Tracing the ancestry of dung beetles

One of the largest and most important groups of dung beetles in the world evolved from a single common ancestor and relationships among the various lineages are now known, according to new research by an entomologist from Western Kentucky University.

The study by Dr T. Keith Philips, recently published in the open access journal ZooKeys, provides important insights into the evolution and diversity of these dung beetles, which make up about half of the world’s dung beetle fauna.

The two tribes studied, the onthophagines and oniticellines, evolved from a single common ancestor and are found worldwide, except for Antarctica. These dung beetles make up the vast majority of species and dung beetle biomass in many ecosystems, feeding on mammal dung.

Dung beetles are well known to many people because many species are colorful and active in the daytime. Additionally, many taxa have unusual behaviors, such as making and rolling balls of dung away from a dung pile. Often thought of as nature’s garbage collectors, the important ecosystem service offered by dung beetle helps recycle nutrients, reduces parasites, and can even help seeds germinate.

While the two tribes studied do not have species that create balls, they instead have evolved many other diverse behaviors. This includes species that do not feed on dung but specialize on fungi, carrion, and dead millipedes. Many species that evolved from the same common ancestor even live in close association with termites and ants, where they might be feeding on nest debris.

“This is one of the most important groups of dung beetles that finally has a hypothesis on how they evolved and diversified on earth,” Philips notes. “The evolutionary scenario can now be tested and refined in the future with more data.” Although relatively well known, this group still may have as many as 1,000 undiscovered species left for scientists to document.

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Original source:

Philips TK (2016) Phylogeny of the Oniticellini and Onthophagini dung beetles (Scarabaeidae, Scarabaeinae) from morphological evidence. ZooKeys 579: 9-57. doi: 10.3897/zookeys.579.6183.

Dragons out of the dark: 6 new species of Dragon millipedes discovered in Chinese caves

Six new species of Chinese dragon millipedes, including species living exclusively in caves, are described as a result of an international cooperation of research institutes from China, Russia and Germany. These cave species have unusually long legs and antennae, with one of them resembling a stick insect, only with a lot more legs. Others appear ghostly white and semi-transparent. The study is published in the open-access journal ZooKeys.

Underresearched in many tropical countries, numerous millipede species are still awaiting discovery and description in China as well. In the present study, three researchers from South China Agricultural University, the Russian Academy of Sciences, and Zoological Research Museum Alexander Koenig describe six particularly extraordinary new species of so-called ‘dragon millipedes’ from the two southern Chinese regions of Guangdong and Guangxi Zhuang. Both areas host a large number of spectacular caves, which have only recently been thoroughly surveyed. Four of the species never leave their underground homes.

Dragon millipedes, a genus of millipedes living in southeastern Asia, are characterised with their ‘armour’ of unusual spine-like projections. Furthermore, some of these species produce toxic hydrogen cyanide to ward off predators.

Among the public, the genus gained particular attention when the “Shocking pink dragon millipede” was discovered in Thailand in 2007. This discovery highlighted a large number of unknown millipede species in the Mekong region and worldwide. While the newly described cave dragon millipedes from China lack the “shocking” warning colour of their surface-living relatives, they are no less spectacular.

7825_Millipedes mating couple of Desmoxytes laticollis sp n

One of the new millipedes has received a formal name translating to the “stick insect dragon millipede” because of its extremely long legs and antennae. Therefore, it looks a lot like a stick insect, only with much more legs. Another two of the species have fully lost their colours, which is a common characteristic among exclusively cave-living animals. As a result, they appear ghostly white and even semi-transparent.

Miss Liu Weixin, PhD candidate at the South China Agricultural University in Guangzhou, China, and co-author of the present study, has conducted the research at the Centre of Taxonomy at the Research Museum Koenig (ZFMK), Leibniz Institute for Animal Biodiversity in Bonn, Germany as a part of her PhD, which focuses on Chinese cave millipedes. She worked along with her advisor and lead author Prof. Tian Mingyi, and renowned millipede expert Dr. Sergei Golovatch from the Russian Academy of Sciences, Moscow.

Over the course of her PhD, Miss Liu Weixin has explored more than 200 Chinese caves, where she has discovered over 20 new millipede species. The dragon millipedes are among her most spectacular discoveries as they exhibit extreme cave adaptations including loss of pigmentation and extremely elongated legs and antennae.

Still on her guest research year in Germany, Liu is currently busy describing additional batch of more than two dozen millipede species, she collected from the Chinese caves, literally bringing to light an unknown world.

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Original source:

Liu WX, Golovatch SI, Tian MY (2016) Six new species of dragon millipedes, genus Desmoxytes Chamberlin, 1923, mostly from caves in China (Diplopoda, Polydesmida, Paradoxosomatidae).ZooKeys 577: 1-24. doi: 10.3897/zookeys.577.7825

Huge organs defy austerity for tiny cave snails in the subterranean realm

While most of the knowledge about tiny snails comes from studying empty shells sifted out from piles of dust and sand, the present research is the first contemporary microscopic exploration of organs in cave snails tinier than 2 mm. The paper, published in the open-access journal Subterranean Biology, reveals that underneath the seemingly fragile shells of the Zospeum genus, there are strikingly huge organs.

A number of remarkable observations such as an enormous kidney, grooved three-pointed teeth and a huge seasonally present penis are reported in the recent study, conducted by Adrienne Jochum, Naturhistorisches Museum der Burgergemeinde Bern, Switzerland, and her international team of researchers from University of Bern, Switzerland; Shinshu University, Japan; Universitaetsklinikum Giessen und Marburg GmbH, Germany; Justus-Liebig University Giessen, Germany; University of Ljubljana, Slovenia; University of Bern Goethe-University Frankfurt, Germany; Ruhr University Bochum, Germany; Croatian Biospeleological Society, Croatia and University Duisburg-Essen, Germany.

The scientists describe these characteristics as adaptations the miniature creatures have acquired in order to survive austerity in the subterranean realm.

Usually, adaptations to cave life can include blindness or lack of eyes, loss of pigmentation, sensitivity to changes in temperature and humidity, a high starvation tolerance, or anatomical compromises such as small size and transparent shells. The present study shows that miniscule carychiid subterranean snails have developed huge organs to tolerate the unique conditions of cave life.

“Studying adaptations in extreme environments such as those found in snails of subterranean habitats can help us to understand mechanisms driving evolution in these unique habitats,” explains the first author.

Glassy cave-dwelling snails known only from Northern Spain, the southern Eastern Alpine Arc and the Dinarides might have tiny hearts, but their enormous kidney extends from one to two thirds of the total length of their minute shells. This phenomenon could be explained as an effective mechanism used to flush out large amounts of excess water during flooding seasons in caves.

The same impressive creatures have also developed elaborate muscular plates, forming the girdle that surrounds the gastric mill (gizzard) in their digestive tract. The muscular gizzard grinds the grainy stew of microorganisms and fungi the snails find in moist cave mud. These mysterious creatures graze stealthily using an elastic ribbon (radula), aligned with seemingly endless rows of three-pointed, centrally-grooved teeth, as they glide through the depths of karst caves while searching for food and partners.

Deprived from the hospitable aspects of life we have grown used to, some of the snails discussed in the present paper have evolved their reproductive system in order to be able to reproduce in the harshest of environments, even when they fail to find a partner for an extended period of time.

As a result, not only are these snails protandric hermaphrodites, meaning that they possess male sexual features initially, which later disappear so that the female phase is present, but they have a large retractable, pinecone-shaped penis for instantaneous mating in the summer when mating is most probable. To guarantee offspring, a round sac, known as the receptaculum seminis, stocks sperm received from a partner during a previous mating and allows them to self-inseminate if necessary.

Teeth in these cave snails are also described using histology for the first time. They bear a median groove on the characteristic cusps known for the Carychiidae.

Sketchy, past dissections provide the current knowledge upon which the findings from this investigation are based. Otherwise, historical descriptions of these tiny snails are only known from empty shells found in samples of cave sediment. The genus Zospeum can only be found alive by inspecting cave walls using a magnifying glass.

“Knowledge of their subterranean ecology as well as a “gut feeling” of where they might be gliding about in their glassy shells is necessary to find them,” comments Adrienne Jochum. The authors also emphasize that this groundbreaking work is important for biodiversity studies, for biogeographical investigations and for conservation management strategies.

Adrienne Jochum and her team investigated the insides of the shells using nanoCT to differentiate species in synchronization with molecular approaches for genetic delimitation. Four well-defined genetic lineages were determined from a total of sixteen Zospeumspecimens found in the type locality region of the most common representative, Zospeum isselianum. This investigation is the first integrative study of live-collected Zospeum cave snails using multiple lines of data (molecular analyses, scanning electron microscopy (SEM), nano-computer tomography (nanoCT), and histology.

This work is dedicated to the industrious Slovenian malacologist Joze Bole, whose work greatly inspired the present research.

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Original source:

Jochum A, Slapnik R, Klussmann-Kolb A, Páll-Gergely B, Kampschulte M, Martels G, Vrabec M, Nesselhauf C, Weigand AM (2015) Groping through the black box of variability: An integrative taxonomic and nomenclatural re-evaluation of Zospeum isselianum Pollonera, 1887 and allied species using new imaging technology (Nano-CT, SEM), conchological, histological and molecular data (Ellobioidea, Carychiidae). Subterranean Biology 16: 123-165. doi: 10.3897/subtbiol.16.5758

How did the stonefly cross the lake? The mystery of stoneflies recolonising a US island

Massive glaciers once covered an island in one of the Great Lakes, USA, leaving it largely devoid of life. Its subsequent recolonisation by insects triggered the curiosity of entomologist R. Edward DeWalt and graduate student Eric J. South of the Illinois Natural History Survey and Department of Entomology. Not only did they prove there were significantly fewer species, compared to the mainland, but also that smaller stonefly species appeared to be more capable of recolonizing the island. This study was published in the open-access journal ZooKeys .

Isle Royale is a large island and national park in the middle of Lake Superior, isolated from the mainland by 22 — 70 km distance. As recently as 8,000 — 10,000 years ago, glaciers completely covered the island making it almost uninhabitable.

Over the last 10 millennia mammals as large as moose and wolves, swam, floated, flew, or walked on ice bridges to the island. Therefore, it seemed logical that it was the larger size that allowed some species to cross the water. However, as far as stoneflies are concerned, the results turned out quite different.

“We sampled stoneflies (Plecoptera), mayflies (Ephemeroptera), and caddisflies (Trichoptera), because they are important water quality indicators. Our laboratory has expertise in the taxonomy and ecology of these important species and we know that national parks potentially provide us with wilderness quality conditions,” says DeWalt.

Being much better fliers, the mayflies and caddisflies did not show a particular relation between a species’ body size and their ability to recolonise the island. Conversely, stoneflies on the island were considerably smaller than their mainland counterparts.

“Stoneflies are clumsy fliers, especially the larger species. Large ones are not very aerodynamic and because of this they don’t have the energy reserves to cover the distance to the island. Few species of stoneflies can actually live in the lake, so most could not swim to the island,” explains DeWalt. “Mayflies and caddisflies, on the other hand, are known to be better fliers and tolerant of lake conditions, which would allow for more of the mainland species and similarly sized species to reach Isle Royale.

“Smaller stoneflies have probably used updrafts from the mainland and prevailing winds to get to the island,” the scientist suggests. “The wind just held them up until they reached the island.”

Future research is to use molecular techniques to identify the possible mainland origin for several species inhabiting Isle Royale National Park.

 

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Original source:

DeWalt RE, South EJ (2015) Ephemeroptera, Plecoptera, and Trichoptera on Isle Royale National Park, USA, compared to mainland species pool and size distribution. ZooKeys 532: 137-158.doi: 10.3897/zookeys.532.6478

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.

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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