Species interaction

Question 1

Name 3 category of species interaction

Answer 1

Antagonistic

Mutualistic

Plant-plant communication

Question 2

What is mutualism?

Answer 2

+/+

Individuals of 2 species live together and BOTH benefit

Question 3

What is parasitism?

Answer 3

Individuals of 2 species live together, one member benefit while other is harmed but not killed

Question 4

Name 3 types of antagonistic interactions

Answer 4

Plant-plant (parasitic plants)

Host-parasitoid

Predator-prey

Question 5

Name 2 types of mutualistic interactions

Answer 5

Plant - pollinator

Plant - seed dispersor

Question 6

Name 2 types of plant-plant communication

Answer 6

Allelopathy

Mycelial networks

Question 7

What are some classification of parasitic plants?

Answer 7

Holoparasite

Hemiparasite

Root/stem parasite

Question 8

What is a holoparasite

Answer 8

Plant parasite
- obligate parasite
- Produce no chlorophyll, and are totally relient on the host

Question 9

What is a hemiparasite?

Answer 9

Plant parasite
- Derive some of their nutrition from the host, but produce chlorophyll and are functionally photosynthetic (ex mistletoe)

Question 10

What is a root/stem parasite?

Answer 10

Plant parasite
- Whether the parasite attaches to the root or stem system of the host plant (ex: Striga spp. or witch weed)

Question 11

What is striga?

Answer 11

Plant parasite
=> hemi/holoparasite of roots (all except 3 genera)

• Parasite on cereals
• One of the most destructive plant pests in Africa
• Affects 40% of Africa’s subsahara region, resulting in about 13 billion US$ loss every year
• Striga infest 40 million hectares of crops in subsaharan Africa alone
• Seeds can survive for 10 years

Question 12

What are some control options against Striga spp.

Answer 12

• Hand pulling before seed production stage
• Planting trap crops => suicide germination (seeds germinate, but cannot attach to the roots)
• Tolerant crop varieties
• Biological control agents (fungal pathogens)

Question 13

What is a difference between a parasite and parsitoid?

Answer 13

Parasitoid=> causes death of the host

Question 14

What are ectoparasitoids?

Answer 14

Feed from the outside of their host

Question 15

What are endoparasitoids?

Answer 15

They feed from the inside of their hosts

Can be either ido or koinobionts

Question 16

What are idiobiont vs koinobiont?

Answer 16

Idobiont: feed on paralyzed host

Koinobiont: feed on live, active host

Question 17

At what stages can host insects be attacke by parasitoids?

Answer 17

Egg

Larvae

Pupae

Imago

Question 18

What is hyperparasitism ?

Answer 18

A parasite of a parasite

First primary parasitoids attack the host, and then secondary parasitoids have a primary parasitoid as their host.

Question 19

What are some defense mechanisms of prey?

Answer 19

Mimicry

Distraction

Chemical defense

Mechanical defense

Question 20

What is meat by mimicry? Give some examples

Answer 20

Evolved resemblance between between organisms and another object, often an organism of another species

Ex:
Batesian mimicry: hoverflies mimic stinging wasps

Stick insect camouflage

Question 21

Give an example of distraction as defense mechanisms of prey

Answer 21

Large swarms or flocks reduce success rate of predators

Question 22

Give an example of mechanical defense mechanism of preys

Answer 22

Turtles..

Question 23

Give an example of chemical defense mechanism of preys

Answer 23

Beetles producing a liquid that is sticky and acidic…

Question 24

Where should seeds be dispersed, what is the role of animals in seed dispersion?

Answer 24

Janzen-Connell Hypothesis

Seeds need to esape the mother plant.

Seeds that are dispersed farther have better chances of survival. However, probability of seed dispersal decreases as distance from parent plant increases.

Question 25

What are some plant-plant communication ways?

Answer 25

Allelochemicals: intra/interspecific

Pheromones: only intraspecific
=> semiochemicals/messengers

These have as effect to deter herbivores, attract beneficials inform neighbours, induce immune systems

Through:

volatile organic compounds and common mycelial network

Question 26

How does plant-plant communication through allelochemicals impact the plants? What plants use this type of communication?

Answer 26

It influences the germination, growth, survival and reproduction of other plants

• Basis of success for some invasive weeds (e.g. garlic mustard)
• Also in crop plants: rie, rye, squash, radish

Question 27

What are some ways of allelochemicals into the environment?

Answer 27

• Volatilization from leaves
• Leaching from plant litter
• Leaching from leaves by rain, fog or dew
• Exudation from roots
• Decomposition of plant litter

Question 28

Give examples of communication via VOCs (volatile organic compounds)

Answer 28

Acacia trees: when wounded, emit ethylenes => rise in tannin levels in trees nearby

Herbivore-induced plant volatiles that attract parasitoid wasps

Question 29

What are some ways that mycorrhizae connect to plant? What is the effect/impact?

Answer 29

FRIENDSHIP
- ex: stess trt in Douglas tress leads to stress signalling in neighbouring pine trees via CMN => neighbors receive these messages can modify their behavior through altered morphology, physiolgy and biochem, reduce their stress and improve their fitness

SABOTAGE
ex Tagetes sends allelochemicals via the CMN to its neighbouring plants, by this reducing germination and growth
=> allelochemicals are much more effective if sent via CMN, not just via soil diffusion

FIRE ALERT
Aphid attack causes systematic changes in the production of plant volatiles making bean plants repellent to aphids
=> only if plants are connected through CMN
=> allows neighbouring plants to invoke herbivore defences before attacks