s.camazine mtfrazier insects: dressed for success
TRANSCRIPT
Who Eats Insects?
• birds• fish• arthropods (insect and non-insect)• amphibians• mammals• reptiles• humans• even plants!
Insects have an arsenalof defense mechanisms
• Morphological / Physical– camouflage (crypsis)– mimicry– mechanical
• Chemical
• Behavioral
Insects have an arsenalof defense mechanisms
• Morphological / Physical– camouflage (crypsis)– mimicry– mechanical
• Chemical– toxins– venoms– pheromones
• Behavioral
Insects have an arsenalof defense mechanisms
• Morphological / Physical– camouflage (crypsis)– mimicry– mechanical
• Chemical– toxins– venoms– pheromones
• Behavioral– death feigning– “house” construction
Monarch butterfly = toxic
Viceroy butterfly = aposematically "dressed" because it doesn’t have the chemical toxins
1) Morphological:Mimicry
Aposematism: warning coloration
Mimicry:
• Batesian - the aposematic inedible model (monarch) has an edible mimic (viceroy)
- the model suffers, aposematic signal is diluted
Mimicry:
• Müllerian - both the model and the mimic are distasteful
- all benefit from co-existence because predators associate all aposematic color individuals as toxic
Chemically defended insects are typically very apparent to their
predators: warning colors
S. Camazine
S. Camazine
These defense mechanisms often work in combination:
Toxins and venoms + aposematic coloration (or sometimes camouflage)
Camouflage + behavior
Mechanical + chemical
In some cases toxins and venoms can be costly for insects
to produce
Aposematic coloration = primary defenseVenoms and toxins = secondary defense
S. Camazine
MTFrazier
It’s not enough to look like a twig (or thorn, stick, etc.)
You have to ‘act’ like one to survive!
Camouflage +
Behavior
MTFrazier
Governing principles of Natural Selection
• Populations of species have variability
• Variation is maintained by sexual reproduction
• Variations can be passed from one generation to the next
• Individuals that have variations (traits) that make them better able to survive (adapted) in their environment are more likely to survive and pass on their variation (traits/genes) to the next generation
Other factors, in addition to natural selection, influence how species evolve
over time:
• Mutations• Genetic isolation