Lec 12 Flashcards
(3 cards)
1
Q
How do cestodes and acanthocephalans differ?
A
- Attachment
Cestodes: Use suckers & hooks on their scolex (head region) to attach to the host’s intestinal wall
Ancanthocephalans: Use fluid filled, retractable proboscis armed w/ hooks to attach deeply into the intestinal lining - Reproductive Strategy
Cestodes: Hermaphroditic (each individual has both m&f organs)
Ancan: Dioecious (seperate m&f sexes) and sexually dimorphic - Intermediate hosts
Cestodes: can have vertebrae or invertebrate depending on species
Ancan: will always arthropod
2
Q
How are cestodes and acanthocephalans similar?
A
- Endoparasites of vertebrates
→ Both live inside the intestines of their definitive (final) hosts, which are usually vertebrates like fish, birds, or mammals. - Indirect life cycles
→ Both require intermediate hosts and use trophic transmission (the definitive host becomes infected by eating the intermediate host). - Sexual reproduction inside the host
→ Both reproduce sexually in their definitive host (though cestodes are hermaphroditic and acanthocephalans are dioecious).
3
Q
Describe how namatomorphs can have community level effects on their surroundings
A
- Nematomorphs infect insects like grasshoppers or crickets and manipulate their behavior, making them jump into the water
-This is essential for the worm’s life cycle, as the adult nematomorph must return to water to reproduce
-Infected insects that enter water become easy prey for fish and other aquatic predators - Because infected terrestrial insects are pulled into aquatic environments, nematomorphs effectively transfer energy from land to water ecosystems
- in one study, nematomorph-infected grasshoppers and crickets became up to 20 times more likely to enter water than uninfected individuals
- In certain areas, these infected orthopterans made up to 60% of the annual energy intake for a fish species (Char), showing a direct influence on predator diets and energy flow between ecosystems
-By forcing terrestrial insects into aquatic environments, nematomorphs transfer biomass and energy from land to water - This can shift nutrient cycling and energy distribution in both ecosystems
- These shifts can alter food webs and trigger trophic cascades, demonstrating how a single parasite can influence the structure and function of entire ecological communities.
