Overwintering-pest
Guides
Muscina pascuorum
Pasture Fly, European Scavenger Fly
Muscina pascuorum is a muscid fly native to Europe that has become established across North America. The species is closely allied to M. stabulans and M. levida. It is known to enter homes in autumn and winter, where adults accumulate on windowsills. Larvae develop in fungi, particularly woodland mushrooms, rather than in carrion or manure like many related muscids. The specific epithet 'pascuorum' refers to pastures, reflecting its original European habitat association.
Padaeus trivittatus
boxelder bug
Padaeus trivittatus, commonly known as the boxelder bug, is a true bug in the family Pentatomidae. Adults and nymphs feed primarily on seeds of boxelder, maples, and ash trees. The species is notable for aggregating in large numbers on sunny building exteriors in autumn and seeking winter shelter in homes and structures. It completes one to three generations per year depending on geographic location. Despite its nuisance status as a home invader, it does not bite, sting, or reproduce indoors.
Pollenia labialis
cluster fly
Pollenia labialis is a species of cluster fly in the family Polleniidae. It is one of several Pollenia species introduced to North America from Europe, likely arriving in the 1950s or 1960s. Like other cluster flies, it is associated with earthworms as larval hosts. The species is distinguished from congeners by microscopic characters including the number, position, and length of setae on various body parts. It is considered a nuisance pest when adults enter buildings to overwinter.
Pollenia rudis
common cluster fly, attic fly, loft fly, buckwheat fly
Pollenia rudis, the common cluster fly, is a medium-sized blow fly in the family Polleniidae. Adults are notable nuisance pests of buildings, overwintering in attics and wall voids in large aggregations during cold months. The species is an obligate parasite of earthworms in its larval stages, with well-documented host specificity to certain lumbricid species. Native to Europe, it has been introduced to North America and New Zealand, where it occurs wherever its earthworm hosts are present.
Pollenia vagabunda
cluster fly
Pollenia vagabunda is a cluster fly in the family Polleniidae, widespread across Europe and introduced to North America, where it was first recorded in 1958. Unlike carrion-associated blow flies, this species has a life cycle tied to earthworms and other hosts rather than decomposition. Adults are known to overwinter in buildings and have been documented on carrion, though not tied to specific decomposition stages. The species has also been recorded in Algeria and shows potential forensic relevance.