Insect Behaviour : Patterns And Determinants
- 1. INSECT BEHAVIOR PATTERNS AND DETERMINANTS ARSHAQ AREEB 23ZYMLA102 GM2707 Department of Zoology 20/01/2025 Department of Zoology
- 2. I N S E C T B E H AV I O R Patter ns And Deter minants
- 3. Insect Behavior • It refers to the various ways in which insects interact with their environment, other organisms, and themselves. • This behavior is influenced by a combination of genetic, physiological, and environmental factors. 1
- 4. Types of Behavior Learn Behavior Innate Behavior Mixed Behavior Also known as Instinctive/ Programmed/ Inborn Genetically Determined No need of practice Stereotype Best performed in 1st Attempt Learn via experience or trial and error Non-inheritable Practice is required to perform better Behavior can be modified by changing environment It is required for adaptation Actions that have both innate and learned components. Innate Basis : The behavior has a genetic foundation that ensures it occurs naturally. Modifiable by Learning : Experience and practice can shape, refine, or improve the behavior. 2
- 5. Experimental Methods To Study Types Of Insects Behavior Deprivation Experiment Hybridization Method Gene knock out method 3
- 6. A deprivation experiment systematically isolates an organism from specific environmental stimuli to ascertain whether a behavior is innate or learned. If the behavior persists in the absence of exposure, it is considered innate; if it fails to appear, it is identified as learned. Deprivation Experiment 1. Nest-Building in Wasps (Paper Wasps) • Setup: Wasps are reared in isolation without exposure to adult wasps or existing nests. • Observation: Isolated wasps still construct nests with a species-specific structure. • Conclusion: The ability to build a nest is innate, as it occurs even without learning or observation. 2.Waggle Dance in Honeybees • Setup: Newly emerged honeybees are isolated from experienced bees and do not observe the waggle dance. • Observation: When introduced into a hive, isolated bees exhibit a crude waggle dance to communicate food sources but lack precision in their movements. • Conclusion: The basic structure of the waggle dance is innate, but the precision and refinement of the dance are learned through social interactions. Fig. Nest-Building Paper Wasp Image source: WIKIPEDIA Fig. Waggle Dance In Honey Bee Image source: SHUTTERSTOCK 4
- 7. Gene knockout is a technique used to study the function of specific genes by completely or partially disabling them in an organism. Gene knock out method Gene Knockout in Drosophila to Study Memory The amnesiac gene in Drosophila plays a critical role in memory formation and ethanol sensitivity. Procedure • knock out the amnesiac gene in Drosophila. • After the knockout, the flies are exposed to an odor-shock conditioning paradigm, where a specific odor is paired with a mild shock. Conclusion • In normal Drosophila, this would result in the flies learning to avoid the odor. • In the knockout flies, which lack the amnesiac gene, they would not show this conditioned avoidance behavior, indicating that the amnesiac gene is essential for memory formation and learned behavior. 5
- 8. Example: Nest-Building Behavior in Honeybees • Parental Populations: African honeybees (Apis mellifera scutellata) and European honeybees (Apis mellifera mellifera) have distinct nest-building behaviors: 1.African honeybees build smaller cells and are more aggressive. 2.European honeybees build larger cells and are less aggressive. Two genetically distinct individuals, populations, or species are crossed to produce offspring called Hybrids. The behavior of hybrids can be analyzed to determine which traits are genetically inherited (innate) and which are influenced by experience or environmental factors (learned). HYBRIDIZATION Fig. European Honey Bee. Image source: Entomology and Nematology Department, University of Florida. Fig. African Honey Bee. Image source: Nature picture bay 6
- 9. • Hybrid Offspring (Killer Bee): Hybrids are produced by mating African and European honeybees. 1. Innate Behavior: If the hybrids build cell sizes that are intermediate between the two parental types (e.g., smaller than European but larger than African), this behavior is likely innate and genetically determined. Aggressiveness is also examined. If hybrids display intermediate aggression levels, this suggests an innate basis. 2. Learned Behavior: If hybrids adopt nest-building techniques that closely resemble the environment they are reared in (e.g., influenced by the hive or colony type), this indicates learned behavior. • Key Observations: 1. Innate Behavior: Cell size and general architecture are largely innate, as hybrids consistently show intermediate traits regardless of the environment. 2. Learned Behavior: Foraging behavior and specific hive interactions may depend on exposure to colony-specific cues, indicating a learned component. Fig. Africanized Honey Bee (Killer Bee) Image source: earth.com 7
- 10. Kinesis Taxis Reflexes Motivation Types Of Innate Behavior 8
- 11. Kinesis is the random, non-directional movement shown by an organism in response to a stimulus. Taxis Kinesis OrthoKinesis: The intensity of stimulus determine the speed of movement. Example, Woodlice (Oniscidea): Move faster in dry areas and slow down in humid areas. Klinokineses: The intensity of stimulus determine the rate of turning. Example, Maggots (Fly Larvae) increase their rate of turning when exposed to bright light. Taxes (Taxis) is a directed movement of an organism in response to a specific stimulus. Positive Taxis: Movement towards the stimulus. Negative Taxis: Movement away from the stimulus. Stimuli can be, water , light, gravity , current, chemicals, etc. E.g., Mosquito larvae show positive hydrotaxis, Moth show positive phototaxis, etc. Fig. Lice - Image source: west coast seed Fig. Fly Maggots - Image source: Colonial Pest control Fig. Mosquito larvae - Image source: scientific american Fig. Moth - Image source: iStock 9
- 12. Reflex is rapid, involuntary response to a specific stimulus, mediated by a simple neural pathway called a reflex arc. Examples:- Motivation Reflex Autohaemorrhage: Blister Beetles release hemolymph containing cantharidin, a highly toxic substance, as a defense mechanism. Thanatosis: organism mimics death by becoming motionless shown by, mantis, stick insect, etc. Motivation is the internal process that drives an organism, to perform specific actions or behaviors to fulfill its needs or respond to stimuli. Fig. Blister beetle Image source iiab.me Fig. Mantis Image source Insectic.com Key Features of Motivation: Internal Factors: Hormonal changes, energy levels, or physiological needs (e.g., hunger or thirst). Example: A hungry insect is motivated to search for food. Rhythms and Timing: Biological rhythms, such as circadian rhythms (daily cycles of activity and rest), influence motivation. Example: Insects are motivated to be active or inactive depending on their internal clock and the time of day. 10
- 13. Special case • Hygienic behavior is a natural defense mechanism in honey bees that helps control diseases and pests. • It involves worker bees detecting and removing dead or diseased brood from sealed cells. • It involves two major genes: 1. The "Alcove" gene (a) controls uncapping. 2.The "Cleanup" gene (c) controls the removal of the dead brood. • Hygienic behavior in honey bees is recessive,require two copies of the recessive allele to express the behavior. Hygienic Behavior Of Honey Bee • Phenotypic Outcome: The offspring with aa (for uncap) and cc (for cleanup) will show hygienic behavior. Bees with A or C alleles (dominant for either trait) will not show hygienic behavior. 11
- 14. Types of Learning behavior Habituation Associative learning Latent behavior Imprinting Cognitive Behavior Spatial learning 12
- 15. Cognitive Behavior • There is decrease in responses to a repetitive stimulus that is neither beneficial nor harmful. • Organism learns to ignore the stimulus because it no longer signals danger or reward. • Cognitive learning in insects is their ability to think, remember, and solve problems based on experience. • Instead of just relying on instincts, they learn from their environment to make smarter decisions. Example • Some bees learn to pull strings to access hidden food, showing innovative problem-solving. • Ants work together to move large objects, adapting strategies as needed conditions for their offspring. Example • Crickets are highly sensitive to vibrations, as these can signal the presence of predators. • However, if a non-threatening vibration (e.g., a fan's low hum) is repeated over time, crickets habituate to it and stop reacting. Habituation 13
- 16. Associative Learning Operant Conditioning Classical conditioning • A learning process that involves associating a neutral stimulus with a stimulus that already produces a response. • First described by Ivan Pavlov. Example • Cockroaches (Periplaneta americana) trained to associate a specific odor with a sugar reward. • After repeated pairings, the cockroaches began to salivate upon exposure to the odor alone. 1. Classical conditioning Fig. Classical Conditioning in Cockroach. Image source: (Watanabe et al., 2006). 14
- 17. A • Operant conditioning in insects involves learning through rewards or punishments. • An insect modifies its behavior based on the consequences of its actions. Example: The fruit fly maze experiment • Flies are exposed to two distinct odors: 1. One paired with a positive stimulus, such as sugar. 2. Other with a negative stimulus, like an electric shock. Over time, the flies learn to approach the odor associated with the reward and avoid the one linked to the punishment. Fig. T maze apparatus. Image source: Dong et al., 2023 2. Operant conditioning 15
- 18. Latent Learning Imprinting Latent learning is a type of learning that occurs without any immediate reward or reinforcement and remains hidden until it is needed. Imprinting in insects is when they learn to recognize something important during a special period in their life, usually when they are very young. A bee exploring flowers might learn the location of nectar-less flowers without any immediate benefit. Later, it avoids those flowers when foraging. Example: Example: Oviposition Site Selection in Butterflies: Female butterflies often imprint on specific host plants during their larval stage. As adults, they preferentially lay eggs on the same plant species, ensuring optimal conditions for their offspring. 16
- 19. Spatial learning in insects is how they remember places and use that knowledge to navigate their surroundings. Spatial Learning Example: Digger wasp • Nikolaas Tinbergen placed a ring of pinecones around a wasp's nest, which the wasp memorized. When he moved the pinecones, the wasp flew to the pinecones instead of the actual nest. This proved that wasps rely on spatial lear ning. Fig. Digger wasp experiment – Tinbergen et al., 1972 17
- 20. A Blend of Innate and Lear ning Behavior Fig. Waggle Dance Of Honey Bee Image source: WIKIPEDIA Mixed Behavior The waggle dance of honeybees • waggle dance of honeybees is a behavior used to communicate the direction and distance of a food source. • Innate: Angle of the waggle run corresponds to the angle between the food source and the sun. • Learn: Duration of the waggle indicates the distance to the food. Example: 18
- 21. • Insect behavior is influenced by genetics, environment, and experience. • Includes innate, learned, and mixed behaviors critical for survival (e.g., foraging, reproduction, defense). • Experimental methods like deprivation studies and gene knockout techniques reveal behavior mechanisms. • Understanding insect behavior has practical applications in pest control, pollination, and biodiversity conservation. • The blend of instinctive and adaptive behaviors allows insects to thrive in diverse environments, making them essential for ecosystems. Conclusion 19
- 22. References • Pultz, D. L., & McDonald, M. P. (2000). "The Role of the amnesiac Gene in Learning and Memory in Drosophila." Learning & Memory, 7(1), 32-41. • Spivak, M., & Reuter, G. S. (2001). "Performance of hygienic behavior by honey bees in relation to brood age and the expression of a recessive genetic trait." Apidologie, 32(6), 273–281. • Watanabe, H., & Mizunami, M. (2006). Pavlov's cockroach: classical conditioning of salivation in an insect. Genes, Brain and Behavior, 5(4), 356-368. https://doi.org/10.1111/j.1601-183X.2006.00241.x • Tinbergen, N. (1972). The Animal in Its World: Explorations of an Ethologist, 1932-1972. Harvard University Press. • Dong, S., Xiang, H., & Nieh, J. C. (2023). Social signal learning of the waggle dance in honey bees. Science, 379(6628), 305–308. • "Insect Behavior: From Mechanisms to Ecological and Evolutionary Consequences" by Alex Córdoba- Aguilar and Duarte M. S. Bueno • "Insect Ecology: Behavior, Populations and Communities" by Peter W. Price et al. 2011 20
- 23. Thank You