Heredity/Evolution English
2018-03-02 00:00:00
Vittorio Hernandez

In the update of the list of insect names, the Entomological Society of America reclassified termites as cockroaches or Blattodea. Mike Merchant, a member of the ESA naming committee confirmed that the insect that loves to eat wood no longer has its own order.

With the taxonomic change, termites were added to the 4,500 species of cockroaches, of which 55 are found in the US. While it is big news for the ESA, to ordinary people who dislike pests, the termite is an insect that they want exterminated from their homes just like the cockroach.

No shock to bug community

Gil Bloom, the president of Standard Pest Management in New York, compared the reclassification of the termite to what happened to Pluto which used to be known as the ninth planet from the Sun but was eventually degraded to a dwarf planet.

Experts in the bug community expected the taxonomic change. As early as 2007, a study published in Biology Letters journal cited genetic evidence to declare that termites are just social cockroaches that do not deserve its own order, Newsweek reported.

The demotion started way back in 1934 when specialists had a discussion of termites as a form of cockroaches. The discussion was made after researchers observed that several groups of microbes that digest wood in termite guts live also in some cockroaches that also eat wood, Science News noted.

After biologists learned how to use DNA to work out genealogical relationships, evidence started to grow that termites evolved as a branch of the family tree of cockroaches which also has many limbs. By using genetic evidence from an unusually broad sampling of species, Paul Eggleton, a termite biologist at the Natural History Museum in London, published a new tree of the insect. The study, which he titled “Death of an order,” placed termites on the tree near a Cryptocercus cockroach.

The species of cockroach lives in the Appalachian Mountains in an almost termite-like style. It is near where Coby Schal, a chemical ecologist at the North Carolina State University in Raleigh, works. He said the monogamous pairs of Cryptocercus cockroaches eat through wood, making tunnels where they raise their young there. The adult cockroach feeds its offspring via its anal secretions that provide the young insect nutrition and starter doses of gut microbes that could digest wood and eventually let the young cockroach eat on their own into homes.

Bloom said that the taxonomy of the termite and cockroaches are similar. One difference, however, is that cockroaches prefer the company of fellow cockroaches while termites mingle and share harborage sites because it wants to be near food, shelter, and water.

However, termites typically fly solo. The method to treat termite infestation is different from the one used on cockroaches although both are unwelcome house guests.

Social hierarchies

Inverse noted the complex, intricate society that makes up the termite life which has kings, queens, soldiers, and workers. To keep things running smoothly, the insect uses an elaborate chemical communication system.

It is different with cockroaches that live in family groups and engage in collective decision-making. The insect does not have the social hierarchies of the termites and other social insects.

Genetic study

The reclassification was the result of a genetic study of termites which researchers believe came from ancient solitary cockroaches. The researchers examined the DNA of the ancient cockroach and termite and their RNA. They found that the termites evolved into eusocial creatures from the solitary cockroach ancestor about 150 million years ago.

The adaptation happened 50 million years before Hymenoptera separately developed similar social habits. It is the family of bees, ants, and wasps.

It was the genomes of the German cockroach (Blatella germanica) and a species of drywood termite (Cryptotermes secundus) that the researchers sequenced and analyzed. They placed a special focus on the genes that encode the chemical signaling and sensing and compared the genomes to 16 other eusocial and non-eusocial insects. It allowed the scientists to track how the solitary ancestor of the termite gradually became a highly developed social organism.

The website noted that the change – which happened at a different rate in Hymenoptera – is a classic example of convergent evolution. It is the phenomenon by which different organisms end up with similar traits that were developed under different selection pressures.

The authors said in the report published in the Nature Ecology & Evolution journal in early February that further analysis will help researchers gain a better understanding of the intricacies of cockroach and termite chemical signaling.

The ESA common names committee, after several years of debate, voted to reclassify the termite as a cockroach. Whitney Cranshaw, a member of the ESA naming committee and from Colorado State University in Fort Collins, said some of them, including himself, did not want to make the change because they liked it the way it was. It was easier for the undergraduate students he teaches to memorize termites and cockroaches as separate orders, but he nevertheless voted for the change because it was the right thing to do.

[researchpaper 리서치페이퍼= Vittorio Hernandez 기자]

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