Cockroaches Are Evolving To Become Almost Impossible To Kill

by : Julia Banim on : 02 Jul 2019 18:32
Cockroaches Are Evolving To Become Almost Impossible To KillCockroaches Are Evolving To Become Almost Impossible To KillPixabay

Cockroaches are already renowned for being able to survive whatever life throws at them, known for being stubbornly indestructible little beasts who laugh in the face of the apocalypse.


Now cockroaches are becoming even more indestructible, reaching a point where they are resistant to all sorts of pesticides, and soon they could well be nearly impossible to kill.

A not-for-the-squeamish study from Purdue University has found some German roaches – one of the most common types found creeping around the UK – can pass down resistant genes to their descendants.


Cockroaches pose a real threat to human health, making this icky news even more disquieting. They carry numerous types of harmful bacteria, including E. coli and salmonella.


Furthermore, the saliva, faeces and body parts left behind by roaches can trigger allergies and asthma and even cause such conditions in some children.

This gruesome study, published in Nature, found the fabled roach resistance could be boosted by up to six-fold within just one generation, with the problem being particularly prevalent in urban areas and low-income housing.

Researchers tested various treatments of three insecticides – abamectin, boric acid, and thiamethoxam – within cockroach-infested apartments across Indiana and Illinois over a six-month-period, and were left surprised by how quickly they developed resilience.


With a rotation of three insecticides, researchers found cockroach populations could be kept flat for a six-month period. However, they could not reduce populations. The two-insecticide mixture was ineffective, with cockroach populations proceeding to thrive.

In one of the single-insecticide experiments, there was low starting resistance to the insecticide in question, and researchers could all but eliminate the cockroach population. In the other, there was an approximate 10 per cent starting resistance, with populations continuing to grow.

In later lab tests, a certain percentage of cockroaches were found to have resistance to a particular type of pesticide. Treatment survivors and their offspring would be then be more or less immune to that insecticide.

Surprisingly, these weeny warriors also became resistant to other insecticides, even if they hadn’t yet been exposed to them and had no previous resistance.


Study co-author, Michael Scharf, has made the following statement in a press release:

This is a previously unrealised challenge in cockroaches.

Cockroaches developing resistance to multiple classes of insecticides at once will make controlling these pests almost impossible with chemicals alone.

Scharf added:

We would see resistance increase four- or six-fold in just one generation.

We didn’t have a clue that something like that could happen this fast.

Seriously, why can’t a cute and fluffy species like pandas develop this sort of dogged resilience?

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Julia Banim

Jules studied English Literature with Creative Writing at Lancaster University before earning her masters in International Relations at Leiden University in The Netherlands (Hoi!). She then trained as a journalist through News Associates in Manchester. Jules has previously worked as a mental health blogger, copywriter and freelancer for various publications.

Topics: Animals, Science


Scientific Reports and 1 other
  1. Scientific Reports

    Rapid evolutionary responses to insecticide resistance management interventions by the German cockroach (Blattella germanica L.)

  2. Purdue University

    Rapid cross-resistance bringing cockroaches closer to invincibility