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DESCRIPTIONHerbivores offense. Vasakorn Bullangpoti, Ph.D. Email: firstname.lastname@example.org. Contents. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE Feeding choice Oviposition choice PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS – sometime aggressive Enzymes Sequestering Host Chemicals Morphological Adaptations - PowerPoint PPT Presentation
Herbivores offenseVasakorn Bullangpoti, Ph.D.Email: email@example.com
ContentsBEHAVIORAL MECHANISM LEAST AGGRESSIVEFeeding choiceOviposition choice PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS sometime aggressiveEnzymesSequestering Host ChemicalsMorphological AdaptationsSymbiontsHerbivores Manipulate their host- AggressiveGall and Induced Plant susceptibilityTrenching, Mowing, Haying and GardeningGregarious Feeding
BEHAVIORAL MECHANISM LEAST AGGRESSIVEFeeding choiceSelf-selection of food is likely to be more important for herbivores that are more mobile and can gain access to varied diets.When herbivores fail to make appropriate decision, these mistake tend to conservative. Such that herbivores reject food that are actually nutritious to them
BEHAVIORAL MECHANISM LEAST AGGRESSIVECannibalism and predation on other herbivores is associated with nutritional benefits and is more likely when plant foods are scarce or less nutritious.
Three Mormon crickets eating a fourth Mormon cricket
Behavioral adaptations Selectively in space and time or seasonwinter moth, feeding on oak leaves early in the season maximized the amount of protein and nutrients available to the moth, while minimizing the amount of tannins produced by the treeHerbivores can also spatially avoid plant defenses. The piercing mouthparts of species in Hemiptera allow them to feed around areas of high toxin concentration. Several species of caterpillar feed on maple leaves by "window feeding" on pieces of leaf and avoiding the tough areas, or those with a high lignin concentration. Similarly, the cotton leaf perforator selectively avoids eating the epidermis and pigment glands of their hosts, which contain defensive terpenoid aldehydes.
Behavioral adaptationsSome animals ingest large amounts of poisons in their food, but then eat clay or other minerals, which neutralize the poisons. This behavior is known as geophagy.
Behavioral adaptationsPlant defense may explain, in part, why herbivores employ different life history strategies. Monophagous species (animals that eat plants from a single genus) must produce specialized enzymes to detoxify their food, or develop specialized structures to deal with sequestered chemicals.Polyphagous species (animals that eat plants from many different families), on the other hand, produce more detoxifying enzymes (specifically MFO) to deal with a range of plant chemical defenses.
BEHAVIORAL MECHANISM LEAST AGGRESSIVE
Oviposition choiceMany herbivorous insects cannot move much during the course of their development. According to the prevailing paradigm, mobile ovipositing female assess different host plant species and place their eggs or offspring on those host that result in the highest performance.More than half of the recent literatures supported this positive correlation between adult oviposition and offspring performance
BEHAVIORAL MECHANISM LEAST AGGRESSIVE
Oviposition choiceThe correlation between mean oviposition preference and survival and growth of larvae averaged across many females in an herbivore population.Herbivores may select host plants that provide poor growth but good protection from their own natural enemies
BEHAVIORAL MECHANISM LEAST AGGRESSIVE
Oviposition choiceOne recent study, the correlation between adult choice and performance of offspring.The future field studies of the preference-performance correlation should consider adult performance as distinct from offspring performance.
EX: Dr.Kainohs lab
PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS sometime aggressive-Teeth Structures
Insect mouthpartsThe development of insect mouthparts from the primitive chewing mouthparts of a grasshopper in the centre (A), to the lapping type (B) and the siphoning type (C). Legend: a, antennae; c, compound eye; lb, labium; lr, labrum; md, mandibles; mx, maxillae.
Figure female soapberry bugs from Florida in a 100 year period http://www.fiu.edu/~biology/class_sites/pcb4674/CH2-EVIDENCE-SPRING-2008/CHAPTER2_SPR_2008.HTML
Morphological adaptationMany other herbivores traits besides mouthparts can be important and offensive.Bruchid seed beetles, female adjust egg size and probably other traits in response to particular host plant.On host with hard seeds, fitness is maximized by laying large eggs whereas on hosts with softer seeds, fitness is higher when females lays more, but smaller, eggs (Fox et al, 1997)
PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS sometime aggressive-ENZYME
EnzymesDetoxification enzyme system
Detoxification Enzyme system
Phase I reaction
Includes oxidative, reductive and hydrolytic reactions.
In these type of reactions, a polar group is either introduced or unmasked, so the drug molecule becomes more water-soluble and can be excreted.
EsteraseA type: arylesterase that are not inhibited by organophosphate. B type: alliesterase, carboxylesterase and cholinesteraseThere are inhibited by organophosphate due to irreversible phosphorylation of the active serine site
Carboxylesterase mechanismParanitrophenylacetate (pNPA) -------> paranitrophenol
P450 enzymesCytochrome P450 (abbreviated CYP, P450, infrequently CYP450) is a very large and diverse superfamily of hemoproteins found in all domains of life.
Usually they form part of multicomponent electron transfer chains, called P450-containing systems.
P450 enzymesOne of very important enzymehttp://www.uky.edu/Pharmacy/ps/porter/CPR_partners.gif
P450 enzymesThe most common reaction catalysed by cytochrome P450 is a monooxygenase reaction
Phase II reactionThese reactions involve covalent attachment of small polar endogenous molecule such as glucuronic acid, sulfate, or glycine to form water-soluble compounds.
This is also known as a conjugation reaction.
The final compounds have a larger molecular weight.
Glutathione-s-transferaseEnzymes of the glutathione S-transferase (GST) family are composed of many cytosolic, mitochondrial, and microsomal proteins.
GSTs catalyse a variety of reactions and accept endogenous and xenobiotic substrates.
They are members of Membrane Associated Proteins in Eicosanoid and Glutathione metabolism family of transmembrane proteins.
Excretion of ToxinsToxins leave the body through:Kidney (Urine)FecesLungs (e.g., mucus, breathing out)
Proteinase inhibitor Plant also contain antinutritive compounds that make essential constituents unavailable for digestion by herbivores.Inhibit the action of digestive protease enzymes in herbivores and thus make protein unavailableHowever, careful work have reveled that although proteinase inhibitors effectively reduced the function of particular protease in the gut of six lepidopteran species, corresponding reduction in catepillar growth were minimal (Broadway, 1995,1997)
Salivary enzymesHerbivores also produce salivary enzymes constitutively, prior to ingestion, that minimize the effectiveness of plant defenses.Such enzymes are applied to leaf wounds as the herbivores chew and these may reduce the activation of induced defense in plants.
Salivary enzmesGlucose oxidase is a major constituent of caterpillar saliva that appears to suppress early signaling events in plant defense (Felton and Eichenseer, 1999)Glucose oxidase inhibits lipooxygenase activity, a critical step in the biosynthesis of the induction signal and thereby reduces induced resistance in plantsCaterpillars that were inhibited from producing glucose oxidase fed less and grew les, indicated that offense had been block (Musser et al, 2002)
Salivary enzymesOther herbivores may also secrete saliva that interferes with plant defense.
Salivary constituent from grasshoppers have been implicated in enhanced growth of plant
In this case, the offensive strategy may be to stimulate plant growth. However, to the individual herbivores has not been demonstrated in this sample.
PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS sometime aggressive-Herbivores that specialize on particular host plant often have very specific enzymatic systems that allow them metabolize the secondary chemicals of those hosts.
Sequestering host chemicalsMany herbivored incorpate or sequester the biologically active chemicals of their host plants into their own tissues or glands, and thereby gain protection from their predators and parasites (Duffey, 1980)PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS sometime aggressive-
Sequestering host chemicals (Kargan & Agrawal, 2002)The herbivore must willing to ingest the hosts secondary chemicals
The herbivores must be relatively tolerant of the chemicals
The herbivores must ingest the chemicals without metabolizing them into biologically inactive products
The herbivores must deposit the secondary chemicals in particular tissues, or otherwise store them.
http://www.biozentrum.uni-wuerzburg.de/fileadmin/REPORT/BOT2/bot2004.htmInteractions between plant, herbivorous insects and