1 / 17

Insect Ecology

Insect Ecology . Lecture 19. Addo Dung Beetles ( Circellium bacchus ). Ecology ( oikos + logos ): scientific study of interactions between organisms and environment. Insect ecology is a huge discipline. Trophic relationships Insect-plant interaction Prey-predator interaction

luther
Download Presentation

Insect Ecology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Insect Ecology Lecture 19

  2. Addo Dung Beetles (Circelliumbacchus)

  3. Ecology (oikos+ logos): scientific study of interactions between organisms and environment

  4. Insect ecology is a huge discipline • Trophic relationships • Insect-plant interaction • Prey-predator interaction • Parasite-host interaction • Mutualistic association • Pollination ecology • Ecosystem function • Population ecology • Demography • Life histories and reproductive strategies • Behavioral ecology • Ecological genetics • Population dynamics • Community ecology • Intraspecific and interspecific competition • Community structure and organization • Diversity and stability • Paleoecology, biogeography

  5. Ecology begins with knowing a taxon How many times does it lay eggs? What are the major predators, parasites, and pathogens? What distinguishes this insect? Where are the eggs laid? How does it defend against enemies? What does it eat as nymphs? Where does it live and what limits its distribution? What does it eat as adults? Does the female mate multiple times? What is the general nutritional quality of the food? Where does mating take place? What does its closest relative eat? At what season does development begin? How far can it travel? When is it active? How does it find food?

  6. Insect predation and parasitism • Predator: kills and consumes prey • Parasitoid: lives at the expense of a host that eventually dies as a result • Parasite: lives externally or internally at the expense of a host that does not die as a result

  7. Type of foraging: Sit and wait (ambush) Many display aggressive foraging mimicry

  8. Type of foraging: Active foraging • Random, non-directional foraging Coccinellid larvae (left) and syrphid larvae (right) searching for clumped prey (aphids)

  9. Type of foraging: Active foraging • Non-random, directional foraging • Chemical cues (pheromone, plant chemical, frass) • Acoustic cues (specific frequencies) Trichogrammawasp locating moth eggs using female moth sex pheromone Ormiafly parasitizing a cricket

  10. Type of foraging: Phoresy • A phenomenon in which an individual is transported by a larger individual of another species • Many parasitoid wasps • Bird lice on ectoparasitic flies

  11. Parasitoid life-style • Great diversity found in Diptera and Hymenoptera • Host specific • Host discriminate • Hyperparasitism Host selection by the hyperparasitoid, Alloxystavictrix

  12. Host manipulation of parasitoids • Idiobiont: parasitization kills or paralyzes the host (zombie-making: Jewel wasp-cockroach interaction) • Koinobiont: a parasitoid lays eggs in a young host, which continue to grow, providing more resource to youngs(wasp, polydnaviruses, lepidopteran host)

  13. How insects interact with abiotic environments • Environmental extremes • Cold • Heat • Unsuitable environments • Diapause • Migration

  14. Tolerance to cold • Chill susceptible: lack cold hardiness • Chill tolerance: mainly from temperate areas, can survive low temperature, but not for long • Freeze avoidance: physiological ability to survive low temperature within internal freezing by supercooling (remaining liquid at subzero without ice formation) • Freeze tolerance: most cold-hardy, by seasonal production of icenucleating agents (freeze from outside) and internally protected by supercooling Eurostasolidaginis

  15. Tolerance to heat • Acclimation: some species can increase tolerance by a gradual exposure • Some flies can live in thermal springs: Ephydridae (temperature up to 43oC) • Many insects have heat-shock proteins, which are stress-induced proteins involved in temperature related activities

  16. Diapause • Arrested development along with adaptive physiological changes, recommencing after particular physiological stimuli • Difference from hibernation or quiescence • Obligatory vs. facultative • Length variable • Any life-history stage from egg to adult Photoperiod Temperature Food quality Moisture pH Chemicals

  17. Migration • Directional movement to more appropriate conditions • Seasonal migration: to avoid altered environmental conditions (monarch example) • Adaptive migration: to seek better resources • Active and passive migration: active walking or flight vs. aerial floating

More Related