Learn Biology Through Bees

A collection of the more-scientific content, presented in order of publication.

Sex-Based Differences in Bees

Did you know that ~20% of males in the solitary bee genus Megachile (“leafcutter bees”) have modified forelegs that serve as pheromone-secreting glands for attracting a female, or that male longhorn bees have antennae that exceed their body lengths? Well, you do now. Honey bee biology is a mature field and well documented, it is the solitary bees that surprise …

What Traits Do Queen Breeders Want?

While researching how honey bees learn to forage I came across a paper titled “Beekeepers’ preferences for honeybee breeding goals: a French case study” and found it to be a far more interesting rabbit hole (beeline? Beehive?). How do the breeding goals of French beekeepers compare to the rest of the region, and the rest of the world? It won’t …

The Evolution of Pollen Transport in Bees

With the first plants came the first plant-feeding insects, some 300 million years ago in the Carboniferous period. Later emergents were the flowering plants of the late Cretaceous, which had increased angiosperm diversity (“flowering plants”), displacing the then-dominant conifers, ferns, cycads and the long-extinct bennettiales. A caveat here is the fossil record itself, as there few samples if early fossilised …

How Did Bees Go from Solitary to Social Living?

The first bees were solitary and many species continue living these lifestyles, so how did honey bees grow so large? The development into group living, task allocations, reproductive priorities and even a simple “mummy said we should share” was built through trial and errors. How did these Hymenopterans go from a solitary lifestyle like that of the blue banded bee, …

Honey Bee Immunity at the Colony Level

A honey bee colony’s immunity goes beyond combining the immune system of multiple individuals. When a hive exceeds the population threshold of “many bees nesting together” it creates a non-linear effect as the resulting entity is not “XYZ bees working together”, rather a “superorganism”. A worker insect can survive on its own. When joined with other workers, it becomes part …

Honey Bee Immunity at the Individual Level

Insects lack an “adaptive” immune system. They don’t have the long-lived B- & T- cells that target specific pathogens and remember infections for future encounters. Their primary approaches involve encapsulation of bacteria and parasites, along with an antimicrobial peptide-driven response. Paternal genetics, hormones, nutrition, microbiota and age indirectly influence this process, either enhancing or hindering it depending on the creature’s …

Honey Bees as Test Subjects: Behavioural & Cognitive Research

Broadly, experiments with bees as subjects are for assessing learning & memory, decision making, orientation and navigation, social behaviour, social communication, stress and motivation, motor-sensory coordination tasks, amongst others. This article will give an overview of the experiments used in honey bee research beyond the more-general molecular methods like PCR, imaging & -omic based studies. First, a definition: behavioural and …

Addressing Deficiencies in Commercial Bee Feeds

Honey bees are generalist foragers, meaning their diet consists of a variety of nutrients and microbials. Bees also feed one another trophallaxicaly (“mouth to mouth”), resulting in further chemical and microbial processing of the foraged food. In times of dearths, there is a shortage of nectar and/or pollen, so bees utilise their hive stores to continue colony operations. If this …

Sex Determination in Honey Bees

A summary on how sex is determined in an egg of the honey bee Apis mellifera
Male drones are produced when a queen lays unfertilized eggs, whereas the female workers come from fertilized eggs. It’s not the presence of a sperm alone that produces workers, for Cape honey bees (A.mellifera capensis) workers can lay unfertilized eggs that develop into female workers without mating, so what is determining the bees’ sex? Early studies found the gene csd …

Honey Bee Drone Development and Reproduction

Apis mellifera drones take 24 days to emerge from the cell. They spend the next 8-12 days maturing in preparation for mating with a virgin queen. Once mated, the drone dies and provides the queen with a modest amount of sperm that’ll eventually fertilize an egg and produce worker (or queen) bees. If the sperm is “good” (as defined by …

How Honey Bees Use Propolis

Propolis is a combination of plant resins and wax used by worker bees inside the hive to mend cracks and defects, preserve the dead, and sticking frames together to annoy beekeepers. Foragers collect resin from wounded trees or new leaf buds and carry it in their corbiculae (the hind leg baskets) back to the colony for further processing. Inside the …

Jelly Production in Honey Bees

Worker bees secrete “jelly” from the hypopharyngeal glands located in their heads. Royal jelly is fed to all brood in the first few days after hatching, and then exclusively to queen larva throughout their larval stage and much of her adult life. Another secretion is “worker” jelly, which was identified as a less-nutritious (but still very good) food given to …

Factors Influencing Queen Bee Health

Diet, genetics and hive environment are what most beekeepers think of when assessing queen health, and fair enough, these are 80% of it. The other 20% is in factors like mating success, internal hive environment and hormonal profile (amongst others). In the larval stage, nutrition heavily influences the adult queen’s characteristics- think size, weight, ovariole development. In the adult stage, …

Thermoregulation in A. mellifera Subspecies

Variations in temperature control within Apis mellifera subspecies arose in response to their local climate. They still belong under the umbrella term of “A. mellifera: the Western/European honey bee”, and have received more precise classification on the basis of their habits, environment, and/or beehaviour. For example, honey bees adapted to the Arabian deserts (e.g. A.m. jemenica) have better heat tolerance …

Temperature Limits of Honey Bees

Apis mellifera aims to maintains a stable colony temperature of ~36°C during environmental extremes. In hot weather, worker bees fan their wings, beard outside the hive and spread water over frames, or huddle into a ball and shiver to maintain warmth during a cold cluster. A consistent temperature is necessary for optimal brood rearing – too hot and they die, …

How Bees Digest Pollen

Apis mellifera uses pollen as their primary source of proteins, fats, vitamins, and minerals (honourable mention to the starches). Pollen consumption contributes to development, brood rearing, and maintaining overall colony health. However, the grains are well-protected by tough outer walls (“exines”) that resist degradation​. Over evolutionary time, honey bees developed specialised techniques to access the nutrients inside: nectar rehydration to …

The Superorganism Model of Social Insects

The superorganism model describes how social insects like bees, ants, wasps and termites behave as single, coordinated parts within a whole (the colony). Each part (or worker) partakes in division of labour, communication, and decision-making processing analogous to the cells of our body. Our cells are too specialised to survive on their own. When sufficient groups of cells get together, …

Varroa-Sensitive Hygiene & The Basis of Natural Resistance

Hygiene is defined as the removal of dead or injured brood to defend against diseases and parasites of the colony. Varroa-Sensitive Hygiene (VSH) is the selective breeding of bees with the ability to self-manage Varroa destructor and is a work in progress. VSH honey bees are more likely to detect and remove mite-infested pupae in capped brood than unspecialised colonies. …

How Do Worker Bees Know Their Role?

Internal (hormones, genetics) and external (hive environment) influence a worker bee’s role in the colony. After all, how does a nurse bee know when it’s time to stop brood rearing and begin building comb? Bees are not “conscious” in the human sense – they do not suddenly change their mind without a signal or cue. Temporal polyethism is defined as …

Absconding Colonies: Survival Outside the Hive

This is a followup investigation to my winter hive deaths. My three colonies are no more, having absconded from severe Varroa infestation. Absconding is when the colony quietly leaves the hive in search of a new home. It is not acontrolled process like swarming, where a new queen is formed and around half the colony leaves with the mother queen. …

Honey Bee Ancestry: Descended from Wasps?

Reader John asked this in response to bees eating their larvae. From a human perspective, bees are not “vegetarian”. Indeed, diseased and weak young larvae is eaten to recycle nutrients and prevent the infection of other brood cells. Before there were bees, there were wasps, and before there were wasps, there were predatory insects. Bees are one branch of the …

How Honey Bees Defend Themselves

Asian honey bees (Apis cerana) bee ball hornets to death. Giant honey bees (Apis dorsata) deter predators by synchronised shimmering atop their open combs, whereas the dwarf honey bees (Apis florea) abandon their nest and reform elsewhere in response to predation. Social insects like honey bees have multiple defences against predators, ranging from the physical (bites, stings), psychological (shimmering, faeces …

Biology of a Drone Congregation Area

The male honey bee is known for his role in reproduction and not much else. Ejaculate in the queen, rupture your abdomen, die a few moments later. This is an oversimplification, for drones produce pheromones for communication, and (perhaps) assist with hive heating during low temperatures. Sexually-mature drones cluster in the sky, forming “drone congregation areas” to await the arrival …

Signals and Cues in Honey Bee Communication

Signals are a form of communication that directly alter the behaviour of the receiver, whereas a cue is a feature of the environment that guides an organism’s behaviour. In the honey bee colony, signals range from the waggle dance to pheromones, whereas cues are more complex. An example cue is that the more rejections a water-foraging bee gets from the …

Pheromones in Honey Bees & Their Functions

Honey bee have two forms of communication: mechanical and chemical. The former includes “piping”, buzzing and waggle dancing. The latter relates to pheromones released by the brood and adult bees, and will be examined here. By definition, pheromones are signalling chemicals released by an animal (e.g. queen) to control the behaviour of other animals in the vicinity (e.g. workers and …

Laying Workers, Worker Policing & Worker Relatedness

Pedigree of worker bee relatedness
Workers laying eggs could either be due to queen failure, random genetic mutations or a recent swarm. The foremost sign of a laying worker is the presence of multiple scattered eggs per cell, as their abdomens are too short to reach the bottom. If these eggs develop, they will emerge into male drones, as workers lay unfertilized eggs. Under normal …

Bees as Pests: Cape Honey Bee

A dark honey bee in a colony of lighter ones
The South African Cape honey bee, Apis mellifera capensis is a social parasite of the African (“Savannah”) honey bee Apis mellifera scutellata. A.m. capensis workers can activate their ovaries within queenright colonies and start laying diploid eggs, maturing into other laying workers (a process termed “thelytokous parthenogenesis”). These bees are genetically identical clones of their mothers, and within parasitised colonies, …

Honey Bee Predators

Animals consume bees for the brood or adults (most birds, insects) or hive stores (Mammals and some birds). Insects are the first predators that come to mind, either parasitising their host with eggs or consuming them completely. Then come the spiders, birds, reptiles, mammals… the list goes on. The honey bee colony is a source of high nutrition for predatory …

How do Bees Pollinate Apple Trees?

Self-pollination is when the pollen from the anthers (male reproductive part) is deposited into the stigma (female reproductive part) from flowers of the same plant. Apples require cross-pollination, which transfers pollen from one tree (e.g. Crabapples) to the stigma of another apple tree of the same species (e.g. Granny Smith). Insect-mediated pollination is a form of cross-pollination where pollen from …

Are Honey Bees Evolving?

“Are honey bees still evolving, or is this it for them?” Asked an attendee at my beekeeper’s club. “Bees evolved to live in trees and now we use selective breeding to requeen our hives, is this the end of their evolution?”. I forgot the presenter’s response, as I was thinking about my own answer for this topic. In short, honey …

When Honey Bees Eat Larvae

From Posada-Florez etr al., 2021 - canniblisation - bees eat the soft parts and discard the chitin outside the hive
Considering that honey bees are descended from wasps, it’s no surprise they can consume animal tissue. Within the colony, cannibalism is a response to environmental stressors where there is a shortage of proteins (pollen). Apis mellifera workers consume younger larvae (<3 days of age) for proteins, generally sparing the older larvae (>3 days of age) who have had more resources …

What Do Bees Do With Their Dead?

Bring out your dead… Undertaker bees are middle-aged workers who specialize in adult corpse removal to prevent pathogen buildup. This behaviour is triggered by a reduction of cuticular hydrocarbon emissions, as a result of decreasing body temperature from the deceased. For dead brood, odour cues (β-ocimene and oleic acid) are used to determine if the larva or pupa should be …

Routes of Transmission: Deformed Wing Virus

Your hives are already infected with Deformed Wing Virus (“DWV”). Low levels of DWV are naturally found in honey bees, and rarely (if ever) cause issues. However, when a colony is infested with mites, symptoms frequently emerge. Mites are vectors, carrying viruses in their bodies and injecting them into bees as they feed on the pupae. DWV infections are fatal …

Health & Honey Bee Gut Bacteria

Gut bacteria distribution, from Raymann & Moran, 2018
Much like our own microbiome, except far simpler, the honey bee gut microbiota is involved in metabolism and immune stimulation. When the gut microbiome is disrupted through antibiotic treatments, pesticide exposure or poor nutrition, it usually leads to increased colony adverse effects. In the healthy colony, there is a core group of 5 bacterial phylotypes (“group similarities”), each having their …

Why is European Foulbrood Treatable?

EFB with arrows - emphaiss mine image from https://www.ontario.ca/page/european-foulbrood
European foulbrood (“EFB”) is a treatable condition as the bacterium Melissococcus plutonius does not form spores like Paenibacillus larvae, the agent of American foulbrood. To confirm EFB diagnosis, samples can be sent to a laboratory for cell culture and microscopy testing, or through field test kits. EFB on comb. note the grey, dead larvae. Emphasis mine. Image from https://www.ontario.ca/page/european-foulbrood Larvae …

Chalkbrood-Infected Larvae

honey bee on leaf
Mummified larvae were the first sign of something wrong. My hive was only months old when it started placing little white-black bricks at the hive entrance. I didn’t know much at the time, so I panicked. What was going on? Chalkbrood is caused by the fungus Ascosphaera apis. The fungal spores consume the bodies of young larvae, leaving the cadaver …

When Robber Bees Attack a Swarm

I started 2024 with a swarm. I walked in the mid-morning sun, hearing the buzzes of the garden. I….Wait… why are getting louder? and why are so many bees flying around aimlessly? Turns out a clump of bees landed on the bottlebrush tree Melaleuca citrina – it was time to deal with a honey bee swarm. Fortunately, it was a …

Science Gone Wrong: Africanised Honey Bees

map showing the introduction of african queens and later spread of africanized bees
Africanised honey bees are the result of crossbreeding between an African honey bee (Apis mellifera scutellata) and various European subspecies (such as Apis mellifera ligustica and Apis mellifera carnica). Scientists intended to breed a honey bee better adapted to tropical conditions, as the European honey bee colonies were poor honey producers and only survived under intensive management. Due to their …

Honey Bees’ Life Cycle: From Egg to Eclosion

Honey comb showing pupa with darkened eyes
Bees are holometabolous insects (undergo a change of form via complete metamorphosis) with four distinct developmental stages: egg, larva, pupa and adult bee. There are caste-specific variations in honey bees, based on diet, wax cell size or the duration from egg to adult, as summarised in the table below. StageDrone (Male)QueenWorker (Female)EggLaid in larger cells. Unfertilized. Develops for about 3 …

Flumethrin for Varroa

For readers in Australia, Varroa mites is slowing spreading from New South Wales and into the remaining states. As of writing, surveillance teams have been deployed with sticky mats and flumethrin for Varroa screening. Yours truly recently had a check for Varroa via the sticky mat test, and the results came back positive – mites detected. It is November, the …

Apis dorsata: the “Giant” Honey Bee

3x apis dorsata bivouacking colonies at a mango orchard in Northern Thailand. Emphasis my own; image credits Robinson 2021
The giant honey bee Apis dorsata is native to south- and south-east Asia. Known for building large, exposed combs, A. dorsata colonies have seasonal migration patterns, moving from areas of low to high forage availability. In their native range, they are pollinators of wild plants and local agricultural crops, as well as a major source of wild honey for local …

Requeening a Hive

Queen cage containing the queen and her attendees
Requeening a hive is a standard beekeeping practice that replaces an old queen with a newly-mated one. An “introduction cage” containing the queen and several worker bees is the most common method, with a direct release of Her Majesty into a queenless hive being less frequently used. Queen replacements are done every 1-2 years during the spring and summer to …

What do Bees do with Water?

On hot days, worker bees will collect water to spread throughout the hive. The bees fan their wings to evaporate this water and cool the colony. This is one use of the water, Bees however, use water for many other purposes, as in humidity & temperature control (both the individual bee and colony), digestion and larval care (i.e. production of …

Why Do Bees Buzz?

The buzzing sound of bees is generated by their wings and flight muscles. This movement of air generates an audible buzz as the wings vibrate rapidly following contraction by the thorax’s indirect flight muscles. Buzzing serves a variety of purposes including pollination, communication and defence. Elaborating on the function of the wings covered in the bee thorax, this article exams …

Head of a Bee

For beekeepers, the honey bee’s head is about vision and perception, containing organs for vision, smell, touch, and ingestion (proboscis & mandibles), and housing the brain that coordinates behaviour. Worker bees have the hypopharyngeal gland for making royal jelly, drones have larger eyes & brains dedicated to mating flights and spotting the virgin queen during said flight. The head of …

Thorax of a Bee

The thorax contains structures essential for locomotion and respiration, namely the six legs, the four wings, flight muscles and (part of) the tracheae. It is divided into three segments, each associated with a pair of legs: prothorax (closer to the head), mesothorax (middle), and metathorax (closer to the abdomen). A wing pair is located on the mesothorax and metathorax, and …

Honey Bee Stomach

Honey bee on a mullberry leaf
In the anatomy of bees, the abdomen is the “soft posterior” section, containing the striped pattern that gives it its characteristic appearance. Within it are the wax glands, for beeswax production, and the Nasonov glands, for communication, amongst others. The bee abdomen is also used for navigation, digestion and reproduction. In the female bees, it is tapered at the end …

The Anatomy of Bees

Bees have three body segments: the head, thorax and abdomen. The head contains the eyes, the mouthparts, antennae and brain, the thorax contains the muscles: insect legs, insect wings and their respiratory system. Everything else is in the abdomen – the honey stomach, the digestive system (and in bees & wasps: the stinger). These features are general and are largely …

The Giant Asian Hornet

Japanese beehive design effectively dettering the Asian Giant Hornets, from https://www.youtube.com/watch?v=onq9ixC7OEg
A native hornet to Asia, the Giant Asian Hornet is the world’s largest hornet species, with workers reaching 45–55 mm long and a wingspans of ~75 mm. This also makes it the largest insect predator of honey bee colonies, killing adult bees and feeding on their larvae. For those Asian beekeepers unlucky enough to sight them, there are several hive …

Altered Brood Pattern & Sacbrood Virus

Sacbrood virus causes the skin of infected larvae to form into a bulging “sac” of fluid, filled with viral particles (not to be confused with “sack” [English is difficult]). This is a minor brood disease that honey bees can clear on their own with good hygiene. The beekeeper assists by removing infected brood cells and minimizing stress from honey bee …

American Foulbrood: Pathology, Biology & Beekeeper-do-this-ology

The most serious of the honey bee diseases, American foulbrood (AFB) is a bacterial disease that infects brood. Forager (or robber) bees contract the disease from the environment (or infected hives), whereby they return the contaminated nectar and/or honey back to their hive for processing. As nurse bees feed young larvae, they introduce the AFB bacterial spores into the larval …

How Do Neonicotinoids Affect Bees?

worker bee gathering pollen from sunflower
Neonicotinoid insecticides are are synthetic compounds modelled after the natural plant-based pesticide nicotine and are systemically distributed throughout the plant tissue (including its nectar and/or pollen) when applied as a seed coating. These agricultural chemicals work by binding to the nicotinic acetylcholine receptors (AChR for short) in the insect nervous system, leading to death by overstimulation. This widespread distribution makes …

Does Roundup Kill Bees?

Glyphosate-based herbicides like the Roundup products have been investigated for a variety of health and ecological reasons. Despite the differences in glyphosate pesticide formulations, studies show that this active ingredient has lethal and sublethal effects on exposed bees. Readers familiar with the effects of herbicides and fungicides on bees know that extensive exposure to agrichemical products can affect bees at …

Bees, Herbicides and Fungicides

When discussing chemical use in residential and agricultural settings, insecticides are quickly blamed due to their harmful impacts on bees. However, Insecticides are just one element within the “pesticide” category, with other components being fungicides and herbicides. Pesticides are blamed for killing beneficial insects and contributing to the colony collapse phenomenon. The issues with herbicides and fungicides is that they …

How do Pesticides Affect Honey Bees?

The many ways honey bees can get exposed to pesticides
Pesticides (insecticides, herbicides and fungicides) are chemicals used for pest control in residential and commercial environments. Not all pesticides kill bees instantly, and many have delayed sub-lethal effects that appear when a critical threshold is reached. Broadly, the effects of pesticides are based on their impact on brood, adult bees, or both life stages. These chemicals may be deliberately introduced …

Honey Bee Mites

A Varroa destructor protein atlas reveals molecular underpinnings of developmental transitions and sexual differentiation - McAfee et al., 2017
Varroa mites are the biggest threat to bee populations worldwide. Mites feed on the haemolymph (bee blood) fat body tissue of developing bee larva (& adult bees; see Ramsey et al., 2019), weakening them and infecting them with pathogens during the feeding process. The emerging adult bee exhibits stunned growth, body deformation and a shortened lifespan. Severe infestation can lead …

Are Honey Bees Invasive?

The many types of wild bees. Photo credit https://www.treehugger.com/how-identify-different-types-bees-4864333
The short answer is yes, for the majority of the new world (Americas/Australasia), honey bees are invasive. HOWEVER! there is a distinction between “invasive” and “introduced”; A species is introduced when humans transport it outside its native range. It is considered invasive when/if it causes significant harm (ecological or economic) in its new environment. A species like the European honey …

The Natural Beehive

There are two definitions to the term “natural beehive”: As a reference to “Natural Beekeeping”, the practice that involves using hive styles and management methods mimicking the nesting conditions of bees in nature, as in top bar hives. As a standalone definition, “Natural Beehives” refer to the suitable locations a swarm seeks when scouting for a new hive. This is …

Raising Queen Bees

Queen Bee on the fence
The queen bee caste is present in social bees (and most social insects), like the honey bee Apis mellifera and the bumble bees (Bombus spp.). Her Majesty’s primary purpose is to lay eggs and maintain colony cohesion through pheromones. Genetically, the bee queen is no different from her sister worker bees. She appears different because of being fed a royal …

The Scientific Name of Bees

In commonspeak, the word “bees”, refers to “honey” bees 90% of the time, bumble bees 9.9% of the time, and solitary bees 0.1% of the time (if you’re lucky). The European Honey Bees Apis mellifera (A. mellifera; also referred to as the “Western Honey Bee”) has the Latin genus name, “Apis” for “bee”, and species name, “mellifera“, for “honey bearing“. …