They are often cited as the one creature likely to survive in the event of all out-nuclear war. But it seems that the lowly cockroach has now found a brand new way to survive.
American scientists have discovered that a strain of European cockroach has managed to completely reorganize its sense of ‘taste’. Instead of being attracted to the ‘sweet’ glucose used in traps around the continent, these intrepid little bugs perceive the bait as bitter.
The phenomenon was first noted over two decades ago, when pest controllers reported a failure to eradicate the roaches because the insects were stubbornly refusing to eat the bait.
Subsequent scientific studies have confirmed these anecdotal observations. When offered a choice between sweet jam or the more savoury peanut butter, hungry cockroaches from the mutant strain showed a much greater aversion to the glucose rich jam, physically jumping back when contact was established.
The neural mechanism behind the response was identified using tiny electrodes to record activity in the cells responding to flavour, which are housed in microscopic hairs on the insect’s mouthparts; the cockroach taste receptor.
Scientists found that the cells normally responding to bitter compounds were instead responding to glucose in the mutant roaches, over-riding signals from the traditional sweet-sensing cells.
George Beccaloni, the Natural History Museum’s curator of cockroaches, explained that any genetic change which caused the cockroaches to avoid human bait would be strongly favoured by natural selection.
The mutants have therefore been far more successful in their ongoing attempts to survive and reproduce, resulting in the widespread propagation of the novel allele. Indeed, for the European cockroach it seems that victory really is bitter sweet.