Across the final weekend of October, ladybirds appear to have proliferated in two places - indoors and on social media.
And their behaviour depends on whether they are a native species, such as the Seven-spot, or non-native Harlequin.
One of the many people responding to the ladybird movement on Twitter is Helen Roy, who runs the UK Ladybird Survey as a volunteer alongside Peter Brown but works as an ecologist at the Centre for Ecology and Hydrology in Oxfordshire.
"The Harlequin ladybird numbers are quite high this year," Helen told the BBC. "They built up in large numbers over summer, so we expected to see high numbers reported as they entered people's houses to spend the cold winter months."
Helen has been encouraging the UK public to record ladybird sightings and numbers for more than a decade and the survey, utilising online recording, Twitter (@UKLadybirds) and a smartphone app, has gathered more than 100,000 sightings from around 20,000 contributors which Helen was then able to share with many others and use in her research.
Abby Semple Skipper, an "informal" surveyor of ladybirds who reports south-west London sightings to Helen, said "last week was my first visit to Boxhill and I've never seen so many flying at once".
She added: "It seems a lot of people have been reporting similar sights but it will be interesting to see if there's been a major increase in estimated numbers. Last winter was so mild I wouldn't be surprised if there was a significant increase."
The inundation of ladybirds gained prominence on Saturday with a tweet from Lineker, host of Match Of The Day.
Cricket journalist Elizabeth Ammon pointed out to Lineker that the collective noun is a loveliness of ladybirds. However, as the former England striker was tweeting, several other public figures happened to notice encroaching ladybirds.
Sky presenter Nicole Holliday posted this image:
And actor-director Adam Lannon tweeted his own home invasion:
Among the many replies to Lineker's tweet were those worried by the news that ladybirds carry sexually-transmitted diseases, but Helen explained such fears were unfounded.
"All ladybirds carry parasites and diseases," she said. "They can't be transferred to humans, or in most cases even other beetles."
Bed for the winter
Across the weekend #ladybirds hashtag began to build up momentum and pictures of Seven-spotted and Harlequin varieties multiplied across social media.
"We encourage people to record their sightings and we don't recommend you kill them as they can be confused with native species," said Helen. "Brush them gently into a box and put them outside if they are in the way but otherwise leave them where they are.
"This time of year all ladybirds go into a dormant state and Harlequin ladybirds choose to go into buildings as their winter habitat. They particularly like pale buildings. Native species, such as the Seven-spot ladybird, tend to bed down in leaf litter, some species over winter in the stems of plants or behind bark."
Lancashire to London
By Monday, from Preston to Chiswick, there was no let-up in the numbers of congregating ladybirds.
"Attack of the #ladybirds," tweeted Dan Ibison from Preston Golf Club. "Never seen anything like this before."
"A plague of... #ladybirds?!" asked Chris Gutch, who filmed this at Chiswick House in West London.