Model Answer
0 min readIntroduction
Social behaviour, defined as interactions between individuals of the same species, is particularly well-developed in certain insect groups, notably Hymenoptera (bees, wasps, ants) and Isoptera (termites). Both Apis (honeybees) and termites exhibit highly complex social structures, often referred to as eusociality, characterized by cooperative brood care, overlapping generations within a colony, and a division of labour into reproductive and non-reproductive groups. However, despite convergent evolution towards eusociality, the underlying mechanisms and specific manifestations of social behaviour differ significantly between these two insect orders. Understanding these differences provides valuable insights into the evolution of sociality.
Social Behaviour in Apis (Honeybees)
Honeybees are renowned for their intricate social organization within a colony, typically consisting of a single queen, numerous worker bees (sterile females), and a smaller number of drones (males). The colony functions as a superorganism, with individuals working cohesively for the survival and reproduction of the entire group.
Caste System and Division of Labour
- Queen: Solely responsible for laying eggs, ensuring colony propagation.
- Workers: Perform a variety of tasks throughout their lifespan, including foraging for nectar and pollen, building and maintaining the honeycomb, caring for the brood, and defending the hive. Tasks are often age-related (temporal polyethism).
- Drones: Their primary function is to mate with the queen.
Communication
Honeybees employ a sophisticated communication system, most famously the “waggle dance,” discovered by Karl von Frisch (Nobel Prize, 1973). This dance conveys information about the direction and distance of food sources to other worker bees. Pheromones also play a crucial role in communication, regulating various aspects of colony life, including queen recognition and alarm signalling.
Foraging and Nest Building
Foraging is a highly coordinated activity, with scout bees locating resources and communicating their location to other workers. Nest building involves the construction of hexagonal wax cells, providing storage for honey and pollen, and serving as nurseries for developing larvae.
Social Behaviour in Termites
Termites also exhibit eusociality, but their social structure differs significantly from that of honeybees. Termite colonies are typically larger and more long-lived, and include distinct castes: king, queen, workers, soldiers, and reproductives (alates).
Caste System and Division of Labour
- King and Queen: The primary reproductive pair, responsible for producing all the offspring in the colony. Unlike honeybees, both king and queen remain reproductive throughout their lives.
- Workers: Perform tasks such as foraging, nest building, and brood care. They are typically both male and female.
- Soldiers: Defend the colony against predators and intruders, often possessing enlarged mandibles or specialized chemical defenses.
- Alates: Winged, reproductive individuals that disperse to establish new colonies.
Communication
Termite communication relies heavily on pheromones and tactile signals. They use pheromones to mark trails to food sources, regulate caste development, and coordinate defense. Tactile communication, such as antennal tapping, is also important for conveying information within the colony.
Foraging and Nest Building
Termites are primarily wood feeders, and their foraging activities can cause significant economic damage. They construct elaborate nests, often underground or within trees, using a mixture of soil, saliva, and fecal matter. Nest architecture varies greatly depending on the species.
Comparative Analysis: Apis vs. Termites
| Feature | Apis (Honeybees) | Termites |
|---|---|---|
| Haplodiploidy | Present (females develop from fertilized eggs, males from unfertilized eggs) | Absent (both sexes develop from fertilized eggs) |
| Caste Determination | Primarily genetic and nutritional factors | Primarily environmental factors (pheromones, nutrition) |
| Communication | Waggle dance, pheromones | Pheromones, tactile signals |
| Diet | Nectar and pollen | Wood (primarily) |
| Colony Size | Typically 20,000 - 60,000 individuals | Can range from a few hundred to several million individuals |
The differences in social behaviour between Apis and termites reflect their distinct evolutionary histories and ecological niches. Haplodiploidy in honeybees is thought to promote altruism, as sisters are more closely related to each other than to their own offspring. In termites, the absence of haplodiploidy suggests that other factors, such as kin selection and environmental influences, play a more significant role in the evolution of eusociality.
Conclusion
In conclusion, both Apis and termites demonstrate remarkable examples of eusociality, showcasing the power of cooperation and division of labour in insect societies. While both exhibit complex social structures, the underlying mechanisms and specific behaviours differ considerably. Honeybees rely on a genetically determined caste system and sophisticated communication through the waggle dance, while termites exhibit greater plasticity in caste determination and rely heavily on pheromonal communication. Studying these differences provides valuable insights into the diverse pathways through which sociality can evolve.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.