1. A study of the insect’s environment
Ecology
A study of the insect’s environment

2. Organization of an Ecosystem
Individual
Population = all of one species in a study area
Community = all of the populations in a study area
Ecosystem = inclusion of the influence of both biotic and abiotic factors in a study area
Biosphere = inclusion of all the ecosystems on the earth

3. The Aquatic Environment
Properties of water as an influence
Usually found in liquid state
Gets heavier as it cools until maximum density at 4 deg C., result is that water freezes from the top down allowing depth and length of freezing weather to determine how much of the water solidifies.
Water is capable of absorbing large amounts of heat (500 X that of air) but diffusion of heat is several thousand times slower than air.

4. This capacity creates a relatively stable and uniform situation compared to air
Relationship to gases, the temperature of water determines the amount of oxygen that can remain dissolved, the warmer the water the less oxygen remain dissolved.
Molecular cohesion of surface water when in contact with the atmosphere known as surface tension can be used by insects
Uneven distribution of charges along the molecule give it a distinct polar characteristic which cause an arrangement that neutralizes electrical charges allowing water to act as a (universal solvent)

5. Water is dense and viscous

6. How do the characteristics affect Oxygen content
Cold water < oxygen
Oxygen level in day higher but drops at night when plants stop photosynthesis
Greater the depth the more difficult to get oxygen to the bottom because of the slow diffusion
Turbulent water adds atmospheric oxygen easier than still water

7. Salinity reduces the solubility of oxygen Effects
Dead and decaying materials lowers oxygen levels because of bacterial respiration
Salinity reduces the solubility of oxygen
Effects
Insects without low oxygen tolerance are restricted to cool turbulent waters and need adaptations such as gills to increase surface area for oxygen absorption. Most immatures have closed tracheal systems that won’t function in this environment

8. Gills allow the insect to be larger and survive in lower oxygen environments
Some insects larvae breath atmospheric oxygen through a tube protruding through the surface tension of water (mosquito).
Some insects carry oxygen in a bubble
Few insects can survive salt water environments

9. Salts
The more dissolved materials in the water the more difficult it is to maintain a balanced osmotic pressure.
Hyperosmotic insects must extrude oxygen and ammonia.
Hyposmotic insects must guard against water loss and extrude uric acid and/or use a dessication resistant coating/cuticle

10. Alkalinity and Acidity
Acidity/Alkalinity is a description of the relationship of H+ ions vs OH- ions
pH represents parts hydrogen
pH of 7 represents little difference in the concentrations and as you lose a number the H+ ions increase 10 fold, conversely as you increase a number the OH- ions increase 10 fold so that a pH of 3 is very acidic and a pH of 13 is alkaline. The pH range is from 0 to 14

11. Sea water has a fairly stable pH of slightly more than 8
Fresh water generally varies from around a pH of 3.5 to 10.5
Affect:
Some insects can have a wide range of tolerance such as the whirligig beetle that can tolerate acidity to as high as 3.5, but most often need specific a fairly specific pH to survive, example mayfly nymphs will be gone long before you reach a pH of 5.