Social Behaviour of Insects - Archit [email protected]

SOCIAL BEHAVIOUR OF INSECTS

1. SOCIAL BEHAVIOR OF INSECTS ARCHIT KUMAR SINGH MSc. ZOOLOGY [I] - 2204634

2. INTRODUCTION Social behavior refers to the actions and interactions among individuals within a social group or society. It includes all forms of communication, cooperation, conflict, and competition that occur between individuals or groups Social behavior of insects has been a topic of interest for scientists for decades. Insects are known to exhibit various forms of social behavior, ranging from simple cooperation to complex societies. Understanding the social behavior of insects is important not only for scientific purposes but also for practical applications such as pest control and agriculture.

3. Common Behaviour in insects Insects are incredibly diverse and exhibit a wide range of social behaviors, depending on the species. Here are a few examples of different types of social behavior in insects: Solitary behavior : Some insects, such as dragonflies and grasshoppers, are typically solitary and do not live in groups. Aggregating behavior : Many insects, such as ladybugs and aphids, aggregate in large groups for protection or to mate. Territorial behavior : Some insects, such as wasps and bees, defend a territory around their nest or hive. Eusocial behavior : Certain insects, such as ants, bees, and termites, have highly organized societies with distinct castes (e.g., workers, soldiers, queens) and cooperative brood care.

4. Cooperative hunting : Some insects, such as certain species of ants, engage in cooperative hunting and foraging where they work together to subdue and kill larger prey than they could individually. Trophallaxis : This is a behavior where insects exchange food and other fluids with each other. It is common in social insects such as ants, bees, and termites, where workers and other colony members regurgitate and share food with each other. Altruism : Many social insects exhibit altruistic behavior, where individuals may sacrifice their own well-being for the benefit of the colony. For example, worker bees will defend their hive and sacrifice themselves to protect the queen and the rest of the colony. Division of labor : Social insects often have specialized roles within the colony, such as foragers, builders, nurses, and soldiers. This division of labor allows for more efficient use of resources and better survival of the colony as a whole Nest construction : Many social insects, such as bees and termites, are highly skilled at building complex structures such as hives, nests, and mounds. These structures often serve as protection for the colony, and may include features such as ventilation systems, nursery chambers, and storage areas.

5. Kin recognition : In many social insects, individuals can recognize and distinguish between kin and non-kin. This can influence behaviors such as feeding, grooming, and aggression, and can help ensure that resources are allocated to related individuals. Swarm intelligence : Some insects, such as locusts and bees, can exhibit swarm intelligence, where large groups of individuals work together to make collective decisions. This can lead to emergent behaviors such as coordinated movement, efficient foraging, and even complex problem solving. Trail marking : Some social insects, such as ants, use chemical signals to mark trails between food sources and their nests. This allows other colony members to easily find and follow the trail, increasing the efficiency of foraging and resource gathering. Nest relocation : In response to environmental changes such as temperature or resource availability, social insects may relocate their nests or colonies to a new location. This can involve a coordinated effort by colony members to move eggs, larvae, and other nest materials to the new location. Hibernation : Insects such as bees and bumblebees may enter a state of hibernation during the winter months , where they reduce their metabolic rate and wait out the cold weather in a sheltered location. This can be a critical survival strategy in areas with harsh winters.

6. Polygyny : Some insect societies, such as certain species of ants, allow for multiple queens to coexist within a single colony. This can increase the reproductive outpu t of the colony and improve its survival chances. Parasitism : Some insects, such as cuckoo bees and wasps, have evolved to parasitize the nests of other social insects. They may lay their eggs in the host nest or kill the host's young in order to take over the nest. Superorganisms : Some social insect colonies, such as those of ants and termites, can be considered "superorganisms" because of their high level of organization and cooperation. In these colonies, individual ants or termites are like cells in a larger organism, working together to ensure the survival and success of the colony as a whole.

7. In nature no individual animal can live in isolation. Groups of individuals of the same species- Aggregation Aggregations are of 2 types:- SOCIAL ORGANIZATION

8. A group of individuals belonging to the same species and organised in a co-operative manner-Social Organisation Altruism :-Any behaviour that results in an increase in the fitness of another individual at the expense of one’s own fitness. Social Behaviour :-Any interaction between one individual of a species with another member of same species. ASSOCIATIONS SOCIETIES/SOCIAL ORGANISATIONS

9. According to Eisenberg(1965), any aggregation will be considered a social organisation if it has the follow properties:- Division of labour Communication Cohesion Permanence and impermeability PROPERTIES OF A SOCIETY

10. ADVANTAGES OF A SOCIETY Guarding behaviour Detection of predators Mutual vigilance Defence against predator Co-operative foraging Reproduction success Division of labour Increase in competition More chances of spread of diseases Inbreeding depression DISADVANTAGES OF A SOCIETY

11. In class Insecta, two orders Hymenoptera and Isoptera possess social organisation. Ants , honeybees and wasp come under Hymenoptera group. Termites come under Isoptera group. These species live in colonies of thousands of individuals, with a reproductive Queen and sterile workers and soldiers. Caste differentiation by:- Different kind of food 2.Pheromone

12. TERMITES CASTES : The colony has 3 castes A nd each includes both sexes. They are:- Reproductive caste- Queen and King Workers Soldiers Workers are responsible for nest construction, foraging for food, and caring for the young. Soldiers have larger heads and mandibles and are responsible for defending the colony against predators. Reproductives are responsible for reproduction and forming new colonies. Mandibular soldiers have large, powerful jaws that they use to crush or slice their enemies. They are typically the first line of defense and will attack intruders directly. Nasute soldiers , on the other hand, have a specialized nose-like structure on their head called a nasus, which they use to spray a sticky, toxic secretion at intruders. The secretion is made up of a mixture of defensive chemicals, including formic acid, benzaldehyde

13. Communication Termites communicate with each other using chemical signals called pheromones. These signals can be used to mark trails, signal alarm, and coordinate activities. Some species of termites also use physical signals, such as head-banging, to communicate with each other Sound production:-Soldiers and workers produce sound by tapping their head on the roof. . Nest Building Termites build elaborate nests, often out of soil or wood. The nests can be very large and can contain multiple chambers and galleries. Workers are responsible for constructing and maintaining the nest. Food Acquisition Termites are able to break down cellulose, which is the main component of wood and plant material. They do this with the help of symbiotic microorganisms in their gut. Workers are responsible for foraging for food and bringing it back to the nest. Swarming : In the raining season, the king and the queen leaves the colony and fly away to new sites and start new colony.

14. HONEYBEES Show a high order of social organisation. Castes : Queen is the largest bee in the colony and is responsible for laying eggs Drones are male bees whose primary role is to mate with the queen. Workers are responsible for nest construction, foraging for food, caring for the young, and other tasks.. . Eggs destined to become queen is laid in a larger brood cells and the larvae are feed only royal jelly . When the colony is crowded with adult bees, the queen bee leaves with a set of workers to establish a new colony- Swarming

15. CHARACTERS QUEEN DRONE WORKERS 1. Number per 1 Few hundreds 10-30,000 colony 2. Gender Fertile female Fertile male Sterile female 3. Formation Formed from a Develop Formed from a fertilized egg parthenogenetically fertilized egg from unfertilized egg 4. Size Largest Larger than worker Smallest but smaller than queen ;Stout 5. Duty To lay eggs Fertilize queen Repairing comb Gathering pollen, nectar Making honey, royal jelly Feeding and taking care of queen, larvae Guarding the hive and keeping it cool

16. Communication Honeybees communicate with each other using a combination of chemical and physical signals. Chemical signals are used to mark trails, signal alarm, and coordinate activities. Physical signals, such as the waggle dance, are used to communicate the location of food sources. Nest Building Honeybees build elaborate nests, known as hives, out of wax. The hive can contain multiple combs, each of which contains cells for brood rearing and food storage. Workers are responsible for constructing and maintaining the hive. Food Acquisition Honeybees primarily collect nectar and pollen from flowers. Nectar is converted into honey and stored in the hive for later use. Pollen is used as a protein source for the developing brood. Workers are responsible for foraging for food and bringing it back to the hive.

17. 1. Waggle dance :- To communicate about the location of food and water source A figure of 8 is traced against the surface of comb. Number of waggles signifies the distance of the food source. 2. Pheromones :-2 categories Those concerned with communication:-secreted by workers Those concerned with the maintenance of colony structure or the caste system:-secreted by queen Communication in Honeybee

18. Karl von Frisch determined that the critical distance for switching between the round dance and the waggle dance exists at 50 meters away from the hive.

19. The round dance tells the watching bees only one thing about the flower patch’s location: that it is somewhere close to the hive [ WITHIN 165 FEET] This dance does not include a waggle run, or any information about the direction of the flower patch. In this dance, the bee walks in a circle, turns around, then walks the same circle in the opposite direction. She repeats this many times. Sometimes, the bee includes a little waggle as she’s turning around. The duration of this waggle is thought to indicate the quality of the flower patch she has found. Round dance

20. FOR EVERY ONE SECOND OF DANCE , FOOD IS APPROX 1 KM AWAY. Waggle Dance

21. Direction

22. Finding the best flowers Honey bee colonies collect two main resources from flowers: nectar and pollen . Their goal is to find the flowers with the most of these two resources. Individual bees do two things when searching for flowers to get the most resources. they specialize to collect one resource at a time: either nectar or pollen. Specializing and focusing on one resource at a time helps bees more easily recognize the best flowers. bees look for and remember which flower species is the most rewarding. This can change over time. A species of flower that had the most nectar one month might not be the species with the most nectar the next month, for example. Once a bee finds a good flower, she collects resources and returns to the hive, and dances to tell other members of her colony where to find the flower so they can go and collect more resources from it. To motivate other bees to find the correct flower patch, the dancing bee shares a sample of nectar she collected with them.

23. Ants Highly developed social insect. Castes : Queen Kings Workers Soldiers Worker are responsible for nest construction, foraging for food, caring for the young, and other tasks. Soldiers have a more specialized role and are responsible for defending the colony against predators. Reproductives are responsible for reproduction and forming new colonies.

24. In rainy season swarming takes place. King usually dies after mating. Communication : Tactile signals :- by touching and strocking each others bodies with their antennae and forelegs. Pheromones :- facilitates mate attraction, kin recognition etc.

25. Communication Ants communicate with each other using chemical signals called pheromones. These signals can be used to mark trails, signal alarm, and coordinate activities. Some species of ants also use physical signals, such as tapping or vibration, to communicate with each other. Nest Building Ants build elaborate nests, often out of soil or other materials. The nests can be very large and can contain multiple chambers and galleries. Workers are responsib le for constructing and maintaining the nest. Food Acquisition Ants are able to obtain food from a wide variety of sources, including other insects, plant material, and even dead animals. Workers are responsible for foraging for food and bringing it back to the nest. Some species of ants have evolved specialized methods of obtaining food, such as farming aphids or other insects for honeydew.

26. YELLOW WASP(VESPOID WASP) Castes : Queen Queens are responsible for reproduction and founding new colonies. Drones Males are responsible for mating with the queen. Workers Workers are responsible for building and maintaining the nest, caring for the young, and foraging for food.

27. No swarming takes place. In winters, the queen hibernates and the nest perishes. The queen starts new colony next spring. Communication : Pheromone :- Secreted by workers-to communicate with other workers Secreted by queen-to Inhibit ovarian development in workers Provide stability to colony Attract drones These signals can be used to mark territories, attract mates, and coordinate activities. Some species of wasps also use physical signals, such as wing vibrations, to communicate with each other.

28. Nest Building Wasps build nests out of a variety of materials, including mud, wood, and paper. The nests can be simple or complex, depending on the species. Workers are responsible for constructing and maintaining the nest. Food Acquisition Wasps are predators and feed on a variety of insects, spiders, and other small animals. Workers are responsible for foraging for food and bringing it back to the nest. Some species of wasps also feed on nectar and pollen. Social Organization Wasps have a relatively simple social organization compared to other social insects. Queens are the most important individuals in the colony and are responsible for reproduction and founding new colonies. Workers are responsible for most of the colony's activities, including building and maintaining the nest, caring for the young, and foraging for food. Wasps are less specialized than other social insects, such as ants and bees, and some species have even evolved to live solitary lives.

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