Ghostly antics

It happened again this morning. A chocolate rice crispie cake that was to have formed the final flourish of my daughter's packed lunch had disappeared overnight - and I was getting the blame. Two reasons were given for pointing the finger of shame at me: first, what script writers for The Bill would doubtless call my "previous"; and second, the lack of any other scientifically plausible explanation. It is remarkable how children will accept that, on one night, a white-bearded old man visits all the houses in the world to bring them presents but will treat with contempt their father's explanation that perhaps a ghost has stolen a rice crispie cake.

Fortunately, I did have a better theory; one furnished by the most recent edition of the New Scientist. On page 12, this august publication revealed that "Britain has been invaded by an insect so small that it is almost impossible to see with the naked eye" - Tapinoma melanocephalum, or the ghost ant. Whole colonies can exist unsuspected in those odd spaces beneath floorboards - or behind cake-tins. At night these creatures emerge, gorge themselves on whatever has been left out for the next day's packed lunch, and flee, leaving innocent fathers to suffer under suspicion's shadow. Even when the occasional tapinoma fails to get home by dawn, its tiny size and lack of colour means that it is unlikely to be detected.

What strengthened my argument was the fact that ghost ants are natives of Florida and scientists believe that they have probably been imported by unwitting tourists. And guess what? Last Sunday night la famille Aaronovitch arrived back in London after a fortnight on the Gulf Coast of ... Florida. Somewhere in our luggage, packed between two weeks' worth of dirty beach towels and Disneybilia, a tapinoma community had obviously stowed away - a huddled mass seeking freedom in a new land.

Fortunately, my children understand something about how nasty things can be inadvertently carried between continents. They learnt this lesson, ironically, at the hands of the Miami customs police. Or, more precisely, at its paws.

There we were at baggage reclaim with 200 other tired Britons and 30 testosterone- and oestrogen-stuffed American teenagers, when a Jamie Lee Curtis lookalike - all trim, efficient and sexy in a navy uniform - came amongst us with a sniffer dog. This being Miami, there could not be much doubt about what they were looking for. Virgin flight 05 had clearly brought with it a courier for the Cali cartel, now clutching a case full of coke.

And then the floppy-eared beagle stopped at our bags and emitted a low whine. The whole reclaim area turned to look at us. Had drug smugglers no shame, using two young children as a front for their infernal trade? "Excuse me sir," said Jamie, frowning, "are you carrying any fruit?" As it happened, we were not carrying fruit. Not even a stray grape. But the beagle's nose was so sensitive that it had smelled the remaining trace scent of an orange consumed somewhere over Nova Scotia.

That shows how keen Americans are to keep alien infections, viruses and insects from entering their pristine portals. And the episode serves another purpose than just illustrating why my children are now persuaded of the ant theory. For it also begs the question of why, if Miami's hounds can prevent alien mangoes from entering the US, British dogs (like British beef, probably the best in the world) cannot sniff out Floridian ghost ants at Gatwick and Stansted.Think of the other unwelcome invaders that we might be spared by judicious employment of such animals: the red-eared terrapin (too large for our lakes), the snapper turtle (can take the thumb off a toddler), the Himalayan rhododendron (stifling our native heathers) and the grey squirrel (digs up my busy lizzies to bury its nuts). Best of all, it would give gainful employment to the dogs of Britain, while saving innocent fathers from the baleful and unjust stares of their children.