announcements - sonoma state university · •integrated with endocrine glands that secrete...
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Announcements
Lab Quiz todayOne minute per station
Postpone submission of first insectcollection until April 2
Propose Pepperwood trip in firstweekend of May
Circulation- dorsal heart– In pericardial
sinus– Muscular vessel
enclosed by bodywall anddiaphragm
– Valves preventbackflow
– Pumps pushblood fromposterior towardshead
Circulation- ventral diaphragm
– encloses
perineural sinus– contracts and
directs bloods
blood laterally
and backwards
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Ingestion, storage, grinding• Subdivisions
– Pharynx– Esophagous– Crop for food storage– Proventriculus- grinding organ (gizzard)
• opening to salivary glands
Digestive System• Salivary glands• gut• Malpighian tubules
– free ends distributed through hemocoel– Eliminates non-gaseous wastes– contents emptied into gut and eliminated through anus
Midgut• digestive enzymes secreted for absorption• peritrophic membrane
– non-living area separates food from epithelium sieves foodbetween inner and outer gut
– food circulates for digestion or conservation of digestiveenzymes
• subdivisions– ventriculus– gastric caecae
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Hindgut• Malpighian tubules absorb water, salts, waste amino acids and urea
from hemolymph• Transport urine to hind gut• Hindgut recovers water and nutrients• Uric acid and undigested food excreted
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Nervous system• Nerve cells aggregated into ganglia along
ventral nerve cord.• Coordinates motor, sensory, physiological
processes• Integrated with endocrine glands that
secrete chemical messengers (hormones)
Nervous systemTrends toward fusion and concentration of ganglia
beetle cockroach wasp fly bug
Neural organs in head• Brain- eyes, antennae, signals from body• Subesophageal ganglion- controls and
processes information from mouthparts
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Endocrine system
• Neurosecretory cells producemost insect hormones
• Hormones produced in neuronal,neuroglandular, or glandularcenters.
• Prothoracic glands (moltinghormones) and corpora cardiacaand corpora allata (juvenilehormone)
Interactions of endocrine and nervous systems
Muscles• Insects have only striated muscles• Crossbanding appearance from actin and
myosin
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Crawling locomotion• Walking with three
legs on ground atonce
• Larvae have circularand longitudinalmuscles pressingagainst hydrostaticskeleton
Flight(http://www.zoo.cam.ac.uk/zoostaff/ellington/aerodynamics.html)
• Muscles in thorax control wingbeats in adult insects• Each wingbeat consists of
– Downward forward motion– Upward and backward motion
• Vortices create extra lift
IndirectAttached tothoraxContract tomove wingup
DirectAttached towingStrong flight,weak hover
Flight musculature
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Detail musculature w indirect flight
• muscles deformthorax wherewings are attached
• thorax 'clicks'back into placewhen muscles arerelaxed
• found in moreadvanced insects
Reproductive system• Dioecious- female and male• Usually reproduce sexually, and both sexes present• If asexual reproduction, males absent• Internal fertillization• Sperm stored in spermatophore• Usually eggs laid, some live birth