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1.
Biol Lett ; 17(3): 20200669, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33653092

RESUMO

Predators can reduce prey population densities by driving them to undertake costly defences. Here, we report on a remarkable example of induced antipredator defence in spider mites that enhances the risk to rainstorms. Spider mites live on the undersides of host plant leaves and usually oviposit on the leaf undersurface. When they are threatened by predatory mites, they oviposit on three-dimensional webs to avoid egg predation, although the cost of ovipositing on webs has not yet been clearly determined. We prepared bean plants harbouring spider mite (Tetranychus kanzawai) eggs on either leaf surfaces or webs and exposed them to rainstorms outdoors. We found that fewer eggs remained on webs than on leaf surfaces. We then examined the synergistic effect of wind and rain by simulating both in the laboratory. We conclude that ovipositing on webs comes at a cost, as eggs are washed off the host plants by wind and rain. This may explain why spider mite populations decrease drastically in the rainy season, although they inhibit leaf undersides where they are not directly exposed to rainfall.


Assuntos
Ácaros , Tetranychidae , Animais , Feminino , Oviposição , Plantas , Comportamento Predatório
2.
Zootaxa ; 4941(1): zootaxa.4941.1.3, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33756948

RESUMO

The egg, all three larval instars, and pupa are described for the cucujoid beetle species Monotoma (s. str.) testacea Motschulsky, which develops in decomposing plant matter. Adults and larvae were fed with baker's yeast under laboratory conditions; this food source allowed for successful breeding of several generations. Detailed and illustrated descriptions of all immature stages are given. It is suggested that simple, pointed setae may represent a diagnostic character for Monotoma (s. str.), whereas clavate setae characterize Monotoma (Gyrocecis). Only minor differences in the number and patterns of setae were found between first, second and third larval instars, supporting observations of previous authors. Morphological differences are listed to distinguish between the three larval instars. An arrow-head aggregation of coarse asperities on the frontal region of the L1 larva, lacking in older instars, is hypothesized to be an egg-burster. Only 34-42 days elapsed from egg laying to emergence of the adult; the egg stage lasted 5-6 days; L1 larvae 2-3 days; L2 3-5 days; L3 2-5 days; the immovable prepupal stage 12-13 days; and the pupa 7-10 days. One female laid 1-5 eggs daily, averaging ~1.5 egg per day during her entire life; the total number of eggs in two independent cultures produced by one female accompanied by one male was 57 and 94.


Assuntos
Besouros , Animais , Feminino , Larva , Masculino , Oviposição , Pupa
3.
An Acad Bras Cienc ; 93(1): e20190686, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33787751

RESUMO

The corn leafhopper Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae), transmits three important plant pathogens that adversely affect corn crop and ranges from the USA to Argentina. The vector has a rich natural enemy complex that generates high levels of parasitism, but its populations are persistent and prevalent. We characterized the oviposition sites of D. maidis on young corn plants in order to verify the hypothesis that the vector has an oviposition strategy for mitigating parasitism. Oviposition locations on plants were assessed in the laboratory and eggs within corn plants were exposed to natural parasitism in a cornfield. Eggs were located mostly laid in the unfolded leaves and were attacked by five parasitoid species. Parasitism was significantly affected by the class of leaf and the position of the egg in the leaf. Anagrus virlai Triapitsyn was the most abundant parasitoid species, which emerged significantly higher in the basal blade than other species. Our results suggest that leafhoppers minimize egg parasitism by laying their eggs within concealed locations on the plant.


Assuntos
Hemípteros , Himenópteros , Animais , Argentina , Feminino , Oviposição , Zea mays
4.
Poult Sci ; 100(3): 100896, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33518306

RESUMO

An experiment was conducted to evaluate the digestible tryptophan (Trp) requirement of laying hens from 22 to 34 wk of age. A total of 252 Hy-line W-36 laying hens were selected at 16 wk of age and allocated by weight (P = 0.90) to 7 dietary treatments resulting in 12 replicate cages of 3 birds for each treatment. A Trp-deficient basal diet was formulated using corn, corn gluten meal, and soybean meal for each of the 3 dietary phases and supplemented with synthetic L-Trp to provide 105, 119, 133, 147, 162, 176, and 190 mg digestible Trp on a daily basis over the experimental period. To adapt the hens to experimental diets, pullets were fed complete diets that contained increasing amounts of corn gluten meal. Hens received a controlled amount of feed daily based on feed intake expected under commercial conditions. Linear and quadratic broken-line, and quadratic polynomial models were used to estimate digestible Trp requirements based on hen-housed egg production (HHEP), egg mass (EM), and feed efficiency (FE). FE was calculated using EM and feed intake. Digestible Trp requirements were estimated to be 137, 183, and 192 mg/d for HHEP; 133, 180, and 183 for EM and 133, 177, and 173 for FE using linear broken-line, quadratic broken-line, and quadratic polynomial analysis, respectively. The quadratic broken line model in this experiment resulted in the best fit (R2) for all parameters measured. Linear broken line estimates resulted in lower estimates that the other models, and HHEP resulted in higher estimated digestible Trp requirement than EM and FE.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Galinhas , Dieta , Triptofano , Ração Animal/análise , Animais , Galinhas/metabolismo , Dieta/veterinária , Feminino , Oviposição/fisiologia , Triptofano/metabolismo
5.
Poult Sci ; 100(2): 835-843, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518137

RESUMO

Magnolol is a multifunctional plant polyphenol. To evaluate the effects of magnolol on laying hens in the late laying period, 360 (50-week-old) laying hens were randomly assigned to 4 dietary treatments: a non-supplemented control diet (C), and control diets supplemented with 100, 200, and 300 mg/kg of magnolol (M100, M200, and M300), respectively. Each treatment had 6 replicates with 15 hens per replicate. Results showed that dietary supplementation of 200 and 300 mg/kg of magnolol increased the laying rate and the M200 group had a lower feed conversion ratio (P < 0.05). Magnolol supplementation (200 and 300 mg/kg) could linearly increase albumen height and Haugh unit of fresh eggs in the late phase of the laying cycle (P < 0.01). And magnolol linearly alleviated the decline of the albumen height and Haugh unit of eggs stored for 14 d (P < 0.01). The total superoxide dismutase activity in the ovaries of M100 group was greater than that in the other treatments (P < 0.05). As dietary magnolol levels increased, villus height of jejunum and ileum linearly increased (P < 0.01). M200 and M300 groups had higher expression level of occludin in the ileum compared with group C (P < 0.01). The level of nitric oxide production and inducible nitric oxide synthase expression in the ileum of M200 group were lower than that in the C group (P < 0.05). In conclusion, dietary supplementation of 200 and 300 mg/kg magnolol can improve hen performance, albumen quality of fresh and storage eggs, and hepatic lipid metabolism in the late laying cycle. Also, magnolol has a good effect on increasing villi and improving the intestinal mucosal mechanical barrier function.


Assuntos
Antioxidantes/farmacologia , Compostos de Bifenilo/farmacologia , Galinhas/fisiologia , Ovos/normas , Intestinos/efeitos dos fármacos , Lignanas/farmacologia , Oviposição/efeitos dos fármacos , Ração Animal/análise , Animais , Antioxidantes/administração & dosagem , Compostos de Bifenilo/administração & dosagem , Galinhas/metabolismo , Dieta/veterinária , Suplementos Nutricionais , Feminino , Intestinos/anatomia & histologia , Intestinos/fisiologia , Lignanas/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Óvulo
6.
Poult Sci ; 100(2): 452-460, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518096

RESUMO

Ovomucoid is a major egg white protein which is considered as the most dominant allergen in chicken eggs. Owing to the difficulty of separating ovomucoid from egg whites, researchers have adopted genetic deletion for development of hypoallergenic eggs. Previously, we used CRISPR/Cas9 to establish chickens with ovomucoid gene (OVM) mutations, but it remained unknown whether such hens could produce eggs at maturity. Here, we have reported on eggs laid by OVM-targeted hens. Except for watery egg whites, the eggs had no evident abnormalities. Real-time PCR revealed alternative splicing of OVM mRNA in hens, but their expression was limited. Immunoblotting detected neither mature ovomucoid nor ovomucoid-truncated splicing variants in egg whites. Sixteen chicks hatched from 28 fertilized eggs laid by OVM-targeted hens, and fourteen of the sixteen chicks demonstrated healthy growth. Taken together, our results demonstrated that OVM knockout could almost completely eliminate ovomucoid from eggs, without abolishing fertility. Thus, the eggs developed in this study have potential as a hypoallergenic food source for most patients with egg allergies.


Assuntos
Galinhas/genética , Ovos/normas , Mutação , Ovomucina/genética , Alérgenos/genética , Animais , Galinhas/crescimento & desenvolvimento , Galinhas/fisiologia , Clara de Ovo/efeitos adversos , Clara de Ovo/química , Clara de Ovo/normas , Feminino , Deleção de Genes , Masculino , Oviposição/genética , Ovomucina/efeitos adversos , Óvulo
7.
Poult Sci ; 100(2): 1109-1119, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518070

RESUMO

The difference in microbiota was examined for breeders with different egg-laying rates, and the impact of dietary Enterococcus faecium (EF) was also determined in the present study. A total of 256 Arbor Acres broiler breeders (48-wk-old) were used in a 2 × 2 factorial design, which encompassed 2 egg-laying rate levels [average (average egg laying: AP, 80.45 ± 0.91%) and low (lower egg laying: LP, 70.61 ± 1.16%)] and 2 different dietary groups [control (no additive), 6 × 108 cfu/kg EF]. The results showed that the AP breeders presented a lower egg weight, feed conversion ratio, abdominal fat rate, and serum leptin level (P(laying) ≤ 0.05) as well as a higher egg-laying rate (P(laying) < 0.01) than the LP breeders. Dietary supplementation with EF improved the egg weight (P(EF) = 0.03) and had a higher concentration of follicle-stimulating hormone (FSH) in the serum (P(EF) = 0.04). The relative expression of Caspase 9, Bax, AMHR, BMP15, and GATA4 in the ovary of AP breeders was lower, whereas the FSHR and BMPR1B expression was higher than that measured in LP breeders (P(laying) ≤ 0.05). LP increased the abundance of Bacteroidetes (phylum), Firmicutes (phylum), Bacteroidia (class), Clostridia (class), Bacteroidales (order), Clostridiales (order), and Lachnospiraceae (family), whereas the AP promoted the enrichment of Proteobacteria (phylum) and Gammaproteobacteria (class) (P(laying) < 0.05). The genera Bacillus, Rhodanobacter, and Streptomyces were positively correlated with the egg-laying rate and BMPR1B expression (P < 0.05) but negatively correlated with the abdominal fat rate (P < 0.05) and Caspase 9 (P < 0.05). These findings indicate that the low reproductive performance breeders had lower microbiota diversity and higher Firmicutes, which triggers the energy storage that led to higher fat deposition. Besides, increases in the abdominal fat rate, leptin level, and apoptosis (Caspase 9, Bax) and reproduction-related gene (BMP15, AMHR, BMPR1B, and GATA4) expression would possibly be the potential mechanisms under which breeders have different reproductive performance. Dietary EF increased the egg weight and serum FSH level and decreased the Bacteroidetes (phylum) in low reproductive breeders.


Assuntos
Galinhas/fisiologia , Enterococcus faecium/fisiologia , Microbioma Gastrointestinal , Oviposição/fisiologia , Ração Animal/análise , Animais , Galinhas/microbiologia , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Reprodução
8.
Poult Sci ; 100(2): 1120-1131, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518071

RESUMO

In this study, we analyzed the parent stock of ISA Brown hens reared in closed and open aviary (CA and OA, respectively) sections with regard to the productive performance of hens, hatchability, and quality of chicks. The flocks were reared (1,570 cocks and 17,515 hens) for 16 wk in a three-level aviary system. On the 7th wk of rearing, half of the birds (OA group of birds) were allowed to leave the section and use half of the area of the poultry house and to use all levels. The remaining half of the birds were kept in the CA section for the entire duration of rearing. After the duration of rearing, the birds were moved to 2 neighboring production poultry houses (OA = 680 cocks and 8,126 hens; CA = 685 cocks and 8,133 hens). Reproduction was performed in a litter system in accordance with the norms for parent stock of laying hens. During the production cycle (53 wk), laying performance, feed conversion ratio, water consumption, and mortality were analyzed. On 27th, 37th, and 49th wk of production, the following analysis was performed: rate of fertilization (%), rate of hatching (%), and quality of chick. In accordance with the results, birds in OA flock required less amount of feed (P < 0.001) and water (P = 0.020) to produce a laid egg, a hatching egg (respectively: P < 0.001; P = 0.009), and a chick (both P < 0.001) in comparison with the birds in CA flock. In addition, a lower number of litter eggs were found in the OA flock (P < 0.001). Mean laying production, production of hatching eggs, and number of waste eggs did not depend on the flock rearing system (P > 0.05); however, a combined analysis of all these parameters using multivariate analysis of variance demonstrated a better (P < 0.001) result for OA flock than that of CA flock. Rate of fertilization, rate of hatching, and quality of chicks did not depend on the flock rearing system (P > 0.05). In summary, it is possible to rear parent ISA Brown hens in open sections of aviary system without the fear of subsequent deterioration of indicators of future egg production.


Assuntos
Criação de Animais Domésticos/métodos , Galinhas/fisiologia , Abrigo para Animais/classificação , Reprodução/fisiologia , Animais , Feminino , Masculino , Oviposição/fisiologia
9.
Poult Sci ; 100(2): 982-992, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33518152

RESUMO

This study investigated the effects of dietary arsenic supplementation on laying performance, egg quality, hepatic and renal histopathology, and oxidative stress in the livers and kidneys of laying hens. Furthermore, the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway was explored to reveal the molecular mechanism of the stress. Five hundred and twelve 40-week-old Hyline White laying hens were randomly allocated to 4 groups with 8 pens per group and 16 hens per pen. The doses of arsenic administered to the 4 groups were 0.95, 20.78, 40.67, and 60.25 mg/kg. The results revealed that dietary arsenic supplementation significantly reduced hen-day egg production (P < 0.05), average egg weight (P < 0.05), Haugh units (P < 0.05), albumen height (P < 0.05), and eggshell strength (P < 0.05). Dietary arsenic supplementation also induced the accumulation of arsenic and histopathological damages in the liver and kidney. In accordance, dietary arsenic supplementation significantly enhanced serum alanine aminotransferase (P < 0.05), aspartate aminotransferase (P < 0.05), blood urea nitrogen (P < 0.05), and uric acid (P < 0.05) levels. After arsenic exposure, the activities of superoxide dismutase (SOD) (P < 0.05), catalase (P < 0.01), glutathione reductase (P < 0.05), and glutathione peroxidase (P < 0.05), and glutathione content (P < 0.05) were significantly decreased, while the malondialdehyde level was significantly increased (P < 0.05) in the liver and kidney. Positive correlations occurred between antioxidant enzyme activities and antioxidant enzyme gene expressions in the liver and kidney, except for renal manganese superoxide dismutase gene expression and SOD activity. Additionally, hepatic and renal Nrf2 mRNA expression was positively correlated with antioxidant gene expressions and negatively correlated with Keap1 mRNA expression. In summary, dietary arsenic supplementation induced oxidative stress by suppressing the Nrf2-Keap1 pathway in the livers and kidneys of laying hens.


Assuntos
Arsênico/administração & dosagem , Galinhas/metabolismo , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ração Animal/análise , Animais , Antioxidantes/metabolismo , Arsênico/toxicidade , Dieta/veterinária , Suplementos Nutricionais , Ovos/normas , Feminino , Proteína 1 Associada a ECH Semelhante a Kelch/efeitos dos fármacos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Rim/metabolismo , Fígado/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Oviposição/efeitos dos fármacos , Distribuição Aleatória
10.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560354

RESUMO

The western tarnished plant bug, Lygus hesperus Knight, overwinters as a diapausing adult in response to short day lengths. Once environmental conditions are favorable, the bugs revert to an active reproductive state. To determine the impact on life-history traits of diverting resources toward diapause rather than oogenesis during early adulthood, diapausing and nondiapausing L. hesperus females were reared from the same cohorts. Body mass, ovarian maturation, ovipositional activity, and survivorship were monitored starting either at the time of release from diapause-inducing conditions or at adult eclosion for diapausers and nondiapausers, respectively. Females that had gone through 2 wk of diapause were larger and able to mobilize the resources necessary for oogenesis faster than nondiapausers, initiating oogenesis and ovipositing sooner and at a faster initial rate. However, lifetime egg production and average daily rates were similar for both groups. Postdiapausers lived longer than nondiapausers by an average of 19 d, which is five more than the 2-wk period when they were reproductively senescent. Overall, the results indicate that short-term diapause does not have a negative impact on life history. Furthermore, the extra endogenous resources stored during diapause may be able to enhance the alacrity with which the female can take advantage of improved environmental conditions and may prolong life by shielding the females against environmental stressors such as temperature extremes, oxidative agents, or food deficits.


Assuntos
Diapausa de Inseto , Heterópteros/crescimento & desenvolvimento , Traços de História de Vida , Oviposição , Animais , Feminino
11.
Animal ; 15(1): 100030, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33579651

RESUMO

Gregarious nesting has often been observed in laying hens, where hens prefer to visit a nest already occupied by other hens over empty nests. This may result in overcrowding of the nests which is considered a welfare issue and, moreover, can increase the economic issue of floor eggs. This study aimed to describe gregarious nesting and spatial behavior in broiler breeders and how this relates to genetic background, fearfulness and mating behavior. Five commercially available genetic lines of broiler breeders were housed in 21 pens of 550 females and 50 males (six pens for lines 1 and 2, five pens for line 3 and two pens for lines 4 and 5) during the ages 20-60 weeks. Every 10 weeks, the plumage condition and wounds were assessed of 50 random hens per pen. Avoidance distance and novel object tests were performed to assess fearfulness at four time points. Distribution of eggs over nests was observed for 6 weeks at the onset of egg production at 26 weeks of age, and use of space was recorded at four time points, while (floor) egg production was noted daily per pen. We found differences between genetic lines over time in plumage condition and prevalence of wounds. Fear of humans was highest at the earliest age tested and did not correlate with general fearfulness as assessed by the novel object test. The distribution of eggs over nests was related to genetic background and was more uneven at the earliest age compared to later ages, and a more uneven distribution was correlated with an increased percentage of floor eggs. Distribution of birds over the litter area differed between the genetic lines, and less use of the litter area was correlated with an increased fear of humans and presence of wounds, suggesting an association with aggressive mating behavior. This difference in distribution of the birds could also explain the correlation between increased presence of wounds and decreased percentage of floor eggs. It is concluded that broiler breeders do show gregarious nesting, which is affected by genetic background. Both increased gregarious nesting and wounds are related to increased floor egg percentage, which should be studied further in broiler breeder research. Genetic selection for even use of the available nests and of the litter and slatted area would therefore support both broiler breeder welfare and performance.


Assuntos
Galinhas , Abrigo para Animais , Animais , Galinhas/genética , Ovos , Feminino , Pisos e Cobertura de Pisos , Oviposição , Óvulo , Reprodução
12.
BMC Plant Biol ; 21(1): 38, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33430784

RESUMO

BACKGROUND: Black gram [Vigna mungo (L)] seeds are a rich source of digestible protein and dietary fibre, both for human and animal consumption. However, the quality and quantity of the Vigna seeds are severely affected by bruchid beetles during storage. Therefore, analyses of the expression of the bruchid induced transcript dynamics in black gram pods would be helpful to understand the underlying defense mechanism against bruchid oviposition. RESULTS: We used the RNAseq approach to survey the changes in transcript profile in the developing seeds of a moderately resistant cultivar IC-8219 against bruchid oviposition using a susceptible cultivar T-9 as a control. A total of 96,084,600 and 99,532,488 clean reads were generated from eight (4 each) samples of IC-8219 and T-9 cultivar, respectively. Based on the BLASTX search against the NR database, 32,584 CDSs were generated of which 31,817 CDSs were significantly similar to Vigna radiata, a close relative of Vigna mungo. The IC-8219 cultivar had 630 significantly differentially expressed genes (DEGs) of which 304 and 326 genes up and down-regulated, respectively. However, in the T-9 cultivar, only 168 DEGs were identified of which 142 and 26 genes up and down-regulated, respectively. The expression analyses of 10 DEGs by qPCR confirmed the accuracy of the RNA-Seq data. Gene Ontology and KEGG pathway analyses helped us to better understand the role of these DEGs in oviposition mediated defense response of black gram. In both the cultivars, the most significant transcriptomic changes in response to the oviposition were related to the induction of defense response genes, transcription factors, secondary metabolites, enzyme inhibitors, and signal transduction pathways. It appears that the bruchid ovipositioning mediated defense response in black gram is induced by SA signaling pathways and defense genes such as defensin, genes for secondary metabolites, and enzyme inhibitors could be potential candidates for resistance to bruchids. CONCLUSION: We generated a transcript profile of immature black gram pods upon bruchid ovipositioning by de novo assembly and studied the underlying defense mechanism of a moderately resistant cultivar.


Assuntos
Besouros , Resistência à Doença/genética , Interações Hospedeiro-Parasita , Oviposição , Doenças das Plantas/genética , Vigna/genética , Vigna/parasitologia , Animais , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Locos de Características Quantitativas
13.
Am Nat ; 197(1): 93-110, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417521

RESUMO

AbstractAdaptive topography is a central concept in evolutionary biology, describing how the mean fitness of a population changes with gene frequencies or mean phenotypes. We use expected population size as a quantity to be maximized by natural selection to show that selection on pairwise combinations of reproductive traits of collared flycatchers caused by fluctuations in population size generated an adaptive topography with distinct peaks often located at intermediate phenotypes. This occurred because r- and K-selection made phenotypes favored at small densities different from those with higher fitness at population sizes close to the carrying capacity K. Fitness decreased rapidly with a delay in the timing of egg laying, with a density-dependent effect especially occurring among early-laying females. The number of fledglings maximizing fitness was larger at small population sizes than when close to K. Finally, there was directional selection for large fledglings independent of population size. We suggest that these patterns can be explained by increased competition for some limiting resources or access to favorable nest sites at high population densities. Thus, r- and K-selection based on expected population size as an evolutionary maximization criterion may influence life-history evolution and constrain the selective responses to changes in the environment.


Assuntos
Densidade Demográfica , Aves Canoras/genética , Aves Canoras/fisiologia , Animais , Evolução Biológica , Feminino , Aptidão Genética , Masculino , Oviposição/fisiologia , Seleção Genética , Suécia
14.
Pest Manag Sci ; 77(5): 2324-2336, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33423378

RESUMO

BACKGROUND: Yacon (Smallanthus sonchifolius) is a broadleaf host plant suitable for rearing the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Here, the possibility of using yacon as an alternative host plant for production of the parasitoid, Encarsia formosa Gahan, one of the most important natural enemies of whiteflies, was explored. Data on the demographic characteristics, parasitism rate, and host-feeding rate were collected and analyzed using the TWOSEX-MSChart, CONSUME-MSChart, and TIMING-MSChart computer programs, and then contrasted with comparable data from the more commonly utilized host plant, tobacco. RESULTS: Higher fecundity (F) (190.13 eggs/female) and more oviposition days (Od ) (16.60 days) were observed in E. formosa when yacon was used as the host plant for rearing T. vaporariorum, compared with when tobacco was used (F = 150.13 eggs/female, Od = 15.27 days). The intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0 ) were significantly higher in E. formosa parasitizing T. vaporariorum reared on yacon compared with those parasitizing tobacco-reared T. vaporariorum. Furthermore, the net host-feeding rate (C0 = 40.87 prey/parasitoid), net killing rate (Z0 = 239.73 prey/parasitoid), and finite killing rate ( υ = 0.2560/day) for E. formosa on yacon-reared whiteflies were significantly higher than those from tobacco-reared whiteflies. CONCLUSION: Our results showed that yacon is more suitable than tobacco as a host plant for mass-rearing E. formosa for biological control programs to manage whiteflies. An innovative application of the multinomial theorem for calculating the exact probability of bootstrap samples in life table research was also introduced. © 2021 Society of Chemical Industry.


Assuntos
Hemípteros , Himenópteros , Animais , Feminino , Tábuas de Vida , Oviposição , Taiwan
15.
Zool Res ; 42(2): 217-220, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33496092

RESUMO

Recent studies have examined the cost of raising parasitic cuckoos and highlighted the importance of "no extra cost" in explaining the low levels of defense in hosts. To clarify the reasons for parasitization in typical hosts, we present a simple model to explore the immediate and future costs of parasitism in shaping the evolution of defense behavior in hosts. Our results suggest that any cost of parasitization is maladaptive to the host and learned egg recognition is always favored to overcome these costs. Furthermore, although facing a potential cost of mis-imprinting, learned nestling recognition may still evolve when there is a non-zero immediate cost from raising a parasitic nestling. Therefore, we contend that "no extra cost" does not provide sufficient evidence to explain the low levels of defense behavior in hosts per se.


Assuntos
Metabolismo Energético/fisiologia , Comportamento de Nidação/fisiologia , Aves Canoras/fisiologia , Aves Canoras/parasitologia , Animais , Evolução Biológica , Feminino , Interações Hospedeiro-Parasita/fisiologia , Comportamento Materno/fisiologia , Oviposição/fisiologia , Especificidade da Espécie
16.
Ecotoxicol Environ Saf ; 208: 111581, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396104

RESUMO

Lead (Pb) stress affects hormone-mediated responses (e.g., reproduction) in insects. In this study, the effects of Pb stress (12.5-50 mg Pb/kg in larval artificial diets) on the reproduction of the common cutworm Spodoptera litura (Lepidoptera: Noctuidae) were investigated after 7 generations. The results showed that Pb stress did not reduce the longevity of adult females, but 50 mg Pb/kg significantly reduced the longevity of adult males, regardless of the generation. After 50 mg Pb/kg stress for one or 7 generations, the peak time of egg-laying was delayed, and egg production and hatchability were decreased significantly. The vitellin content in eggs was significantly inhibited by Pb stress. The S. litura vitellogenin (Vg) gene promoter was cloned and analyzed. Multiple putative transcription factors were predicted for the 2321 bp Vg promoter region, including the TATA box, GATA, basic helix-loop-helix (bHLH) transcription factor, Broad-Complex (BR-C) binding sites, etc. The fragment from -2222 to -211 bp of the Vg promoter was the activation domain for Vg, whereas the region from -211 to -55 bp repressed the activity of the Vg promoter. The construct promoter (-782/+76) in Trichoplusia ni (Hi5) cells significantly improved Vg expression, which was not affected by Pb stress (1 or 10 mg/ml). Therefore, Pb stress significantly inhibited the reproduction of S. litura but not by regulating the Vg promoter.


Assuntos
Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Spodoptera/fisiologia , Vitelogeninas/genética , Animais , Dieta , Poluentes Ambientais/metabolismo , Feminino , Larva/efeitos dos fármacos , Chumbo/metabolismo , Longevidade , Masculino , Mariposas , Oviposição/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Spodoptera/efeitos dos fármacos , Vitelogeninas/metabolismo
17.
Gene ; 776: 145446, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33484761

RESUMO

Bumblebees are important pollinators that have evolved between solitary and advanced eusocial insects. Compared with advanced honeybees, workers of social bumblebee species are prone to laying eggs during the competition phase, which leads to the end of the colony. Therefore, worker reproductive behavior has become a popular research topic for exploring various biological phenomena. Here, we demonstrate a novel reproduction-related function of an immune response protein-encoding gene (Immune Responsive Protein 30, IRP30) in Bombus terrestris by employing RNA interference (RNAi) and a transgenic Drosophila melanogaster system. The results show that worker egg-laying was significantly affected by IRP30 expression levels (P < 0.01). Compared with those in the dsGFP-treated groups, the first egg-laying time was delayed by 3.7 d and the egg number was decreased by 41% in the dsIRP30-treated group. In addition, the average size of the largest oocyte and the relative mRNA expression levels of Vg (vitellogenin) were significantly reduced in the dsIRP30-treated group (P < 0.05). Cellular localization by immunofluorescence demonstrated that IRP30 has important functions in the germ cells of workers' ovarioles. Overexpression of IRP30 was confirmed to increase the reproductive capability of the transgenic D. melanogaster. In conclusion, IRP30 regulates worker egg-laying by affecting the expression of Vg, the size of the ovary and the formation of the oocyte. These findings provide essential information for understanding the mechanisms underlying worker reproductive regulation.


Assuntos
Abelhas/genética , Abelhas/metabolismo , Reprodução/genética , Animais , Animais Geneticamente Modificados/genética , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Expressão Gênica/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Ovário/metabolismo , Oviposição , Óvulo/metabolismo , Polinização , Reprodução/fisiologia , Comportamento Sexual Animal/fisiologia , Vitelogeninas/genética
18.
Animal ; 15(1): 100047, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33515991

RESUMO

Laying hens are increasingly kept in barn or free-range systems, which not only allows birds to move freely but also potentially entails higher energy expenditures due to higher locomotor activity. Therefore, the aim of our study was to quantify the daily energy expenditure (DEE) and water turnover in freely moving laying hens. For that purpose, 10 Lohmann Selected Leghorn (LSL) and 10 Lohmann Brown (LB) hens were obtained from a conventional breeding company at 17 weeks of age. The trial started when birds reached an age of 34 weeks. All 20 birds were kept together in the same littered floor pen (12.1 m2). The pen was equipped with perches, a nest box, feeding and nipple drinkers. The DEE was determined individually for all experimental birds (n = 20) for a total of nine days using the doubly labelled water (DLW) method. Lohmann Brown hens were heavier than LSL hens, but laying rate did not differ between the two breeds, that is, one egg per hen and day during the study period. Average egg mass was 63.1 ±â€¯0.20 g in LB and 61.7 ±â€¯0.12 g in LSL hens, which converted to an egg energy content of 420 and 410 kJ/egg, respectively. Dilution spaces for oxygen and hydrogen differed between the breeds but not the respective turnover rates. Total body water as a percentage of body mass (LB: 54.4%, LSL: 53.8%; SEM = 0.7, F1,18 = 0.41, P = 0.513) and total water intake (TWI) per day (LB: 275 ml/day, LSL: 276 ml/day; SEM = 20, F1,17 = 0, P = 0.994) did not differ between LB and LSL hens. Individual DEE increased with body mass in LB but not in LSL hens. Average DEE did not differ between the two breeds (LB: 1501 kJ/day; LSL: 1520 kJ/day; SEM = 32.1, F1,17 = 2.54, P = 0.131). However, when comparing the DEE on a metabolic mass basis, LSL hens expended with 984 kJ/kg0.75 on average significantly more energy per day than LB hens (895 kJ/kg0.75; SEM = 20.3, F1,18 = 10.1, P = 0.005). Our results suggest that the DLW technique is a viable method to measure the energy expenditure and water turnover over several days in laying hens. Furthermore, we show that laying hens kept in floor pens fit into the general pattern of DEE among wild birds.


Assuntos
Galinhas , Abrigo para Animais , Animais , Cruzamento , Galinhas/genética , Metabolismo Energético , Feminino , Oviposição , Água
19.
Animal ; 15(1): 100010, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33515998

RESUMO

Excessive fecal excretion of phosphorus (P) has increasingly become an environmental issue due to oversupply of P in layer rations, and thus it is imperative to minimize safety margins for P to ensure the sustainability of the egg industry. In this study, a 12-week feeding trial (22 to 34 weeks of age) was conducted to evaluate the effects of phytase supplementation on production performance, plasma biochemistry, egg and bone quality and P excretion of laying hens fed various levels of non-phytate P (NPP). Forty-eight Lohmann white laying hens were randomly allocated to one of six corn-soybean meal-oat-based diets: diets containing 2.0, 2.5 or 3.0 g/kg NPP without phytase, and diets containing 1.0, 1.5 or 2.0 g/kg NPP with phytase (1 000 U/kg diet) where phytase inclusion was expected to provide 1.0 g/kg NPP to laying hens, thus making the phytase-unsupplemented treatment served as a control for the phytase-supplemented treatment accordingly. Productive performance was recorded during the experimental period. Blood and egg samples were collected, and digestibility studies were conducted at weeks 6 and 12 of the experiment. Bone mineralization was evaluated at the end of the experiment. Egg weight and egg production, feed consumption, BW and feed conversion ratio of laying hens fed lower NPP diets supplemented with phytase were comparable to those of hens fed high NPP phytase-unsupplemented controls. Eggshell thickness, specific gravity, Haugh units, tibia bone mineral density, tibia ash percent, plasma P and other biochemical parameters were not significantly different among dietary treatments. Total P intake, excretion and retention were affected by diet (P < 0.001), but its deposition in eggs was not significantly different. Contrast analysis further showed that total P excretion of phytase present vs phytase absent was averagely reduced by 40.4 mg/hen per day (P < 0.01). Moreover, total P excretion was linearly (P < 0.01) reduced with lowering dietary NPP, and this relationship was similar regardless of whether phytase was supplemented or not. The results from this study indicated that NPP levels in laying hen diets could be reduced to 1.0 g/kg (excluding the portion of NPP released by phytase) with the inclusion of phytase, without negative effects on production performance and health of the hens, thereby diminishing P excretion into environment.


Assuntos
6-Fitase , Fósforo na Dieta , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas , Dieta/veterinária , Suplementos Nutricionais , Feminino , Minerais , Oviposição , Óvulo , Fósforo , Plasma
20.
Exp Appl Acarol ; 83(2): 211-227, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33387143

RESUMO

The webbing life type of three spider mite species of the genus Oligonychus was studied based on web-associated behavioral characteristics. All tested Oligonychus species-viz., avocado brown mite, Oligonychus punicae (Hirst), date palm mite, Oligonychus afrasiaticus (McGregor), and banks grass mite, Oligonychus pratensis (Banks)-exhibited a complicated-web (CW) life type on various host plants. A new life type, 'CW-c,' was documented for O. punicae on the adaxial leaf side of Conocarpus erectus L. (Combretaceae). The weaving pattern with guy ropes is spun by the O. punicae female and is associated with stalked eggs; it appeared as a unique character in the CW-life type. Oligonychus afrasiaticus, also showed a new life type, 'CW-d,' when reared on the abaxial side of leaves of four host plants, viz., desert fan palm, maize, sorghum, and sugarcane. Oligonychus afrasiaticus showed a site for quiescence and a site for oviposition as variables, whereas the site for defecation (SD) was a persistent characteristic on all four tested host plants. Oligonychus pratensis showed the characteristics of the sub-type 'CW-u' on the abaxial leaf side of Washingtonia filifera (Lindl.) H. Wendl. (Arecaceae). The SD was a distinguishing behavioral characteristic used to separate O. afrasiaticus from O. pratensis when inhabiting the same host plant, W. filifera.


Assuntos
Ácaros , Persea , Phoeniceae , Tetranychidae , Animais , Feminino , Masculino , Oviposição
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