What do bees antenna do?

Honey bee antennae are highly functional, extremely sensitive, and vital sensory organs that help bees detect smells, tastes, sounds, and environmental conditions like humidity, temperature, CO2 levels, and even decode their hive mates waggle dances in the dark. They play crucial roles in foraging, communication, and mating, with male bees typically having longer antennae than females to better sense pheromones.

Highly Functional

Chemical Detection

Honey bee antennae are crucial for sensing chemicals in the environment. They contain receptors that help bees detect odors, which are essential for communication, foraging, and navigation. The antennae function similarly to a human nose, allowing bees to smell and identify various chemical signals.

Communication and Social Behavior

Antennae play a vital role in the social behavior of honey bees. In the dark of the hive they help bees interpret the waggle dances of their hive mates, which communicate the location of food sources. Bees adjust their antennae positions to decode these dances, integrating signals from their antennae with their sense of gravity to determine direction and distance.

Antennae Functions

• Smell: Antennae are equipped with receptors that detect chemical odors, helping bees locate flowers and food sources.
• Taste: The tips of the antennae have taste sensors that are more sensitive than those on their tongues.
• Touch: Mechanoreceptors on the antennae allow bees to sense texture and vibrations.
• Sound Detection: Bees can detect sound vibrations through their antennae, despite lacking traditional ears.
• Communication: Antennae facilitate communication among bees, especially during the waggle dance.

Extremely Sensitive

Honey bee antennae are complex sensory organs made up of three main parts:

• Scape: The first and largest segment, connecting the antenna to the head.
• Pedicel: The second segment, attached to the scape.
• Flagellum: The remaining segments that extend from the pedicel, forming the bulk of the antenna. These segments contain many types of Sensilla.

Locations of Sensilla

• Antennae: Main site for olfactory and gustatory sensilla.
• Mouthparts: Contains gustatory sensilla for taste detection.
• Forelegs: Houses various types of sensilla, including those for taste and touch.

Segment Differences

• Male bees have longer antennae with 13 segments.
• Female bees (workers) have shorter antennae with 12 segments.

Honey bees have specialized sensory structures called sensilla, which help them interact with their environment. Some specialized sensilla can pick up environmental status such as CO2, humidity and temperature. Functionally, sensilla are categorized as mechano -, chemo -, thermo -, or hygro-receptors. Sensilla are crucial for mating, foraging, recognition and communication between colony members through the sharing of pheromones. These sensilla can be classified based on their structure and function.

Trichoid                                                                                     Basiconic

Placoid                                                                               Coeloconic

Coelocapitular                                                            Ampulloid

Chaetica

Vital Sensory Organs – Pesticides and Acaricides

Pesticides, particularly neonicotinoids, can significantly affect the functioning of honey bee sensilla. Chronic exposure to these chemicals alters the bees’ ability to respond to olfactory cues. This impairment can lead to difficulties in locating food sources and communicating within the hive.

Mechanisms of Impact

• Direct Contact: Bees may experience immediate effects from pesticides through direct contact while foraging.
• Indirect Exposure: Pesticides can also be transported back to the hive via contaminated nectar or pollen, affecting the entire colony.

Symptoms of Pesticide Exposure

• Behavioral Changes: Bees may show reduced foraging efficiency and altered social interactions.
• Colony Health: Long-term exposure can lead to broader issues, including weakened colonies and increased susceptibility to diseases.

Acaricides are substances used to control mite infestations in honey bee colonies. They can be categorized into organic, soft, and chemical types.

Organic Acaricides

• Thyme Oil: Derived from thyme, it has natural insecticidal properties.
• Formic Acid: A naturally occurring acid that can penetrate the mite’s protective cuticle.
• Oxalic Acid: Found in many plants, it is effective against Varroa mites when applied in various forms.

Soft Acaricides

• Amitraz: A formamidine compound that is less toxic to bees and has a slower development of resistance.
• Coumaphos: An organophosphate that is effective but can have residual effects in hive products.
• Essential Oils: Various essential oils, such as those from mint or eucalyptus, can be used for their acaricidal properties.

Chemical Acaricides

• Fluvalinate: A synthetic pyrethroid that has been widely used but can lead to resistance in mite populations.
• Chlorfenvinphos: An organophosphate that is effective but poses risks of contamination in hive products.
• Benzyl Benzoate: Used for its effectiveness against mites but can have residual effects.

Numerous commercially available acaricides and their active substances have been shown to have negative effects on honey bee brood development, queen and drone reproductive health, learning, longevity and colony strength. Acaricides do not only act alone, but also in synergic combinations to affect bee health. Since some drugs cause substantial weakening of bee colonies, they can make them more susceptible to other diseases such as nosematosis or to extreme climatic events. As wax combs are contaminated with high concentrations of acaricide residues and Varroa mites are chronically exposed to them, the parasite may develop resistance faster. In combination with other stressors, acaricides could be a contributing factor to colony collapses.

While they are effective in managing pests, their impact on bee health, particularly on antennae and sensory structures, is a growing concern.

Effects on Antennae

• Sensory Function: Honey bee antennae are crucial for olfactory sensing, which helps bees locate food and communicate. Chemical acaricides can impair this sensory function.
• Structural Damage: Exposure to certain acaricides may lead to physical damage to the antennae, affecting their ability to detect pheromones and other environmental cues.

Effects on Sensilla

• Sensilla Types: Honey bee antennae contain various sensilla, which are hair-like structures that house sensory neurons. These sensilla are vital for detecting odors and pheromones.
• Chemical Exposure: Studies indicate that chemical acaricides can alter the morphology and functionality of these sensilla. This can lead to reduced olfactory sensitivity, impacting foraging behavior and colony communication.

Key Takeaways

• Chemical Exposure: Acaricides, whether organic or synthetic, can alter the chemical environment that bees rely on for communication.
• Pesticide Interactions: The combination of acaricides with other chemicals, such as fungicides and insecticides, has been shown to be particularly harmful. This can lead to impaired sensory responses in bees.
• Nurse Bees Vulnerability: Nurse bees, which are critical for colony health, may be especially affected by these chemicals, potentially disrupting their ability to respond to pheromones.

Referenced Materials

• Bee antennae offer links between the evolution of social behavior and communication
• Bees use antennae to decode hive mates’ dances
• The Antennae and their Sensilla
• Unlocking the Secrets of Bee Antennae: Function and Evolution
• Dynamic Range Compression in the Honey Bee Auditory System toward Waggle Dance Sounds
• Sensilla
• Trichoid sensilla on honey bee proboscises as inspiration for micro-viscometers
• Campaniform Sensilla
• Impact of Chronic Exposure to Two Neonicotinoids on Honey Bee Antennal Responses to Flower Volatiles and Pheromonal Compounds
• Structural and functional differences in the antennal olfactory system of worker honey bees of Apis mellifera and Apis cerana
• Olfactory subsystems in the honeybee: sensory supply and sex specificity
• Effect of Some Aromatic Oils and Chemical Acaricides on the Mechanical Defense Behavior of Honey Bees Against Varroa Invasion and Relationship with Sensation Responses
• Effects of synthetic and organic acaricides on honey bee health: A review
• Sustainable beekeeping: The impact of organic molecules on honey bee health and apiculture
• Synthetic and natural acaricides impair hygienic and foraging behaviors of honey bees
• Pesticides and adjuvants disrupt honey bee’s sense of smell