CPT 31 Beneficial Arthropods and Microorganisms

 

CPT 31Beneficial Arthropods and Microorganisms SHIENNA A. A. LEONAR  LE ONAR 

 

Summary (Course Outcome 1)  

I. The Biological World World and Its Balancing Mechanism II. Review of Ecological Concepts- Bases of Biological Control



III. Definition of Pests and Their Characteristics Characteristics  IV. Factors that Determine the Existence of an Organism in an Ecosystem

 

I. The Biological World and Its Balancing Mechanism

 

Habitat vs Niche

 

I. The Biological World and Its Balancing Mechanism 

Habitat - refers to the kind of place where an organism normally lives 



Niche- “occupation” of an organism. It defines the role of an organism in an ecosystem. 

Heron-“fish-eating wader”



Cicada- “plant-juice-sipping summer buzzer”

An organism’s organism’s niche may change during different life stages 

E.g. tadpole

 

I. The Biological World and Its Balancing Mechanism 

The _____is the source of energy for all life on Earth.  _______ are are the only organisms that can directly capture the sun’s energy and change it into a form that other organisms can use. 

Photosynthesis- plants use sunlight to change carbon dioxide and water into sugar and oxygen.

 

I. The Biological World and Its Balancing Mechanism 

oxygen is given off into the air a ir,, where it is available to other organisms including humans. 

Simple sugar molecules make energy available to plants and, by forming the basic units of complex carbohydrates, contribute to  plant structure.



Organisms then eat the plants, or eat organisms that eat plants,  indirectly

gain the benefit of the sun’ sun’ss energy to run their bodies.

 

I. The Biological World and Its Balancing Mechanism 

The flow of sunlight energy is therefore passed from___________ (green plants) to 2. _________ (animals that eat plants, such a leafhoppers) to 3.  _____________(animals that eat other animals, such as  birds); this sequence is known as a 4. ___________.

 

I. The Biological World and Its Balancing Mechanism  

energy is passed along the food chain much is used up a teach level as it works to run each organism



Less energy available at the next stage of food chain.



Consequence many green plants on the Earth, fewer animals that eat plants, and even fewer animals that eat animals; this is known as the ________.

 

I. The Biological World and Its Balancing Mechanism 

sunlight energy is used up as it is passed along the food chain and there is an abundant supply of this energy. energy. 

Contrary, materials from which all living things are made are limited Contrary, in supply and must be used over and over over..



The primary building blocks of all living things include only six materials: carbon, hydrogen, oxygen, nitrogen, phosphorous, and sulfur.

 

I. The Biological World and Its Balancing Mechanism 

When the organism dies and decomposes these materials are returned to the system and are used again.

‘The carbon that was once part of a dinosaur’s tail may now be in the tomato that you eat for dinner!’ 

 

I. The Biological World and Its Balancing Mechanism

 If

these compounds are removed from the cycle in some way, way, they may become limited in supply su pply..  E.g.

trees which wood is undecomposed (nutrients

trapping).  Affects the entire health of ecosystem. E.g.

soil, MO that depends on soil, and so on..

 

I. The Biological World and Its Balancing Mechanism 

Water cycle.  Rain that falls on a hillside percolates down into the ground water water,, or may flow above ground into a lake or the ocean. 

Water in the lake or ocean then evaporates, and drops join together into clouds, to eventually fall again as rain

 

I. The Biological World and Its Balancing Mechanism 

What causes water to be unavailable?  Use of water: How we consume water. water. 

Underground aquifer-water storage (water present in the

 bedrock below ground)

 

I. The Biological World and Its Balancing Mechanism 

Cycling of materials.  Introduction of toxin. 

Concentration of toxins increases along food chain since predator eats many prey with toxins ( biomagnification)

 

Biomagnification

 

I. The Biological World and Its Balancing Mechanism 

Through the flow of energy and the cycling of materials, all living things are interrelated.  Mouse

not only gets energy from the seed that it eats, but also gets materials that will help to build more mouse tissue.

 The

mouse breathes out carbon dioxide which is taken in by  plants, which in turn give off oxygen oxygen used by the mouse.

 The

mouse also depends on plants for finding shelter, and it

 provides food for a snake or or owl.

 

I. The Biological World and Its Balancing Mechanism   

Others are more subtle, such as water flowing underground. But these connections make our actions even more important. Pesticides applied to our fields may add toxic t oxic materials to the river, affecting not only the water itself but also all al l the organisms that depend on the water.

 

Water pollution brought by pesticide application

 

I. The Biological World and Its Balancing Mechanism 

human-induced changes have much different effects on the ecosystem 

By understanding the ecological systems in which we live, we interact with them, we can begin to lessenand ourhow impact on Earth.

 

I. The Biological World World and Its Balancing Mechanism Trophic level •

•

•

Determine the routethe that energy takes in flowing through ecosystem. Pattern of feeding relationship Pattern for chemical cycling

 

II. Review of Ecological Concepts- Bases of Biological Control 

1. Biological control is..  a manifestation of the natural associations of different kinds of living organisms: parasite and pathogens with

their hosts 

 predators with their prey

 

II. Review of Ecological Concepts- Bases of Biological Control

 1. Biological control is..  dynamic: subject to disturbances

by various

factors  subject  subject

to changes in the environment

to the adaptations, properties and limitations of the organisms involved

 

II. Review of Ecological Concepts- Bases of Biological Control

 2.

Population of Ecology

 Populations

are groups of actually or potentially interbreeding individuals at a given locality locality..

 

Characteristics of a Population Populationss

Size – changes in the number of individuals due to:

 1.

 a.  b.

environmental factors (biotic and abiotic)

migrations of individuals into or or out of the local  population

 

Characteristics of a Population Populationss 

2. Age structure/ population structure -

in some species, all the members at any time may be approximately the same age or in the same stage of development

 

Characteristics of a Population Populationss



2. Age structure/ population structure  in

some insect species however, individuals of all ages occur together, and generations are not synchronized but strongly overlap. This is commonly found in short-lived insects with many generations per year (e.g. aphids, hoppers, mites, etc.)

 

Characteristics of a Population Populationss



2. Age structure/ population structure  in

some insect species however, individuals of all ages occur together, and generations are not synchronized but strongly overlap. This is commonly found in short-lived insects with many generations per year (e.g. aphids, hoppers, mites, etc.)

 

Characteristics of a Population Populationss



3. Populations are dynamic with regards to geographic distribution.  They

tend to spread until some limiting limiti ng environmental condition is encountered

 Geographical

barriers like:

 coast,  mountain  desert

ranges,

boundary, or

 absence

of a required resources like food or habitat.

 

Characteristics of a Population Populationss

4.

Population do not exist in isolation.

They

occur in habitats in association with other species, forming communities.

 

Importance of Age Structure in Biocontrol

 In

respect to host populations in which only one or two stages of development are utilizable by a particular natural enemy, enemy, a close synchronization sy nchronization between natural enemy and host life cycles must occur if successful control of the host is to be achieved.

 

Importance of Population Studies in Biocontrol 

1. Aids Aids in classifying the role played by natural enemies as well as the other forces. 

2. In communities, trophic or nutritional association between interacting species can be distinguished: 

Primary producers –green plants



Primary consumers – herbivores

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Secondary consumers –carnivores, decomposers, scavengers

 

III. Definition of Pests and Their Characteristics

A

pest is:

 Any

organism which competes with mankind for a limited resources or is threatening to man’s health or comfort and possessions.

 

III. Definition of Pests and Their Characteristics



A pest is:  Ecologically,

there are no pests, only consumers. However, when an organism begins to take what mankind wants, that organism  becomes a pest. pest.

 

IV. Factors that Determine the Existence of an Organism in an Ecosystem

 1.

Food Supply 

 basic

need of any organism in an ecosystem

 Starvation  Decline

in Supply

 Dependence

up food chain

 

Potential food exists but is unavailable for consumption

1. Accidental

loss of food 

 

Potential food exists but is unavailable for consumption

2. Insect behavior

 

Potential food exists but is unavailable for consumption

3.Cannibalism

 

Potential food exists but is unavailable for consumption

4. Effects of insect  feeding on hosts

 

Potential food exists but is unavailable for consumption

5. Nutrient deficiencies   deficiencies

Mites

 

Potential food exists but is unavailable for consumption

6. Lack of food at critical time 

Hover fly  

 How do Insects overcome food food problem?

 Dispersal  Polyphagy-

eat multiple species of predators or

 plants.  Storage

of food- social insects-ants, bees

 

IV. Factors that Determine the Existence of an Organism in an Ecosystem  

2. Predator Number The numerical response is ecology is the change in predator density as a function of change in prey density.



numerical response was coined by M.E. Solomon in 1949.



associated with the functional response 

change in predator’s rate of prey consumption with change in prey density

 

IV. Factors that Determine the Existence of an Organism in an Ecosystem 2.

Predator Number

 The

numerical response has two mechanisms: the demographic response and the aggregational response

 

IV. Factors that Determine the Existence of an Organism in an Ecosystem 2. Predator Number  numerical response is not necessarily proportional to the change in prey density 



usually resulting in a time lag between prey and predator  populations.

 

Demographic Response

 Changes

in the rates of predator reproduction or survival due to a changes in prey density.

 

Aggregational Response



is a change in predator population due to immigration into an area with increased prey population (Readshaw, 1973).



In an experiment conducted by Turnbull Turnbull in 1964, he observed o bserved

the consistent migration of spiders from boxes without prey to  boxes with prey. prey.  He

proves that hunger hung er impacts prey movement.

 

Ecological Relevance



The study of spiders as a biological mechanism for pest control has driven much of the research on aggregational response.



Antisocial predator populations that display territoriality territoriality,, such as spiders defending their web area, may not display the expected aggregational response to increased prey density.