Herbivores offense

1. Herbivores offense Vasakorn Bullangpoti, Ph.D. Email: fscivkb@ku.ac.th

2. Contents • BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Feeding choice • Oviposition choice • PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS – sometime aggressive • Enzymes • Sequestering Host Chemicals • Morphological Adaptations • Symbionts • Herbivores Manipulate their host- Aggressive • Gall and Induced Plant susceptibility • Trenching, Mowing, Haying and Gardening • Gregarious Feeding

3. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Feeding choice • Self-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

4. http://www.treesaregood.org/treecare/insect_disease.aspx

5. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Cannibalism and predation on other herbivores is associated with nutritional benefits and is more likely when plant foods are scarce or less nutritious.

6. Three Mormon crickets eating a fourth Mormon cricket

7. Behavioral adaptations • Selectively in space and time or season • winter 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 tree • Herbivores 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 terpenoidaldehydes.

8. http://www.infonet-biovision.org/res/res/files/970.400x400.jpeghttp://www.infonet-biovision.org/res/res/files/970.400x400.jpeg Trichoplusia caterpillars http://www.flickr.com/photos/9546698@N07/2148457971/

9. Behavioral adaptations • Some 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.

10. Behavioral adaptations • Plant 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.

11. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Oviposition choice • Many 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

12. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Oviposition choice • The 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

13. BEHAVIORAL MECHANISM – LEAST AGGRESSIVE • Oviposition choice • One 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.Kainoh’s lab

14. WIND TUNNEL

16. PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS – sometime aggressive- • Teeth Structures

18. Insect mouthparts The 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.

20. Labrum

21. Mandible

22. Siphoning Insects

23. Stylet

24. Proboscis

26. 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

27. Morphological adaptation • Many 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)

29. PHYSIOLOGICAL AND MORPHOLOGICAL TRAITS – sometime aggressive- ENZYME

31. Enzymes • Detoxification enzyme system • Proteinase Inhibitors • Salivary enzymes

32. Detoxification Enzyme system

35. 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.

37. A type: arylesterase that are not inhibited by organophosphate. B type: alliesterase, carboxylesterase and cholinesterase There are inhibited by organophosphate due to irreversible phosphorylation of the active serine site Esterase

38. Carboxylesterase mechanism Paranitrophenylacetate (pNPA) -------> paranitrophenol

39. O O C2H5 C2H5 NH - C NH - C 0 = C 0 = C NH - C NH - C O O NO2 NO2 OP (OC2H5)2 OP (OC2H5)2 S O OH Phenobarbitone p- hydroxyphenobarbitone Parathion Paraoxon

40. P450 enzymes • Cytochrome 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.

41. P450 enzymes • One of very important enzyme http://www.uky.edu/Pharmacy/ps/porter/CPR_partners.gif

42. P450 enzymes • The most common reaction catalysed by cytochrome P450 is a monooxygenase reaction

43. Phase II reaction • These 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.

44. Process in vivo reactant Product Glucuronide formation  UDP-alpha-D-glucuronate Glucuronide (X = O, N, or S)  Glutathione conjugation glutathione (Glu, Cys, Gly)  Mercapturic acid  Sulfate conjugation PAPS = Adenosine-3'-P-5'-Phosphosulfate Aryl or alkyl sulfates and sulfamates

45. Glutathione-s-transferase • Enzymes of the glutathione S-transferase (GST) family are composed of many cytosolic, mitochondrial, and microsomalproteins. • GSTs catalyse a variety of reactions and accept endogenous and xenobioticsubstrates. • They are members of Membrane Associated Proteins in Eicosanoid and Glutathione metabolism family of transmembrane proteins.

47. Excretion of Toxins • Toxins leave the body through: • Kidney (Urine) • Feces • Lungs (e.g., mucus, breathing out)

48. 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 unavailable • However, 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)

49. http://www.ysbl.york.ac.uk/~proteinase/

50. Salivary enzymes • Herbivores 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.