Under pressure: the extraordinary survival of seal lice in the depth of the sea

Lice from pinnipeds – sea lions, seals and walruses – are the only insects capable of surviving marine dives. Throughout their evolutionary history, they have adapted to tolerate hypoxia, high salinity, low temperature and, in particular, to tolerate conditions of high hydrostatic pressure. To understand the limits of the capacity of lice to survive during host deep dives, we conducted a series of controlled experiments in the laboratory. We collected lice from elephant seals and submitted the different life stages to high pressure conditions. Lice were first exposed to one of four hydrostatic pressures: 30, 80, 150 or 200 kg cm−2. They were then exposed a second time to higher or lower hydrostatic pressure conditions to test for the impact of the first experience, which could either be deleterious or trigger physiological adaption, allowing them a better tolerance to high pressure. We found that lice from elephant seals can tolerate hydrostatic pressures higher than 200 kg cm−2 (close to 200 atm), which is equivalent to 2000 m depth. Adults exhibited lower recovery times than nymphs after immersion at high hydrostatic pressure. Our findings show that lice have developed unique adaptations to endure extreme marine conditions. We discuss these extreme performances in relation to the morphological characteristics and physiological responses to diving in these insects.

In addition, you can view the media coverage of the research publicaiion in the following media news

El poder de lo minúsculo by CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) 19-8-2020 edition - https://www.conicet.gov.ar/el-poder-de-lo-minusculo/ and http://phthiraptera.info/node/95123

An exception to the rule that there are no marine insects by The Economist, Science & Technology 6-8-2020 edition - https://www.economist.com/science-and-technology/2020/08/06/an-exception...

Des poux sous haute pression by Pour la Science 1-9-2020 edition  - https://www.pourlascience.fr/sd/biologie-animale/des-poux-sous-haute-pre... and http://phthiraptera.info/node/95122

You Can’t Escape Lice, Even 6,500 Feet Below the Ocean by New Tork Times 26-8-2020 edition - https://www.nytimes.com/2020/08/26/science/lice-elephant-seals.html and http://phthiraptera.info/node/95102

Intrepid lice survive extreme pressure when hitching rides on elephant seals, INSIDE JEB- https://jeb.biologists.org/content/223/17/jeb234260 and http://phthiraptera.info/node/95124