Image caption Critics say that the 'electronic backpack' is inhumane

A US company that has developed an "electronic backpack" that fits onto a cockroach allowing its movements to be controlled by a mobile phone app has defended itself against cruelty claims.

The Backyard Brains company says that the device is intended to get children to be interested in neuroscience.

A spokeswoman told the BBC that the device - being formally launched on Saturday - was not a gimmick.

But critics say that the company's stance is "disingenuous".

For the "electronic backpack" to work the cockroaches have to be placed in icy water to subdue them before sandpaper is used to remove the waxy coating on the shell of the insect's head.

Cockroach facts There are about 4,600 species of cockroach and fewer than 30 of these are considered pests. (By contrast, there are about 5,400 species of mammals)

The world's smallest cockroach is only 0.3mm long and lives in ant nests

The heaviest cockroach is the huge Australian Rhinoceros Cockroach at 8cm in length Source: Natural History Museum

An electrode connector and electrodes are then glued on to the insect's body and a needle is used to poke a hole in their thorax in order to insert a wire.

Their antennae are then cut and electrodes are inserted. A circuit is attached to their backs, and signals are received through a mobile phone app allowing users to control the cockroaches' movements to the left and to the right.

Animal behaviour scientist Jonathan Balcombe has been quoted on US scientific websites as saying that the insects are harmed in the process.

"If it was discovered that a teacher was having students use magnifying glasses to burn ants and then look at their tissue, how would people react?" he is quoted as saying.

Likewise Queen's University philosophy Professor Michael Allen warned that the device will "encourage amateurs to operate invasively on living organisms" and "encourage thinking of complex living organisms as mere machines or tools".

The Michigan-based company has even received emails saying the the backpack - known as Roboroach - "teaches kids to be psychopaths".

Image caption Roboroach works by controlling the movements of the cockroach through electrodes that connect to a smartphone via Bluetooth.

Image caption Critics say that the "electronic backpack" is cruel and subjects the insects to unnecessary stress.

Image caption To attach the backpack, the insect is immersed into ice water to subdue it. Electrodes are stuck to it using glue and groundwire is inserted into the thorax.

Image caption The Roboroach weighs 4.5g and is compatible with most mobile phones. It overrides the insect's antennae making it turn left and right at the flick of a switch.

But Backyard Brains says the backpacks "allow students to do graduate level research early in life".

A company spokeswoman told the BBC that the backpack had been developed solely to encourage children to take an interest in neuroscience which, she said, needed to be better taught in American schools.

"At the moment this crucially important subject is woefully under-taught," she said, "with many schools teaching neuroscience within the biology syllabus when it should be a subject in its own right.

"That is especially the case when diseases of the brain such as Alzheimer's take a heavier toll within society."

The spokeswoman insisted that the insects are treated humanely and that the backpack - first developed in 2011 - does not harm them.

The backpack will be widely available in November in the US priced at $99 (£61).