scholarly journals Polyphenol-Rich Purple Corn Pericarp Extract Adversely Impacts Herbivore Growth and Development

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 98 ◽  
Author(s):  
Mandeep Tayal ◽  
Pavel Somavat ◽  
Isabella Rodriguez ◽  
Tina Thomas ◽  
Bradley Christoffersen ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Growth And Development ◽  
Control Diet ◽  
Insect Pest ◽  
Plant Secondary Metabolites ◽  
Mass Gain ◽  
Developmental Time ◽  
Egg Hatching ◽  
Indirect Defenses ◽  
Purple Corn

Plant secondary metabolites such as terpenes, phenolics, glycosides, and alkaloids play various functional roles including pigmentation, foliar and floral volatile synthesis, hormonal regulation, and direct and indirect defenses. Among these, phenolic compounds are commonly found in plants, but vary in the distribution of their specific compounds among plant families. Polyphenols, including anthocyanins and tannins, are widely distributed and have been well documented for their roles- primarily in plant pigmentation and also in plant defenses. However, commercialization of such compounds for use in insect pest management is severely hampered by expensive, inefficient, and time-consuming extraction protocols. Using a recently developed inexpensive and easy extraction method using the byproducts of pigmented (purple) corn processing, we examined whether the crude pericarp extract rich in polyphenols can affect the growth and development of tobacco hornworm (Manduca sexta L.) caterpillars. Our findings show that purple corn pericarp extract negatively affected M. sexta egg hatching and larval mass gain and prolonged developmental time compared to regular yellow corn extract or an artificial control diet. We also found that these effects were more severe during the early stages of caterpillar development. These results conclusively demonstrate that purple corn pericarp, an inexpensive by-product of the corn milling industry, is a valuable product with excellent potential as an insect antifeedant.

Effect of Temperature on the Predator, (Reuter) (Hemiptera: Anthocordiae) Feeding on Cryptolestes pusillus (Schon.) (Coleoptera: Cucujidae)

1970 ◽  
Vol 15 ◽  
pp. 41-46 ◽  
Author(s):  
MM Rahman ◽  
W Islam ◽  
KN Ahmed
Keyword(s):  
Life History ◽  
Insect Pest ◽  
Developmental Time ◽  
Effect Of Temperature ◽  
Hatching Rate ◽  
Immature Stages ◽  
Egg Hatching ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
Cryptolestes Pusillus

Xylocoris flavipes (Reuter) is one of the dominant predators of many stored product insect pest including Cryptolestes pusillus. The influence of temperature on predator development, survival and some selected life history parameters was determined. Eggs laid/female (27.27±2.52) and egg hatching rate (%) (88.25±2.19) were highest at 30°C and lowest at 20°C (5.43±1.19 and 30.79±4.63%) respectively but no eggs laid at 15°C. Mortality among immature stages (%) was highest (51.71±1.48) at 35°C and lowest (24.25c±1.14) at 25°C. Developmental times decreasing with the increasing of temperature. Maximum numbers of progeny/female/day (3.55±0.76) were produced at 25°C and minimum (0.83±0.04) were at 20°C.The sex ratios (% female) of X. flavipes were 47.04, 56.68, 51.66 and 50.07 for 20, 25, 30 and 35°C respectively. Survivorship of ovipositing females was highest at 25°C but lowest at 35°C respectively. Key words: Xylocoris flavipes, Cryptolestes pusillus, life history, temperature, developmental time   doi: 10.3329/jbs.v15i0.2201 J. bio-sci. 15: 41-46, 2007

scholarly journals Phenotypic effects induced by knock-down of the period clock gene in Bombyx mori

2007 ◽  
Vol 89 (2) ◽  
pp. 73-84 ◽  
Author(s):  
FEDERICA SANDRELLI ◽  
SILVIA CAPPELLOZZA ◽  
CLARA BENNA ◽  
ALESSIO SAVIANE ◽  
ANTONIO MASTELLA ◽  
...  
Keyword(s):  
Bombyx Mori ◽  
Clock Gene ◽  
Developmental Time ◽  
Economic Importance ◽  
Circadian Clock Gene ◽  
Egg Hatching ◽  
Knock Down ◽  
Production Parameters ◽  
Silk Production ◽  
Practical Level

SummaryThe lepidopteran Bombyx mori is an insect of considerable scientific and economic importance. Recently, the B. mori circadian clock gene period has been molecularly characterized. We have transformed a B. mori strain with a construct encoding a period double-strand RNA in order to knock-down period gene expression. We observe that this post-transcriptional silencing produces a small but detectable disruption in the egg-hatching rhythm, as well as a reduction in egg-to-adult developmental time, without altering silk production parameters. Thus we show that both circadian and non-circadian phenotypes can be altered by changing per expression, and, at a practical level, these results suggest that per knock-down may provide a suitable strategy for improving the efficiency of rearing, without affecting silk productivity.

scholarly journals The Gut Microbiota in Camellia Weevils Are Influenced by Plant Secondary Metabolites and Contribute to Saponin Degradation

mSystems ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Shouke Zhang ◽  
Jinping Shu ◽  
Huaijun Xue ◽  
Wei Zhang ◽  
Yabo Zhang ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Microbial Communities ◽  
Bacterial Communities ◽  
Insect Pest ◽  
Plant Secondary Metabolites ◽  
Sole Source ◽  
Chemical Defenses ◽  
Plant Interactions ◽  
Content Type ◽  
Tea Saponin

ABSTRACT The camellia weevil (CW [Curculio chinensis]) is a notorious host-specific predator of the seeds of Camellia species in China, causing seed losses of up to 60%. The weevil is capable of overcoming host tree chemical defenses, while the mechanisms of how these beetles contend with the toxic compounds are still unknown. Here, we examined the interaction between the gut microbes of CW and camellia seed chemistry and found that beetle-associated bacterial symbionts mediate tea saponin degradation. We demonstrate that the gut microbial community profile of CW was significantly plant associated, and the gut bacterial community associated with CW feeding on Camellia oleifera seeds is enriched with genes involved in tea saponin degradation compared with those feeding on Camellia sinensis and Camellia reticulata seeds. Twenty-seven bacteria from the genera Enterobacter, Serratia, Acinetobacter, and Micrococcus subsisted on tea saponin as a sole source of carbon and nitrogen, and Acinetobacter species are identified as being involved in the degradation of tea saponin. Our results provide the first metagenome of gut bacterial communities associated with a specialist insect pest of Camellia trees, and the results are consistent with a potential microbial contribution to the detoxification of tree-defensive chemicals. IMPORTANCE The gut microbiome may play an important role in insect-plant interactions mediated by plant secondary metabolites, but the microbial communities and functions of toxic plant feeders are still poorly characterized. In the present study, we provide the first metagenome of gut bacterial communities associated with a specialist weevil feeding on saponin-rich and saponin-low camellia seeds, and the results reveal the correlation between bacterial diversity and plant allelochemicals. We also used cultured microbes to establish their saponin-degradative capacity outside the insect. Our results provide new experimental context to better understand how gut microbial communities are influenced by plant secondary metabolites and how the resistance mechanisms involving microbes have evolved to deal with the chemical defenses of plants.

Light-Mediated Hormonal Regulation of Plant Growth and Development

2016 ◽  
Vol 67 (1) ◽  
pp. 513-537 ◽  
Author(s):  
Mieke de Wit ◽  
Vinicius Costa Galvão ◽  
Christian Fankhauser
Keyword(s):  
Plant Growth ◽  
Hormonal Regulation ◽  
Growth And Development ◽  
Plant Growth And Development

Environmental regulation of sex determination in reptiles

1988 ◽  
Vol 322 (1208) ◽  
pp. 19-39 ◽  
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Growth And Development ◽  
Incubation Temperature ◽  
Sex Differentiation ◽  
Developmental Time ◽  
Alligator Mississippiensis ◽  
Phylogenetic Implications ◽  
History Of ◽  
Determining Factor

The various patterns of environmental sex determination in squamates, chelonians and crocodilians are described. High temperatures produce males in lizards and crocodiles but females in chelonians. Original experiments on the effects of incubation at 30 °C (100% females) or 33 °C (100% males) on development in Alligator mississippiensis are described. These include an investigation of the effect of exposing embryos briefly to a different incubation temperature on the sex ratio at hatching, and a study of the effects of 30 °C and 33 °C on growth and development of alligator embryos and gonads. A 7-day pulse of one temperature on the background of another was insufficient to alter the sex ratio dramatically. Incubation at 33 °C increased the rate of growth and development of alligator embryos. In particular, differentiation of the gonad at 33 °C was enhanced compared with 30 °C. A hypothesis is developed to explain the mechanism of temperature-dependent sex determination (TSD) in crocodilians. The processes of primary sex differentiation are considered to involve exposure to a dose of some male-determining factor during a specific quantum of developmental time during early incubation. The gene that encodes for the male- determining factor is considered to have an optimum temperature (33 °C). Any change in the temperature affects the expression o f this gene and affects the dose or quantum embryos are exposed to. In these cases there is production of females by default. The phylogenetic implications of TSD for crocodilians, and reptiles in particular, are related to the life history of the animal from conception to sexual maturity. Those animals that develop under optimal conditions grow fastest and largest and become male. A general association between the size of an animal and its sex is proposed for several types of vertebrate.

A numerical study of the growth and development of Trichodorus christiei

1968 ◽  
Vol 46 (2) ◽  
pp. 109-114 ◽  
Author(s):  
G. W. Bird ◽  
W. F. Mai
Keyword(s):  
Excretory Pore ◽  
Reproductive System ◽  
Growth And Development ◽  
Numerical Study ◽  
Developmental Time ◽  
Morphometric Character ◽  
Time Interval ◽  
Allometric Growth ◽  
Morphometric Characters ◽  
Stylet Length

An analysis of morphometric and allometric characters was used to study the growth and development of Trichodorus christiei Allen, 1957. The magnitude, location, and time of morphometric growth was determined for 14 characters. With the exception of the stylet length, body width, and characters pertaining to the reproductive system, morphometric characters increased in size more in the second and fourth than in the third developmental time interval. An analysis of 45 pairs of characters was used to study the allometric growth of nematodes belonging to four stages of the life cycle. The reproductive system was found to be relatively stable and numerous pairs of characters exhibited significant allometric growth. Because of the lack of significant allometric growth between the pairs of characters used to form the a and c ratios, these ratios are not suitable for taxonomic purposes pertaining to this species. The lack of significant allometric growth between the stylet and esophagus lengths indicated that these characters should not be combined as neck length for use in the b ratio. Because of the variability of the esophagus as a morphometric character, the excretory pore position defined in terms of distance from the lip region is more suitable for Trichodorus spp. than the excretory pore position defined in relation to its distance from the base of the esophagus.

The possible rôle of xanthoxin in plant growth and development

1978 ◽  
Vol 284 (1002) ◽  
pp. 499-507 ◽  
Keyword(s):  
Abscisic Acid ◽  
Hormonal Regulation ◽  
Growth And Development ◽  
Higher Plants ◽  
The Other ◽  
Regulatory Function ◽  
Root Tip ◽  
Root Tips ◽  
Root Primordia ◽  
Lateral Root Primordia

In higher plants, abscisic acid and xanthoxin are two potent growth regulators. Although similar properties in both substances have been demonstrated in several biological tests including biochemical interconversion of the substances, evidence is available that in the plant as a whole, xanthoxin has regulatory functions other than those of abscisic acid. Several environmental factors, such as water supply, photoperiod and low temperature, which affect growth and development also greatly change the level of abscisic acid in the plant; however, only small variations in the xanthoxin level have been observed in response to changes in the environmental conditions. On the other hand, a strong enhancement of the xanthoxin level can be induced when dark-grown seedlings are briefly illuminated; this treatment, however, has no influence on the abscisic acid level. This observation supports the hypothesis that light-induced inhibition of growth may be mediated by an increased formation of the growth inhibitor xanthoxin. Light-induced enhancement of the xanthoxin level may also contribute to the phototropic bending in dictyledonous seedlings. Evidence has been obtained from experiments in this laboratory that xanthoxin may be involved in the regulation of root branching. Decapitation of root tips causes a significant increase in the number of lateral root primordia. Chromatographic studies reveal the presence of two substances in the root, which, in a specific bioassay, are active inhibitors of the development of root primordia. The activity of these root inhibitors in the basal part decreases when the root tip is removed. They are probably produced in the root tip and are transported to the base. One of these inhibitors has been identified as xanthoxin, the other is cytokinin. The hormonal regulation of abscission is another process where xanthoxin may have a regulatory function. Senescent, abscinding petioles contain a factor called ‘senescence factor’ which promotes the abscission of leaves. In an attempt to identify its chemical nature, it was found that at least three different abscission accelerating substances, including xanthoxin, participate in the composition of the senescence factor.

scholarly journals Influence of Insect Growth Regulators on Stephanitis pyrioides (Hemiptera: Tingidae) Eggs and Nymphs

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 189 ◽  
Author(s):  
Shimat V. Joseph
Keyword(s):  
Growth Regulators ◽  
Insect Pest ◽  
Close Monitoring ◽  
Insect Growth Regulators ◽  
Egg Hatching ◽  
Insect Growth ◽  
Significant Difference ◽  
The Usa ◽  
Series Of Experiments ◽  
The Aesthetic

The azalea lace bug, Stephanitis pyrioides (Scott) (Hemiptera: Tingidae), is an important insect pest of azaleas (Rhododendron L. spp.) in the USA. Stephanitis pyrioides feeds on azalea foliage and causes extensive chlorosis, which reduces the aesthetic value and marketability of these plants. Because the use of neonicotinoid insecticides has been dramatically reduced or discontinued, growers and landscape managers are seeking alternative tools or strategies to control this insect. Although insect growth regulators (IGRs) are known for their activity against immature insect stages, their activity against egg hatching has not been addressed thoroughly, specifically against S. pyrioides. Thus, a series of experiments was conducted to understand the ovicidal activity of IGRs using novaluron, azadirachtin, pyriproxyfen, and buprofezin against S. pyrioides. The number of newly emerged young instars was significantly lower when leaves implanted with eggs were sprayed on both sides with novaluron, azadirachtin, and buprofezin compared to nontreated and pyriproxyfen treatments. When IGRs plus adjuvant were applied to the adaxial surface of the leaves, the densities of the newly emerged nymphs were significantly lower under the novaluron treatment compared to the nontreated leaves. However, there was no significant difference in the number of nymphs that emerged in the absence of adjuvant. Furthermore, close monitoring revealed reduced levels of egg hatching in the presence of adjuvant with novaluron compared to its absence. The data show that the survival of S. pyrioides first instars was not affected by exposure to dried IGR residues.

Hormonal regulation in insects: facts, gaps, and future directions

1997 ◽  
Vol 77 (4) ◽  
pp. 963-1032 ◽  
Author(s):  
G. Gade ◽  
K. H. Hoffmann ◽  
J. H. Spring
Keyword(s):  
Hormonal Regulation ◽  
Metabolic Regulation ◽  
Color Change ◽  
Insect Pest ◽  
Neurosecretory Cells ◽  
Pheromone Biosynthesis ◽  
Functional Studies ◽  
Juvenile Hormones ◽  
Continue Research ◽  
Species Specific

There are two main classes of hormones in insects: 1) the true hormones produced by epithelial glands and belonging to the ecdysteroids or juvenile hormones and 2) the neuropeptide hormones produced by neurosecretory cells. Members of these classes regulate physiological, developmental, and behavioral events in insects. Detailed accounts are given on isolation, identification, structure-activity relationships, mode of action, biological function, biosynthesis, inactivation, metabolism, and feedback for hormones involved in 1) metabolic regulation such as the adipokinetic/hypertrehalosemic peptides and the diuretic and antidiuretic peptides; 2) stimulation or inhibition of muscle activity such as the myotropic peptides; 3) control of reproduction, growth, and development such as allatotropins, allatostatins, juvenile hormones, ecdysteroids, folliculostimulins and folliculostatins, ecdysis-triggering and eclosion hormones, pheromone biosynthesis activating neuropeptides, and diapause hormones; and 4) regulation of tanning and of color change. Because of the improvements in techniques for isolation and structure elucidation, there has been rapid progress in our knowledge of the chemistry of certain neuropeptide families. With the employment of molecular biological techniques, the genes of some neuropeptides have been successfully characterized. There are, however, areas that are still quite underdeveloped. These are, for example, 1) receptor studies, which are still in their infancy; 2) the hormonal status of certain sequenced peptides is not clarified; and 3) functional studies are lacking even for established hormones. The authors plead for a concerted effort to continue research in this field, which will also advance our knowledge into the use of insect hormones as safer and species-specific molecules for insect pest management.

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