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| The Symbol Of The Dutch Foundation Against Senseless Violence photo credit: Ziko |
Ladybirds, or ladybugs, are a regular sign of
summer and have long provided entertainment in counting the spots on their wing
cases. They are bright and colorful and are popular as logos. Perhaps the most
interesting is the picture of a ladybird used as symbol by the Dutch Foundation
For Senseless Violence where it is on a tile embedded in the sidewalk where a
particularly nasty and senseless crime has taken place.
The term “lady” comes from the religious
connotation and in the Netherlands the name refers to “The Lord’s” animal, so
we see it as a rather benign creature. Even in the nursery rhyme where we urge
it to “fly away home” to take care of its children, we are looking on it as
benevolent fellow creature.
But let’s look at its children. A different picture
emerges. The rose lovers amongst us are
already aware that the larvae munch their way through lots of aphids every day.
They have voracious appetites and the aphids have to breed like crazy to keep
up.
Of course, it isn’t just our roses that have
aphids. For some strange reason, the world seems to becoming more and more
addicted to soya beans and that’s fine with the aphids who see acre after acre
of grazing stretch out before them. It is also easy pickings for the ladybird
larvae.
The fields in Québec are the focus of Gagnon et al who decided to look at the darker
side of ladybird larval lifestyle (1). They identified four species of ladybirds
were using the fields as cafeterias for their kids. However, the ladybird kids
weren’t very well brought up. They did eat what was in front of them, as good
kids should, but if that happened to be a different strain of lady bird, too
bad, it went the way of the aphids.
This has the fancy name in intraguild predation
(IGP) and simply means dog-eat-dog when the predators are hungry. Gagon et al analyzed the DNA from the stomachs
of a large group of each species of larvae and showed that they were very
catholic (with a small “c”) in their eating habits. There was a year-to-year
difference and this was put down to the aphid supply chain, but it was
recognized that IGP provided a better nutrition source. Ladybird eggs were also
a delicacy.
So ladybirds have a dark side. Maybe it’s wise
not to look too deeply into a lady’s past.
