Feeding and foraging behaviour of a generalist caterpillar: are third instars just bigger versions of firsts?

Johnson, Marie-Louise; Zalucki, Myron P.

doi:10.1017/s0007485307004750

Cited by 44 publications

(56 citation statements)

References 38 publications

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“…Avoiding induced tissue early would give insects time for their own physiological adaptations to defensive metabolites [16] to develop. Previously, we have found that first instar H. armigera spend less time feeding and more time moving than third instars, but despite this, first instars have a higher relative growth rate [38]. Moving on from and therefore avoiding induced plant tissue could contribute to this higher growth rate.…”

Section: Discussionmentioning

confidence: 89%

Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts

et al. 2013

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Plants are sessile, so have evolved sensitive ways to detect attacking herbivores and sophisticated strategies to effectively defend themselves. Insect herbivory induces synthesis of the phytohormone jasmonic acid which activates downstream metabolic pathways for various chemical defences such as toxins and digestion inhibitors. Insects are also sophisticated animals, and many have coevolved physiological adaptations that negate this induced plant defence. Insect behaviour has rarely been studied in the context of induced plant defence, although behavioural adaptation to induced plant chemistry may allow insects to bypass the host's defence system. By visualizing jasmonate-responsive gene expression within whole plants, we uncovered spatial and temporal limits to the systemic spread of plant chemical defence following herbivory. By carefully tracking insect movement, we found induced changes in plant chemistry were detected by generalist Helicoverpa armigera insects which then modified their behaviour in response, moving away from induced parts and staying longer on uninduced parts of the same plant. This study reveals that there are plant-wide signals rapidly generated following herbivory that allow insects to detect the heterogeneity of plant chemical defences. Some insects use these signals to move around the plant, avoiding localized sites of induction and staying ahead of induced toxic metabolites.

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Section: Discussionmentioning

confidence: 89%

Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts

et al. 2013

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“…In general, young caterpillars have higher relative growth rates, consumption rates, metabolic rates, and assimilation efficiency, but lower net growth efficiency, than older ones (Scriber and Slansky 1981;Johnson and Zalucki 2007). They are more selective of food sources and more sensitive to plant chemistry, possibly due to a more limited array of digestive enzymes (Hochuli 2001).…”

Section: Early-instar Biologymentioning

confidence: 99%

Effects of phenological synchronization on caterpillar early-instar survival under a changing climate

Despland

2018

Can. J. For. Res.

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Early-instar caterpillars experience very high and often very variable mortality; if it is density dependent, it can be a key factor in outbreak dynamics. Plant physical and chemical defenses can be extremely effective against young caterpillars, even of specialists. Phenological asynchrony with host plants can lead to dispersal and mortality in the early instars and increased predation or poor nutrition in later instars. Predation on early-instar larvae (including cannibalism) can be extremely high, parasitism appears generally low, and pathogens acquired early in larval development can lead to high mortality in later stadia. Four well-studied species reveal very different roles of early-instar mortality in population dynamics. In spruce budworm and gypsy moth, early-instar mortality rates can be very high; they do not drive outbreak cycles because density dependence is weak, but can modulate cycles and contribute to outbreak size and duration. For the autumnal moth, early-instar survival depends on host plant synchrony, but may or may not be density dependent. For monarch butterflies, the relative importance of larval mortality rates in population dynamics remains unclear. Tritrophic interactions between herbivores, host plants, natural enemies, and microbes play complex and species-specific roles in early-instar ecology, leading to emergent dynamics in population fluctuations. The phenology of these relationships is often poorly understood, making their responses to climate change unpredictable.Key words: Lepidoptera, hatchlings, synchronization, outbreaks.Résumé : Les chenilles des premiers stades larvaires connaissent des taux de mortalité très élevés et souvent très variables; si ces taux varient avec la densité, ils peuvent devenir un facteur clé dans la dynamique des épidémies. Les défenses physiques et chimiques des plantes sont souvent extrêmement efficaces contre les jeunes chenilles, même celles des espèces spécialisées. L'asynchronie phénologique avec les plantes hôtes peut entraîner la dispersion et la mortalité chez les premiers stades larvaires, et une augmentation de la prédation ou une mauvaise nutrition chez les derniers stades larvaires. La prédation lors des premiers stades larvaires (incluant le cannibalisme) peut être extrêmement élevée, le parasitisme semble généralement faible et les pathogènes qui infectent tôt dans le développement des larves peuvent entraîner un taux de mortalité élevé chez les stades ultérieurs. Quatre espèces bien étudiées révèlent différents rôles de la mortalité chez les premiers stades larvaires dans la dynamique des populations. Chez la tordeuse des bourgeons de l'épinette et la spongieuse, les taux de mortalité peuvent être très élevés chez les premiers stades larvaires; ils n'ont pas d'effet déterminant sur les cycles épidémiques parce que la dépendance à la densité est faible, mais ils peuvent moduler les cycles et contribuer à l'ampleur et à la durée des épidémies. Dans le cas de l'épirrite automnale, la survie des premiers stades larvaires dépend ...

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“…The factors determining nutrient availability for growth and maintenance over a given time of development are the quantity and type of food consumed and the efficiency with which is utilized (Barton Browne & Raubenheimer, 2003). Feeding and foraging behaviour of H. armigera on mung bean, Vigna radiata (L.) R. Wilczek were determined by Johnson & Zalucki (2007). The effect of morpho-physical factors on consumption and coefficient of utilization of H. armigera has been already demonstrated (Ashfaq et al, 2003).…”

Section: Soybean Cultivars Pods Affecting the Nutritional Indices Of mentioning

confidence: 99%

Soybean Cultivars Affecting Performance of Helicoverpa armigera (Lepidoptera: Noctuidae)

Fathipour¹,

Naseri²

2011

Soybean - Biochemistry, Chemistry and Physiology

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Feeding and foraging behaviour of a generalist caterpillar: are third instars just bigger versions of firsts?

Cited by 44 publications

References 38 publications

Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts

Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts

Effects of phenological synchronization on caterpillar early-instar survival under a changing climate

Soybean Cultivars Affecting Performance of Helicoverpa armigera (Lepidoptera: Noctuidae)

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