scholarly journals Variation in growth and instar number in field and laboratory Manduca sexta

2007 ◽  
Vol 274 (1612) ◽  
pp. 977-981 ◽  
Author(s):  
Joel G Kingsolver
Keyword(s):  
North Carolina ◽  
Body Size ◽  
Manduca Sexta ◽  
Growth Rates ◽  
Developmental Plasticity ◽  
Larval Growth ◽  
Physiological Control ◽  
Larval Instars ◽  
Laboratory Colony ◽  
Early Larval Development

The tobacco hornworm Manduca sexta has been an important model system for understanding physiological control of growth, development and metamorphosis of insects for more than half a century. Like all Manduca , M. sexta typically has five larval instars, with developmental commitment to metamorphosis occurring early in the 5th (final) instar. Here we show that M. sexta from a field population in North Carolina (USA) shows substantial intraspecific variation in the number of larval instars when feeding on a modified artificial diet. Individuals with six instars consistently exhibited slower growth rates during early larval development than individuals with five instars. The frequency of individuals with six instars decreased with increased rearing temperature. In contrast, M. sexta from a laboratory colony consistently had five instars, and had more rapid larval growth rates than M. sexta from the field. We identify a threshold body size at the start of the 5th instar that predicts whether an individual will have five (greater than 600 mg) or six instars (less than 600 mg). Variation in field populations in Manduca provides an important resource for understanding physiological control, developmental plasticity and evolution of growth rate, body size and instar number.

Maternal body size and condition determine calf growth rates in southern right whales

2018 ◽  
Vol 592 ◽  
pp. 267-281 ◽  
Author(s):  
F Christiansen ◽  
F Vivier ◽  
C Charlton ◽  
R Ward ◽  
A Amerson ◽  
...  
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Maternal Body ◽  
Calf Growth ◽  
Right Whales ◽  
Southern Right Whales

The missing links: larval and post-larval development of the ascoglossan opisthobranch Elysia viridis

2000 ◽  
Vol 80 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Cynthia D. Trowbridge
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Shell Length ◽  
Larval Growth ◽  
Model Organism ◽  
Larval Life ◽  
Codium Fragile ◽  
Planktotrophic Larvae ◽  
Algal Diet ◽  
Better Than

The stenophagous ascoglossan (=sacoglossan) opisthobranch Elysia viridis has long been a model organism for the study of endosymbiosis or kleptoplasty as well as one of the few herbivores to consume the introduced green macroalga Codium fragile on European shores. Larval and post-larval dynamics of the ascoglossan were investigated. Planktotrophic larvae of E. viridis grew at 5–10 μm d−1 (shell length) at 15°C on a unicellular algal diet (the cryptophyte Rhodomonas baltica); larvae became competent one month post-hatching. Effective feeding and chloroplast acquisition typically started within 2–3 d of metamorphosis. Slugs grew about 8 mm in the first month of post-larval life. During this period, juveniles held in the light did not grow faster or survive better than conspecifics held in the dark; thus, functional kleptoplasty did not occur during first three weeks of benthic life. While larval growth rates and the nature of metamorphic cues are consistent with those of many other opisthobranch species with planktotrophic larvae, measures of post-larval growth—particularly as it pertains to kleptoplasty—is a new contribution to opisthobranch biology.

scholarly journals Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

2013 ◽  
Vol 10 (8) ◽  
pp. 5267-5280 ◽  
Author(s):  
F. H. Chang ◽  
E. C. Marquis ◽  
C. W. Chang ◽  
G. C. Gong ◽  
C. H. Hsieh
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Specific Growth ◽  
Size Structure ◽  
Scaling Exponent ◽  
The East China Sea ◽  
Size Category ◽  
Grazing Mortality ◽  
Specific Growth Rates

Abstract. Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the metabolic theory of ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scale with the body size with an exponent of −1/4 after temperature correction, as MTE predicts. To do so, we couple a dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that would be very difficult to obtain in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. On average, the size-specific growth rates and grazing mortality scale almost isometrically with body size (with scaling exponent ∼0.1). However, this finding contains high uncertainty, as the size-scaling exponent varies substantially among assemblages. The fact that size-scaling exponent varies among assemblages prompts us to further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by normalized biomass size spectrum (NBSS), among assemblages. We test whether the variation of microphytoplankton NBSS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the ratio of the grazing mortality of the large size category to that of the small size category best explains the variation of NBSS slopes across environments, suggesting that higher grazing mortality of large microphytoplankton may release the small phytoplankton from grazing, which in turn leads to a steeper NBSS slope. This study contributes to understanding the relative importance of bottom-up versus top-down control in shaping microphytoplankton size structure.

scholarly journals Divergence and ontogenetic coupling of larval behaviour and thermal reaction norms in three closely related butterflies

2010 ◽  
Vol 278 (1703) ◽  
pp. 313-320 ◽  
Author(s):  
David Berger ◽  
Magne Friberg ◽  
Karl Gotthard
Keyword(s):  
Developmental Plasticity ◽  
Larval Growth ◽  
State Dependence ◽  
Reaction Norm ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Feeding Strategies ◽  
Species Differentiation ◽  
Larval Behaviour ◽  
Trade Offs

Genetic trade-offs such as between generalist–specialist strategies can be masked by changes in compensatory processes involving energy allocation and acquisition which regulation depends on the state of the individual and its ecological surroundings. Failure to account for such state dependence may thus lead to misconceptions about the trade-off structure and nature of constraints governing reaction norm evolution. Using three closely related butterflies, we first show that foraging behaviours differ between species and change remarkably throughout ontogeny causing corresponding differences in the thermal niches experienced by the foraging larvae. We further predicted that thermal reaction norms for larval growth rate would show state-dependent variation throughout development as a result of selection for optimizing feeding strategies in the respective foraging niches of young and old larvae. We found substantial developmental plasticity in reaction norms that was species-specific and reflected the different ontogenetic niche shifts. Any conclusions regarding constraints on performance curves or species-differentiation in thermal physiology depend on when reaction norms were measured. This demonstrates that standardized estimates at single points in development, or in general, allow variation in only one ecological dimension, may sometimes provide incomplete information on reaction norm constraints.

Inheritance of geographic variation in body size, and countergradient variation in growth rates, in the southern brown bandicoot Isoodon obesulus.

2000 ◽  
Vol 22 (1) ◽  
pp. 9 ◽  
Author(s):  
ML Hale
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Geographic Variation ◽  
Growth Rates ◽  
Habitat Type ◽  
Adaptive Divergence ◽  
Common Environment ◽  
Countergradient Variation ◽  
Large Animals

The inheritance of geographic variation in body size in the southern brown bandicoot (Isoodon obesulus) was investigated through a common-environment crossbreeding experiment. The geographic variation in body size is related to habitat type, suggesting that it may be adaptive. Adults from two locations in Western Australia, Perth (large animals) and Albany (small animals), were collected and offspring from both hybrid and non-hybrid matings were reared under controlled conditions. All four variables examined (head length, pes length, ear length and body weight) were found to possess a large genetic component, supporting the interpretation that the geographic variation in size is adaptive. The three length variables initially showed additive genetic variation, although the variation in body weight displayed dominance. Genetically controlled differences in growth rate were also detected, with the smaller animals, found in the relatively poorer environment, possessing the faster intrinsic growth rate. Thus, not only does there appear to be adaptive divergence in initial body size, but the countergradient variation in growth rates provides additional evidence for adaptive divergence in this species.

scholarly journals Ovarian growth during larval development of queen and worker of Apis mellifera (Hymenoptera: Apidae): a morphometric and histological study

2003 ◽  
Vol 63 (1) ◽  
pp. 121-127 ◽  
Author(s):  
R. D. Reginato ◽  
C. Cruz-Landim
Keyword(s):  
Weight Gain ◽  
Apis Mellifera ◽  
Larval Development ◽  
Growth Rates ◽  
Histological Study ◽  
Larval Instars ◽  
Ovarian Growth

The present work reports the differences between the ovarian grow in queen and worker larvae of A. mellifera, from the start of differential feeding. The observations made of the growth rates in larvae of both castes showed that the queen and worker larvae have the same rates of cephalic capsule growth from one instar to another but the weight gain is greater in queens. In the same way, the draw areas of ovaries of queens increase more and continuously, while from the 5th instar on the ovaries of workers decrease in size. The decrease is due to a loss of ovariole numbers that starts early in the worker larvae and increases in the 4th-5th instar. The ovarian shape in queens and workers became different in the last larval instars.

Carcass additions increase juvenile salmonid growth, condition, and size in an interior Columbia River Basin tributary

2020 ◽  
Vol 77 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Matthew J. Kaylor ◽  
Seth M. White ◽  
Edwin R. Sedell ◽  
Dana R. Warren
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Life Histories ◽  
Freshwater Ecosystems ◽  
Steelhead Trout ◽  
Juvenile Salmonids ◽  
Early Fall ◽  
Juvenile Chinook ◽  
The Relationship

Numbers of anadromous fish returning to freshwater ecosystems have declined precipitously across much of western North America, reducing a potentially important resource subsidy for juvenile salmonids. We added carcasses to three sections of a Snake River tributary and assessed juvenile Chinook salmon (Oncorhynchus tshawytcha) and steelhead trout (Oncorhynchus mykiss) growth, body condition, size, and diet responses in summer and early fall. Juvenile salmonids consumed an abundance of eggs and carcass tissue, which increased energy rations. Within 3 weeks of carcass additions, juvenile Chinook and steelhead growth rates were 1.1–5 and 6–23 times greater in treatment reaches relative to control reaches, respectively. We used long-term tagging and detection data from this system to assess the relationship between juvenile Chinook size and emigration survival for two different juvenile life histories. The increased growth rates and body size in response to carcass additions, coupled with a positive relationship between body size and survival, suggest that juvenile salmonid rearing productivity and emigration survival may be limited by depressed returns of anadromous fishes in this system and potentially other tributaries of the Columbia Basin.

GROWTH AND DEVELOPMENT OF LARVAE OF THE GRANARY WEEVIL, SITOPHILUS GRANARIUS (COLEOPTERA: CURCULIONIDAE), ON NATURAL AND MERIDIC DIETS

1973 ◽  
Vol 105 (2) ◽  
pp. 249-256 ◽  
Author(s):  
J. E. Baker ◽  
J. M. Mabie
Keyword(s):  
Wheat Flour ◽  
Growth Rates ◽  
Adult Stage ◽  
Larval Growth ◽  
Pupal Stage ◽  
Sitophilus Granarius ◽  
Granary Weevil ◽  
Whole Wheat Flour ◽  
Whole Wheat ◽  
Meridic Diet

AbstractA procedure is described for obtaining free eggs and first-stage larvae of Sitophilus granarius (L.) and rearing the larvae to the adult stage on whole wheat, corn, and rice flours and on diet 2, a casein–starch-based meridic diet.Larval growth rates of males and females reared at 29 °C and 65% R.H. on whole wheat flour were comparable although males attained a higher maximum mean weight. Days to 50% adult emergence (eclosion) were 25.5 and 26.5 for females and males, respectively.Larval growth rates on whole wheat flour were comparable with those on whole corn flour but were better than the rates obtained on whole rice flour; however, growth on diet 2 was improved compared with that on whole wheat flour. The mean weights of 14-day-old larvae were 2.51 ±.40 mg and 1.25 ±.16 mg for those reared on diet 2 and wheat flour, respectively. Similarly, survival to the adult stage was slightly greater (79%) on diet 2 than on wheat (70%). On diet 1, a casein–glucose-based meridic diet, no larvae developed to the pupal stage.

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