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A Quantitative Analysis of Growth and Size Regulation in Manduca sexta: The Physiological Basis of Variation in Size and Age at Metamorphosis.

dc.contributor.author Grunert, LW
dc.contributor.author Clarke, JW
dc.contributor.author Ahuja, C
dc.contributor.author Eswaran, H
dc.contributor.author Nijhout, HF
dc.coverage.spatial United States
dc.date.accessioned 2015-10-15T14:49:28Z
dc.date.issued 2015
dc.identifier http://www.ncbi.nlm.nih.gov/pubmed/26011714
dc.identifier PONE-D-14-56257
dc.identifier.uri https://hdl.handle.net/10161/10745
dc.description.abstract Body size and development time are important life history traits because they are often highly correlated with fitness. Although the developmental mechanisms that control growth have been well studied, the mechanisms that control how a species-characteristic body size is achieved remain poorly understood. In insects adult body size is determined by the number of larval molts, the size increment at each molt, and the mechanism that determines during which instar larval growth will stop. Adult insects do not grow, so the size at which a larva stops growing determines adult body size. Here we develop a quantitative understanding of the kinetics of growth throughout larval life of Manduca sexta, under different conditions of nutrition and temperature, and for genetic strains with different adult body sizes. We show that the generally accepted view that the size increment at each molt is constant (Dyar's Rule) is systematically violated: there is actually a progressive increase in the size increment from instar to instar that is independent of temperature. In addition, the mass-specific growth rate declines throughout the growth phase in a temperature-dependent manner. We show that growth within an instar follows a truncated Gompertz trajectory. The critical weight, which determines when in an instar a molt will occur, and the threshold size, which determines which instar is the last, are different in genetic strains with different adult body sizes. Under nutrient and temperature stress Manduca has a variable number of larval instars and we show that this is due to the fact that more molts at smaller increments are taken before threshold size is reached. We test whether the new insight into the kinetics of growth and size determination are sufficient to explain body size and development time through a mathematical model that incorporates our quantitative findings.
dc.language eng
dc.relation.ispartof PLoS One
dc.relation.isversionof 10.1371/journal.pone.0127988
dc.subject Age Distribution
dc.subject Animals
dc.subject Body Size
dc.subject Food
dc.subject Genetic Variation
dc.subject Larva
dc.subject Manduca
dc.subject Metamorphosis, Biological
dc.subject Stress, Physiological
dc.subject Temperature
dc.title A Quantitative Analysis of Growth and Size Regulation in Manduca sexta: The Physiological Basis of Variation in Size and Age at Metamorphosis.
dc.type Journal article
pubs.author-url http://www.ncbi.nlm.nih.gov/pubmed/26011714
pubs.begin-page e0127988
pubs.issue 5
pubs.organisational-group Biology
pubs.organisational-group Duke
pubs.organisational-group Trinity College of Arts & Sciences
pubs.publication-status Published online
pubs.volume 10
dc.identifier.eissn 1932-6203


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