Insects Flashcards
Why are insects successful?
Widely distributed in all available habitats- found everywhere except the poles
Insects are species-rich, numerically enormous and structurally diverse
How many species of insects are there?
6-10 million species of insects
How do insects exploit different habitats?
Diverse in shape and size and structure
What are there manner of life strategies?
Adaptable to season, rapid life cycles allow for genetic change
What are the Seven Reasons for success?
- Metamorphosis
- Feeding strategies
- Sophisticated behaviour
- Small size
- Chitin
- Wings
- Life cycles
What is metamorphosis?
Sharp change in form during postembryonic development (after they have become an embryo and egg)
Separate growth from reproductive stages (more dramatically
What does metamorphosis provide?
Opportunities for surviving extremes during different phases
What are the different stages in metamorphosis?
Larvae, lymph (development, growth), final stages reproduction
What does metamorphosis allow?
Period of growth when environment won’t allow it
What are feeding strategies?
The ability to exploit highly specific resources:
• Herbivores
• Predators
• Parasites
• Saprophages (scavenging decaying organic material/dead things!)
Mouthparts of insects highly specific to what they are eating
What do sensory and neuro-motor systems allow (sophisticated behaviour)?
Response to different environmental stimulus in different ways
What is the response to environmental stimuli?
Chemical stimulus and mechanical stimulus
What are the other sophisticated behaviours in insects?
Complex patterns developed
Social insects
Communication in sophisticated ways- warn prey
What are the benefits of insects being small?
Simply there is more room for small organisms than large ones in the same habitat
Can survive states of cold periods
What are the disadvantages of insects being small?
Loss of water rapidly, can only grow to a certain size based on water capacity, can lose heat rapidly
What are the consequences of there small size on surface area/volume?
Loss of water more rapid but have chitinous integument
Rapid loss of heat – temperature regulation has profound effect on biology, e.g., if cold then a state of torpor allows survival; warmer then accelerated activity shortens life span.
Flight more difficult for tiny species but wind-borne migration possible.
Power/weight ratio high- body cant support weight, because exoskeleton is shed and the new one isn’t fully hardened so insects would die if they were larger
Feeding on or within other organisms
Small animals attain maturity quickly and have short life spans (average for insects 6 months; vertebrates 5 years)- accelerate processes much better
What is chitin?
Exoskeleton of insect
What is the integument of a insect?
Complex structure made of tanned proteins, layers of hydrocarbon waxes and polysaccharides
What are the benefits of chintin?
It is physically tough, chemically resistant but plastic
The great variety of shape and form is made possible by the cuticle
Pigments are incorporated as are reflective and refractive effects
It is light enough to provide membranous materials such as for wing surfaces but is strong enough to enable jaws to cut through timber or even metal- allows flexibility
How do wings make insects successful?
Escape earthbound predators
Colonise newly created habitats quickly- flexibility
Abandon unsuitable areas
Find new food sources
How do life cycles make insects successful?
Rapidity a product of small size
Fecundity determined by selection
By comparison with mammal longevity insects have x10 more breeding cycles
Pesticides massive issue for insects- rapid life cycles allows adaptations to pesticides
What is forensic entomology?
Combines the study of insects with the science of criminal investigations
How are insects useful in post mortem?
Insects accumulate on and around the body
Become apart of evidence
Able to estimate time of death or post mortem interval (PMI) from insects present- can be used to determine whether body has moved, if drugs are involved, or if something was involved in another crime
After what time can you no longer identify time of death using body temperature?
After 72 hours, body stone cold
