Animal of the Week -- July 7, 2008

After the most recent animal of the week a goodly number of folk contacted me to let me know that they had recently seen silverfish, a surprisingly small number, or zero, of these correspondents felt as well disposed towards the graceful little darlings as I do -- most feeling repulsion, disgust, or even fear.

I suspect that this week's animal might also divide opinion, but I'll probably have one or two more people on my side, as this week's animal is the scourge of one of the biggest causes of animosity among neighbours in modern day towns, villages, and suburbs. Although they are a gift to the producers of TV shows about societal conflict in the form of boundary disputes, a great many people abhor leyland cyprus arbors; but across the land, there is a new friend to those living in the shadow of the much loathed conifers -- Cinara cupressi (cypress aphid).

Probably originating in southeastern Europe, these grey 2–3 mm aphids are now found on every continent but Antarctica where it is warm enough for them to breed. In the UK their numbers are largely kept in check as cold winters kill off large numbers of them. However, due to global warming caused by people reading ridiculous almost-weekly emails about animals and the like, last winter the temperature in the southeast was practically tropical throughout. As a consequence these little beasties survived in large numbers. A couple of months ago they began their onslaught, sucking the sap from leylandii hedges up and down the country. Now, the damaged plants are turning brown, whole section and some complete plants dying.

Obviously, this is pestilent behaviour by the aphids, but the hedges are stupid, so good on them I say. Except for those attacking mazes, the only acceptable use for a leylandii. I love a maze, even though I know how to do them and have to resist the temptation to cheat.

Throughout the summer the aphids reproduce parthenogenetically -- ie, the females spew out identical miniatures of themselves without the involvement of any male aphids. A female may contain another female that is already pregnant with the first female's granddaughter, like an entomological russian doll. As winter approaches males are produced by withholding one of the sex chromosomes from some offspring, these mate with females who then lay eggs which overwinter. I like this about aphids, it's neat.

Next week, I hope there will be an animal and maybe even not an insect.

Until then, stay safe, and look out for dying shrubberies.