Plants emit a specific blend of volatiles in response to herbivory and these volatiles, which often attract predators and parasitoids function as an indirect plant defense. The impact of plant volatiles in shaping herbivore defenses is unclear. Here, we report that specific plant volatiles induce immune responses in the polyphagous herbivore, Spodoptera litura. We characterized the hemocyte profile and established their functional significance with respect to ontogeny and exposure to specific plant volatiles. Fifth instar larvae showed the highest number and hemocytes diversity. We characterized seven different types of hemocytes, of which granulocytes performed phagocytosis, oenocytoids showed melanization activity, and plasmatocytes along with granulocytes and oenocytoids were found to be involved in encapsulation. Among the six volatiles tested, exposure to (E)-β-ocimene caused the highest increase in total hemocytes number (THC) followed by linalool and (Z)-3-hexenyl acetate exposure. Although THC did not differ between these three volatile treatments, circulating hemocytes diversity varied significantly. (E)-β-ocimene exposure showed higher number of plasmatocytes and phenol oxidase activity. The interaction of the parasitic wasp Bracon brevicornis with (E)-β-ocimene exposed larvae was poor in terms of delayed paralysis and lower egg deposition. In choice assays, the wasp showed clear preference towards control larvae indicating (E)-β-ocimene treatment renders the host unattractive. Hemocyte profiles post-parasitoid exposure and (E)-β-ocimene treatment were similar indicating cue-based priming. When challenged with Bacillus thuringiensis, linalool exposure resulted in the highest survival as compared to other volatiles. Our results show that specific HIPVs can modulate cellular immunity of S. litura, revealing a new role for HIPVs in tri-trophic interactions.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
The datasets supporting the conclusions of this article are included within the article and its supplementary files.
Arimura G, Muroi A, Nishihara M (2012) Plant-plant-plant communications mediated by (E)-β-ocimene emitted from transgenic tobacco plants, prime indirect defense responses of lima beans. J Plant Interac 7(3):193–196. https://doi.org/10.1080/17429145.2011.650714
Beier RC, Byrd JA, Kubena LF, Hume ME, Mcreynolds JL, Anderson RC, Nisbet DJ (2014) Evaluation of linalool, a natural antimicrobial and insecticidal essential oil from basil: effects on poultry. Poult Sci 93:267–272. https://doi.org/10.3382/ps.2013-03254
Carton Y, Poirié M, Nappi AJ (2008) Insect immune resistance to parasitoids. Insect Sci 15:67–87. https://doi.org/10.1111/j.1744-7917.2008.00188.x
Cascone P, Iodice L, Maffei ME, Bossi S, Arimura G, Guerrieri E (2015) Tobacco overexpressing β-ocimene induces direct and indirect responses against aphids in receiver tomato plants. J Plant Physiol 173:28–32. https://doi.org/10.1016/j.jplph.2014.08.011
Clark KD, Strand MR (2013) Hemolymph melanization in the silkmoth Bombyx mori involves formation of a high molecular mass complex that metabolizes tyrosin. J Biol Chem 288:14476–14487. https://doi.org/10.1074/jbc.M113.459222
Contreras-Garduño J, Lanz-Mendoza H, Bernardo F, Adriana N, Mario PR, Jorge CL (2016) Insect immune priming: ecology and experimental evidences. Ecol Entomol 41:351–366. https://doi.org/10.1111/een.12300
Cotter SC, Wilson K (2002) Heritability of immune function in the caterpillar Spodoptera littoralis. Heredity (Edin) 88:229–234. https://doi.org/10.1038/sj.hdy.6800031
De Moraes CM, Lewis WJ, Pare PW, Alborn HT, Tumlinson JH (1998) Herbivore-infested plants selectively attract parasitoids. Nature 393:570–573. https://doi.org/10.1038/31219
Dicke M (2009) Behavioural and community ecology of plants that cry for help. Plant Cell Environ 32:654–665. https://doi.org/10.1111/j.1365-3040.2008.01913.x
Ebrahim SAM, Dweck HKM, Stökl J, Hofferberth JE, Trona F, Weniger K (2015) Drosophila avoids parasitoids by sensing their semiochemicals via a dedicated olfactory circuit. PLoS Biol 13:e1002318. https://doi.org/10.1371/journal.pbio.1002318
Engelberth J, Alborn HT, Schmelz EA, Tumlinson JH (2004) Airborne signals prime plants against insect herbivore attack. Proc. Natl Acad Sci USA 101:1781–1785. https://doi.org/10.1073/pnas.0308037100
Erb M, Meldau S, Howe GA (2012) Role of phytohormones in insect-specific plant reactions. Trends Plant Sci 17:250–259. https://doi.org/10.1016/j.tplants.2012.01.003
Farré-Armengol G, Filella I, Llusià J, Peñuelas J (2017) β-Ocimene, a key floral and foliar volatile involved in multiple interactions between plants and other organisms. Molecules (Basel, Switzerland) 22:1148–1157. https://doi.org/10.3390/molecules22071148
Gasmi L, Martínez-Solís M, Frattini A, Ye M, Collado MC, Turlings TCJ, Matthias E, Herrero S (2019) Can herbivore-induced volatiles protect plants by increasing the herbivores’ susceptibility to natural pathogens? Appl Environ Microbiol 85(1):e01468–e01418. https://doi.org/10.1128/AEM.01468-18
Gupta GP, Rani S, Birah A, Raghuraman M (2012) Improved artificial diet for mass rearing of the tobacco caterpillar, Spodoptera litura (Lepidoptera: Noctuidae). Int J Trop Insect Sci 25:55–58. https://doi.org/10.1079/IJT200551
Heil M (2008) Indirect defence via tritrophic interactions. New Phytol 178:41–61. https://doi.org/10.1111/j.1469-8137.2007.02330.x
Kares EA, El-Sappagh GHIA (2009) Biological studies on the larval parasitoid species Bracon brevicornis Wesm. (Hymenoptera: Braconidae), reared on different insect hosts. Egypt J Biol Pest Control 19:165–168. https://doi.org/10.21608/eajbsa.2014.13138
Kos M, Houshyani B, Overeem AJ, Boumeester HJ, Weldegergis BT, Van loon JJ, Dicke M, Vet LE (2013) Genetic engineering of plant volatile terpenoids: effects on a herbivore, a predator and a parasitoid. Pest Manag Sci 69:302–311. https://doi.org/10.1002/ps.3391
Kranthi KR, Jadhav DR, Kranthi S, Wanjari RR, Ali RR, Russell DA (2002) Insecticide resistance in five major insect pests of cotton in India. Crop Prot 21:449–460. https://doi.org/10.1016/S0261-2194(01)00131-4
Kurihara Y, Shimazu T, Wago H (1992) Classification of hemocytes in the common cutworm, Spodoptera litura (Lepidoptera: Noctuidae). 1. Phase microscopic study. Applied Entomol Zool 27:225–235. https://doi.org/10.1303/aez.27.225
Li S, Xu X, SHakeel M, Xu J, Zheng Z, Zheng J, Yu X, Zhao Q, Jin F (2018) Bacillus thuringenesis suppresses the humoral immune system to overcome defense mechanism of Plutella xylostella. Front Physiol 9:1478. https://doi.org/10.3389/fphys.2018.01478
Lochmiller RL, Deerenberg C (2000) Trade-offs in evolutionary immunology: just what is the cost of immunity? Oikos 88:87–98. https://doi.org/10.1034/j.1600-0706.2000.880110.x
Loeb GM, Cha DH, Hesler SP, Linn CEJ, Zhang A, Teal PEA, Roelofs WL (2011) Monitoring grape berry moth (Paralobesia viteana, Lepidoptera) in commercial vineyards using a host plant based synthetic lure. Environ Entomol 40:1511–1522. https://doi.org/10.1603/EN10249
Loughrin HJ, Manukian A, Heath RR, Turlings TCJ (1994) Diurnal cycle of emission of induced volatile terpenoids by herbivore-injured cotton plants. Pro Natl Acad Sci USA 91:11836–11840. https://doi.org/10.1073/pnas.91.25.11836
McCormick AC, Unsicker SB, Gershenzor J (2012) The speciality of herbivore induced plant volatiles in attracting herbivore enemies. Trends Plant Sci 17:303–310. https://doi.org/10.1016/j.tplants.2012.03.012
Nakahara Y, Kanamori Y, Kiuchi M, Kamimura M (2003) In vitro studies of hematopoiesis in the silkworm: cell proliferation in and hemocyte discharge from the hematopoietic organ. J Insect Physiol 49:907–916. https://doi.org/10.1016/S0022-1910(03)00149-5
Netea MG, Quintin J, Van der Meet JWM (2011) Trained immunity: a memory for innate host defence. Cell Host Microbe 9:355–361. https://doi.org/10.1016/j.chom.2011.04.006
Pardo-Lopez L, Soberon M, Bravo A (2012) Bacillus thuringiensis insecticidal three-domain Cry toxins: mode of action, insect resistance and consequences for crop protection. FEMS Microbiol Lett 37:6–22. https://doi.org/10.1111/j.1574-6976.2012.00341.x
Pickett JA, Khan ZR (2016) Plant volatile-mediated signalling and its application in agriculture: successes and challenges. New Phytol 212:856–870. https://doi.org/10.1111/nph.14274
Rantala MJ, Roff DA (2005) An analysis of trade-offs in immune function, body size and development time in the Mediterranean field cricket, Gryllus bimaculatus. Funct Ecol 19:323–330. https://doi.org/10.1111/j.1365-2435.2005.00979.x
Ribeiro C, Brehélin M (2006) Insect haemocytes: what type of cell is that? J Insect Physiol 52:417–429. https://doi.org/10.1016/j.jinsphys.2006.01.005
Rose USR, Lewis WJ, Tumlinson JH (1998) Specificity of systemically released cotton volatiles as attractants for specialist and generalist parasitic wasps. J Chem Ecol 24:303–319. https://doi.org/10.1023/A:1022584409323
Schwenke RA, Lazzaro BP, Wolfner MF (2016) Reproduction–immunity trade-offs in insects. Annu Rev Entomol 61:239–256. https://doi.org/10.1146/annurev-ento-010715-023924
Shim J, Mukherjee T, Mondal BC, Liu T, Young T, Wijenwarnasuriya DP, Banerjee U (2013) Olfactory control of blood progenitor maintenance. Cell 155:1141–1153. https://doi.org/10.1016/j.cell.2013.10.032
Srinivasan T, Chandrikamohan (2017) Population growth potential of Bracon brevicornis Wesmael (Braconidae: Hymenoptera): a life table analysis. Acta Phytopathol Entomol Hung 52:123–129. https://doi.org/10.1556/038.52.2017.010
Stettler P, Trenczek T, Wyler T, Pfister-Wilhelm R, Lanzrein B (1998) Overview of parasitism associated effects on host haemocytes in larval parasitoids and comparisons with effects of the egg-larval parasitoid Chelonus inanitus on its host Spodoptera littoralis. J Insect Physiol 44:817–831. https://doi.org/10.1016/S0022-1910(98)00014-6
Strand MR (2008) The insect cellular immune response. Insect Sci 15:1–14. https://doi.org/10.1111/j.1744-7917.2008.00183.x
Teng ZW, Xu G, Gan SY, Chen X, Fang Q, Ye GY (2016) Effects of the endoparasitoid Cotesia chilonis (Hymenoptera: Braconidae) parasitism, venom, and calyx fluid on cellular and humoral immunity of its host Chilo suppressalis (Lepidoptera: Crambidae) larvae. J Insect Physiol 85:46–56. https://doi.org/10.1016/j.jinsphys.2015.11.014
Van Poecke RMP, Roosjen M, Pumarino L, Dicke M (2003) Attraction of the specialist parasitoid Cotesia rubecula to Arabidopsis thaliana infested by host or non-host herbivore species. Entomol Exp Appl 107:229–236. https://doi.org/10.1046/j.1570-7458.2003.00060.x
Veyrat N, Robert CAM, Turlings TCJ, Erb M (2016) Herbivore intoxication as a potential primary function of an inducible volatile plant signal. J Ecol 104:591–600. https://doi.org/10.1111/1365-2745.12526
Ye M, Nathalie V, Xu H, Hu L, Turlings TCJ, Matthias E (2018) An herbivore-induced plant volatile reduces parasitoid attraction by changing the smell of caterpillars. Sci Adv 4:eaar4767. https://doi.org/10.1126/sciadv.aar4767
The authors acknowledge Dr. Tina Mukherjee lab (inStem, Bengaluru) and Dr. Deepa Agashe (NCBS, Bengaluru) for their help. We thank Prof. Paul Ode for his valuable comments and help in editing the manuscript. The authors thank National Bureau of Agriculturally Important Insect Resources, Bengaluru for providing insects. NCBS central imaging and flow cytometry facility is gratefully acknowledged.
This work was supported by Department of Science and Technology (Early Career Award, Ramanujan Fellowship), Max Planck Society (DST-Max Planck Partner group program) and Department of Biotechnology.
Conflict of Interest
The authors declare no competing interests.
Electronic supplementary material
Fig. S1. Diet based changes in THC of fifth instar S. litura larvae. Data represent mean ± SE and show differences between artificial diet and castor bean plant (R. communis) diet. To compare the changes in THC, unpaired t-test was done (P˂0.0001, n = 5). Fig. S2. Hemocyte profile of S. litura (a) prohemocyte, (b) granulocyte, (c) oenocytoids, (d) plasmatocytes, (e, f, g, h) forms of podocytes, (I) vermiform cell, (j, k, l) plasmatocytes with filapodia, (m, n, o) granular plasmatocytes. (p) Functional significance of hemocytes in S. litura, Encapsulation: Encapsulated sephadex beads (50 μm) showing three morphologically different hemocytes (q: granulocytes, r: granular plasmatocytes, s: oenocytoids), bars: 10 μm. Fig. S3. Functional significance of hemocytes in S. litura, granulocytes performing phagocytosis of (a, b) E. coli mCherry (c) Bacillus thuringiensis and (d) latex beads, (e) melanization by oenocytoids; granulocytes, plasmatocytes and oenocytoids involved in encapsulation (f) stacked image of encapsulated nylon thread (0.5 mm) showing E. coli mCherry tagged granulocytes are part of encapsulation, (g) dark brown melanin formation on top of encapsulated nylon thread, (h) encapsulated sephadex beads (50um) showing beta-integrin positive cells, (i) plasmatocytes show highest beta-integrin staining, bars: 50um; substrate independent encapsulation (j) encapsulation of sephadex beads (k) encapsulation of nylon thread in control larvae. Bars: 50 μm. Fig. S4. Effect of (E)-β-ocimene exposure and incubation period on larval immunity, (a) THC (P˂0.0001, n = 10), (b) PO activity in fourth instar larvae of S. litura (P˂0.05, n = 10). Data represent mean ± SE. Statistical differences are based on Tukey’s post-hoc test after one-way ANOVA. Different letters indicate significant difference between treatments (small letters: exposure time x feeding time and comparison between exposure time (bold letters); capital letters: comparison between feeding time). Numbers on x-axis indicate exposure and feeding time period, respectively. NE- no exposure, E- exposure, NF-no feeding, F-feeding. Fig. S5. Specific HIPV mediated immune boost improves tolerance against ecto-parasitoid (a) time taken by B. brevicornis to paralyze the larvae upon exposure to different HIPV (P˂0.05, n = 10), (b) number of parasitoid eggs laid per host larvae (P˂0.05, n = 10). Data represent mean ± SE. Statistical differences are based on Tukey’s post-hoc test after one-way ANOVA. Different letters indicate significant difference between treatments. Fig. S6. Effect of (E)-β-ocimene on B. brevicornis behaviour (a) number of eggs laid per host larvae, (b) time taken to paralyze in hours. Data represent mean ± SE (P = 0.06, n = 10). Statistical analysis is based on one-way ANOVA, NS-not significant. (PDF 587 kb)
About this article
Cite this article
Ghosh, E., Venkatesan, R. Plant Volatiles Modulate Immune Responses of Spodoptera litura. J Chem Ecol 45, 715–724 (2019). https://doi.org/10.1007/s10886-019-01091-3
- Plant volatiles
- Insect immunity
- Tritrophic interaction