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Titolo:
Instar-specific sensitivity of specialist Manduca sexta larvae to induced defences in their host plant Nicotiana attenuata
Autore:
Van Dam, NM; Hermenau, U; Baldwin, IT;
Indirizzi:
Max Planck Inst Chem Ecol, Jena, Germany Max Planck Inst Chem Ecol Jena Germany ck Inst Chem Ecol, Jena, Germany Free Univ Berlin, Inst Zool, D-1000 Berlin, Germany Free Univ Berlin Berlin Germany D-1000 Inst Zool, D-1000 Berlin, Germany
Titolo Testata:
ECOLOGICAL ENTOMOLOGY
fascicolo: 6, volume: 26, anno: 2001,
pagine: 578 - 586
SICI:
0307-6946(200112)26:6<578:ISOSMS>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
JASMONATE-INDUCED RESPONSES; INDUCED RESISTANCE; GENE-EXPRESSION; HERBIVORE; GROWTH; COSTS; SYLVESTRIS; INDUCTION; NITROGEN; DEFENSES;
Keywords:
compensatory feeding; effects of starvation; induced defence; intraspecific competition; larval development; lepidopteran herbivores; nicotine; optimal defence theory; protease inhibitors; time delay;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Van Dam, NM Netherlands Inst Ecol, POB 40, NL-6666 ZG Heteren, NetherlandsNetherlands Inst Ecol POB 40 Heteren Netherlands NL-6666 ZG s
Citazione:
N.M. Van Dam et al., "Instar-specific sensitivity of specialist Manduca sexta larvae to induced defences in their host plant Nicotiana attenuata", ECOL ENT, 26(6), 2001, pp. 578-586

Abstract

1. The time delay associated with the activation of induced defences is thought to be a liability for this type of defence because it allows herbivores to remove biomass before the defence is fully induced. When defences arecostly and plants grow with competitors, however, it may be more advantageous not to induce defences too fast and motivate the herbivore to move to the neighbour when it is most voracious.2. Such a strategy can only work when the costs for the herbivore of moving to a neighbouring plant are smaller than the costs of staying on a fully induced plant. For lepidopteran herbivores, both the sensitivity to induceddefences and the costs of moving may vary considerably between instars andthis variation may constrain the plant's defensive opportunities.3. This study was designed to examine whether the cost of moving, mimickedby a starvation period of 8 h. was larger than the cost of staying on a fully induced plant for each larval instar of the specialist Manduca sexta feeding on induced and control tissues of Nicotiana attenuata.4. For first- and second-instar larvae, the costs of moving were larger than the costs of staying on a fully induced plant. In contrast, feeding on induced plant material retarded development in third-instar larvae more thandid starvation, indicating that in this instar the costs of leaving are smaller than the costs of staying on an induced plant. More than 98% of the lifetime leaf mass consumed by a M. sexta larva is consumed during the fourth and fifth instars, and during these instars larval development was not affected by either induced defences or starvation. Thus the third instar, thestage just before larvae cause the majority of damage, represents a windowof sensitivity to induced defences during which larvae can be motivated tochange plants.5. These results suggest that N. attenuata plants, which commonly compete with conspecifics in nature. have the opportunity to manipulate the behaviour of the specialist herbivore M. sexta to minimise the fitness effects of inducing defences when these defences are most costly, i.e, when plants grow under intraspecific competition.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 13:46:51