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Ecology of Biological Control
part of Module 1: Intro to Ecology
55
Agriculture
Undergraduate 4
01/24/2017

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Cards

Term
Attributes of natural enemies
Definition
-Host/prey specificity
-Density dependent response
-Strong reproducer – “rate of increase”
-Good searching ability
-Synchrony with target pest
-Ability to survive low food supply
Term
types of Host/Prey Specificity
Definition
-generalists
-specialists
Term
generalists
Definition
attack multiple types of prey
Term
specialists
Definition
attack only one or a few types of prey
Term
Ecological generalists
Definition
those that attack hosts/prey in multiple habitat types (such as in shrubs, grasses, and trees)
Term
ecological specialists
Definition
concentrate on a single or very few habitat types
Term
Density dependent factors
Definition
inflict mortality as a function of the population density (predators, food, pathogens)
Term
Density independent factors
Definition
inflict mortality with no regard for population density (weather, pesticides)
Term
some characteristics of density dependence
Definition
-Number of prey/hosts killed is a function of the number of prey/hosts available
-May be a function of space – Number of prey/hosts per unit area that the natural enemy can traverse
-May be a function of time – Number of prey/hosts available over a period of foraging time
-Considered to be important for pest management
Term
Functional response
Definition
The pattern of attack by a natural enemy in relation to the number of prey/hosts and the time involved
Term
what you want in a stable system
Definition
long-term pest suppression
Term
the goal in biological control
Definition
to reduce the target pest population
Term
metapopulation
Definition
a population of populations where spatially distinct subpopulations occupy separated patches of habitat
Term
how populations in a metapopulation occur in a natural system
Definition
they are embedded in a matrix of space that is not suitable for the populations to persist, but movement among patches by the organisms does occur, and interactions among subpopulations maintain the overall metapopulation
Term
the function of other patches of habitat for metapopulations in a natural system
Definition
serving as refugia, giving the aphids a source from which they can spread and colonize new patches, and allow the predators to have a persistent source of prey in the future
Term
why is density dependence desirable in biological control?
Definition
because it can help relationships be stable
Term
why metapopulations are good for biological control
Definition
because they encourage stability
Term
why it's important to consider which traits are valuable for effective natural enemies
Definition
because if we have solid notions about what attributes are important, then we can target specific traits in natural enemies that may be of most use
Term
density dependence
Definition
the ability of natural enemies to respond positively to increasing host/prey density
Term
the importance of functional response
Definition
it can provide insights into natural enemy performance
Term
Ultimately, biological control is...
Definition
the interaction of populations under a particular set of conditions
Term
the goal in biological control
Definition
to select the most appropriate species for those interactions and conditions
Term
Beauveria bassiana
Definition
-Entomophthoralean fungal pathogen of insects
-White fuzzy coat, often on beetles, caterpillars
Term
a food web consists of...
Definition
all of the linkages through which energy flows in an ecosystem, or food chains
Term
Trophic refers to...
Definition
feeding or nutrition, deriving from the Greek ‘trophikos’, meaning nourishment
Term
in a food web, energy is lost at each transfer due to...
Definition
inefficiency of transfer, conversion of energy into materials that cannot be processed, and energy costs for maintenance of the organisms
Term
this limits the number of trophic levels
Definition
it is limited to a point where the cost of obtaining energy exceeds the energy available for use
Term
Typically, there are no more than ______ trophic levels in an ecosystem
Definition
4
Term
intraguild predation
Definition
predation between species that also feed on the same prey/host item
Term
what top-down forces do in food webs
Definition
they ultimately influence the distribution and populations of the Consumers
Term
what bottom-up forces do in food webs
Definition
they move from the lower levels to affect the upper trophic levels
Term
some things that act in a food web in a bottom-up direction, affecting the higher trophic levels
Definition
defensive plant compounds and trichomes, or plant hairs
Term
some things that act in a food web in a top-down direction, affecting the lower trophic levels
Definition
Elimination or reduction of herbivores
Term
how the third trophic level can shape evolution in the first trophic level
Definition
by altering the distribution of herbivores in space and time, as herbivores try to escape natural enemy pressure
Term
Biological Control relies on...
Definition
the interactions among populations, and on top-down effects within food webs
Term
In biological control, our focus is on ______, emphasizing ______.
Definition
the interactions among populations
the importance of top-down forces
Term
Density of hosts/prey can be influenced by ______, which in turn influences ______.
Definition
the first trophic level
the third trophic level of natural enemies
Term
population distribution that promotes random searching behavior
Definition
-uniform
-random
Term
how natural enemies find food in clumped populagtions
Definition
by using signs to find hosts and prey, just like humans do when looking for clumped food resources
Term
how metapopulations benefit natural enemies
Definition
they provide opportunities for natural enemies to track hosts/prey in space and time, and allow stability of all populations over time by providing refuges for hosts/prey from which they can re-colonize other patches and allow natural enemies to persist
Term
how natural enemies must track their enemies
Definition
in space and time
Term
nature of the breadth of a natural enemy’s host/prey range has this effect
Definition
affects the top-down outcomes
Term
One very important factor that influences synchrony in time
Definition
the developmental time and the time it takes to go through a generation
Term
some important factors of synchrony in predator and pest populations
Definition
-the developmental time and the time it takes to go through a generation
-the number of generations that a natural enemy has per year
Term
generalists need not synchronize with any one host/prey species, but must still...
Definition
assure survival by synchronizing with available food resources
Term
Synchrony can be complicated by...
Definition
the need of organisms to survive through seasonal rough periods, such as winter in temperate climates or the dry season in the Tropics
Term
the options organisms have to survive seasonal rough periods
Definition
-survive the period where you are through hibernation or some other means
-migrate to a better climate
Term
why synchrony in time and space occurs both within and across seasons
Definition
because natural enemies must re-unite with their host/prey resources after conditions have improved
Term
these characteristics of target pests affects biological control
Definition
-density
-distribution
Term
Synchrony in ______ and ______ is critical.
Definition
space and time
Term
scientific name for predatory earwig
Definition
Labidura riparia
Term
some characteristics of predatory earwig
Definition
This insect is actually an omnivore that feeds on plant material and on prey items. It is a generalist found in many cropping systems. Females of this predator guard their eggs after they lay them, for up to 10 days, usually leaving just before they hatch. But then, after the eggs hatch, the kids need to scatter fast before a very hungry mother in the neighborhood eats her young. These predators eat a wide variety of prey, including a number of different species of caterpillars.
Term
[image]
Definition
predatory earwig (Labidura riparia)
Term
[image]
Definition
Beauveria bassiana
Term
some details about Beauveria bassiana
Definition
-Entomophthoralean fungal pathogen of insects
-White fuzzy coat, often on beetles, caterpillars

This fungus is rather common worldwide and is a definite generalist. It has been mass produced and is commercially available in various names (e.g., Mycotrol).
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