /simus), because their presence is unlikely in this ecosystem. While there were species (two birds, two mammals, one reptile) only detected from sediments, water samples recovered a much higher diversity (52 species), indicating better eDNA preservation in the slightly alkaline Bacalar water.  Because DNA from the Amazon sailfin catfish was not detected, we used a mock eDNA experiment that confirmed our methods were effective.

Interesting findings include the detection of rare species, such as an anteater Tamandua mexicana, which was detected by both PGM and S5 instruments from a river sample (Juan Sarabia), and migratory birds, such as warbler Oreothlypis peregrina known to overwinter in the Yucatan Peninsula.

Docks in front of Bacalar town
PHOTO CREDIT: Miguel Valadez

Our study indicates that eDNA can be successfully applied to monitor vertebrates in a tropical oligotrophic lake as well as more eutrophic (higher primary production) wetlands and can aid conservation and monitoring programs in tropical areas by improving our capacity to map occurrence records for resident and invasive species.

Our next step is to convince Mexican and international stakeholders to implement these methodologies and establish a permanent biomonitoring system for this and other pristine freshwater ecosystems found in Yucatan Peninsula. This work is necessary to detect effects of climate change, declining water quality, and the increasing tourism activities in this region.

References:

1. Díaz-Ferguson EE, Moyer GR (2014) History, applications, methodological issues and perspectives for the use of environmental DNA (eDNA) in marine and freshwater environments. Revista de Biología Tropical 62: 1273-1284. DOI: 10.15517/RBT.V62I4.13231

2. Wakida-Kusunoki AT, Luis Enrique Amador-del Ángel (2011) Aspectos biológicos del pleco invasor Pterygoplichthys pardalis (Teleostei : Loricariidae) en el río Palizada, Campeche, México. Revista Mexicana de Biodiversidad 82: 870-878

3. Alfaro REM, Fisher JP, Courtenay W, Ramírez Martínez C, Orbe-Mendoza A, Escalera Gallardo C, et al. (2009) Armored catfish (Loricariidae) trinational risk assessment guidlines for aquatic alien invasive species. Test cases for the snakeheads (Channidae) and armored catfishes (Loricariidae) in North American inland waters. Montreal, Canada: Commission for Environmental Cooperation. pp. 25-49.

4. Schmitter-Soto JJ, Quintana R, Valdéz-Moreno ME, Herrera-Pavón RL, Esselman PC (2015) Armoured catfish (Pterygoplichthys pardalis) in the Hondo River basin, Mexico-Belize. Mesoamericana 19: 9-19.

Written by

Natalia V. Ivanova

Natalia V. Ivanova

Centre for Biodiversity Genomics, Guelph, ON, Canada

Martha Valdez-Moreno

Martha Valdez-Moreno

El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Mexico

Manuel Elías-Gutiérrez

Manuel Elías-Gutiérrez

El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Mexico

May 15, 2019
doi: 10.21083/ibol.v9i1.5474

Don't Miss Out!

Subscribe to the iBOL Barcode Bulletin for updates on DNA barcoding efforts, the iBOL Consortium, and more.

comment on this article

The Barcode Bulletin moderates comments to promote an informed and courteous conversation. Abusive, profane, self-promotional, or incoherent comments will be rejected.