Lecture 2 Flashcards
What are the four lateral interactiosn in insect communities?
amensalistic interaction
facilitative interaction
mutualistic interaction
competitive interaction
What is an amensalistic interaction?
one participant suffers, the other remains unaffected (-,0)
What is a facilitative interaction?
at least one of the participating organisms benefits from the interaction (+,0)
What is a mutualistic interaction?
both participating organisms benefit from the interaction (+,+)
What is a competitive interaction?
both participants are negatively affected (-,-)
What is an example of a mutualistic interaction?
endosymbionts protect aphids from thermal stress, help them digest food, protect them against parasitic wasps and help with adaptation to different host plants and aphids are vehicle for endosymbiont multiplication (can be transferred to other insects)
What is an example of a facilitative interaction?
burying beetles aggregate on a carcass and facilitate preservation of the carcass as food source for larvae of at least one of the beetles
What is an example of an amensalistic interaction?
ibex limit food availability for timarcha weevils, whereas weevil population do not affect food availability for the ibex
What is an example of a competitive interaction?
males fighting for territories or access to mates, also winners lose energy and have a risk of damaging themselves
What are the definitions of intraspecific competition and interspecific competition?
intraspecific competition: individuals of the same species (conspecific) compete
interspecific competition: individuals of different species (heterospecific) compete
What are the definitions of scramble and contest competition?
Exploitative/scramble competition: by using resources, some individuals deprive others of the benefits to be gained from resources
Interference/contest competition: individuals harm one another directly through fighting or killing, or indirectly by aggressively maintaining a territory or producing chemicals that deter other individuals
What is pseudo-interference competition?
Interference competition may occur through chemical compounds left after individuals interact with a resource
e.g. after male butterflies mate, they release chemicals in order to render the female less attractive to other males
What are the definitions of extrinsic and intrinsic competition?
extrinsic competition: adult parasitoids compete over access to host, guarding or fighting off competitors
intrinsic competition: parasitoid larvae compete within host, may physically attack each other in contest competition, larvae may be involved in scramble competition
What is a rule about number of parasitic wasp larvae inside a host?
the more larvae growing inside the host, the smaller each individual gets and the higher the mortality risk
What is competitive displacement?
one species fully outcompetes and replaces a second species, this is often a result of a significant niche overlap
What is apparent competition?
occurs when two individuals that do not directly compete for resources affect each other indirectly by being prey for the same competitor
What are indirect interactions mediated by the plant?
herbivores that share the same plant either simultaneously or sequentially affect each others performance via their effect on plant quality
What is an example of indirect interactions mediated by the plant?
e.g. mustard plant will create a higher concentration of defensive chemicals and a higher density of trichomes on its leaves once the herbivores begin to feed more on the plant
What is the specificity in plant-mediated herbivore interactions?
- Plant defenses are due to specific herbivores trying to feed, therefore interactions are very specific between each species
- Interactions are asymmetric, do not affect each other equally, it depends on the order of events etc.
- The trait matters in the receiver (how they deal with the consequence) more than the inducer (horizontally, the colours match more)
- Interactions may be specific for genotypes
What is indirect plant-mediated interactions among parasitoids?
plants may also mediate interactions between parasitoid larvae that develop inside different caterpillars
e.g. parasites inside herbivore A and parasite inside herbivore B may be able to indirectly interact with each other if herbivore A and B feed on the same plant (affect plant quality)
What is a real life example of indirect plant-mediated interactions among parasitoids?
Cotesia glomerata, more significant negative effect when feeding on plant after a prasitized cotesia rubecula, both parasitic wasps have an effect on each other depending on which one is the intiator and which is the receiver
What is niche differentiation in pollinators?
tongue length of bumblebees is an adaptation for collecting nectar in flowers with various lengths of the floral tube (shows that competition is a force in evolution)
What is character displacement?
adaptation driven by competition
- Change in characteristics that can be traced back due to competitive interaction
- Evolution induced by competition
- E.g. crickets adapted to have different frequencies of sound to avoid competition in mate attraction if in the same environment
What is phenotypic plasticity?
ability of organism to change phenotype in response to environment but genotype remains the same
