All insects in cold places like Scotland need to find a way of coping with winter, when not only is it cold but there is less around to eat.  Adult ladybirds do this by hibernating.  In their hibernating state they can withstand sub-zero temperatures.  They go into suspended animation, their bodies do not develop, they do not eat or move; they must rely on their stored body fat to sustain them until spring.  Their bodily processes slow right down to a 20th of their normal active rate, which helps the body fat last longer.  

There are 10 different species of ladybird that you will see around Glasgow. You may see them hibernating in groups of all sizes.  Some species group together in their thousands.  Some hibernate in plant litter.  Others, such as the two-spot ladybird, will come into buildings and settle in around window frames or in other cracks and crevices.  They do no harm to us in our houses but our central heating and artificial lights don’t seem to do them any good.  The warmth and light fool them into thinking spring has come early; encouraging them to leave their hibernation sites when it is still too cold out and there isn’t enough food around.

There are thought to be a number of reasons why ladybirds hibernate together. Some people believe it is because it helps the ladybirds retain essential heat and moisture.  Others believe it is for defence against predators.  Ladybirds produce chemicals that smell and taste nasty to birds and small mammals.  In a group the ladybird’s smell is more potent and consequently more likely to discourage hungry animals.  If a predator manages to ignore the smell and eats one, it should realise that they taste horrible and leave the others in the group alone.

Ladybirds don’t generally live in groups when they aren’t hibernating.  They live and feed on their own, just meeting up to mate.  When spring arrives hibernating groups disperse in search of food.  These orange ladybirds will be searching for mildew (mould) to eat.  Most other Glaswegian ladybirds will be looking for aphids (greenfly) to feed on.