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Discover the fascinating world of insect defense mechanisms, from morphological camouflage to chemical toxins and behavioral tactics. Explore how insects adapt to survive against predators and uncover the evolution of their protective strategies.
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Insects:Dressed for Success MTFrazier S.Camazine MTFrazier
Who Eats Insects? • birds • fish • arthropods (insect and non-insect) • amphibians • mammals • reptiles • humans • even plants!
Insects have an arsenalof defense mechanisms • Morphological / Physical • Chemical • Behavioral
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
1) Morphological: Camouflage Blend into their background by looking like their background MTFrazier
Blend into their background by breaking up their body outline (disruptive coloration) MTFrazier
…but it doesn’t work from every angle! MTFrazier
Blend into their background by looking like some uneatable part of their background MTFrazier
1) Morphological:Mimicry Aposematism: warning coloration Monarch butterfly = toxic Viceroy butterfly = aposematically "dressed" because it doesn’t have the chemical toxins
Looks like a bee, BUT this is actually a fly! Bee-mimic = No venom to back up aposematism
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
1) Morphological: Mechanical Scott Camazine
Venoms 2) Chemical: S. Camazine S. Camazine Toxins: sequestered or produced S. Camazine Pheromones
Chemically defended insects are typically very apparent to their predators: warning colors S. Camazine S. Camazine
3) Behavioral: MTFrazier MTFrazier
3) Behavioral:DIY ‘House Building’ MTFrazier MTFrazier
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 S. Camazine MTFrazier Aposematic coloration = primary defense Venoms and toxins = secondary defense
MTFrazier Camouflage = primary defense Chemicals = secondary defense
It’s not enough to look like a twig (or thorn, stick, etc.) You have to ‘act’ like one to survive! Camouflage + Behavior MTFrazier
This caterpillar is even MORE ‘painful’ than it looks S. Camazine mechanical + chemical
How did these defenses come about? Evolution Natural Selection By the process of
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
Camouflage in caterpillars First Generation
? Third Generation
Other factors, in addition to natural selection, influence how species evolve over time: • Mutations • Genetic isolation
ReviewInsect Defense Mechanisms: • Morphological / Physical • camouflage (crypsis) • mimicry • mechanical • Chemical • toxins • venoms • pheromones • Behavioral • death feigning • “house” construction