The concept of an insect “queen” is central to understanding eusociality, the highest level of animal social organization. A queen is the reproductive female within a colony of social insects, dedicated almost exclusively to laying eggs and ensuring population growth. She is typically the sole or primary egg-layer, distinguishing her from the sterile workers and soldiers that make up the vast majority of the colony. The queen’s presence maintains the colony’s social structure through reproductive division of labor.
The Hymenoptera: Queens in Ants, Bees, and Wasps
The majority of well-known queen-possessing insects belong to the order Hymenoptera (ants, bees, and wasps). In these species, the queen and female workers are diploid, developing from fertilized eggs, while males (drones) are haploid, developing from unfertilized eggs. This genetic system, called haplodiploidy, is thought to have contributed to the evolution of eusociality in this order.
Ant queens are known for their remarkable longevity, with some species living for decades. After her nuptial flight, the queen sheds her wings and uses stored sperm from that single mating event to fertilize eggs for the rest of her life. She is responsible for founding the colony alone and produces a massive variety of workers and soldiers over her long reign.
Honeybee queens operate on a system tied to colony reproduction through swarming. A colony maintains a single queen who can lay up to 1,500 eggs per day during peak season. When the colony becomes too large or the queen’s pheromone production wanes, workers rear a new queen, and the old queen leaves with a portion of the workers to found a new nest.
Many social wasps, such as yellow jackets and hornets, have an annual cycle where only the newly mated queen survives the winter. She begins a new nest alone in the spring, performing all initial foraging and building until the first generation of sterile workers emerges. Once the workers take over, the queen remains in the nest, focusing solely on egg production for the remainder of the short-lived colony season.
The Unique Eusocial System of Termites
Termites represent a separate evolutionary origin of eusociality, belonging to the order Blattodea (which includes cockroaches). Unlike the Hymenoptera, termite colonies feature both a king and a queen as the primary reproductive pair. Both the king and queen are diploid, and their workers are non-reproductive males and females.
The king and queen form a monogamous, often lifelong pairing. The king remains in the colony to repeatedly mate with the queen, which is necessary because she cannot store sperm for decades like ant and bee queens. A mature termite queen often develops a dramatically swollen abdomen, called physogastry, allowing her to reach an enormous size. This morphological change allows for massive increases in egg-laying capacity, with some queens producing up to 36,000 eggs per day.
Caste Determination: How Queens Develop
The path a female larva takes to become a reproductive queen instead of a sterile worker is determined by environmental factors, known as developmental polyphenism. In honeybees, this process is driven by nutrition. A female larva fed a continuous, large supply of the protein-rich glandular secretion called royal jelly develops into a queen, while larvae destined to become workers are quickly switched to a diet of pollen and honey.
In many ant species and termites, caste determination relies on pheromonal and social suppression rather than diet quantity. The presence of a healthy queen releases chemical signals that inhibit workers from raising new queens. If the queen is removed or dies, the absence of these inhibitory pheromones triggers workers to begin developing a new queen from a young female larva.
Specific hormones also play a role, with juvenile hormone (JH) levels being highly influential in the developmental switch. Higher levels of JH during a sensitive larval period promote the development of the reproductive queen phenotype. This ensures the female larva develops the necessary reproductive organs and specialized morphology required for a long life of egg-laying.
The Queen’s Primary Functions in the Colony
The mature queen’s foremost function is to serve as the colony’s sole reproductive engine. She is an egg-laying specialist, with some fecund queens producing millions of offspring over their lifespan. Her immense reproductive output is the driving force behind the colony’s growth and survival, constantly replacing short-lived workers.
A second major function is maintaining colony cohesion and controlling worker behavior through chemical signals known as pheromones. These complex chemical blends, such as the Queen Mandibular Pheromone (QMP) in honeybees, signal the queen’s fertility and presence throughout the nest. These pheromones suppress the development of worker ovaries, preventing them from laying eggs and maintaining the queen’s reproductive monopoly.
The queen’s long life is a third function, providing genetic stability to the colony over many seasons, contrasting sharply with the worker lifespan of weeks or months. Her presence also influences worker tasks, sometimes guiding foraging behavior or signaling the need for new construction through her chemical output. Ultimately, the queen acts as the colony’s central nervous system, using chemical communication to manage the entire social organism.