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Janani D, Lad SS, Rawson A, Sivanandham V, Rajamani M. Effect of microwave and ultrasound‐assisted extraction methods on phytochemical extraction of bee propolis of Indian origin and its antibacterial activity. Int J Food Sci Technol 2022. [DOI: 10.1111/ijfs.16066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dhanapathi Janani
- National Institute of Food Technology, Entrepreneurship and Management ‐ Thanjavur (NIFTEM‐T, Formerly Indian Institute of Food Processing Technology) Affiliated to Bharathidasan University Thanjavur 613005 Tamil Nadu India
| | - Sunaina Sunil Lad
- Food Safety and Quality Assurance National Institute of Food Technology, Entrepreneurship and Management – Thanjavur (NIFTEM – T, Formerly Indian Institute of Food Processing Technology) Thanjavur 613005 Tamil Nadu India
| | - Ashish Rawson
- Department of Food Safety and Quality Testing National Institute of Food Technology, Entrepreneurship and Management – Thanjavur (NIFTEM – T, Formerly Indian Institute of Food Processing Technology) Thanjavur 613005 Tamil Nadu India
| | - Vignesh Sivanandham
- Department of Academics & Human Resource Development National Institute of Food Technology, Entrepreneurship and Management – Thanjavur (NIFTEM – T, Formerly Indian Institute of Food Processing Technology) Thanjavur 613005 Tamil Nadu India
| | - Meenatchi Rajamani
- Department of Primary Processing Storage and Handling National Institute of Food Technology, Entrepreneurship and Management – Thanjavur (NIFTEM – T, Formerly Indian Institute of Food Processing Technology) Thanjavur 613005 Tamil Nadu India
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Negi A, Pare A, Manickam L, Rajamani M. Effects of defect action level of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) fragments on quality of wheat flour. J Sci Food Agric 2022; 102:223-232. [PMID: 34086293 DOI: 10.1002/jsfa.11349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/05/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Tribolium castaneum (Herbst) is one of the most important secondary storage pests of all types of flour and flour-based products. The present study focuses on the fragment producing behaviour of T. castaneum in wheat flour during storage and its effect on the quality parameters and defect action level (DAL) of fragments. The US Food and Drug Administration has set a DAL of 75 insect fragments in 50 g of flour. Box-Behnken design was used to optimize the storage conditions (storage period in days and temperature in degrees Celsius) and insect density (numbers) to keep insect fragments below the DAL. RESULTS Optimization results indicated that the presence of single number of adult of T. castaneum is enough to cross the DAL of insect fragments within a storage period of 21 days at a storage temperature of 30 °C. Insect fragments cause perceptible changes in the quality of wheat flour. When sample attained DAL of T. castaneum fragments in wheat flour,the various quality parameters were analysed in that moisture content of wheat flour was 10.8 ± 0.26%, total colour change was 2.052 (ΔE value), T. castaneum progeny emergence was 19.66 ± 1, uric acid was 1.8 ± 0.16 g kg-1 and microbial count was 7.34 ± 0.5 cfu g-1 . CONCLUSIONS Results from the present study indicate that the presence of even a single adult of stored pest in wheat flour should not be ignored. It is mandatory to determine the threshold level and frequent sampling is required to achieve zero tolerance of stored product insects in food commodities. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Aditi Negi
- Department of Primary Processing Storage and Handling, IIFPT, Thanjavur, India
- Bharathidasan University, Tiruchirappalli, Tamil Nadu, 620 024, India
| | - Akash Pare
- Department of Academics & Human Resource Development, IIFPT, Thanjavur, India
| | - Loganathan Manickam
- Department of Academics & Human Resource Development, IIFPT, Thanjavur, India
| | - Meenatchi Rajamani
- Department of Primary Processing Storage and Handling, IIFPT, Thanjavur, India
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Rajamani M, Maile A, Sugunan AP, Vijayachari P. Truenat TM - micro real-time-polymerase chain reaction for rapid diagnosis of leptospirosis at minimal resource settings. Indian J Med Res 2021; 154:115-120. [PMID: 34782537 PMCID: PMC8715686 DOI: 10.4103/ijmr.ijmr_2539_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Background & objectives: The biological spectrum of leptospirosis ranges from acute undifferentiated febrile illness to severe fatal syndrome or a combination of syndromes. Diagnosis on clinical grounds alone is difficult and depends on laboratory support. However, no confirmatory tests are available, which is rapid and can be performed with minimum facilities available. The objectives of this study were to evaluate the diagnostic utility, accuracy and reproducibility of a rapid real time-PCR based method (Truenat™) for early diagnosis of leptospirosis, and its usage in low resource settings. Methods: The Truenat™ test was performed using plasma sample collected from confirmed patients and controls. DNA was extracted from plasma samples and the reaction was performed as per the manufacturer’s instructions. Leptospiral isolates were also used to assess the performance using different serovars. Results: Evaluation of the Truenat™ test with RT-PCR as the gold standard showed that Truenat™ had a sensitivity of 97.4 per cent and a specificity of 98.6 per cent. The overall agreement with RT-PCR was 98.2 per cent. Interpretation & conclusions: Our results showed that the test would be a useful tool for early diagnosis of leptospirosis in settings with minimal facilities and the test results could be obtained within an hour. This indicates that a specific therapy can be instituted during the early phase of the disease even at peripheral healthcare facilities as well during the outbreaks.
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Affiliation(s)
- M Rajamani
- ICMR-Regional Medical Research Centre, WHO Collaborating Centre for Diagnosis, Research, Reference & Training in Leptospirosis, Port Blair, Andaman & Nicobar Islands, India
| | - Anwesh Maile
- ICMR-Regional Medical Research Centre, WHO Collaborating Centre for Diagnosis, Research, Reference & Training in Leptospirosis, Port Blair, Andaman & Nicobar Islands, India
| | - A P Sugunan
- ICMR-Regional Medical Research Centre, WHO Collaborating Centre for Diagnosis, Research, Reference & Training in Leptospirosis, Port Blair, Andaman & Nicobar Islands, India
| | - P Vijayachari
- ICMR-Regional Medical Research Centre, WHO Collaborating Centre for Diagnosis, Research, Reference & Training in Leptospirosis, Port Blair, Andaman & Nicobar Islands, India
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Negi A, Anandharaj A, Kalakandan S, Rajamani M. A Molecular Approach for the Detection and Quantification of Tribolium castaneum (Herbst) Infestation in Stored Wheat Flour. Food Technol Biotechnol 2021; 59:112-121. [PMID: 34084086 PMCID: PMC8157093 DOI: 10.17113/ftb.59.01.21.6902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Research background The presence of insect fragments is one of the major constrains in stored food commodities and it causes considerable loss in the quality of the produce. The management of the pest is viewed as a huge challenge in foodprocessingindustry. Conventionally, the detection of Tribolium castenaum in the food processing industry is carried out by acid hydrolysis and staining methods that are time consuming and lack precision. Experimental approach Considering the importance of a quick and effective method, a quantitative polymerase chain reaction (qPCR)-based approach was developed and elucidated in this study. The mitochondrial cytochrome oxidase I (mtCOI) gene was identified as a target due to its abundance in the pest. Specific primers were designed against the target gene by Primer Premier software and amplified in a qPCR. Results and conclusions This method is capable of detecting all the ontogenic stages of T. castaneum in stored wheat flour. Earlier experiments had demonstrated that about 20 µg of DNA can be obtained from 2.2 mg of insects. To quantify the infestation levels, the cycle threshold (Ct) values obtained from known samples were subjected to regression analysis and expressed as adult equivalents. In the unknown samples, the infestation was calculated as 1.74 and 0.046 adult insects in 5 g of wheat flour. The maximum permissible limit of insect fragments in flour is 75 insect fragments or approx. 3 adults per 50 g of flour as per the US Food and Drug Administration (FDA). Hence, by adopting this new method, it is possible for the warehouse operators to arrive at a decision to proceed with efficient management practices where wheat flour is stored. Also, this method can be ratified by government agencies associated with international business to ascertain whether the wheat flour meets the standards set by the respective country before subjecting to foreign trade. Novelty and scientific contribution This study is the first of its kind in the detection and quantification of T. castaneum in milled products. So far, only conventional methods have been employed to assess the presence of the pests and manual counting of fragments are practiced to quantify the infestation levels. The developed qPCR method is faster, reliable and can be employed in milling industries, bakery industries, food processing plants and foreign trade units for critical detection and quantification of T. castaneum pest infestation.
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Affiliation(s)
- Aditi Negi
- Department of Primary Processing, Storage and Handling, Indian Institute of Food Processing Technology, 613005 Thanjavur, Tamil Nadu, India.,Bharathidasan University, 620024 Tiruchirappalli, Tamil Nadu, India
| | - Arunkumar Anandharaj
- Department of Food Safety and Quality Testing, Indian Institute of Food Processing Technology, 613005 Thanjavur, Tamil Nadu, India
| | - Sureshkumar Kalakandan
- Department of Food Safety and Quality Testing, Indian Institute of Food Processing Technology, 613005 Thanjavur, Tamil Nadu, India
| | - Meenatchi Rajamani
- Department of Primary Processing, Storage and Handling, Indian Institute of Food Processing Technology, 613005 Thanjavur, Tamil Nadu, India
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Mangang IB, Tiwari A, Rajamani M, Manickam L. Comparative laboratory efficacy of novel botanical extracts against Tribolium castaneum. J Sci Food Agric 2020; 100:1541-1546. [PMID: 31769025 DOI: 10.1002/jsfa.10162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/03/2019] [Accepted: 11/23/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Citrus sinensis, Allium sativum, Ocimum basilicum, Mentha spicata, Curcuma longa, Carica papaya, Andrographis paniculata, Azadirachta indica, Cymbopogon citratus and Acorus calamus were compared in the form of extracts of chloroform, hexane and aqueous media for their effectiveness in repelling Tribolium castaneum. Filter paper of 9 cm in diameter was cut into halves. Using a micro-pipette, each extract was applied to one half of the filter paper. The volume applied was kept constant at 0.6 mL per 30 cm2 . The filter paper was dried and reattached leaving a 0.5 cm gap between, in a Petri-plate. Ten adults of T. castaneum were introduced and the repellency was observed after 30, 60 and 180 min. RESULTS The aqueous extract of C. papaya exhibited the highest repellency (82-97%) followed by that of garlic bulbs (aqueous extract) with 86.67% repellency. Further, gunny bags were sprayed separately using bottle sprayers with the two most effective extracts at a constant volume of 42 mL per 575 cm2 . These treated gunny bags were compared with malathion-treated gunny bags in the insect management unit. The observations were taken after 2, 8 and 24 h. Papaya leaf extract-treated gunny bags showed relative repellent activity similar to that of malathion-treated gunny bags after 24 h of treatment. Thus, gas chromatography-mass spectrometry analysis of aqueous extract of papaya leaves was performed. CONCLUSIONS It can be concluded that extract of papaya leaves containing 2-methoxy-4-vinylphenol (8.47% peak area) can be used as a repellent biopesticide. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Irengbam Barun Mangang
- Indian Institute of Food Processing Technology (Ministry of Food Processing Industries, Government of India), Thanjavur, India
| | - Abhinav Tiwari
- Indian Institute of Food Processing Technology (Ministry of Food Processing Industries, Government of India), Thanjavur, India
| | - Meenatchi Rajamani
- Indian Institute of Food Processing Technology (Ministry of Food Processing Industries, Government of India), Thanjavur, India
| | - Loganathan Manickam
- Indian Institute of Food Processing Technology (Ministry of Food Processing Industries, Government of India), Thanjavur, India
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Tung S, Rajamani M, Joshi A, Dey S. Complex interaction of resource availability, life-history and demography determines the dynamics and stability of stage-structured populations. J Theor Biol 2018; 460:1-12. [PMID: 30300650 DOI: 10.1016/j.jtbi.2018.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/15/2022]
Abstract
The dynamics of stage-structured populations facing stage-specific variability in resource availability and/or demographic factors like unequal sex-ratios, remains poorly understood. We addressed these issues using a stage-structured individual-based model that incorporates life-history parameters common to many holometabolous insects. The model was calibrated using time series data from a 49-generation experiment on laboratory populations of Drosophila melanogaster, subjected to four different combinations of larval and adult nutritional levels. The model was able to capture multiple qualitative and quantitative aspects of the empirical time series across three independent studies. We then simulated the model to explore the interaction of various life-history parameters and nutritional levels in determining population stability. In all nutritional regimes, constancy stability of the populations was reduced upon increasing egg-hatchability, critical mass, and proportion of body resource allocated to female fecundity. However, the effects of increasing sensitivity of female-fecundity to adult density on constancy stability varied across nutrition regimes. The effects of unequal sex-ratio and sex-specific culling were greatly influenced by fecundity but not by levels of juvenile nutrition. Finally, we investigated the implications of some of these insights on the efficiency of the widely-used pest control method, the Sterile Insect Technique (SIT). We show that increasing the amount of juvenile food had no effects on SIT efficiency when the density-independent fecundity is low, but reduces SIT efficiency when the density-independent fecundity is high.
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Affiliation(s)
- Sudipta Tung
- Population Biology Laboratory, Biology Division, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune 411 008, India
| | - M Rajamani
- Evolutionary Biology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bengaluru 560 064, India
| | - Amitabh Joshi
- Evolutionary Biology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bengaluru 560 064, India
| | - Sutirth Dey
- Population Biology Laboratory, Biology Division, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune 411 008, India.
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Rajamani M, Kawali A, Vijayalakshmi P, Puthuran GV. Response to ‘Role of miotics and cycloplegics in angle closure’. Eye (Lond) 2015; 29:1515-6. [DOI: 10.1038/eye.2015.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Rajamani M, Raghavendra N, Prasad NG, Archana N, Joshi A, Shakarad M. Reduced larval feeding rate is a strong evolutionary correlate of rapid development in Drosophila melanogaster. J Genet 2007; 85:209-12. [PMID: 17406096 DOI: 10.1007/bf02935333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M Rajamani
- Behaviour, Ecology and Evolution Laboratory, Biology Department, Poornaprajna Institute of Scientific Research, P.O. Box No. 18, Devanahalli, Bangalore 562 110, India
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Shakarad M, Prasad NG, Gokhale K, Gadagkar V, Rajamani M, Joshi A. Faster development does not lead to correlated evolution of greater pre-adult competitive ability in Drosophila melanogaster. Biol Lett 2007; 1:91-4. [PMID: 17148136 PMCID: PMC1629059 DOI: 10.1098/rsbl.2004.0261] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In comparisons across Drosophila species, faster pre-adult development is phenotypically correlated with increased pre-adult competitive ability, suggesting that these two traits may also be evolutionary correlates of one another. However, correlations between traits within- and among- species can differ, and in most cases it is the within-species genetic correlations that are likely to act as constraints on adaptive evolution. Moreover, laboratory studies on Drosophila melanogaster have shown that the suite of traits that evolves in populations subjected to selection for faster development is the opposite of the traits that evolve in populations selected for increased pre-adult competitive ability. This observation led us to propose that, despite having a higher carrying capacity and a reduced minimum food requirement for completing development than controls, D. melanogaster populations subjected to selection for faster development should have lower competitive ability than controls owing to their reduced larval feeding rates and urea tolerance. Here, we describe results from pre-adult competition experiments that clearly show that the faster developing populations are substantially poorer competitors than controls when reared at high density in competition with a marked mutant strain. We briefly discuss these results in the context of different formulations of density-dependent selection theory.
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Affiliation(s)
- Mallikarjun Shakarad
- Behaviour, Ecology & Evolution Laboratory, Biology Department, Poornaprajna Institute of Scientific Research, P. O. Box 18, Devanahalli-562 110, Bangalore, India.
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Shakarad M, Prasad NG, Gokhale K, Gadagkar V, Rajamani M, Joshi A. Correction for Shakarad
et al.
, Faster development does not lead to correlated evolution of greater pre-adult competitive ability in
Drosophila melanogaster. Biol Lett 2005. [DOI: 10.1098/rsbl.2005.2000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Correction for ‘Faster development does not lead to correlated evolution of greater pre-adult competitive ability in
Drosophila melanogaster
’ by Mallikarjun Shakarad, N. G. Prasad, Kaustubh Gokhale, Vikram Gadagkar, M. Rajamani and Amitabh Joshi (Biol. Lett.
1
, 91–94.
(doi:
10.1098/2004.0261
)).
On p. 91, the Digital Object Identifier should be 10.1098/rsbl.2004.0261.
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Prasad NG, Shakarad M, Anitha D, Rajamani M, Joshi A. Correlated responses to selection for faster development and early reproduction in Drosophila: the evolution of larval traits. Evolution 2001; 55:1363-72. [PMID: 11525460 DOI: 10.1111/j.0014-3820.2001.tb00658.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Studies on selection for faster development in Drosophila have typically focused on the trade-offs among development time, adult weight, and adult life span. Relatively less attention has been paid to the evolution of preadult life stages and behaviors in response to such selection. We have earlier reported that four laboratory populations of D. melanogaster selected for faster development and early reproduction, relative to control populations, showed considerably reduced preadult development time and survivorship, dry weight at eclosion, and larval growth rates. Here we study the larval phase of these populations in greater detail. We show here that the reduction in development time after about 50 generations of selection is due to reduced duration of the first and third larval instars and the pupal stage, whereas the duration of the second larval instar has not changed. About 90% of the preadult mortality in the selected populations is due to larval mortality. The third instar larvae, pupae, and freshly eclosed adults of the selected populations weigh significantly less than controls, and this difference appears during the third larval instar. Thereafter, percentage weight loss during the pupal stage does not differ between selected and control populations. The minimum amount of time a larva must feed to subsequently complete development is lower in the selected populations, which also exhibit a syndrome of reduced energy expenditure through reduction in larval feeding rate, larval digging and foraging activity, and pupation height. Comparison of these results with those observed earlier in populations selected for adaptation to larval crowding and faster development under a different protocol from ours reveal differences in the evolved traits that suggest that the responses to selection for faster development are greatly affected by the larval density at which selection acts and on details of the selection pressures acting on the timing of reproduction.
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Affiliation(s)
- N G Prasad
- Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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Shakarad M, Prasad NG, Rajamani M, Joshi A. Evolution of faster development does not lead to greater fluctuating asymmetry of sternopleural bristle number in Drosophila. J Genet 2001; 80:1-7. [PMID: 11910118 DOI: 10.1007/bf02811412] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Both strong directional selection and faster development are thought to destabilize development, giving rise to greater fluctuating asymmetry (FA), although there is no strong empirical evidence supporting this assertion. We compared FA in sternopleural bristle number in four populations of Drosophila melanogaster successfully selected for faster development from egg to adult, and in four control populations. The fraction of perfectly symmetric individuals was higher in the selected populations, whereas the FA levels did not differ significantly between selected and control populations, clearly indicating that directional selection for faster development has not led to increased FA in sternopleural bristle number in these populations. This may be because: (i) development time and FA are uncorrelated, (ii) faster development does result in FA, but selection has favoured developmentally stable individuals that can develop fast and still be symmetrical, or (iii) the increased fraction of symmetric individuals in the selected populations is an artifact of reduced body size. Although we cannot discriminate among these explanations, our results suggest that the relationship between development time, FA and fitness may be far more subtle than often thought.
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Affiliation(s)
- M Shakarad
- Poornaprajna Institute of Scientific Research, 4 Sadashivanagar, Bangalore 560 080, India
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Prasad NG, Shakarad M, Anitha D, Rajamani M, Joshi A. CORRELATED RESPONSES TO SELECTION FOR FASTER DEVELOPMENT AND EARLY REPRODUCTION IN DROSOPHILA: THE EVOLUTION OF LARVAL TRAITS. Evolution 2001. [DOI: 10.1554/0014-3820(2001)055[1363:crtsff]2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Prasad NG, Shakarad M, Gohil VM, Sheeba V, Rajamani M, Joshi A. Evolution of reduced pre-adult viability and larval growth rate in laboratory populations of Drosophila melanogaster selected for shorter development time. Genet Res (Camb) 2000; 76:249-59. [PMID: 11204972 DOI: 10.1017/s0016672300004754] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Four large (n > 1000) populations of Drosophila melanogaster, derived from control populations maintained on a 3 week discrete generation cycle, were subjected to selection for fast development and early reproduction. Egg to eclosion survivorship and development time and dry weight at eclosion were monitored every 10 generations. Over 70 generations of selection, development time in the selected populations decreased by approximately 36 h relative to controls, a 20% decline. The difference in male and female development time was also reduced in the selected populations. Flies from the selected populations were increasingly lighter at eclosion than controls, with the reduction in dry weight at eclosion over 70 generations of selection being approximately 45% in males and 39% in females. Larval growth rate (dry weight at eclosion/development time) was also reduced in the selected lines over 70 generations, relative to controls, by approximately 32% in males and 24% in females. However, part of this relative reduction was due to an increase in growth rate of the controls populations, presumably an expression of adaptation to conditions in our laboratory. After 50 generations of selection had elapsed, a considerable and increasing pre-adult viability cost to faster development became apparent, with viability in the selected populations being about 22% less than that of controls at generation 70 of selection.
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Affiliation(s)
- N G Prasad
- Evolutionary Biology Laboratory, Evolutionary & Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box No. 6436, Jakkur, Bangalore 560 064, India
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