Double beat for tarantula heart

A novel application of MRI has revealed a tarantula has a double beating heart.

Magnetic resonance imaging (MRI) is usually used in medicine to distinguish between different types of tissue, but researchers from Edinburgh University have used a specialised scanner to reveal the inner workings of a tarantula – with some surprising results.

The non-invasive scan – performed at the Glasgow Experimental MRI centre – revealed the arachnid has a double beating heart.

“In the videos you can see the blood flowing through the heart and tantalisingly it looks as though there might be ‘double beating’ occurring, a distinct type of contraction that has never been considered before,” said Gavin Merrifield, a PhD researcher.

“This shows the extra value of using a non-invasive technique like MRI.”

The use of MRI reduces the need for dissection and provides a greater insight to the internal workings as the animals are live and unharmed. Using the special scanner – built for medical research on rodents – researchers measured the tarantula’s cardiac output, giving a much more accurate reading than other methods, which are either indirect or highly invasive.

Application of this technology is often purely medical, but it can have practical uses in answering fundamental biological questions.

“One potential practical use of this research is to ascertain the chemical composition of spider venom,” said Merrifield. “Venom has applications in agriculture as a potential natural pesticide. On a more academic side of things if we can link MRI brain scans with a spider’s behaviour, and combine this with similar data from vertebrates, we may clarify how intelligence evolved.

You can view a video of the tarantula’s double heartbeat on the Lab News YouTube Channel: http://youtu.be/WX4csPh4HIg