Fri 03 May 2013: 3.00pm @ S1A SR: Tang Qian on “Origin and spread of the German cockroach, Blattella germanica”

Qualifying  Examination


Origin and spread of the German cockroach, Blattella germanica (Blattodea: Blattellidae)

Graduate Student
Dept. of Biological Sciences, NUS

Fri, 3 May 2013: 3.00pm
@ S1A, #02-17
Supervisor: Assoc Prof Evans, Theodore Alfred

All are welcome


“The German cockroach (Blattella germanica) is likely to be the world’s most widespread domestic pest, from large cities to rural areas, on all continents (except Antarctica) and across most latitudes.

How this situation transpired is unknown, even the origin of this species is unknown; the name indicates where it was named, as an invasive species. Historical records and morphological phylogeny suggest that the German cockroach is of African or Asian origin.

Considering the evidence from both sources, I hypothesize that the German cockroach and its Asian relatives share a common ancestor out of Africa, and that the ancestors of the German cockroach was brought to Europe and domesticated there.

Adaptation to buildings allowed for transportation by humans, and thus spread to the rest of the world.

I will test my hypothesis using different genetic markers on cockroach samples collected from over 100 cities or regions.  I will use various genetic analyses to trace the history of the Genus Blattella (ribosomal DNA, mitochondrial DNA) and the species B. germanica (microsatellites). 

This study may also provide evidence for the expansion of B. germanica and suggest processes of domestication by pest species in the urban environment.”


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