Beached ladybirds

Question: Recently walking along my local beach I noted large number of Ladybirds washed up. Why might this occur?

Answer: Ladybirds are beetles from the family Coccinellidae. Since 1758, entomologists have classified about 5,000 different species, or kinds, of Ladybird in the world with about 500 of these species found in Australia.

Ladybirds range in size from 1 to 10mm, and their often bright and patterned colouring means they readily attract the attention of humans. Perhaps this is also why Ladybirds were known to some of the world’s earliest entomologists.

Ladybirds are holometabolous insects, meaning they undergo a complete metamorphosis with four discrete life stages: egg, larva, pupa and adult beetle. Of these stages, only the adult beetle is particularly mobile. Ladybirds hibernate over winter then come out to feed and find a mate in spring. Most species of Ladybird are predatory, these species feeding in particular on a group of insects known as aphids. Also targeted are scale insects, mites and other small insects; they may supplement their diet with pollen, sap, nectar or honeydew. Adult Ladybirds are capable of flight and can cover some distances to find new food sources or mating partners.

We have received a number of reports at the Museum of large numbers of Ladybirds being washed up on the beach. It is possible that the Ladybirds may be attracted to areas near the beach by a food source such as aphids which may be feeding on crops or in greenhouses.

There are a few species of Ladybird which do cause damage to some crops, so again if these were being grown near the coast the beetles could be attracted to these. As Ladybirds are generally poor fliers it is quite possible that they could then have been caught in strong winds and been blown out to sea where they drown and are then washed back up onto the beach.