Black Garden Ant

Lasius niger — the black garden ant — is the MOST FAMILIAR ANT in European backyard gardens and one of about 100 species in genus Lasius (the common garden ants). The species is widespread across temperate Europe (where it is the dominant garden ant in most regions) and parts of Eurasia, with closely-related Lasius species across temperate North America. Workers are 3-5 mm long, dark brown to black, with the typical formicid body plan. The species' major biological feature in European cultural memory is the SYNCHRONIZED 'FLYING ANT DAY'. Black garden ant colonies produce reproductive 'ALATES' (winged mature reproductive ants — both winged males and winged virgin queens) over the course of late spring and early summer, but the alates DO NOT EMERGE INTO THE AIR until very specific weather conditions develop. Every July or August (the exact day varies by region and year), warm humid afternoon weather following rain triggers SYNCHRONOUS ALATE EMERGENCE — all the mature alates from black garden ant colonies across an ENTIRE REGION emerge SIMULTANEOUSLY into the air over the course of 1-3 hours. The synchronized emergence is one of the most-experienced cultural moments in European insect biology — across the UK, Germany, France, and other European countries, residents emerging from buildings on flying ant day find themselves in clouds of millions of flying ants, with the air filled with mating pairs, individual flying alates, and the post-flight discarded wings drifting down like snow. The synchronized emergence is called 'FLYING ANT DAY' (or 'Flugameisentag' in German) and is one of the most-recognized seasonal natural history events in European backyard ecology. The biological function: SYNCHRONIZATION provides PREDATOR SATIATION (when all the flying ants from a region emerge simultaneously, bird and arthropod predators cannot eat them all — most flying ants escape to mate and disperse) and MATE-FINDING EFFICIENCY (all reproductive ants are in the air at the same time, maximizing the probability that males and virgin queens encounter each other for mating). After mating in flight, MATED QUEENS land, shed their wings, and dig small underground chambers to begin founding new colonies; UNMATED WINGED ANTS are eaten by predators or die of exposure within hours-to-days. Black garden ant colonies are also a major NUISANCE PEST in European gardens and houses — workers forage for sweet foods (honeydew from sap-sucking insects, sugary food residue, fruits), and worker trails through gardens, kitchens, and pantries are a familiar summer annoyance for European residents. The species is harmless to humans (no significant sting — no formic acid spray ability since the species is in subfamily Formicinae which lost the ancestral sting and instead sprays formic acid; though the formic acid spray is quite mild compared to wood ant species). The species is featured in essentially every modern European backyard insect biology curriculum.