Allison Huddleston | May 18, 2026

We’ve all seen it happen: your roommate, your parent, or your child goes off into the world, they contract a case of the sniffles, and bring it home… then, the rest of your household gets the same illness. Fortunately, taking measures like getting vaccinated, masking, and washing our hands can help reduce the spread of disease as we socialize in our communities. For insects, who can’t wear a face mask or get a flu shot, living in a social group has both costs and benefits for survival. It’s easier to efficiently collect food and care for offspring, but living in close quarters means that disease can spread more easily between individuals (Fig. 1).

Figure 1. Pathogens are on the attack for the highly social honey bee! (Photo by Allison Huddleston, modified using Canva)

Furthermore, social units are often closely related, which makes it even easier for a susceptible family to contract the same infections. Social living is common in insects including termites, ants, and some bees, but disease and parasite infections are also very common [1]. So, how do bees prevent parasites and pathogens from taking over? Thankfully, they have social strategies to prevent illness.

A fascinating kind of defense that is common for insect colonies is called “social immunity” [2]. We may typically think of immunity as a personal, individual defense against disease. Social immunity is unique because it requires a collective response from many members of the social unit to function. In human society, vaccination works this way – effective disease prevention requires that the majority of people get vaccinated to protect the entire group. Several examples of social immunity can be found in honey bees, which display behaviors such as a “social fever” and communal hygienic behavior.

Honey bees and social fever:

One instance of social immunity occurs when honey bees respond to a heat-sensitive pathogen by generating a fever in response to certain pathogens [3]. Immature eggs, larvae, and pupae develop in a special “nursery” region of the hive called “brood.” Adult bees can generate heat when a large group of individual bees all vibrate their wing muscles. They regularly use this ability to moderate the temperature of the brood nest, but it can be amplified to create extra warmth, hence the “social” aspect of the fever.

Honey bee brood is often targeted by pathogens like the fungal infection known as chalkbrood (Ascosphaera apis). Chalkbrood gets its name from the dry, chalky appearance of “mummies,” which are corpses of larvae that have died from the fungus (Fig. 2). Researchers have found that honey bees generate this fever response when they detect chalkbrood infection and that the fever occurs in the early stages of an infection before larvae start to die [3]. Chalkbrood fungus is heat sensitive, so heating up the brood nest before the infection progresses may act as a preventative form of social immunity.

Figure 2. This honey bee colony has many chalkbrood “mummies” at the entrance to the hive (Photo by Jeff Pettis via Bugwood.org).

Honey bee hygiene:

Another form of social immunity in honey bees is known as hygienic behavior. Hygienic behavior is where adult bees are able to detect parasite infestation in brood and remove it [4]. Eliminating disease as it develops in brood is an effective way for bees to slow down the spread of pathogens within their colony; given that one hive can hold 50,000 or more individual bees [5], this task requires the collective effort of the hive to detect, clean out, and repair infested brood cells.

Researchers are eager to understand hygienic behavior, because it may serve as the basis for breeding disease resistant honey bees. Like other agricultural animals that are kept in large numbers, honey bees are prone to disease infections, but they can also be bred to display particular traits that benefit their health. Varroa sensitive hygiene (VSH) is one such trait. The Varroa destructor mite (Fig. 3) is a large threat to honey bee health because it is a vector for several lethal honey bee viruses. Varroa mites reproduce in brood cells, and honey bees with the VSH trait are able to detect and remove parasitized brood to protect the overall health of the colony [4]. Research on VSH as a tool for bee health is especially important as mites become increasingly resistant to common chemical treatments [6].

Figure 3. A honey bee pupa has a Varroa mite attached to the underside of its abdomen (Photo by Denis Anderson via CSIRO).

So no, bees don’t wash their hands. However, they do have a fascinating diversity of behaviors that provide immune protection for individuals and for the entire social unit. Studying honey bees provides a unique system that can help us to understand the social components of disease transmission and immune defense in other organisms. Ultimately, the management of potential future epidemics in humans and agricultural animals may improve with insights gained from social insects.

References:

[1] Schmid-Hempel, P. Parasites in Social Insects. Princeton University Press (1998).

[2] Cremer, S., Armitage, S., and P. Schmid-Hempel. Social Immunity. Current Biology 17(16): 693–702 (2007).

[3] Starks, P.T., Blackie, C., and T. Seeley. Fever in honeybee colonies. The Science of Nature 87: 229–231 (2000).

[4] Spivak, M. and Danka, R. Perspectives on hygienic behavior in Apis mellifera and other social insects. Apidologie 52: 1-16 (2021).

[5] The Wildlife Trusts. Honey bee. (n.d.)

[6] Lester, P. Integrated resistance management for acaricide use on Varroa destructor. Frontiers in Bee Science 1:1297326 (2023).