New Assassin Bug Species Discovered in Museum Collections and in the Field

Entomology Today July 12, 2016 Leave a Comment

Zelus gilboventris and Zelus gracilipes, two assassin bugs that are new to science. Photo by Dr. Guanyang Zhang, CC-BY 4.0.

As many as 24 assassin bugs that are new to science were discovered and described by Dr. Guanyang Zhang and his colleagues. In their article, published in the open access Biodiversity Data Journal, they describe the new insects along with another 47 assassin bugs in the same genus. To do this, the scientists examined more than 10,000 specimens from museum collections and from newly undertaken field trips.

Assassin bugs are insects that prey upon other small creatures, as their common name suggests. There are some 7,000 described species of assassin bugs, but new species are still being discovered and described every year. The new species, all of which are from the Americas, belong to the genus Zelus.

To conduct the research, Zhang examined more than 10,000 specimens and nearly all of them have been databased. These specimen records are now freely and permanently available to everybody. Zhang’s work demonstrates the value of natural history collections. The specimens used in his work come from 26 museums in nine countries.

The discovery of the new species would not have been possible without these museums actively collecting and maintaining their insect collections, and demonstrates the importance of insect collections.

It took more than a century for some of the new species to be formally recognized and described. The first specimens of the species Zelus panamensis and Zelus xouthos, for example, had been collected in 1911 and 1915 from Panama and Guatemala. However, since then they had been waiting quietly in the collection of the Smithsonian National Museum of Natural History. Now, over 100 years later, they have finally been discovered and given scientific names.

Meanwhile, more recently collected specimens also turned out to be new species. Specimens of Zelus lewisi and Zelus rosulentus were collected in 1995 and 1996 from Costa Rica and Ecuador about two decades ago, a timeframe considered relatively short for taxonomic research. These interesting patterns of time lapse between specimen collecting and scientific description suggest that it is equally important to examine specimens in museum collections and ones that are newly collected from the field.

The kind of research performed by Zhang and his colleagues is called “revisionary taxonomy.” In revisionary taxonomy, a researcher examines a large number of specimens of a group of organisms of his or her interest. This can be either a monophyletic lineage or organisms from a particular region. The scientist’s goal is to discover and describe new species, but also to examine and revise previously published species.

Besides describing new species, the present taxonomic monograph treats another 47 previously described species. Nearly all of the species now have images of both males and females and illustrations of male genitalia. Some of these insects are strikingly brightly colored, and some mimic wasps.