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Polyneoptera II. Lectures 5. Some major characteristics of Hexapoda : Maxillary plate present 3 body parts (head, thorax, abdomen) 3 thoracic segments each bearing a pair of legs Legs composed of 6 segments 11 maximum abdominal segments Trachea
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Polyneoptera II Lectures 5
Some major characteristics of Hexapoda: • Maxillary plate present • 3 body parts (head, thorax, abdomen) • 3 thoracic segments each bearing a pair of legs • Legs composed of 6 segments • 11 maximum abdominal segments • Trachea • Some major characteristics of Insecta: • External mouthparts • Malpighian tubules • Annulated antennae • 2 pretarsal claws articulated with tarsus • Johnston’s organ • Ovipositor • Posterior tentorial arms fused
Major characteristics • Cylindrical stick-like or flattened leaf-like • Prognathous, mandibulate • Fore wings form leathery tegmina; hind wings broad with toughened fore margine • Often wingless • Legs elongate for walking • Cerci one-segmented • Eggs distinct (http://youtu.be/Cs1Xs3Eheag)
Largest (longest) insect in the world • Phobaeticuschani(Chan’s megastick) • Known from Sabah, Borneo
Chemical defense • Twostripedwalkingstick, Anisomorphabuprestoides • Defense secretion (anisomorphal) produced by two elongate, sac-like glands on the lateral sides of pronotum • Effective defense against ants, beetles, mice and birds
Limb regeneration • Stick insects regularly shed and regenerate lost legs. • Legs can be lost to encounters with predators • Legs can also be lostto complications with molting (usually upside down position) • Complete regenerationof a leg requires three consecutive molts, each producinga successively larger version of the replacement leg, but highly costly Maginnis 2006 (Proc. R. Soc.)
Evolution of wings • Of 3,000 described species, only 40% are fully winged, with the remainder being partially winged or wingless • Ancestral walking sticks must have been wingless • Loss and recovery of wings Whiting et al. (2003) Nature
Evolution of wings • Of 3,000 described species, only 40% are fully winged, with the remainder being partially winged or wingless • Ancestral walking sticks must have been wingless • Loss and recovery of wings Whiting et al. (2003) Nature
Diversity • ~3000 species, 15 families • Three suborders: Agathemerodea (1), Timematodea (1), and Verophasmatodea (13) South American endemic Agathemerodea California endemic Timematodea
Dictyoptera: Superorder consisting of Mantodea (mantis) and Blattodea (cockroach and termite)
Major characteristics • Head small, mobile, triangular • Large compound eyes • Fore legs raptorial • External male genitalia asymmetrical • Predaceous
Sexual cannibalism • Female kills and consumes male of the same species during sexual interaction • Several competing hypotheses • Mate choice • Adaptive foraging
Mantis hearing • Anatomically and functionally single ear comprising two tympana in a deep, cuticular auditory chamber, located in the ventral midline of the caudal metathorax • Ultrasonic hearing for bat detection and evasion (movie) Yager and Svenson 2008 (BJLS)
Mantis hearing • Anatomically and functionally single ear comprising two tympana in a deep, cuticular auditory chamber, located in the ventral midline of the caudal metathorax • Ultrasonic hearing for bat detection and evasion • First mantis deaf, hearing evolved around 117 mya Yager and Svenson 2008 (BJLS)
Diversity • ~2360 species, 436 genera, 14 families • Cosmopolitan, lots of endemic groups • Distribution resulting from vicariance and dispersal • Lots of ecomorph convergence Svenson and Whiting (2009) Cladistics
Mantids of Florida • Little Yucatan Mantid (Mantoidamaya) • Only member of Mantoididae
Mantids of Florida • Brunner’s Mantis (Brunneria borealis) • Obligate parthenogenesis • Mantidae
Mantids of Florida • Stagmomantisfloridensis • Mantidae
Mantids of Florida • Tenoderaaridifolia • Chinese mantis • Mantidae
Mantids of Florida • Grizzled mantis (Gonatistagrisea) • Mantidae
Major characteristics • Antennae slender, filiform • Pronotum oval, shield-like, covering much of head and thorax • Legs adapted for running; tarsi 5-segmented • Front wings thickened; hind wings membranous, pleated • Cerci short, multi-segmented
Various reproductive biology • Hardened oothecae (egg case) • Viviparity • Maternal care • Extreme case: Thorax porcellanafrom India, nymphs feed on mother’s haemolymph
Only about a dozen species (out of ~4000 sp) are known to be pests Most of these are tropical, harmless roaches
Common Blattodea of Florida • Blattidae • American cockroach • Palmetto bug
Common Blattodea of Florida • Blattellidae • German cockroach • Major household pest
Common Blattodea of Florida • Polyphagidae (Arenivaga) • Sand roach
Termites are eusocial cockroaches Termites used to be in its own order, Isoptera, but recent studies have confirmed that they are simply unusual eusocial cockroaches, thus it was reduced to epifamilyTermitoidae.
Termites are the only hemimetabolous insects that exhibit eusocial behavior • Termites build large communal nests that house an entire colony. • Each nest contains adult reproductives (one queen and one king) and hundreds or thousands of immatures that serve as workers and soldiers.
Termites (Termitoidae) • Primary reproductives: queen and king • Supplementary reproductives: potentially reproductive, but with arrested development • Sterile termites: workers and soldiers (nasus) • Nymphs: developmental instars of reproductives • Larvae: instars of sterile lineages
Role of JH in caste differentiation Physogastry: termite queen’s abdomen being distended to 500-1000% of its original size
Common Blattodea of Florida • Rhinotermitidae • Kalotermitidae
Major characteristics • Mandibulate mouthparts • Small and well separated hind coxae • Shield-like pronotum • Front wings leathery (tegmina); hind wings fan-like • Hind legs usually adapted for jumping • Tarsi 3- or 4-segmented • Cerci short, unsegmented
Most diverse order within Polyneoptera • Grasshoppers, locusts, crickets, katydids, mole crickets, weta • More than 20,000 species distributed worldwide • Consists of two suborder: Caelifera and Ensifera • Mostly phytophagous, but many are omnivorous • Well-known for acoustic communication (songs) and the ability to jump • Highly diverse and found in most habitats
Ability to jump • Hind legs are modified to function as a catapult. http://www.st-andrews.ac.uk/~wjh/jumping/legsprng.htm
Ability to sing • Males sing • Usually using stridulation • The vein of the tegmina is sclerotized in a series of sharp teeth to form a file. • Asharp-edged sclerotized ridge on the outer edge of the wing forms a plectrum, or scraper. • By moving the scraper across the other wing's file, a vibration is set up which resonates on an area of the wing known as the harp.
Orthoptera The earliest definitive orthopteran is Oedischiawilliamsonifrom the Late Carboniferous of Commentry, France (Stephanian, circa 300 Ma)
Monophyly of suborders supported • Monophyly of major superfamilies supported • Novel relationships
Common Orthoptera of Florida • Tridactylidae(pygmy mole crickets)
Common Orthoptera of Florida • Tetrigidae(pygmy crickets)