In honey bees a pheromone I-Keto decanoic acid secreted by:

Question

Accepted Answer

The correct option is 1:

The pheromone 9-Keto-2-decenoic acid (9-KDA), often referred to in older texts or simplified as I-Keto decanoic acid, is the single most important chemical signal in the honey bee colony. It is the primary, defining component of the Queen Mandibular Pheromone (QMP), an intricate blend of five compounds that collectively exert profound control over the social structure of the hive. The Queen is the exclusive source of 9-KDA, and it is secreted directly from a pair of highly developed exocrine glands located in her head: the **Mandibular glands**. This pheromone is distributed throughout the hive, primarily through worker bees that groom and feed the Queen, passing the chemical signal from bee to bee. The function of 9-KDA is multifaceted and crucial for the colony's stability. It acts as a primer pheromone, directly inhibiting the development of ovaries in worker bees, thus ensuring only the Queen can reproduce. It also serves as a cohesive signal, preventing workers from starting emergency queen cells, stabilizing swarms, and attracting drones during the Queen's mating flight. Its production is a key indicator of a healthy, fertile Queen.

The incorrect option is 2: Maxillary glands of worker bee

Worker bees possess a variety of exocrine glands, but their maxillary glands are not the source of 9-KDA. The function of the maxillary glands is primarily associated with the processing of food. While worker bees are responsible for many glandular secretions, such as the Hypopharyngeal gland's role in producing royal jelly or the Nasanov gland's role in orientation, the Mandibular glands of the Queen are specialized for the synthesis of the reproductive and social control pheromones. The maxillary glands are not known to produce any major sex or social primer pheromone. Therefore, associating 9-KDA production with the maxillary glands of a worker bee is anatomically and functionally incorrect.

The incorrect option is 3: Intestinal gland of queen bee

This option incorrectly attributes the source of 9-KDA to an internal organ related to digestion and excretion. Glands associated with the intestine, such as the digestive or midgut glands, are responsible for enzyme secretion and nutrient absorption, not the synthesis and external release of volatile chemical signals like pheromones. Pheromones in insects are typically secreted by specialized epidermal or exocrine glands that are directly connected to the surface of the bee's body or mouthparts, allowing the compounds to be easily collected and dispersed by other colony members. The intestinal gland is entirely unrelated to the chemical communication system that maintains the honey bee society.

The incorrect option is 4: Mandibular gland of male bee

Male honey bees, known as drones, do not produce the Queen Mandibular Pheromone. Drones have a sole biological purpose: to mate with the Queen. Consequently, their gland structure is vastly simpler and lacks the complex exocrine machinery necessary for synthesizing compounds like 9-KDA. This pheromone is specifically a reproductive signal produced by the reproductive female (the Queen) to govern the colony's behavior and control the reproductive physiology of the sterile females (the workers). The mandibular glands of a male bee, even if they were present in a developed form, would not be the source of a female-specific pheromone.