Insect Evolution and Paleontology
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Insect Evolution 500 400 Silurian Devonian 300 Carboniferous 200 Permian Triassic Jurassic 100 0 Cretaceous Entognatha Archaeognatha Hexapoda Insecta Pterygota (Paleoptera) ? Neoptera Holometabola Apterygotes Paleoptera Hemimetabolous Holometabolous Zygentoma Ephemeroptera Odonata Plecoptera Embiodea Zoraptera Dermaptera Grylloblattodea Mantophasmatodea Orthoptera Phasmatodea Blattaria Isoptera Mantodea Psocoptera Phthiraptera Thysanoptera Hemiptera Coleoptera Rhaphidioptera Megaloptera Neuroptera Hymenoptera Mecoptera Siphonaptera Diptera Strepsiptera Trichoptera Lepidoptera Relationships among Hexapoda Collembola Entognatha Protura Diplura Hexapoda Archaeognatha Insecta Thysanura Pterygota Evolution of the Insects (Carpenter - 1953) Four stages in insect evolution 4. Development of metamorphosis 3. Development of wing flexion mechanisms 2. Development of wings 1. Appearance of primitive wingless insects Stages of Insect Evolution (Carpenter, 1953) 1. Apterygotes First insect fossils First terrestrial arthropod fossils First terrestrial arthropod trace fossils Trace Fossils Hexapoda Characteristics 1) Fusion of second maxillae 1st maxilla 2) Fixation of abdominal segments at 11 3) Loss of jointed abdominal appendages 2nd maxilla Stages of Insect Evolution (Carpenter, 1953) 1. Apterygotes on Land Devonohexapodus - marine hexapod from the Devonian Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings a. From what structural elements are wings composed? b. For what purpose were wing-like structures first used? 2. Development of wings Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 1. Paranotal Theory paranotal lobes Paleodictyoptera Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 1. Paranotal Theory venation lobes Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 2. Gill Theory Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 2. Gill Theory Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 2. Gill Theory Stages of Insect Evolution (Carpenter, 1953) 2. Development of wings 2. Gill Theory Pros –genes in crustaceans for basal legs are homologous with genes for wing development Cons – skimming (Marsden) – rare in primitive pterygotes - most insect ancestors are terrestrial - aquatic insects appear 100 my after wings - genetic evidence – may be weak since wings are polygenic - Carboniferous insects – big wings but no fossilized aquatic nymphs 500 400 Silurian Devonian 300 Carboniferous 200 Permian Triassic Jurassic 100 0 Cretaceous Entognatha Archaeognatha Hexapoda Insecta Pterygota ? Neoptera Holometabola Zygentoma Ephemeroptera Odonata Plecoptera Embiodea Zoraptera Dermaptera Grylloblattodea Mantophasmatodea Orthoptera Phasmatodea Blattaria Isoptera Mantodea Psocoptera Phthiraptera Thysanoptera Hemiptera Coleoptera Rhaphidioptera Megaloptera Neuroptera Hymenoptera Mecoptera Siphonaptera Diptera Strepsiptera Trichoptera Lepidoptera Stages of Insect Evolution (Carpenter, 1953) 3. Wing Flexion Ephemeroptera 3. Development of wing flexion mechanisms Odonata Ephemeroptera + Odonata = Paleoptera Stages of Insect Evolution (Carpenter, 1953) 3. Wing Flexion Stages of Insect Evolution (Carpenter, 1953) 3. Wing Flexion Development of wing flexion mechanism 1. Neopterous condition 2. Allowed for better running locomotion, etc. 3. Became dominant and today represents 90% of orders and 97% of species 4. Includes all other modern insects Stages of Insect Evolution (Carpenter, 1953) 4. Development of Metamorphosis Hemimetabolous (Incomplete metamorphosis) Holometabolous (Complete metamorphosis) Stages of Insect Evolution (Carpenter, 1953) 4. Development of Metamorphosis Imaginal Discs Stages of Insect Evolution (Carpenter, 1953) 4. Development of Metamorphosis Hemimetabolous Holometabolous Stages of Insect Evolution (Carpenter, 1953) 4. Development of Metamorphosis Evidence for pronymph as holometabolous larva - First instar cuticle in both secreted at same time - Lack wing buds - Similar reduced nervous systems - Both have high levels of JH 500 400 Silurian Devonian 300 Carboniferous 200 Permian Triassic Jurassic 100 0 Cretaceous Entognatha Archaeognatha Hexapoda Insecta Pterygota ? Neoptera Holometabola Apterygotes Paleoptera Hemimetabolous Holometabolous Zygentoma Ephemeroptera Odonata Plecoptera Embiodea Zoraptera Dermaptera Grylloblattodea Mantophasmatodea Orthoptera Phasmatodea Blattaria Isoptera Mantodea Psocoptera Phthiraptera Thysanoptera Hemiptera Coleoptera Rhaphidioptera Megaloptera Neuroptera Hymenoptera Mecoptera Siphonaptera Diptera Strepsiptera Trichoptera Lepidoptera
