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.

Rediscovering an interesting group of ant-loving beetles

Case-bearer leaf beetles, scientifically called Cryptocephalinae, live a secretive life.

While the adults hide their heads inside their torso, like a cloaked, mysterious figure, their eggs stay hidden inside a case, carefully constructed by their mothers, using fecal pellets. Having already hatched, the larvae and, later, the pupae keep this initial case and build on forming a protective ‘fortress’ that their enemies can mistake for a plant twig or caterpillar frass.

The studied Cryptocephalines genus, like most of the 40,000 known species of leaf beetles, feed on leaves, fruits, flowers, roots and stems. Indeed, some species of leaf beetles are some of the biggest threats to our crops.

A study published in ZooKeys, led by Dr. Federico Agrain, an Argentinian researcher of CONICET, and his colleagues in the USA and Germany, has unveiled some remarkable new patterns in the secretive life of a specific group within the leaf beetle genus that live within ant nests.

Their research highlights that these myrmecophilic (literally, ‘ant-loving’) leaf beetles live mainly among species of the ant families Formicinae and Myrmecinae.

“Living with ants might offer these beetles multiple advantages, and it might have aided the colonization of xeric environments,” hypothesised Dr. Agrain.

“Ants are notoriously territorial and aggressive, sniffing out and killing enemies that try to enter the ant nests. We suspect that these beetles sneak inside the ant nests by mimicking the scent and behavioral profiles of the ants,” suggests Dr. Caroline Chaboo, a leaf beetle expert at the University of Kansas and co-author of the paper. “How else could the beetles get the ants to pick them up outside the nest and take them into the nest where they can live undetected and with an endless food supply?”

These hypotheses need to be tested in future research. In addition to these novel aspects and hypotheses. “Specialized natural enemies, especially parasitoid Hymenoptera (the insect order where ants belong), exploit cryptocephaline beetles inside the ant nests,” says Dr. Matthew Buffington, a research entomologist at the ARS-Systematic Entomology Laboratory in Washington DC, and co-author of the present study.

Key evolutionary steps, needed to be taken by these leaf beetles, so that they are able to form an association with ants, are also discussed by Dr Federico Agrain and his colleagues. How does a leaf beetle find a host ant, enter the nest, survive within the nest, and, later, exit the ant nest? How strong is the strength of the host association? What are the benefits for the host? What about the diet specialization of adult and larvae? These are the sort of questions the scientists ask themselves.

Clearly, there is a wide range of new hypotheses to be investigated and inter-disciplinary approaches will be needed to unravel the secrets to myrmecophily and the covert, enigmatic lives of case-bearer beetles.

Photo Credit: 

© Jason Penney

Original source:

Agrain FA, Buffington ML, Chaboo CS, Chamorro ML, Schöller M (2015) Leaf beetles are ant-nest beetles: the curious life of the juvenile stages of case-bearers (Coleoptera, Chrysomelidae, Cryptocephalinae). In: Jolivet P, Santiago-Blay J, Schmitt M (Eds) Research on Chrysomelidae 5. ZooKeys 547: 133–164. doi: 10.3897/zookeys.547.6098

Over 300 new beetle records for New Brunswick, Canada, in a special issue of ZooKeys

Beetles diversity in New Brunswick, Canada, has elicited the interest of biologists for over a century and continues to do so. In 1991, 1,365 species were known from New Brunswick. That number had increased to 2,703 by 2013, as a result of a series of publications in three previous special ZooKeys issues and other publications. In spite of that work, there were still gaps in the knowledge of the Coleopteran fauna.

Now, a group of insect specialists have joined forces in the name of their love for beetles, and compiled their findings from the last three years, reporting another 303 species for New Brunswick, including thirty-two species new to science. All of these records are published in a special issue, titled “The Coleoptera of New Brunswick and Canada: Providing baseline biodiversity and natural history data” of the open access journal ZooKeys.

It might have been only three years, but the authors of the present issue have expanded the beetle fauna of New Brunswick by 13%. On a longer timeline since 1991, the increase rises to an impressive 124%.

These figures come as a result of the 303 new records for New Brunswick that included 32 species, which the team have found to be new to science, 4 new North American records, 21 new Canadian records, 270 new provincial records, and 45 adventive species that have somehow arrived in the region from elsewhere. As a result, the beetle fauna of New Brunswick currently comprises 3,062 species.

“This information constitutes a baseline of biological knowledge that is critical to support other branches of science,” point out the authors.

“It is important to remind ourselves that the understanding of biological diversity is not possible without taxonomic research, which is thought by many to be the foundation of biological science,” they explain. “Data on the mega-diversity of life and knowledge on species identity and distribution require discovery, description, cataloguing, and organization in order to be made accessible to a wide audience.”

“This work would not have been possible to complete without the enthusiasm, determination, and professionalism of a small number of dedicated individuals who are acknowledged in the papers in this special issue,” the researchers conclude. “We hope that this special issue will generate a positive response and further interest in the Coleoptera fauna of New Brunswick and Canada, as many new discoveries await.”

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Original source:

Webster RP, Bouchard P, Klimaszewski J, Sweeney JD (2016) History of Coleoptera collecting in New Brunswick, Canada: advancing our knowledge of the Coleoptera fauna in the early 21st century. In: Webster RP, Bouchard P, Klimaszewski J (Eds) The Coleoptera of New Brunswick and Canada: providing baseline biodiversity and natural history data. ZooKeys 573: 1-18. doi: 10.3897/zookeys.573.8123

Two brand new dung beetle species from montane grazing sites and forests in Mexico

While carrying out a biodiversity study, a Mexican-Italian research team discovered three new dung beetle species in montane forests disturbed by livestock grazing. Mexico has been a mecca for naturalists, and its dung beetle species are among the best known in the world. This is why the discovery of new species there is noteworthy. The present study, published in the open-access journal ZooKeys, describes two of them and highlights the need to further explore the biodiversity of disturbed ecosystems.

Mexico is a country that holds a vast number of creatures and ecosystems. There is in fact a fascinating phenomenon: tropical forests that have close affinities with South America co-occurring with temperate and arid areas shared with North America. Thus, Mexico has been particularly attractive to explorers ever since the 19th century.

A group of animals that has woken up a special interest for studies in Mexico is the so-called ‘dung beetles’. As their name suggests, dung beetles are insects that feed mainly on mammal faeces.

For decades, an international research team, led by Dr Gonzalo Halffter, has studied dung beetles across the world, especially in Mexico. As a consequence, the Mexican species are some of the best-known. However, Dr Halffter and his team are not interested exclusively in dung beetles, but also in evolutive phenomena, the effects of land-use change, ecosystems modification by human activities, and conservation biology. Such concerns seem to be of particular importance now that the terrestrial ecosystems in Mexico have been severely destroyed and disturbed by people.

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Livestock is one of the major drivers of biodiversity loss worldwide, which makes the present discovery particularly impressive. With at least 58% of the area of Mexico occupied with livestock farming, dung beetles are essential in cleaning up. While studying their diversity at conserved forests and cattle grazing sites across the mountains of Mexico, the researchers found some new species of dung beetles.

The first to discover these new dung beetles was Victor Moctezuma, a student of Dr Gonzalo’s at the Instituto de Ecología of Mexico.

“I was carrying out sampling for my Masters Degree studies, but I had no idea that new dung beetles could be found in a forest that is disturbed by human activities, such as livestock grazing and land-use change,” recalls Moctezuma. “So I was really surprised when I discovered three dung beetle species.” One of these species has already been published.

Apart from the two new dung beetles, formally called Onthophagus clavijeroi and Onthophagus martinpierai, the present paper also provides theories about the current distributions of these insects across the Mexican mountains and their putative evolutive relationships. As a whole, the study highlights the importance of disturbed forest for species discovery and conservation.

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Original source:

Moctezuma V, Rossini M, Zunino M, Halffter G (2016) A contribution to the knowledge of the mountain entomofauna of Mexico with a description of two new species of Onthophagus latreille, 1802 (Coleoptera, Scarabaeidae, Scarabaeinae). ZooKeys 572: 23-50. doi:10.3897/zookeys.572.6763