INSECT PHYSIOLOGY ENTO 306
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Date Created: 10/21/15
Breathing without lungs Gaseous exchange in insects If lt AWL Today s objectives Part i Examine the basic structure of the tracheal system Review the process of respiration Discuss the physlcs of gaseous exchange Gaseous exchange in insects n The pmtess o1 respimtiu Gaseous exchange uuursthmughz system Mintermi mbesimiied the uacheai sysiehi aggeii is named diret y o hotcohceme With itsta to its sites ovutiiiutioh and the binud is hspon The tracheal system Acro h sssecuoii Viewthmug the ahoomeh m mo vniminn imohh The tracheal system A russsemun mew thruugh the mom The tracheal system Asagmx mew through the head and thorax VThe tracheal system Thetmthe Sy tem and us ner ends VThe tracheal system Tracheoles innervate the ganglia and muscles i min Vina lVlarlllhrmu or irwu rm mlll Spiracles The external openings of the tracheal system I lateral in position never more than one pair on a segment and never on the head I generally a visible opening leading into a cavity the atrium which is often lined with hairs which lter dust I most terrestrial insects have a closing mechanism to control water loss closer usually from the activity of a single muscle What is respiration I Respiration occurs at two levels i cellularlevel mkes place in dne mitochondriaand reactions within cells are d1e chief source of energy for the cell i organismal level iaking in oxygen remrning carbon dioxide Oxygen consumption is directly related to energy expenditure and is measured by 02 intake or C02 output I The energy expenditure at rest is known as basal metabolism Why is it important Heterotrophs obtain energy by the oxidation of organic molecule a process that requires oxygen an example starch glucose C6H206 602 gt glucose oxygen 6C0 6H20 energy A quick review Hewee gases muve lnthemrhezl system Man lnsenl Oxyps n as enters atthe spmsles ltmuvesthmug thevmdval mbra thrnughtheuxheules nzlly zrrwmgn he ussue cs passesshreeghsheusseueg maveme a he turmlullwwsthls path mthe reverse leE JBH Twe phases l anmrmbetmnspnn phase phase 1 ussue Wnspurt Gaseous exchange D Wusmn What are he mars that Impact on rates of dllluslan e gses o and C01 m Inserts l malemlm welght ewesleh ls lnversely pmpumnnzl tn me square mes enhe mulemlzrwelght e1 me gas MWnlOz v MWnlCmM e 4 sehsehmueh enhe agas auhe we ehes enhe system 3 the permezlmhty enhe submte mmrhmmquot M We mm eheenhm Gaseous exchange Rates e oZ ewes eh Recall that there are 2 diffusion phases h ahalneee phase 7 nnsrui phese Substrate Permeab constant I Muscle 00000 I4 oz 5 755 7l4ume5 mare permeable mmrthzn m mustlelll Gaseous exchange Dlsmnte amhmeh e1 subsmte permeablllty Remember Wusmnunlxnzturfaver and me ah mple yee knwwthe ozpermem unsmntlurmustle yuu sah mltulate the dlsm ie Oz muld dl use thmugh musnle Perme mlvva e h muscle n WWImam H mm mamum mm Haw haiktu the nrlgnzl queslmn ea he msheumeg m2nAANH n menu mew Niven ooooooxslsem new om hem h We seous exchan e Distance 7 a mctiun ofsubstrate permeability Key point e ninhenlss must be quite close to mitochondria Weierugban insect scientist from meri gepredlcted tracheoles n dragon fly muscleswuuld be lessthan IO micronsapart In aesthey ae about 35 micro p Today39s objectives Part 2 Breathing in large bodied insects Breathing in aquatic insects and parasitoids Functions other than breathing Terrestrial insects managing H20 loss The prInCIple oi amusmn can also work against Insects Diffusion is inversely proportional to the square root eme molecular Weight ufthe gas e Thu meznxwzter di uxex iaxmsemenmgen How du insects preventwater loss l cloxexpinclex 2 waxlzyeronth epmcie 3 behavioral regulation What do large insects do about breathing as the di usion distance increases I the cunc e W entratiun gradient smal er 39 be s l J 2 diffusion razeer new decreases insects solve ms problem by using Varmlatiun M 3121 I changes in bodyv l 2 displacement of hemolymph mm my Ventilation via displacement of hemolymph typicaiiy takes piace in admit insects inveivestne airsacsand bio ad How I Inward Ming 7 meme 7 27 backward inning Mme b7 Aquatic Insects asecus excnenge 7 even submerged tney can obtain 02 trcni air have ii hm teiescepic terminzi sipnen spimcies pierce tn e eerencnynie ufaquatic piznts Aquatic insects ch cc submerged insects obtaining oxygen trcni tne sir Must eciietic insects iniistVisit rne surface tc renew tne gases iii iiie trachezi systeiii wtu ne prevent W use water entry intc tne irsciesi Wm 3132 Aceticiecr acre spiracies may nave nycremge properties Aquatic insects How cc aquatic insects use sir bubbiesn ma m cm W Mum irerri mums in wimim in mm m arr ismv an am no r r VAquatic insects How is oxygen obtained from the water nacheal gills leaflike extension of the body Clawmn Pu 719 danieelniee Caddisflies lamentous abdominal gills Stoneflies position varies VAquatic insects Tiacheal gills in dragon ies Dmgonfly lame have gills in the anterior part of the rectum the branchial chamber cumin 7 VAquatic insects Plastron respimtion the use ofa physical gill Plastron a thin lm olgas into which spiiacles open i spiigi m 9 Endoparasitic insects How do endopaiasitic insects obtain oxygenl I via cutaneous diffusion Ichneumondids bmconids Diptera larvae 2 caudal vesicle right 3 caudal laments 4 penetration ofthe host body wall or respiratory system it gives so terrestrial i Other Functions whole system in particular the airsacs lowers the insects The speci c gravity rne degree ol buopncy in aquatic insects but not in ts hemolymph circulation assisting when insects innate alter a rnolt insulation ol the thorax flight muscles nsec act as connective issues involved in delense e cockroaches sorne lorcibly expel quinones Can See Clearly Now The Physiology of InsectVision I Compound eyes constructed from many similar units called ommatidia er of ommztidz wries o ooo m dmgonmes and drone honeybees 5500 m w r erhoney ees 800 m Drmophrla ma Ponem 2N Workers have N cornea lens ll Compound eyes Light gathering by ommatidia I corneal lens transparent and colorless cuticle it is biconveX semper cells 4 in total lie beneath the corneal lens and they produce a second lens the crystalline cone 2 V semper cells bordered laterally by primary pigment cells 3 V corneal lens nucleus ol Semper cell crystalline cone primary pigmenl cell rhabdom retinula cell secondary pigment cell basal lamina 4 5 V V lll Compound eyes Sensory responses to light there are generally 8 elongate neurons sensory elements called retinula cells the axons of retinula cells pass through the basal lamina and into the lamina of the optic lobe the margin of each retinula cell is differentiated into closepacked microvilli collectively the microvilli of each retinula cells form a rhabdom visual pigment is located within the microvilli corneal lens nucleus oi Semper cell crystalline cone primary pigmenl cell rhabdom retinula cell secondary pigment cell basal lamina axon Ommatidia structure 2 V 3 4 I Functioning of the eye Transduction the conversion of light to electrical energy the conversion of light to electrical energy involves visual pigments insects use rhodopsins which are a type of chromoprotein rhodopsin consists of i retinal the aldehyde of vitamin A ii opsin a protein rhodopsin is a transmembrane protein in the microtubules that form the rhabdomeres 6 CH3 CH3 CH3 CH3 CHZ OH vitamin A CH3 CH3 CH3 CH3 CH3 CHO trans retinal CH3 CH3 CH3 CH3 l 11 cis retinal CH3 CH3 retinal opsin protein rhodopsin ll Functioning of the eye How transduction works I retinal in rhodopsin catches light 2 retinal changes form it goes from bent cis to straight trans 3 opsin separates and triggers a nerve cell sending a signal to the brain b light 480 nm rhodopsin I dephosgngrylation diark active release from arrestin Disretinal rhodopsin rhodopsin transretinal in ctive x Emilequot Inac Ive light 39 580 nm metarhodopsin metarhodopsin low efficiency high efficiency I I V I G protein retina active phosphorylatlon opsin E binding to arrestin depolarization ll Functioning of the eye wavelength discrimination occurs in many insects the ability to discriminate between light of different wavelengths requires the presence of photopigments with maximum sensitivity to light of different wavelengths yeiiaw ullravlolel blue green red I all insects have a visual pigment with maximum absorption in the green range of the spectrum 490540 nm but this pigment often extends to A 39e 400 nm and into orange 600 nm 2 usually 2 other pigments are present relative absorption 0 39o o i one with maximum sensitivity to 39 0 300 400 ii one with maximum absorption in the blue region 50 60 70quot Wavelength nm 3 ong waveengths such as red do not stimulate Fig 2214Visua1pigmems absorpiionofiigiuofdi ercm h h h f wavelengthsby rhreecommonly occurring visual pigments in t 8 eyes In mOSt InseCtS Wlt t e eXcePtlon 0 insecleyeswithpenkabsurptionintheultravioletblueandgreen ranges urine 5 mum The absorption by each pigment is expressed as a percentage of the maximum for that pigment dragonflies some leps and a few hymenoptera l 2 LA v U39I v Insect vision what is possible eld of view insects with well developed eyes generally have an extensive eld of view cockroach can see 360 horizontally and in the vertical plane the eyes overlap dorsally distance perception two mechanisms to judge distance i a stereoscopic mechanism via binocular vision ii motion parallax side to side peering movements keeping the feet still and the head vertical eggrasshoppers visual tracking the ability to keep a moving target within a speci c area of the retina often when the animal is itself moving visual flow elds during forward locomotion objects appear to move backwards with respect to the organism important in flight form perception the ability to detect form depends on an insect s resolving power honeybees exhibit good pattern recognition see adjacent gure a vemcal panems msmuwsruu rim dishnguisha I i T E 0 b havimmal pallevns dislil gmshc nu amgmgu 0 El irnh l m mnulmuh y i Am mm l mm Mqu milismmmsliVlimcnulvrummu linm mm 1 immulmuh hm m Mosaic vision W W 39 39 W 86600 K Mg gm 39 Dorsal ocelli found in adult insects and larvae of hemimetabolous insects I a typical ocellus has a single thickened cuticular lens 2 each ocellus contains a large number of retinula cells 800 l 000 in a locust packed closely together without any arrangement LA v illumination produces a sustained depolarization of the retinula cell no action potential is produced rather graded receptor potentials are passed along the axons to the synapse 4 their function remains uncertain corneal i they produce an image but it is not in focus on the l ensl retina and form perception would be crude plgmen r 39 quot halfting ii structure and physiology suggest they are adapted for concentration of light and perception of changes in 4 5321 intensity l Wellalmr in locust they are involved in detecting rolling during flighthelps lens would bring integrhaenulmn with perception in changes in the position of the horizon Imag ahlo a locus al 7X ispmn vv vv Stem mata the only visual organs of larval holometabolous insects a head b stemma c stemma longitudinal section llansverse sections cemeagen cell distal rhabdorn envelope cells distal rhabdom Damagequot I cell proxlma b l proxmal ihabdom mahdom envelope cells envelope cells in caterpillars each stemmata has a cuticular lens beneath which lies a crystalline lens and each crystalline lens has seven retinula cells associated with it the visual elds of adjacent stemmata do not overlap so caterpillars perceive objects as a very coarse mosaic this is improved by sidetoside movements which increase the eld of view caterpillars can differentiate between shapes and orient towards boundaries between black and white areas caterpillars have three visual pigments and can distinguish between colors Thicker than H20 Circulation Blood and the Immune System cal ix hunim u Aninsmhlnod d1 mmum Today s objectives Part I 0 Examine how hemolymph circulates in insects I Discuss what hemolymph is and what39s in it I Discuss some ofthe proteins found in hemolymph Insects have an open blood system a mosl insects in lchneumanidae has haan Vsnnardiai sinus dorsal assimian 9 perwiscslal Sinus venlrai diaphragm Parinauml news curd sinus quotewe cold Fig 51 Main siiiusss m the liemacoel shnwn in diagrammnic crcsysectinns a cr Richards 1963 The heart and hemopoietic organs the dorsal vessel runs along the dorsal midline opening anterioily and abruptly in most insects 2 regions 7 mm awn mi impiei unperlurated tube hemopoietic organs mm in ma cmquot in mi How is blood circulated in insects Insect hemolymph circulation http 397 vu ow hemolymph circuiltion In Insect 0mm mg 5m h Hemolymph and what it does 0 consists ofa fluid plasma in which blood cells called hemocytes are suspended 0 it contains many chemicals can you name some 0 circulates around the body bathing the tissues directly 0 plays a role in melting volume regulated by hormones e demoiympn which is aqueous 39 doessstegoniesoiiipopdonin 39 nighdensiniipopnoninHDip 39 iondensiniipopdoninddDLp 39 denydigddensiniipopdoninWHDL dd one none ioid pnesensnne ionensne density dd Lipid Transort I Midgotto Fat Bodd Fat Bodto Fight Mosde3 For Body toDeieiooing Oocytesnnddiinansien 0in in the Hemoismpn sdipoiinett nonnone minnow I 0 ion Today s objectives 2 eimedimmudnvenusmammdimmumn 39MWWMWMM omnmmmmmm Hemolymph also provides immunity What is immunity resistance tn or protecuon uninv a 391 4 4 insects and omer invertebrates practice a diirerent form of immunity tnan mammais s iack iympiiccytesmceiis or heiper ceiis ct biosynthesize immunogiobuiins two maicramsciinsectimmunity ic or r humorai or ceiirhee immunity 7 mucii siowen nours iater Insect pathogens What are tne cnaracteristics of insect pathogensz e tney kiii reduce sicw grcwtn or snorten tne We of an insect pest e tney are usuaiiy speci c to target species or to a specinc We sage abundance unpredimbie prcin de adequate commi e tney may cause epizootics an outbreak tnat kiiis many nests Insect pathogens How do Bacteria andVirusesWorkl i immisyirus inninige i inset imminent a inseam er imam mar Virus is relaxed Bacteria Viruses A baculovirus at work II Insect pathogens H Mancungmmnemmueswmr Fung Nemzwde III Insect pathogens haw an prmuzmns and mmmspn dm wurkl c mom WWW m Mmmpn dmmmmu mmummm mm Mtamman WWW mmmmmmmmwm Insect parasitoids mmsimids a N Amen m Emums MWMWW mammm I neWMmmmm gym kw my 19mm mm mm W Mymmm s quotmmtmm M mus ammm Mammmmm Y wmw mm mummm mm 19mm mm mm mm mm We imman m Hemocytic immunity I Phagoc osis I Gmnquiytesznd PIzsmzwtytes phageer smII Wmss sun 5 banana nnd39ungI eg ya 51 phagutyumtmn refersw me pmtess a mum Wernzhutmn mmgn Invaders mm mm mxmg aims setundany n erwnrds Hemocytic immunity ii Nodule formation nnduieszre aggregates ememeeyxesmm ant2p meme mitmbes en ewemve m 5 e1 ieznngthe hemeiymm and pmmbiy n39greaterimpumntet n pmgntylnsis m irng inr ge ns 5 mi wiyhedmns mng sparesznd prmuzmnszrezisumken upin nuduies WW Hemocytic Immunity i ncapsulat39 n when nr gzmsms nr dumps are an big in be pmgeeyuzee arm em nnduiesithey my be enmpsuizted enmpseieuen isme ssquesleriutmn e1 urymsms er dumps mm muitiizyered aggreytes memes zisu invuivesthe reiease e1 mguium whith pminbiy aids in ermine izyers ei eiis seggeeee kiiiing meeiemems intiude permeeuem meizmutmn and iysuzymes Humoral Immunity Amineenei Pmteins Hemeim xrmii wequot 45 km in mm m xymiem e mu m mum mm awnamumMiymmmMnumanuim Cetmpins Wmmxemm M m USA mummuwn mums newquot mman meme we no mo Lysuzymes mAmiylAquiymmieba m mmmu m My mu mum wan mum Wequot Making It All Go Insect Muscle Physiology Today s objectives m 0 Explore and describe muscle structure View muscle structure and contraction animations 0 Explore muscle nerve innervation Muscle structure Each muscle is made up of a number of bers What are bers long multinucleate cells running the length of the muscle What are the characteristic feature of bers myo brils my muscle embedded in sarcoplasm sarc tissue brils are composed of molecular laments hiyagin protein thick made up of numerous myosin molecules actin protein thin consist of two chains of actin molecules twisted round each other laments are arranged in units called sarcomeres a bril comprises a large number of sarcomeres stacked end to end within sarcomeres there are Zdiscs plus lA amp Hbands The structure of insect muscle Leg muscle Muscle flber Myolibril Myofilamenls Aclln FIGURE 101 39 r39 me the K gt m mung ufmany muscle bers arch muscle ber is a cell surrounded by an slsslrlcrrlly cxcmble cell mrmhmneWllull rlrs cytoplasm ol rrruscls ber ch longlmdinal arrays ohrryo brlls that extend rrs lung s banding prrrcm vrsrhls 1n the myo bnls lesnlts from the degree arm11w ofuclln sud myosm myol39rlmrrenrsrlre dark A band rssulls from mm ml nlymin overlapsTlle H 10m wllhm me l 39 39 W I l and rhr z llnc u the Icun end platz Ttubules Myofibrils Vesicles of sarcoplasmic Trachea reticulum Muscle nucleus Mitochondria FIGURE 102 A cross section through a ight muscle ber showing the myofibrils in the cyto plasm and the invaginations of the T tubules that permit membrane depolarizations to reach inside the cell From Pringle 1975 Reprinted with permission Muscle structure Attachment of muscle ber to the integument Muscles attached at cuticle are not digested by molting fluid this allows insects to continue activity after apolysis separation of cuticle connections to old cuticle broken during ecdysis shedding of old cuticle Fouticle gtllt epidermal ceII gt muscle hemidesmosome desmosome attachment i er 4 muscle fiber actin myosin microtubule filament filament epicuticle procuticle plasma membrane Muscle structure Two broad categories I Skeletal muscle attached at either end to cuticle moves skeleton A Synchronous the majority direct relationship between motor neuron activity and contraction one impulse one contraction B Asynchronous one impulse multiple contractions only in the flight muscle of a few insects eg Diptera Hymenoptera 2 Visceral muscle moves viscera gut ducts of reproductive system Muscle contraction how do muscles work Contraction requires lots of 02 muscles have good tracheal supply Mechanisms of muscle contraction in insects httpinsectstamued ustudentsundergradento306animationshtml l muscle structure overview sarcomere structure Dr Larry Keeley Emeritus Professor Department of Entomology Texas AampM University sarcomere bril contraction actinmyosin crosslinking sliding filament O U39IALAJN crosslink biochemistry Muscle innervation How are nerves connected to the muscles Multiterminal each axon has many nerve V e n d i n gs 2 Polyneuronal muscle bers innervated by more than one neuron cuticle I ber with last bers Myth 3935 A i y axon terminals wxulnddumm E Irmanmmldapmssov g mme Cuiicle Single neuron Innervates slow axon multiple muscles inhibitors M uscle innervation What happens in different types of flight muscle Synchronous flight muscle Asynchronous flight muscle each contraction of the flight muscle is several contractions follow the arrival of produced by the arrival ofa nerve each nerve impulse lmany relationship impulse relationship the motor neurons to the antagonistic muscles Eire approximateiy in amiphase a synchronous muscle b asynchronous muscle nefura l l l l l l l l neural l I Sl39muquot l l l l l l l l stimuli T I muscle MWJUUUUHUU mmiMMMWMMW contractions neural l l l l l l l l I mquot I I I I I I 2353 l l l muscle WMJUUUUUUU mmmmmmmmm contractions Insect Cuticular Transpiration Introduction to me sclenliflc memod lt Dsnnsmsqussuun 2 Game mmmanun and vssumces abssz 3 Fuvmhypmhsws a a Ec data 5 Analyze data cnvmvs smusncax ana ysws e Mamet data and dvaw cancmswms rtms can 52va as a stamng pumnm usvsmpng new hypumeses 7 a FE Eusequm ydnne bymnsvsmsnuss mdmevemdasses What is the funclion of amide pays a me m suppanng m2 msect pnvmss pmssnun sxpsy uce was 055 pamsmanyms my Enesma msects madman m puduce sense mgans mysma swucmve s mpuvtarmn pmucmn mcmm Insects and transp alien Why Is uznspnzom Impu znl nanspvamn s me guess by much way s 055 mm me my man mgamsm Waugh apuvannn Quesnun Haw as mass thEc memsewas awnst Watev uss7 The insect cuticle mode 5 secvennn m we epuenms that tux215 m2 mm m m mama m m mdyas WEN as hmng 2mmd2nna mxagmanms Theve ave MD ma m veg ms Unsws s m Enducume and Exncume u we lt mnevvegmn 2mm um m ck 2 umnegunwum mmK cansws smmnevandumavepcu The outer region ep u le mnevepcumercnnswsts m pwmamym anned um hpupmams m u vepcumerws mvmemayevmnew v quotWquot cume nextenswtle v 7 My a waxrplenuml mly ny mczlhms WM wzhelpmullng m me cuncle 4 cementrpmacnnnmme mum Wan mm 77 Laboratow Obieclives TD demunsn ale m2 lmpullance m m2 cunnulaw Wax layel val Wm lElmlan m msecls TD delamme m2 mellmg mm cannula Wax Grumphadummipunenmsi Madagascav hlssng camst Data collection and analysis Vuumlwmkmpawsarmeachpawuwmkwnhcuckmachss upunlne cunclusmn mm expsnmsm lmllal Mass mad and dammed The classdalawlll be analvzed nvms TA amuuwm vecewe a um um mm vesunswa emall m me mm m a PDF 2 Spec c queslions to answer Whal lempevaluve nu Vuu esllmale aslhe cvmcal lempevaluve 1mm byeakduwm ls lheve a dmevence belween me msmng pmm values 1m unlvealed and uswaxsu msecl57 m7 vvm hae agsms such aslalc smca get and alummum dusls been successm as msscucmssv Cardioacceleratory Activity by the Hypertrehalosemic Hormone A Comman Cause of Heart 7 Attacks among Plies Introduction to the scientific method 1 Define the question 2 Gather information and resources observe 3 Form hypothesis Null hypothesis Alternative hypothesis 4 Perform experiment and collect data 5 Analyze data involves statistical analysis 6 Interpret data and draw conclusions this can serve as a starting point for developing new hypotheses 7 Publish results in the case of this lab write a scientific report 8 Retest frequently done by other scientists or different classes A closed circulatory systems 1 Common in vertebrates and a few invertebrates 2 Blood carried within vessels of different size and wall thickness 3 Blood is pumped by a heart through vessels and does not normally fill body cavities The Circulatory System 329333 n CLquot Mitral Valve Pulmonary quotAortic Valve Valv Tricuspid L Valve C I Inferior Vena Cava An open circulatory systems 1 Found in arthropods and molluscs 2 Hemolymph is pumped forward by the heart 3 It bathes the tissues and acts as a carrier of various nutrients and carrier proteins eg lipophorin INTERNAL ANATOMY OF A CRICKET DORSAL VESSEL HEARTl OF MEN Anterior optic lobes gastric W antenna of brain gizzard cecum stomach ovary heart colon brain rectum anus r7 crop If esophagus genital labrurn ori ce a i labium duct oi salivary ventral intestine oviduct salivary gland gland nervous system i r i ii iii 140234 man u Hypertrehalosemic hormone and circulation How does hypertrehalosemic hormone HTH influence circulation Last week we learned about the importance of HTH in the regulation of insect blood sugar levels HTH also acts in a second fashion as a cardioaccelerator that increases the rate of heart beats Question Why might HTH increase heart beat rate A reminder Where does HTH come from HTH is secreted by paired neurosecretory cells called the corpora cardiaca Laboratory objectives Demonstrate the effect of hypertrehalosemic hormone HTH on the heart Illustrate a hormone bioassay Illustrate how physiologists can work with insect tissue in vivo l Blaberus discoidalis false death head roach Data collection and analysis You will work in pairs and each pair will work with a roach You will record heartbeat counts for three treatments Counts will be scored over 60 seconds and each count will be replicated 3X for each treatment 1 Basal Count 2 HTH Count 3 Post HTH Count The class data will be analyzed by the TA and you will receive a print out of the results via email in the form of a PDF file Specific questions to answer What is the effect of adding HTH to insect fat body Was the mean count rate for the basal treatment the same as for the after wash count rate If so why If not why not What we would like from you content Introduction brief 45 sentences Materials and Methods as subheadings Something about the insect A brief description of the protocol used A quick description of the statistics used Results brief summary of key findings When possible present the data as a figure bar graphs with standard errors Discussion short about 810 sentences References Hormone Regulation of Trehalose Synthesis by the Fat Body Introduction to the scientific method 1 Define the question 2 Gather information and resources observe 3 Form hypothesis Null hypothesis Alternative hypothesis 4 Perform experiment and collect data 5 Analyze data involves statistical analysis 6 Interpret data and draw conclusions this can serve as a starting point for developing new hypotheses 7 Publish results in the case of this lab write a scientific report 8 Retest frequently done by other scientists or different classes Energy for life Why are sugars important Sugar is an important source of energy During digestion sugars such as sucrose a disaccharide are broken down into single molecules glucose and fructose Glucose that occurs in excess is stored as glycogen Question How do human and insect blood sugars differ 9H O Joohho OH HO quotquot0 O quotquotOH OH H L OH Glucose Trehalose Insect blood sugar levels are regulated by hypertrehalosemic hormone HTH 1 HTH is a peptide consisting of 10 amino acids 2 It stimulates fat body to degrade glycogen stored sugar 3 Glucose precursors are synthesized to generate trehalose 4 The result is an elevation in the synthesis of hemolymph sugar HTH FAT BODY Glycogen phosphorylase phosphorylas PP P TP inactive actiVe UT4 Glucose 1P UDPGlucose f2 ADP UDP ATP mutase GlucoseGP trehalose synthase TrehaloseGP y HEMOLYMPH Trehalose Where does HTH come from HTH is secreted by paired neurosecretory cells called the corpora cardiaca What about sugar regulation in humans 1 What hormone controls bloodsumr levels in humans 2 Where is this hormone synthesized in humans 3 What disease is associated with this hormone Laboratory objectives Demonstrate the action of HTH on the fat body to increase the synthesis of trehalose Illustrate a hormone bioassay Illustrate how physiologists can work with insect tissue in vitro l Blaberus discoidalis false death head roach Data collection and analysis You will work in pairs and each pair will work with a roach either a male or female adult You will record six absorbance measurements and give them to the TA upon the conclusion of the experiment 1 Reagent blank 50 pl Ringer 2 Standard50 pl 20 pg Trehalose 3 Standard50 pl 40 pg Trehalose 4 Standard50 pl 100 pg Trehalose 5 Control 50 pl incubation medium 6 HTHtreated 50 pl incubation medium The class data will be analyzed by the TA and you will receive a print out of the results via email in the form of a PDF file Specific questions to answer What is the reason for generating a standard curve What is the effect of adding adult HTH to insect fat body Did you observe a difference in trehalose production from adult female fat body that was treated with HTH from adult males or females If so why If not why not What we would like from you content Introduction brief 45 sentences Materials and Methods as subheadings Something about the insect A brief description of the protocol used A quick description of the statistics used Results brief summary of key findings When possible present the data as a figure bar graphs with standard errors Discussion short about 810 sentences References Come on Down the Physiology of Walking and Locomotion 0 Explore Today s objectives m leg musculature and nerve innervation Discuss leg movements and sensory input 0 The mechanisms of crawling climbing and jumping The thorax design Chapman Fig 73 ll 3 a Perla 2 Iclgum anaplaurils gt complexme prasfamum spinasfnmum Daslslemum slemellum Chapman Fig 75 0 three segments each bearing a pair of legs 0 winged insects have a pair of wings on the meso and metathoric segments collectiver the pterothorax 0 membranous regions allow greater degree of movement b Nomadacris b typical wingbearing segment ag zwfslis basisremum scum SCU19 Wquot posmomm 11 quot7715 eeeee a quot 39 K j preaiar Z quotflllil 3quot quot quot l poslalar S emal mesothorax Dismal 7 quotquot39 r I arm ap phySlS 9mm T subalar 0 va basalar 7 pleural sulcus eplslernum eplmaran 53 melathorax IrnciwmlmI V L 338231 My 93 I l quot39coxa J 39 Basic leg structure lrochamsr apodemes ul aapvessur muscles apodemes oi levamv muscles aniculaunn with coxa Ircchanlsr pvelarsus c extensar must 2 proximal end proximal end cl lemur distal end l of femur proximal end 0 Ilbia hollow tubes six segments articulated with each other by mono or dicondylic articulations apodemes internal projection of cuticle for the attachment of muscle oHibIa a b c 4 anlenor eplslemum w e pleural pleural sulcus amculallon llexlbls Pleu39al comm amculamn E tmcnamln 9 lruchaminalv amculauon slemal slamum amculauon Muscles of the legs Two main categories extrinsic amp intrinsic a extrinsic muscles abdumor muscle ham plsumn pleural amculalion llexlble Junction or lmchanlin wnn epistemum pranwmr muscle Irom ergum lrochanlln anlenor rotator muscle lrom sternum adductor musclmv from sternum V I extrinsic arising outside the leg 0 the coxa is moved by extrinsic muscle coxa muscles also attached to wings promotor and remotor muscles on the tergum abductor and adductor muscles from the pleuron and sternum rotator muscles from the sternum intrinsic wholly within the leg running from one segment to another typically a pair of antagonistic muscles in each segment extensor amp flexor muscles levator amp depressor muscles Muscle innervation Innervation of the leg muscles is complex inhibitory axons I four depressor muscles of the trochanter in a cockroach I35d 35d gt exhibitory synapse sow axon I O InthItory synapse fast axon I I 1 I I I I I I I I I I I l I I I i 35e I35e The physics of moving lift drag thrust weight gravity angle of attack angle at which wind strikes the body zero for a walking insect Sensory systems How do insects know when to move 0 proprioceptors monitor the position of leg segments and stance hair plates campaniform sensilla amp chordotonal organs 0 exteroceptors involved in the perception of environmental stimuli mechanoreceptors and chemoreceptors 69 V nlml View ui imchamar CA a 0 M4 0 CA CA CA CA 2 2 I 1 0 CA campanllcrm sensilla HP hair plan 80 chumomnal urgan b externrsceplms nosieuav tarsumem 2 mma 1 lt has alsus mechanossnsllln pmva venlral pulvilli Leg actions Maintenance of stance standing still requires muscular activity I extensor muscles 2 involves slow axons campaniform sensilla on the legs monitor strains in the cuticle a standing insect o proximal O distal banding Iowa c reflex responses to stimulation of proximal sensilla unstimulated 7 sllmulaled sensory input exlensor tibiae llexor ibiae 6150 quotochameris mm exor irochameris M M l Movements of the legs De nitions Protraction complete movement forward of the whole limb relative to its articulation with the body Retraction the backward movement of the leg relative to its articulation between the time the foot is placed on the ground and the time it is raised Levitation the raising of the leg or a part of the leg part of protraction Depression lowering of the leg or a part of the leg Extension an increase in the angle between two segments of the leg Flexion a decrease in the angle between two segments of the leg Leg actions Walking and running pattern of movement Legs move in sequence which are varied at different speeds so that stability is maintained coordination involves a central pattern generator cpg protraction leg moves forward retraction leg moves backwards a protraction time 1 b protraction time 1 retraction time 5 retraction time 2 1 foot left 1 left 2 left 3 right 1 right 2 right 3 39 L1 L2 L1 L2 L1 L2 Stepplng R3 R2 R1 L3 L2 L1 R3 R2 H1 L3 L2 L1 R3 R2 Fl1 L3 L2 L1 L3 sequence R2 R3 R2 R3 R2 R3 Leg actions Walking and running neuromuscular activity alternating movements of protraction and retraction the result of regular patterns of activity of antagonistic muscles in the different segments of the leg patterns are generated by a program within the CNS leg L3 retraction protraction retraction protraction lllllllll l llllllll llllll leg R3 protraction retraction protraction retraction depressor of trochanter g g levator of trochanter trochanter depressor of I Leg actions lllWalking and running peripheral modulation 0 propriorecptors often connect directly with motor neurons 0 input from exteroceptive mechanoreceptors is integrated by spiking local interneurons sensory spiking intemeuruns nonAspiking molar neumns local neurons local lntarsegmenlal imamemns pruptiocsplor Q exzsruceplurs Q 4 e 4 j 0 4 muscles 39 externcaplors 4 39 0 4 39 y 1 4 4 excilalory synapse m next c inhibitory synapse segmenl Leg actions IV Crawling insects move by changes in the shape of their body rather than moving legs cuticle is soft so hemolymph provides a hydrostatic skeleton muscles keep the body turgid body fluid is incompressible so compression of one part of the body causes some other part to expand move by serial contraction of the longitudinal muscles laxeval body l an m retraclur 1 muscles ventral body wall proleg l creams relmmur muscla of wales W 1 l proleg 5 pmlag 5 prolag 4 ploleg a abdcmlnal 2 0 platholax mssolhorax mexalnarax abdominal l la abdominal 3 abdominal 5 abdomlna o 10 20 llme s Climbing on to smooth surfaces tenent hairs adhesive setae that form adhesive pads adhesion is the result of surface tension of a fluid at the tips of the hairs or on the pads secrete lipoproteins produced by gland cells alternatively adhesion may result from molecular forces a tenent hairs b suckers adhesive cups 0 Iarsamere a v Iarsumere 4 arsomere 5 Jumping With and without the use of legs jumping with legs hind femora house large extensor tibia muscles tibia femur joints are heavily sclerotized rapid release of energy is required mechanisms of jumping not involving legs click beetles Collembola jumping sprintails a hexapod slow contraction of muscle then sudden release energy stored in the muscle and cuticle resilin prosternal peg and median dorsal muscle use a furca jumping is a means of escape landing is uncontrolled The world s greatest leaper Malcolm Burrows 39 e University Nature 424 509 2003 Name Phllaenus Spumartus spmebug r frughuu er Budv mass 12 m hgram Budv 2n 1 5 m mm mdes vaung an wants 5 metres jumped 70 centimeters in the air same as a flea but 60x heavier A camera Everetan at 2mm rrames Der Secand can anw Just capture the ban Nervous System I Components Functioning and Anatomy Neurons of the fanshaped body and one of the A local interneuron in the primary olfactory center two noduli of the cockroach central complex of the sphinx moth Manduca sexta Nick Strausfeld The University of Arizona Carolina Reisenman The University of Arizona Today s objectives m Describe the basic components of a neuron Describe the basic functioning of a neuron Describe the anatomy of the nervous system Three basic types of neurons dendrite terminal arbonzation b bipolar Fig 201 Neurons Diagrammatic representation of basic types of neuron Arrow shows direction of conduction 39 2 3 4 monopolar a single projection from the soma branching in two most insect neurons bipolar unbranched dendrite receives environmental stimuli axon extends to central ganglia multipolar many branches off the soma eg strech receptors for a review of neuron structure visit httpinsectstamuedustudentsundergradento306neuronstructruehtml 2 3 4 Four basic neuron functions sensory neurons nerve cells that innervate sensory organs and located at the periphery PNS and are bipolar in design taste receptors mechanorecptors olfactory receptors light recepetors ratifiar neumns a neuron that innervates muscles they are part of the CNS and are generally monopolar in design interneurons they lie entirely within a ganglion connect afferent neurons sensory neurons with efferent neurons motor neurons are part of the CNS and generally multipolar in design neurosecretory cell a specialized neuron that produces hormones that are released into the hemocoel Glial cells protect neurons neurons except at the branches are invested by glial cells 3 lacuna quot I l longitudinal 39 section of axon 39 tracheole y hemolymph 9 O 39llII 39 gt 1 soma of ranl neuron n 5 glial cell 5 body 239 c neural lamella H z 39 extracellular 39 space processes of glial cells I 2 3 glial cells are more numerous in the CNS than neurons large axon A may be surrounded by several folds several small axons B may be enclosed within a single fold extracellular spaces contain fluid which baths the neurons pass nutrient materials to the neurons and contain extensive reserves of glycogen Glial cells maintain NS homeostasis neurons live in a different chemical environment than other tissues hemolymph neural lamella freer permeable hemolymph Na m Ion exchange pump K V i Q diffusion Na K diffusion through gap junction n hemolymph and extracellular C e t compartment A III extracellular Na 3 K II V quot quot junction ion exchange pumps maintain a high concentration of sodium and a low concentration of potassium in the extracellular compartment As indicated by the size of the arrows potassium ions have greater permeability than do sodium ions Action potentials action potentials are self regenerating waves of electochemical activity that allow neurons to cary a signal over a distance best described as pulselike waves of volatage that travel along cell membranes arise from changes in the permeability of a neuron s axonal membranes to speci c ions the principal ions involved are sodium and potassium cations m V U39 v O v instantaneous firing rate action potentials s 1 membrane potential mV 0 2 action 5 g potential g lt potassium out resting potential 3 4 time ms active neuronal E refractory membrane egion E reglon depolarized K direction of propagation of action potential lt stimulus gt phasic tonic response quot response time Sensory integration how do different neurons talk to one another Motor neurons Sensillum Sensory neuron Ganglion FIGURE 112 Interneurons bridge the connection between motor neurons and sensory neurons Reprinted with permission from RomoserWSG Sto blano Jr 1998 The Scieme quntamology 4th edition Copyright McGraW H l Education How do neurons talk to one another The point at which neurons receive information from or convey it to other cells are known as synapses na se a norma sy p Synaptic cleft l posisynaptic process e neurotransmitter neurotransmitter neurotransmitter Neurons make contact with each other at many synapses plasma membranes of two cells lie parallel and separated by a small gap called the synaptic cleft vesicles of neurotransmitter are found in the cytoplasm of the presynaptic terminal contents of the vesicles of neurotransmitter are released into the synaptic Cleft contain the chemical transmitter l V TH What do neurons secrete Tm 7n 1 prmrmnljimmm Chumical Ilreylrlmlmt ngulm39nmmt Histamine Scmmnm 15 mdmxynypnminc Ocmpaminc c acid GABM Glummam armorquot Allamlmpin a i Damn pcpndc FMRFamidc Lcucuklnin Phuamwnz biasymhcsls PBAN Procmlin thamimmpic honnone Mm in maiorfunclion y Neuramuduiam occasional function Neumhormunc I neurotransmitters released into the synaptic cleft amp have a transient effect on the electrical potential of postsynaptic membrane transient because of enzymatic degradation or re uptake to presynaptic terminal 2 neuromodulators released in the vicinity of the synapse modifying synaptic transmission can occur either pre or postsynaptically effects are relatively slow and long lasting 3 neurohormones released into the hemolymph from neurohemal release areas neurosecretory cells and function as hormones Nervous system anatomy the insect CNS consists of the brain and ventral nerve cord a Dictyopterus b Musca brain brain subesophageal subesophageal nglion ganglion thoraqu eggpg fil gd gangl39a thoracic abdominal abdominal ganglia Fig 2010 Numbers of ventral ganglia from Horridge 1965 a Most ganglia remain separate Dictyopterus Coleoptera b All the ventral ganglia except the subesophageal are fused into a single compound ganglionic mass Muscat Diptera l Aggregated soma or perikarya 2 3 4 of motor neurons and interneurons are called ganglia and each body segment typically has its own ganglia a mass offibers called a neuropil occupies the center of each ganglion axons and dendrites are complexly interwoven in the neuropil and this is where synapses are found no synapses except nervemuscle junctions occur outside the CNS Nervous information transfer How insects receive information at the periphery and transfer it to the CNS Mechanisms of information transfer in insects httpinsectstamued ustudentsundergradento306animationshtm neuron information coding Dr Larry Keeley Emeritus Professor Department of Entomology Texas AampM University receptor information coding and transfer information transfer in the CNS information coding and transfer at the synapse U39Ith information interpretation at the synapse Sixlegged Sex Insect Reproduction TodaYs objectives Part Describe male reproductive structures and reproductive strategies Describe female reproductive structures Male reproduction Anatomy ofthe internai organs testis rioiiides range in number from i peetie to iUU grassnopper vas ei ierens tonnetis eatn foiiitietotne psi iis 3s p i erninai p efore it is transferred to femaie 4 giaiiiis eyariapie in number in ieps i5 pai grassno ersisoo in tritket tetane itnttianai in aunts used in thenitais Insemination Tne transfer of sperrn is separate from fertiiiza on Spermatophores the primitive method of insemination indirect ienaie nannan tntketWitn spernatapnart usuaiiy produlted by tne attessory giands spermistransfe d nesperrnatn re to t eta sperm storage strutture in femaies irnrnediateiy foiiowing transfer spermatophyiax wnitn often tontains nutrients 7 up to 80 protein ta n be eaten dissoived by proteoiytit enzyrnesi or dropped II Insemination directand hemucueiic diredmsemma un nudezgu pm mm Hmwuuicmmau Wm Mum h Mm wwwmqu quotmum my Mm m m am umze ohm We u m up mm W verb1m m i m m vwm mdmen a Sperm m mm mm m hemowei Other effects of mating m humimmmi Hm magma rEduttmn m emaie readiness to Mme mm mm mm mm a m mm mm mm e x r mums m M gem nrviuxi 3 Dansier mam com pounds mm mm Mm mmmypmm quotmm deknsm mime m ummmm Ind mummies mum ikumd byhzkmnhevimx mm Ind lmskr mumpmgammm Female reproducti An on ammy mm mmmai organs WiduEE r iammi WiduEE mm a median mam mdL n Types of ovarioles Two Broad Camgunes i r mpmi EH5 found mm more mm s pmmm Types of ovarioles Two broad categories ll meroistic contain special nurse cells called trophocytes celotrophic all trophocytes remain in the polytrophic trophocytes are closely germarium Hemiptera Coleoptera associated with each oocyte and are enclosed within the follicle any 05 W i no Today s objectives Lt Explore what s in an egg Describe the process of egg production and development Discuss embyronic development and alternatives to egg production What s in an egg What does the oocyte Contain the euplasm O of the total content substances whose synthesis is regulated by the DNA of the germ line yolk 90 of the total content about 6090 of yolk proteins are derived from vitellogenins VHDL which is produced in the fat body uptake of protein is regulated by juvenile hormone JH lipids comprise about 40 of the dry weight of oocyte and are stored as triacylglycerid TG lipid is carried by lipophorin LDLp How to make an oocyte Control of vitellogenin synthesis and yolk accumulation 90 of oocyte content is yolk consisting of lipid and protein The fate of oocytes Resurptmn r mmmwyubma m mm mm W yu k Wm 7 5 Warm a w mu m 9mm mm m 2 mumquot Mm um mm mm mum m Mm 3 Femhzmun mmmm lvxsss mm m mm mmberwen Sperm m mm m m WW 7 me Swede m mm orn nse Sperm mm m mame we 7 me mm m deuvwiverm mam a menuquot mm m Egg structure atthenmeufowpusn mthe pxmmyms aboundmg hysn mHed he nempmmma an megu ar ytuplasrm ventu um 2 M 00942 5 surrounded bme meme eme upe whxth 5 rutemaceuus m mm 5 a Dmp ex Strutmre produced by we owe ens wmme eggxs m we ovary r mum hm mw mpg m m e r WNW Mwspemv mum en Ovipos t on How and where dufemzles wthew eg Embryonic development Whammy and xmenmymml Alternative strategies How else are o spring generated I Vivipzriry giving birth to live young 7 WWW w W a e m w m m 2 Parthenogenesis eggs that develop without lertilixztion lnsuls kmzl is hamagamul xx and he main is huuagzmul xv arXO e i 2 zxuptlmlrszldapumkm z an huuagamul haplardlplaldy mm Hymznaptzm e trtlllztd eggs dzvzlap lnta males 7 unknlllzndng d2vnlapln mats Where to begin the head and what an insect needs Today s objectives m 0 What do insects eat 0 Differences in mouthpart structures 0 How insects taste their food Entognalha i 4E lt Zygannoma 39Thysanuraquot lnsecta Dicundylia quot j A 39Paleoptera39 Mata Ear ula F W eroalanmia Dermaplnra imam H23 Isnpnora Neoptera A I g Hamipm W pmrm Paraneoptera A E BT61 Fix xiii Phth rapmm Cduuptcra AH Neuraptam I Manaluplam Huphiniodaa mnnptnra q Trimmers Holometabola Iquot Polyneoptera Emma Lapmpnara v l W4 7 I i ahanupieru Macqumm39 3 g E E 2 Wheeler et a 2001 Cladzstzcs 17 113169 44 Strepsipuem Dialera Plant Feeders 0 walking sticks aphid Sternorrhyncha V 0 Orthoptera 0 crickets 0 grasshoppers 0 katydid 0 thrips 0 sucking bugs Hemiptera 0 Sternorrhyncha 0 Auchenorrhyncha 0 Heteroptera 0 beetles 0 flies 0 caterpillars 0 sawflies Hymenoptera caterpillar Lepidoptera grasshopper Orthoptera O sa L bristletail Archaeognatha Algae feeders stonefly Pleco ptera mayfly Ephemero ptera barklice Psoco pte ra Lichen feeders 0 bristletails 0 mayflies 0 caterpillars Lepidopter39a Fungus feeders thrips Thysanoptera beetle Coleoptera iing ant Formicidae Myrmicinae Zoraptera mv nljl raskg mummy n mnmnlnnw flies Diptera Predaceous feeders robber fly Dipte ra lacewi ng larvae N eu ropte ra dragonflies Odonata stoneflies Plecoptera Orthoptera katydids Mantophasmatodea true bugs suborder Heteroptera Megaloptera alderflies amp dobsonflies Snakeflies Raphidioptera lacewings Neuroptera scorprion flies Mecoptera caddisflies Trichoptera wasps Hymenoptera flies Diptera What is the head used for a anterior b lateral occipital sulcus ecdysial line occiput postoccipital suture postocciput neck circumocular sulcus membrane subgenal Clrcumantennal sulcus sulcus subocular sulcus postgrior anterior tentorial pit tentor39a39 p39t anterior epistomal sulcus SUbgena artrlretlirl1adtilglre of mandible labium maxilla Fig 13 Common lines or grooves on the insect head and the areas which they de ne italicized modi ed after Snodgrass 1960 Mouthpart designs for eating chewing sucking brain irons pharynx salmary duct pharyngeal dilalor subasophageal muscles ganglion lmnlal ganglion suspensory sclerite mouth saiival ium clbarium lingual sclenle epiphalynx hypopharynx Zl Prcruml mill and some musculature Diagrammatic crlical section through the head Oran insect with bilinga chewing mouthparts Scleriles associated with the hypopharynx are black with white spots Muscles allachcd lo thcsc sclcrites muvc he hypophnrynx afler Snodgruss 1947 a Hemiplera salivary canal c Lepldoplera luod canal maXllla lgaieai b Siphonaptera epiphalynx laud canal sallvary canal W iablum pawl l Dimera Glossinidae laumm loud cannl nwupnarynx slilvury cannl labmm Fluidfeeding insects in plants planthopper salivary flange b style imprinl Imprints o sansilla on labium salivary ange feeding by an aphid Insects taste using chemoreceptors a grasshopper 8300 chemosensory neurons oneac sie HYPOPHARYNX LJ U 50 250 150 600 EPIPHARYNX 200 1000 quot2 50 100g 9 v 75 375 40 200 s 325 1625 Tasting in other insects b caterpillar 48 chemosensory neurons on each side ANTENNA epipharyngeal sensillum labrum 3 neurons 3 olfactory mandible sensilla 16 neurons lateral styloconic sensillum 4 neurons 3 olfactory sensilla medial styloconic 5 contact sensillum 4 neurons chemoreceptors 1419 neurons 2 olfactory sensilla 4 neurons maxillary palp not visible from outside MAXILLA 0 fly 270 chemosensory neurons 0 each side cibarium 4 contact chemoreceptors 10 neurons maxill al 05 o 2 9 8 D Q I m 1 Q E 120 neurons labrum 3 contact chemoreceptors 10 neurons Iabellum 35 contact chemoreceptors 30 39quotterpgg dovamea39 P695 100 neurons eurons Fluidfeeding insects usually have chemoreceptors at the tip of the labium on the palps when these are present adn in the walls of the cibarium Photo Hans Smid Today s objectives m 0 Foods as packages of nutrients 0 Macronutrient requirements 0 Micronutrient requirements Amino acids amino acids are required for the production of proteinswhich are used 0 for structural purposes 0 as enzymes 0 for transport and storage 0 as receptor molecules The general structure of an amino acid essential amino acids non essential amino acids phenylalanine 39 Bambyx Anthanomus Drosopnila malanogasrer arginine hisiidine isoieucine ieucine lysine methionine ihreonine tryptophan vaiine giycine serine tyrosine of total amino acids x essentiai for this species 1 r 1 i i y Fig4 quot 39 391 r v 39 maa1985 Aromatic amino acids needed for cuticular sclerotization eg tyrosine MHZ phenylalanine l essential l Jr osine tyrosine Amino acid synthesis Transamination the transfer of an amino acid group from a preexisting amino acid COCOOH cOOH i sz gt lt CH2COOH CH2COOH aspartlc a ketoglutaric acid acid CCOOH COCOOH I I CH2 CHTCOOH CHTCOOH oxaioacetic glutamic ac acid Glutamate is central in transamination alanine t 39 aquot R U 91 y amino acid 9 oxidasss t a I glutamine keto acids NAD tutamate de ydrogenase NADHE ketoglutarate What about carbohydrates OH glucose general formula CHZOn O O HO OH sumple carbs mono amp dIsaccharldes OH glucose hexose sugar OH OH fructose pentose sugar 2 O OH sucrose glucose fructose H0 CHZOH maltose lucose lucose OH g g fructose complex carbs glycogen a polymer of 8 l2 glucose molecules starch found in plants cellulose found in plants rarely in insects Lipids l Fatty acids general formula CnH2nCOOH Fatty Acid Structure two forms calbum group saturated no double bonds unsaturated I or more double bonds chain length ranges from 620 carbons Hydrocarbon chain usually l6 or l8 carbon atoms palmitoleic Cl6 saturated a b stearic Cl8 saturated linoleic Cl82 2 double bonds linolenic Cl83 3 double bonds r Saturated Mixture of saturated and fatty acids unsaturated fatty acids c d FA stored amp transported as glycerids transport form diacylglycerid CH20 COR CH20 COR storage form triacylglycerid CH20 COR CH20COR CH20 COR Lipids ll Phospholipids phospholipids are important in cell membranes FA phosphate glycerol u m m z 2 E n E quote gt Hydrophobic 39 Choline Phosphate 1 Hydraphilic head Hydrophobic ails Lipids Sterols HO Cholesterol A5 cellular membranes provides support rigidity high density in lipid rafts a precursor to steroid hormones 20OH ecdysone affects development and morphology Micronutrients Vitamins fatsoluble vitamins 5carotene visual pigmentsvitamin E reproduction watersoluble vitamins Bvitamins are essential 39 thamine riboflavin nicotinic acid pyridoxine panthothenic acidfolic acid biotin generally function as cofactors of enzymes catalyzing metabolic transformation some structural roles Micronutrients ll Nonvitamins 0 inorganic compounds essential elements in cell function 0 sodium potassium calcium magnesium chloride and phosphate 0 lipogenic compounds Myoinositol choline found in phospholipids ascorbic acid cuticle sclerotization 0 nucleic acids 0 metals iron found in cytochromes zinc hardening the cuticle of the mandibles Breathing without lungs Gaseous exchange in insects Today s objectives m Examine the basic structure of the tracheal system Review the process of respiration Discuss the physics of gaseous exchange Gaseous exchange in insects The process of respiration 0 Gaseous exchange occurs through a system of internal tubes called the tracheal system 0 Oxygen is carried directly to its sites of utilization and the blood is not concerned with its transport Earlier this year in a report in the 24 January 2003 issue of Science Westneat et al showed that insects like this wood beetle breathe by rapid cycles of tracheal compression and expansion in a mechanism remarkably similar to lung ventilation Their unprecedented look inside living breathing insects including a movie 16 MB showing the inflation and compression of these tiny structures was made possible by use of a synchrotron a large circular particle accelerator that can generate xrays one billion times as intense as conventional xrays Synchrotron xray imaging should prove valuable for probing the structures and functions of other living systems in neverbeforeseen detail quotF 079002 mnv The tracheal system A crosssection view through the abdomen visceral trachea l j spiracle l lateral longitudinal trunk ventral diaphragm nerve cord ventral longitudinal trunk ventral commissure The tracheal system A crosssection view through the thorax 8 dorsal commissure prothorax spiracle 1 mesothorax imaginal also of 39 spiracle 2 metathorax imaginal disc of hindwing first abdominal segment spiracle 3 lateral longitudinal trunk The tracheal system A sagittal view through the head and thorax narrow junction between a cephalic and thoracic systems brain thoracic alrsac subesophageal 7 I 7 r I dorsal an on 39 quot 39 39 9 d9 t 339lf139fr spiracle 1 egenera e trachea Ol39lflce trachea to wing muscles mandibular airsac ventral longitudinal degenerate tracheae base of prothoracic leg VThe tracheal system The tracheal system and its ner details a c j tracheole lracheolar cell irachea with t h d 39 i ml 00 on non laenld a muscle fiber d plasma membranes plasma membrane b of tmcheolarcell ol muscle cell lumen of lrachea Eel mum l I 39 39 eplcu la is lumen of z z z39b z z chmnous tracheule ixfxlehfsi mllochondrlon llcle l gracneal N eplthellal cell basal lamina hemolymph cuilcle of tracheole lracheolar muscle cell ber SEM of an insect trachea VThe tracheal system Tracheoles innervate the ganglia and muscles interganglionic connective cut end of 5 trachea finkMunquot I rJ lOX ll we 22223 l l I a interganglionic connective openings of secondary V supply Shrnl airsac y l l v a J 39 primary supply muscle 1 openings of secondary supply I primary supply secondary SUPP39V muscle Fig 176 Tracheal supply to the ight muscles Arrows indicate the inward ow of air after Weis Fogh 1964a 21 Primary supply is a trachea ventilated by an airsac outside the muscle b Primary supply is an airsac directly associated with the muscle Spiracles The external openings of the tracheal system 0 lateral in position never more than one pair on a segment and never on the head 0 generally a visible opening leading into a cavity the atriumwhich is often lined with hairs which lter dust 0 most terrestrial insects have a closing mechanism to control water loss closer usually from the activity of a single muscle cuticle closer muscle opening of spiracle Irachea Fig 1710 5minquot lhmugli a spiracle an louse Hammwpllms shnwing iiie atrium and branched spines in which dust accumulates nflcr Webb 1948 What is respiration Respiration occurs at two levels i cellular level takes place in the mitochondria and reactions within cells are the chief source of energy for the cell organismal level taking in oxygen returning carbon dioxide Oxygen consumption is directly related to energy expenditure and is measured by 02 intake or C02 output The energy expenditure at rest is known as basal metabolism Why is it important Heterotrophs obtain energy by the oxidation of organic molecules a process that requires oxygen an example amlase starch ygt glucose C6HIZO6 602 gt glucose oxygei a 6C02 6H20 energy water A quick reVIew How do gases move in the tracheal system of an insect Chime 023 enters at the spiracles It moves through the 391139 arriving at the tissue 2 in a through the tracheoles nally Clix passes through the tissue eg 1 I39ii Ev l i53739339 l zi39 in turn follows this path in the reverse direction Two phases an air tube transport phase 2 tissue transport phase to no A 7 Gaseous exchange Diffusion What are the factors that impact on rates of diffusion of gases 02 and C02 in insects molecular weight diffusion is inversely proportional to th square root of the molecular weight of the MW of 01 32 MW of C01 44 the concentration gradient the difference i concentration of the a gas at the two ends of the system 3 the permeability of the substrate August ngh 05744949 Nubia Pm m Physiulug and Memme i910 Gaseous exchange Rates of Oz diffusion Recall that there are 2 diffusion phases an air tube phase 2 a tissue phase Substrate Permeabilit constant cm2minatm Air l 0 Water 0000034 Muscle 00000 l 4 02 is 7857I4 times more permeable in air than in muscle Gaseous exchange Distance a function of substrate permeability Remember diffusion only occurs over short distances an example consider a concentration gradient along a tracheal tube 3 cm long if you know the 02 permeability constant for muscleyou can calculate the distance 02 could diffuse through muscle Q Witquot 1 fl vquot laquotl r39wi39aiiiiilliI C Hquot w hlii39v if perl neabllity of in nmsclei l l i cm2minatm MDCI OO 4 cm2minatm 7857l4 So 02 is 7857l4x more permeable in air than muscle now back to the original question 0 take the tracheal distance 3 cm and divide it by 7857l4 0 so oxygen travels 00000038l8 cm about 004 microns in muscle Gaseous exchange Distance a function of substrate permeability Key point tracheoles must be quite close to mitochondria lracheole WeisFogh an insect scientist from Cambridge predicted tracheoles in dragon fly muscles would be less than l0 microns apart d 153 plasma membranes plasma membrane In fact they are about 35 uflracheolavcell olmusclecell microns apart l milochondrion lIJ lumen of tracheme v mitochondnon w cuticle of quotacheme tracheolar muscle cell fiber Today s objectives M 0 Breathing in large bodied insects 0 Breathing in aquatic insects and parasitoids Functions other than breathing Terrestrial insects managing H20 loss The principle of diffusion can also work against insects Diffusion is inverser proportional to the square root of the molecular weight of the gas I MWofOz32 2 MWoszO l8 This means water diffuses 3X faster than oxygen How do insects prevent water loss I close spiracles 2 wax layer on the epicuticle 3 behavioral regulation What do large insects do about breathing 0 as the diffusion distance increases I the concentration gradient becomes smaller 2 diffusion rate or flowdecreases insects solve this problem by using ventilation l changes in body volume 2 displacement of hemolymph ergum pleu ron slemum puslevior segmenl anlenor Heteroptera Coleoptem Odonata Orthoptera Hymenoptera Diptera Di ptera segment inlersegmemal membrane Chapman Fig l74 Ventilation via displacement of hemolymph typically takes place in adult insects involves the airsacs and blood flow air air out in l forward flowing expanded a 2 backward flowing deflated b 02 emission plmin g x heartbeat anrward bl back p difOYWaM b 14mm IE 0 20 40 time s 60 salmon Chapman Fig m5 Aquatic Insects Gaseous exchange even submerged they can obtain 02 from air hover fly larva respiratory smhon lt Irachea substratum telescopic terminal spiracles pierce the siphon aerenchyma of aquatic plants Aquatic insects How do submerged insects obtaining oxygen from the air Most aquatic insects must visit the surface to renew the gases in the tracheal system 0 Q how to prevent water entry into the spiracles 0 A cuticle or spiracles may have hydrofuge properties SUBMERGED AT SURFACE hairs close over I hairs separated by splracle preventing tension forces entry of water spiracle exposed Aquatic insects How do aquatic insects use air bubbles in air oxygen 21 nitrogen 78 dioxideoos insect dives ms fggsgjggggen 933 ng 39l V in solution in water oxygen 33 nitrogen 64 carbon dioxide v 3 in bubble oxygen 21 nitrogen 78 oxygen 20 nitrogen 79 oxygen 21 nitrogen 78 002 oxygen insect insect insect VAquatic insects How is oxygen obtained from the water tracheal gills leaflike extension of the body Chapman Fig I718 damselflies caudal lamellae epidermis trachea hemocoel Caddisflies lamentous abdominal gills Stoneflies position varies VAquatic insects Tracheal gills in dragonflies c v I 7 7 nteslinal us la I 39 dllalor I 7 V muscles dilator subi muscle m b s Jquot u39l K A c r I x dorsal trachea y lumen of branchlal chamber Dragonfly larvae have gills in the anterior part of the rectum the branchial chamber water in rectum r x o quot0 q r o 30 Lat 6quotxpe lrachea l Q la gag39l 2 l epldermls 7 quot quotlriii r 7 Mullamina hemolymph nucleus Chapman Fig l729 VAquatic insects Plastron respiration the use of a physical gill Plastron a thin lm of gas into which spiracles open a Apheocheirus o enin lastron P 9 P cuticle epidermis josef hlasek39s quot 39 wwwhlaseLcmn v trachea L Aplnlochplrus aestiivalis 519 air cuticular Channei plasiron filaments hairs cuticle W M r39 A 39 39 b Hydrophilus c Elmis hairs erect macroplasiron hairs flattened T plasiron v i 100 pm 20 m I Endoparasitic insects How do endoparasitic insects obtain oxygen I via cutaneous diffusion Ichneumondids braconids Diptera larvae 2 caudal vesicle right 3 caudal laments 4 penetration of the host body wall or respiratory system 3 caudal vesicle poslerior c of head proctodeu m evened to lorm vesicle outer membrane midg ut oslerior occlusion of midgut Fig 1735 Caudal vcsiclc of a parasitic hymcnnpmran larva A lllllL39leX from Wiggleswnrlh 1965 a Whole larva showing the caudal vesicle h Longitudinal section ufcaudxil vesicle Other Functions The whole system in particular the airsacs lowers the insect s speci c gravity it gives some degree of buoyancy in aquatic insects but not in terrestrial insects hemolymph circulation assisting when insects inflate after a molt insulation of the thorax flight muscles act as connective tissues involved in defense eg cockroaches some forcibly expel quinones some produce sounds by force air out through the spiracles
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