SCI 355B: Lecture 12 Predation & Parasitism

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1 SCI 355B: Lecture 12 Predation & Parasitism 1

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3 Vertebrate Animals that Eat Insects Class Osteichthyes: Bony Fishes Class Aves: Birds Class Reptilia: snakes, lizards, turtles Class Amphibia: frogs & salamanders Class Mammalia: mammals 3

4 Mammals that Eat Insects Mammals that Eat Insects Mammals that Eat Insects 4

5 Plants that eat Insects 600 different species eat insects. But why? Plants can prepare their own food. However some grow in bogs or marshes, and the soil does not contain enough minerals, for the plants to grow well. Carnivorous plants make up for nutrient deficiencies in soil by eating insects. They catch their food by creating some unique traps. Then slowly digest it. Plants that eat Insects The tips of the leaves of this plant are actually small traps with spines along the edges. On the trap is a bright redish spot covered with nectar which insects are attracted to. Three tiny hairs on each leaf act as triggers. When insect touches these hairs the trap snaps shut. Then digestive enzymes are secreted and the food is slowly digested by the plant. Invertebrates that eat insects Class Chilopoda: centipedes Class Diplopoda: millipedes Class Arachnida: spiders, etc. Class Nematoda: round worms 5

6 Chewing Insects that eat insects Predation by Insects Insects live in a world of attack and defense between predators and prey Predator = free living, kills more than one prey for food in order to complete development and/or life cycle. Insects may be predaceous at all developmental stages or restricted to one stage only Predatory diet = high amounts of protein (not present in plants) that can be readily converted into own tissue. 6

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11 Strategies Most predators are larger than prey Active searchers Sit and wait/ambush style Specialized structures/adaptations for handling prey 11

12 Parasites & Hosts Some terms Parasite -a type of symbiotic relationship between two different organisms where one organism, the parasite, takes from the host, sometimes for a prolonged time. They are ususally smaller than their hosts, show a high degree of specialization for their mode of life, and reproduce more quickly and in greater numbers than their hosts. Endoparasite - feed internally (e.g., tapeworm) Ectoparasite - feed externally (e.g., pubic louse, mosquito) Some terms Parasitoid -an organism that spends a significant portion of its life history attached to or within a single host organism which it ultimately kills (and often consumes) in the process. This type of relationship seems to occur only in organisms that have fast reproduction rates, such as insects. Idiobiont parasitoid-are those which prevent any further development of the host after initial parasitization, and this typically involves a host life stage which is immobile (e.g., an egg or pupa), and almost without exception they live outside the host. 12

13 Some terms Parasitoid -an organism that spends a significant portion of its life history attached to or within a single host organism which it ultimately kills (and often consumes) in the process. This type of relationship seems to occur only in organisms that have fast reproduction rates, such as insects. Koinobiont parasitoid -allow the host to continue its development and often do not kill or consume the host until the host is about to either pupate or become an adult; this therefore typically involves living within an active, mobile host. Koinobionts can be further subdivided into endoparasitoids, which develop inside of the prey, and ectoparasitoids, which develop outside the host body. Some terms Hyperparasitoid - a parasitoid of a parasitoid. Host Immune Response 13

14 Insect Parasitoid Orders Hymenoptera* Diptera* Strepsiptera Coleoptera *major parasitoid groups 14

15 Other Characteristics they are smaller than host only the female searches for host different parasitoid species can attack different life stages of host eggs or larvae are usually laid in, on, or near host immatures remain on or in host; adults are free-living, mobile, and may be predaceous Some Parasites of Humans Ectoparasites: fleas, lice, ticks, bot flies, mosquitoes 15

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17 Lice Transfer from host to host occurs when hosts are mating/brooding Eggs glued to hair/feathers, except human body louse. Rarely leave host One family (Echinopthiriidae) restricted to seals 17

18 Pubic Lice: (a.k.a. crabs) 18