The evolutionary mystery of the German cockroach
johnhawks.net
johnhawks.net
they proposed that when Asian cockroaches were transported along the trade routes from south and southwest Asia into Europe, this species could not establish persistent populations. Without local success, they were hardly noted by anybody. Only a few survivors that found ways to live within structures could make it through the cold European winters, and over time these survivors evolved into the German cockroach. The species was therefore truly European.
went to work testing the hypothesis by sequencing genetic data from German cockroaches in many parts of the world, as well as Asian cockroaches and other relatives. Last month they published the results of this work. The new data showed something a little different from the urban Europe hypothesis.
B. germanica didn't originate in Germany or elsewhere in Europe as a new species and later spread throughout other parts of the world. Island southeast Asia, Ethiopia, and China all had diversity of B. germanica that was as old as in Europe. Every one of these populations came from common ancestors that shared a history of drift and adaptation around 2100 years long. Before this, those ancestors diverged from the Asian cockroach, B. asahinai.
The German cockroach deserves to be widely known as an example of rapid evolution of a new species. Not only does it inhabit environments where few insects survive, its environments didn't even exist before a few thousand years ago.
From wikipedia:
>The English, the Germans, and the Italians called it "the French disease", while the French referred to it as the "Neapolitan disease". The Dutch called it the "Spanish/Castilian disease".[113] To the Turks it was known as the "Christian disease", whilst in India, the Hindus and Muslims named the disease after each other.[
the selection pressure which produced the starting population - these were the ones who survived long travels along the trade routes while hiding in the human cargo and after that survived in the new environment (new climate, vegetation, etc) of the destination.
https://en.wikipedia.org/wiki/Scutigera_coleoptrata
And fun fact about centipedes(and millipedes), lacking the ability to create a waxy layer on their chitin shell(as insects do) they are more dependent on having a moist environment to live near than insects.
I sometimes see a local species of black-and-yellow millipede, chunky individual several inches long, that have climbed up walls, tree trunks, or fence posts and died. They were victims of a parasitic fungus (Anthrophaga myriapodina) that takes control of them and forces this climbing so spores from the fungus can disperse more widely.
You might think this is Cordyceps, a fungus that does something similar in ants, but it's not closely related, not being in even the same taxonomic class. It's a case of convergent evolution.
> “Some people come by the name of genius in the same way that certain insects come by the name of centipede -- not because they have a hundred feet, but because most people can't count above 14.” —GCL
https://en.wikipedia.org/wiki/Centipede#:~:text=Despite%20th... (why an odd number?)
EDIT: but what about palps? crustaceans also can have even pairs of walking legs, but odd numbers of leg-like structures...