Tag: morphology

Efficiency of insect biodiversity monitoring via Malaise trap samples and DNA barcoding

The massive decline of over 75% insect biomass reported from Germany between 1989 and 2013 by expert citizen scientists proves the urgent need for new methods and standards for fast and wide-scale biodiversity assessments. If we cannot understand species composition, as well as their diversity patterns and reasons behind them, we will fail not only to predict changes, but also to take timely and adequate measures before species go extinct.

An international team of scientists belonging to the largest and connected DNA barcoding initiatives (iBOL, GBOL, BFB), evaluated the use of DNA barcode analysis applied to large samples collected with Malaise traps as a method to rapidly assess the arthropod fauna at two sites in Germany between May and September.

One Malaise trap (tent-like structure designed to catch flying insects by attracting them to its walls and then funneling them into a collecting bottle) was set in Germany’s largest terrestrial protected natural reserve Nationalpark Bayerischer Wald in Bavaria. Located in southeast Germany, from a habitat perspective, the park is basically a natural forest. The second trap was set up in western Germany adjacent to the Middle River Rhine Valley, located some 485 kilometers away from the first location. Here, the vegetation is eradicated annually due to St. Martin’s fires, which occur every November. Their findings are published in the open access Biodiversity Data Journal.

DNA barcoding enables the identification of a collected specimen by comparing its BIN (Barcode Index Number) against the BOLD database. In contrast to evaluation using traditional morphological approaches, this method takes significantly less experience, time and effort, so that science can easily save up on decades of professional work.

However, having analyzed DNA barcodes for 37,274 specimens equal to 5,301 different BINs (i.e., species hypotheses), the entomologists managed to assign unambiguous species names to 35% of the BINs, which pointed to the biggest problem with DNA barcoding for large-scale insect inventories today, namely insufficient coverage of DNA barcodes for Diptera (flies and gnats) and Hymenoptera (bees and wasps) and allied groups. As the coverage of the reference database for butterflies and beetles is good, the authors showcase how efficient the workflow for the semi-automated identification of large sample sizes to species and genus level could be.

In conclusion, the scientists note that DNA barcoding approaches applied to large-scale samplings collected with Malaise traps could help in providing crucial knowledge of the insect biodiversity and its dynamics. They also invite their fellow entomologists to take part and help filling the gaps in the reference library. The authors also welcome taxonomic experts to make use of the unidentified specimens they collected in the study, but also point out that taxonomic decisions based on BIN membership need to be made within a comparative context, “ideally including morphological data and also additional, independent genetic markers”. Otherwise, the grounds for the decision have to be clearly indicated.

The study is conducted as part of the collaborative Global Malaise Trap Program (GMTP), which involves more than 30 international partners. The aim is to provide an overview of arthropod diversity by coupling the large-scale deployment of Malaise traps with the use of specimen-based DNA barcoding to assess species diversity.

Sequence analyses were partially defrayed by funding from the government of Canada through Genome Canada and the Ontario Genomics Institute in support of the International Barcode of Life project. The German Barcode of Life project (GBOL) is generously supported by a grant from the German Federal Ministry of Education and Research (FKZ 01LI1101 and 01LI1501) and the Barcoding Fauna Bavarica project (BFB) was supported by a 10-year grant from the Bavarian Ministry of Education, Culture, Research and Art.

 

 

Original source:

Geiger M, Moriniere J, Hausmann A, Haszprunar G, Wägele W, Hebert P, Rulik B (2016) Testing the Global Malaise Trap Program – How well does the current barcode reference library identify flying insects in Germany? Biodiversity Data Journal 4: e10671. https://doi.org/10.3897/BDJ.4.e10671

Moth genitalia is the key to snout grass borers from the Western Hemisphere

Two scientists have produced an illustrated key to define the subtle differences between the 41 species of snout moth grass borers that currently dwell in the Western Hemisphere. The researchers conclude that the adults moths are too tough to tell apart by external characters, and therefore, the only way to identify the species is by dissecting and comparing genitalia. The study is published in the open-access journal ZooKeys.

This identification key is compiled by Dr. M. Alma Solis and Dr. Mark Metz. Both scientists are Research Entomologists at the Agriculture Research Service’s Systematic Entomology Laboratory, USDA. Dr. Solis is Curator of the U.S. National Pyraloidea Collection located at the National Museum of Natural History, Smithsonian Institution Washington, D.C.

The caterpillars of this group of snout moth grass borers feed on crops such as sugarcane, corn, rice, sorghum, and on native grasses throughout the Western Hemisphere, which makes many of the species quite harmful pests.

“The caterpillars of snout moth borers are economically important worldwide as pests of planted crops used for food or biofuel, so their identity is important for their control,” says Dr. Solis. “A key with images provides a simple way to identify adult moths, especially those that cannot be distinguished easily. A key to their identification is one of the most important results of taxonomic research.”

This research required locating ‘type specimens’ or original individuals that were used to describe the species in museums, borrowing them and preparing them for studies while avoiding inflicting any damage, so that they can be used by future researchers. These special specimens are the “standard bearer” for the scientific name and solidify the morphological as well as the molecular identity of a species.

Furthermore, Dr. Solis explained that it is not only important to be able to recognize if a species is new to science, as she and her colleagues recently discovered with a species feeding on Eastern gamagrass in the United States. It is also crucial for tying a species’ scientific name to its biology or genetic composition.

The biology of many moth species is still a mystery, but a recent study, where Dr. Solis participated, identified and studied the biology of some of the species. It showed that there may have been two introductions of the sugarcane borer moth species to southeastern United States and it is likely that there is a species which is currently ‘hidden’ under the same name. She concluded that there is still much left to discover about these moth species from the Western Hemisphere.

###

Original source:

Solis, M. A. & M. Metz. 2015. An illustrated guide to the identification of the known species of Diatraea Guilding (Lepidoptera: Crambidae: Crambinae) based on genitalia. Zookeys. 565:73-121. doi: 10.3897/zookeys.565.6797.

One new fly species, zero dead bodies: First insect description solely from photographs

The importance of collecting dead specimens or not when verifying a new species has been a hot ongoing discussion for quite a while now. Amid voiced opinions ranging from specimen collection being “no longer required” to relying on anything but physical evidence being defined as mere “malpractice,” science is now witnessing the first description of an insect species based solely on high-resolution photographs.

The unequivocally new bee fly species belongs to an extremely rare genus and was described by Drs. Stephen A. Marshall from the University of Guelph, Canada, and Neal Evenhuis from the Bishop Museum, Hawaii. Their research along with their commentary on the controversial topic are published in the open-access journal ZooKeys.

The authors in no way denounce dead specimen collection and dissection and even speak of it as the “gold standard” in new species description, they stress the fact that given the continued increased difficulty in obtaining permits to collect in many areas, and the resulting low probability of collecting and preserving specimens, there ought to be an alternative.

The newly described bee fly species, called Marleyimyia xylocopae, is a huge fly with a remarkable resemblance to a co-occurring carpenter bee. The new species might be a parasite of the bee, but not much is known about its behaviour. Therefore, the scientists stress that more observations are needed, something that will be encouraged by the availability of a name and an associated image.

Speaking of their own experience while studying their presently described new species, the scientists point out that relying on several high-resolution photographs has not only increased their knowledge of the biodiversity of the area and the genus, but has also provided some “interesting ecological and biological information”.

“As these image collections become curated just as dead specimens are curated today, the digital specimens will find their way into the work of practicing taxonomists, and they will need names,” the team explained. “It is unrealistic to think that distinct and diagnosable new taxa known only from good photographs and appropriate associated metadata should be organized and referred to only as “undescribed species” when they can and should be organized and named using the existing rules of nomenclature.”

###

Original source:

Marshall SA, Evenhuis NL (2015) New species without dead bodies: a case for photo-based descriptions, illustrated by a striking new species of Marleyimyia Hesse (Diptera, Bombyliidae) from South Africa. ZooKeys 525: 117-127. doi: 10.3897/zookeys.525.6143

Night calls reveal two new rainforest arboreal frog species from western New Guinea

Tracked by their calls at night after heavy rains, two species of narrow-mouthed frogs have been recorded as new. During the examinations it turned out that one of the studied specimens is a hermaphrodite and another one represents the first record of the genus Cophixalus for the Misool Island.

The field work, conducted by Steve Richards, South Australian Museum, Adelaide, and his team, took place in the Raja Ampat Islands, Indonesian part of New Guinea. Their findings, compiled by Dr. Rainer Guenther, Museum fur Naturkunde, Berlin, are available in the open access journal Zoosystematics and Evolution.

Belonging to the narrow-mouthed frog genus Cophixalus that occurs mainly in New Guinea and northern Australia, the two new species have been differentiated by their morphological features along with the specificity of their advertisement calls, produced by males to attract their partners. Both are characterised by small and slender bodies, measuring less than 23 mm in length.

Curious enough, when dissected one of the male specimens, assigned to the new species C. salawatiensis, revealed a female reproductive system with well-developed eggs. Simultaneously, neither its sound-producing organs, nor its calls differed in any way from the rest of the observed males from the same species. Therefore, it is to be considered a hermaphrodite.

Both new frog species have been retrieved from logged lowland rainforests. There the scientists noted that after heavy rains at night the males perched on leaves of bushes and produced sounds, characteristic for each species.

All specimens have been placed in the collection of the Museum Zoologicum Bogoriense (MZB) in Cibinong (Bogor), Indonesia.

###

Original source:

Guenther R, Richards S, Tjaturadi B, Krey K (2015) Two new species of the genus Cophixalusfrom the Raja Ampat Islands west of New Guinea (Amphibia, Anura, Microhylidae).Zoosystematics and Evolution 91(2): 199-213.doi: 10.3897/zse.91.5411

Bush Blitz: The largest Australian nature discovery project finds 4 new bee species

Four new native bee species were recognised as part of the largest Australian nature discovery project, called ‘Bush Blitz‘. The South Australian bee specialists used molecular and morphological evidence to prove them as new. Three of the species had narrow heads and long mouth parts – adaptations to foraging on flowers of emu-bushes, which have narrow constrictions at the base. The new species are described in the open access journal ZooKeys.

Bees are important pollinators of crops and native plants, but habitat loss and pesticides are proved to be causing a serious decline in their populations in Europe and the United States of America. Meanwhile, the conservation status of native Australian bees is largely unknown because solid baseline data are unavailable and about one third of the species are as yet unknown to science. Furthermore, identification of Australian bees is hampered by a lack of keys for about half of the named species.

With their present publication, bee specialists Katja Hogendoorn (University of Adelaide), Remko Leijs and Mark Stevens (South Australian Museum) are now trying to make Australian native bees more accessible to the scientific community. The study introduces a new Barcoding of Life project, ‘AUSBS‘, which will be built to contain the barcode sequences of the identified Australian native bees.

In future, this database can help scientists who have molecular tools, but insufficient knowledge of bees, to identify known species. Yet, that is not the only use of the database. “Bee taxonomists can access and use the molecular information to answer specific problems, for example, how certain species are related or whether or not a male and female belong to the same species”, says Dr. Hogendoorn. “And combined with morphological information, the molecular database can help to identify new species”, she adds.

In their publication, the researchers demonstrate the utility of the database. After careful evaluation of the DNA sequence data and subsequent morphological comparison of the collected bees to museum type specimens, they recognised four new species in the genusEuhesma, which they subsequently described.

Three of the species belong to the group of bees that specialise on the flowers of emu-bushes. These bees have evolved narrow faces and very long mouth parts to collect the nectar through a narrow constriction at the base of the flowers. A similar evolution has been already observed in other groups of bees. The fourth species belongs to a different group within this large genus and has a normally shaped head.

So far, the project includes 271 sequences of 120 species that were collected during the Bush Blitz surveys, Australia’s largest nature discovery project. The researchers intend to build on the existing DNA database to cover as many as possible of the Australian species. “It is hoped that this will stimulate native bee research”, says Dr. Hogendoorn. “With about 750 Australian bee species still undescribed and many groups in need of revision there is an enormous job to do”, she concludes.

###

Original source:

Hogendoorn K, Stevens M, Leijs R (2015) DNA barcoding of euryglossine bees and the description of new species of Euhesma Michener (Hymenoptera, Colletidae, Euryglossinae).ZooKeys 520: 41-59.doi: 10.3897/zookeys.520.6185