Identification of genetic and biochemical mechanisms associated with heat shock and heat stress adaptation in grain amaranths.

Heat stress is poised to become a major factor negatively affecting plant performance worldwide. In terms of world food security, increased ambient temperatures are poised to reduce yields in cereals and other economically important crops. Grain amaranths are known to be productive under poor and/or unfavorable growing conditions that significantly affect cereals and other crops. Several physiological and biochemical attributes have been recognized to contribute to this favorable property, including a high water-use efficiency and the activation of a carbon starvation response. This study reports the behavior of the three grain amaranth species to two different stress conditions: short-term exposure to heat shock (HS) conditions using young plants kept in a conditioned growth chamber or long-term cultivation under severe heat stress in greenhouse conditions. The latter involved exposing grain amaranth plants to daylight temperatures that hovered around 50°C, or above, for at least 4 h during the day and to higher than normal nocturnal temperatures for a complete growth cycle in the summer of 2022 in central Mexico. All grain amaranth species showed a high tolerance to HS, demonstrated by a high percentage of recovery after their return to optimal growing conditions. The tolerance observed coincided with increased expression levels of unknown function genes previously shown to be induced by other (a)biotic stress conditions. Included among them were genes coding for RNA-binding and RNA-editing proteins, respectively. HS tolerance was also in accordance with favorable changes in several biochemical parameters usually induced in plants in response to abiotic stresses. Conversely, exposure to a prolonged severe heat stress seriously affected the vegetative and reproductive development of all three grain amaranth species, which yielded little or no seed. The latter data suggested that the usually stress-tolerant grain amaranths are unable to overcome severe heat stress-related damage leading to reproductive failure.

Multifaceted Interplay among Social Dominance, Body Condition, Appetitive and Consummatory Sexual Behaviors, and Semen Quality in Dorper Rams during Out-Of-Season and Transition Periods.

Dorper rams (n = 24) were evaluated during the sexual resting season to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions in northern Mexico (25° N). Aggressive behaviors were quantified during male-to-male interactions, and appetitive and consummatory sexual behaviors during male-to-female interactions. Morphometric, live weight (LW), and body condition score (BCS) were recorded. During the early reproductive season, male-to-female behaviors were newly itemized simultaneously by seminal quality and quantity sampling. Finally, the dependent variables of the hemogram components were also quantified. Neither LW (61.25 ± 2.4 kg) nor morphometric variables differed between SR groups. However, BCS (2.25 vs. 2.66 u), sexual behaviors (i.e., approaches: 59.6 vs. 21.73 n, mating with ejaculation: 77.7 vs. 42.86 %, latency to ejaculation: 16.6 vs. 143.07 s), ejaculate volume (0.57 vs. 0.23 mL), and hemogram components favored the HSR rams (p < 0.05). Moreover, in their first male-to-female interaction, >50% of the LSR rams failed to display any sexual activity. HSR rams displayed a greater number of threatening behaviors, managing to displace LSR rams when exposed to estrus ewes during the male sexual resting season; more sexual behaviors; and an increased seminal volume in a non-live weight-dependent fashion.

Synergism and unintended effects of the association between imidacloprid and sodium chloride (NaCl) on the management of Euschistus heros.

BACKGROUND: The use of insecticidal solutions containing sodium chloride (NaCl) has been proposed as a more environmentally friendly alternative to managing stink bug infestations of Neotropical soybean fields. The potential sublethal and undesirable effects of this practice have, however, been overlooked, especially with novel insecticides. Here, we have evaluated experimentally whether the addition of NaCl (0.5% w/v) to imidacloprid-containing solutions could alter insecticide toxicity and modify the reproductive responses of the Neotropical brown stink bug Euschistus heros. RESULTS: Adding NaCl to imidacloprid solutions significantly increased imidacloprid toxicity against E. heros. The exposure to E. heros to sublethal concentrations of imidacloprid affected the insect's mating abilities in a concentration-dependent manner. The addition of NaCl to solutions containing imidacloprid at concentrations as low as 0.126 µg a.i. cm-2 (i.e. the equivalent to 3% of field rate recommendation) also impacted the sexual behavior of E. heros, reducing mating duration. NaCl-exposed stink bugs, however, exhibited higher fecundity and fertility rates than those insects that were unexposed to NaCl or those that were exposed to sublethal levels of imidacloprid only. CONCLUSIONS: The addition of low amounts of NaCl resulted in a higher toxicity of imidacloprid. This practice, however, can also lead to undesirable effects as increasing reproductive output of E. heros that can potentially compromise the management of these insect pests.

Sublethal concentrations of acetylcarvacrol affect reproduction and integument morphology in the brown dog tick Rhipicephalus sanguineus sensu lato (Acari: Ixodidae).

Rhipicephalus sanguineus sensu lato (s.l.), also known as the brown dog tick, is among the main tick species involved in the transmission of pathogens to humans and other animals and, therefore, the target of numerous control methods. However, due to the disadvantages of synthetic acaricides, the use of alternative products such as plant derivatives has been encouraged. This study aimed to evaluate the acaricidal potential of acetylcarvacrol and to determine its efficacy at sublethal doses for the control of R. sanguineus s.l. female ticks. In addition, as acetylcarvacrol was applied topically, morphological alterations in the integument were assessed. Acetylation of carvacrol was performed by reaction with acetic anhydride in a sodium hydroxide solution, being confirmed by infrared spectroscopy. The lethal concentration for 50 and 90% (LC50 and LC90) of unfed ticks and the efficacy of acetylcarvacrol in engorged females were determined after the Adult Immersion Test (AIT). For the evaluation of effects of acetylcarvacrol in the integument, routine histological techniques were employed after the AIT. The LC50 and LC90 in unfed females were 2.8 and 7.2 µL/mL, respectively. Regarding reproductive performance, after treatment with 8.0 µL/mL acetylcarvacrol 90.9% control was achieved, as ticks showed the lowest egg production index (EPI), hatching rate (HR), and fecundity rate (FR). In the integument, considerable morphological alterations were observed both in cuticle and epithelium. Thus, acetylcarvacrol affected R. sanguineus s.l. external coating and reproduction when applied at sublethal concentrations, probably contributing to a long-term control.

Fluctuating selection strength and intense male competition underlie variation and exaggeration of a water strider's male weapon.

Sexually selected traits can reach high degrees of phenotypic expression and variation under directional selection. A growing number of studies suggest that such selection can vary in space, time and form within and between populations. However, the impact of these fluctuations on sexual trait evolution is poorly understood. In the water strider Microvelia longipes, males display striking trait exaggeration and phenotypic variation manifested as extreme differences in the rear leg length. To study the origin and maintenance of this exaggerated trait, we conducted comparative behavioural, morphometric and reaction norm experiments in a selection of Microvelia species. We uncovered differences both in the mating behaviour and the degree of sexual dimorphism across these species. Interestingly, M. longipes evolved a specific mating behaviour where males compete for egg-laying sites, consisting of small floating objects, to intercept and copulate with gravid females. Through male-male competition assays, we demonstrated that male rear legs are used as weapons to dominate egg-laying sites and that intense competition is associated with the evolution of rear leg length exaggeration. Field observations revealed rapid fluctuation in M. longipes habitat stability and the abundance of egg-laying sites. Paternity tests using genetic markers demonstrated that small males could only fertilize about 5% of the eggs when egg-laying sites are limiting, whereas this proportion increased to about 20% when egg-laying sites become abundant. Furthermore, diet manipulation and artificial selection experiments also showed that the exaggerated leg length in M. longipes males is influenced by both genetic and nutritional factors. Collectively, our results highlight how fluctuation in the strength of directional sexual selection, through changes in the intensity of male competition, can drive the exaggeration and phenotypic variation in this weapon trait.

Reproductive consequences of variation in flowering phenology in the dry forest tree Enterolobium cyclocarpum in Guanacaste, Costa Rica.

PREMISE OF THE STUDY: Flowering initiation, duration and magnitude, and degree of flowering synchrony within a population can affect the reproductive fitness of individuals. We examined the flowering phenology within a population of the tropical dry forest Guanacaste tree (Enterolobium cyclocarpum) to gauge the impact of phenological variation among trees on fruit production and progeny vigor. METHODS: We monitored the flowering phenology of 93 trees weekly during 2005, 2006, and 2007, using a scale based on the percentage of the crown with open flowers. We also monitored fruit production for each tree in 2005, 2006, 2007, and 2008. Finally, we evaluated the relationship between phenological variation and progeny performance. KEY RESULTS: Ten measures of flowering phenology and synchrony among flowering trees, based on the number of weeks when anthesis of the crown exceeded 50%, were used to develop four phenological profiles. These profiles were correlated with significant differences in fruit production and progeny vigor. Trees with flowers in >50% of their crown for at least 2 weeks produced more fruits and more vigorous progeny than trees with other profiles. Trees also tended to produce the same phenological profile among years than predicted by chance. CONCLUSIONS: Guanacaste trees vary significantly in the initiation of anthesis, duration and magnitude of flowering, and degree of synchrony among trees. Trees also tend to maintain the same flowering profile among years. Finally, the flowering behavior of E. cyclocarpum leads to significant differences in fruit and seed production, germination, and early progeny growth.

Twinning and Multiple Birth Rates According to Maternal Age in the City of São Paulo, Brazil: 2003-2014.

The present study investigates the twinning rates in the city of São Paulo, Brazil, during the years 2003-2014. The data were drawn from the Brazilian Health Department database of Sistema de Informações de Nascidos Vivos de São Paulo-SINASC (Live Births Information System of São Paulo). In general, more information is available on the incidence of twinning in developed countries than in developing ones. A total of 24,589 twin deliveries and 736 multiple deliveries were registered in 140 hospitals of São Paulo out of a total of 2,056,016 deliveries during the studied time period. The overall average rates of singleton, twin, and multiple births per 1,000 maternities (‰) were 987.43, 11.96 (dizygotic (DZ) rate was 7.15 and monozygotic (MZ) 4.42), and 0.36, respectively. We further regressed maternal age and historical time period on percentage of singleton, twin, and multiple birth rates. Our results indicated that maternal age strongly positively predicted twin and multiple birth rates, and negatively predicted singleton birth rates. The historical time period also positively, although weakly, predicted twin birth rates, and had no effect on singleton or multiple birth rates. Further, after applying Weinberg's differential method, we computed regressions separately for the estimated frequencies of DZ and MZ twin rates. DZ twinning was strongly positively predicted by maternal age and, to a smaller degree, by time period, while MZ twinning increased marginally only with higher maternal age. Factors such as increasing body mass index or air pollution can lead to the slight historical increase in DZ twinning rates. Importantly, consistent with previous cross-cultural and historical research, our results support the existence of an age-dependent physiological mechanism that leads to a strong increase in twinning and multiple births, but not singleton births, among mothers of higher age categories. From the ultimate perspective, twinning and multiple births in later age can lead to higher individual reproductive success near the end of the reproductive career of the mother.

Fitness Advantage in Heterozygous Ladybird Beetle Eriopis connexa (Germar) Resistant to Lambda-Cyhalothrin.

The pyrethroid lambda-cyhalothrin is widely recommended for use against defoliators in crop ecosystems, but this broad-spectrum insecticide lacks efficacy against aphids; thus, key aphid predators such as the ladybird beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae) must be preserved. Given that populations of E. connexa recently identified as resistant to lambda-cyhalothrin show potential of integrating chemical and biological control in crop ecosystems, a historical goal of integrated pest management. In the present study, the resistance maintenance over F1, F2, and F3 progenies from crossing resistant (R) and susceptible (S) E. connexa populations that might be expected after releasing R predator in the crop field and the F1 offspring performance when the R population is crossed with the S population are evaluated. The offspring performance is determined for F1 progenies from crossing the R population at F40- and F45-reared generations in the laboratory with the S population at F38- and F1-reared generations in the laboratory. The mortality rate in the heterozygous F1 progeny is low and similar to the rate for the R population (<5%), but it is about 75% in F2 and F3 progenies from crossing R and S populations. Fecundity and longevity of the heterozygous F1 progeny are significantly greater compared to the R population. These results suggest that when R population beetles are released and mating with S population residents, their field offspring retains the resistance phenotype with the advantages of greater egg production and longer survival compared to the parental R population.

Causes of failure in british bulls in the breeding soundness evaluation / Causas de reprovação de touros britânicos no exame andrológico

Background: The breeding soundness evaluation is a method that is based on the evaluation of all factors that contribute to the reproductive function in bull, basically is constituted by the general clinical examination, examination of internal and external genital system, measurement of scrotal circumference, semen physical and morphological evaluation and sexual behavior. Most progress in improving the reproductive efficiency can be made by estimating the fertility of the males and by careful selection of the bulls. Reproduction will continue to depend mainly on the ability to manage all available information. The aim of this study was to determine the main causes of failure in British bulls in the steps provided for breeding soundness evaluation, as well as demonstrate the importance of the behavior examination as a norm and not just as a complementary test.Materials, Methods & Results: This study consisted in evaluating the records of breeding soundness evaluation of 10,407 British breeds of bulls (Abeerden Angus, Red Angus, Hereford, Polled Hereford, Shorthorn and Devon) in the State of Rio Grande do Sul. The animals evaluated were grouped into two age classes: young bulls (two years) and adult bulls (three to ten years). Breeding soundness evaluation consisted of four steps: a general clinical examination, special clinical examination; seminal examination and behavior

Background: The breeding soundness evaluation is a method that is based on the evaluation of all factors that contribute to the reproductive function in bull, basically is constituted by the general clinical examination, examination of internal and external genital system, measurement of scrotal circumference, semen physical and morphological evaluation and sexual behavior. Most progress in improving the reproductive efficiency can be made by estimating the fertility of the males and by careful selection of the bulls. Reproduction will continue to depend mainly on the ability to manage all available information. The aim of this study was to determine the main causes of failure in British bulls in the steps provided for breeding soundness evaluation, as well as demonstrate the importance of the behavior examination as a norm and not just as a complementary test.Materials, Methods & Results: This study consisted in evaluating the records of breeding soundness evaluation of 10,407 British breeds of bulls (Abeerden Angus, Red Angus, Hereford, Polled Hereford, Shorthorn and Devon) in the State of Rio Grande do Sul. The animals evaluated were grouped into two age classes: young bulls (two years) and adult bulls (three to ten years). Breeding soundness evaluation consisted of four steps: a general clinical examination, special clinical examination; seminal examination and behavior

Causas de reprovação de touros britânicos no exame andrológico / Causes of failure in British bulls in the breeding soundness evaluation

Background: The breeding soundness evaluation is a method that is based on the evaluation of all factors that contribute to the reproductive function in bull, basically is constituted by the general clinical examination, examination of internal and external genital system, measurement of scrotal circumference, semen physical and morphological evaluation and sexual behavior. Most progress in improving the reproductive efficiency can be made by estimating the fertility of the males and by careful selection of the bulls. Reproduction will continue to depend mainly on the ability to manage all available information. The aim of this study was to determine the main causes of failure in British bulls in the steps provided for breeding soundness evaluation, as well as demonstrate the importance of the behavior examination as a norm and not just as a complementary test. Materials, Methods & Results: This study consisted in evaluating the records of breeding soundness evaluation of 10,407 British breeds of bulls (Abeerden Angus, Red Angus, Hereford, Polled Hereford, Shorthorn and Devon) in the State of Rio Grande do Sul. The animals evaluated were grouped into two age classes: young bulls (two years) and adult bulls (three to ten years). Breeding soundness evaluation consisted of four steps: a general clinical examination, special clinical examination; seminal examination and behavior examination. When the bull was not approved in one of the steps, did not perform the subsequent step. For the analysis of variance, the animals received a score 1 for approval or 0 for disapproval. Data were analyzed using the Statistical Analysis System (SAS ®). To investigate the failures in each steps of the breeding soundness evaluation, we used analysis of variance (PROC GLM) comparing the two age classes of bulls (young and adults). Means were compared by Tukey test at 5%. The pathologies of failures were subjected to multivariate cluster analysis (PROC CLUSTER and TREE). A multiple correspondence analysis (PROC CORRESP) was performed to identify characteristics associated with different breeds. The failure in the behavior examination of bulls of the six breeds, although it has been approved in other steps of breeding soundness examination, indicated that this step should be a norm and not just a complementary test. Discussion: In young bulls Polled Hereford and Aberdeen Angus and adults bulls Hereford eyes were the major causes of failure, probably due to infectious bovine keratoconjunctivitis affecting more animals no pigment around the eyes (Polled Hereford and Hereford), than other pigmented breeds. Physical causes of failures found in this study suggest that there is a greater predisposition for failure due the use of these bulls, which causes a constant physical and natural wear, to work at irregular and extensive fields, looking for cows in estrus, predisposing to physical conditions as the locomotor system. The behavioral evaluation of the bulls is not always done, only although there are reports of failure in adult bulls for libido and physical ability problems to perform the mounts. Although tests of libido and phisical ability may not be sufficient to accurately determine pregnancy rates, there is greater security for obtaining good pregnancy rates with the use of bulls that have been approved in all stages of the breeding soundness evaluation.

Causes of failure in british bulls in the breeding soundness evaluation / Causas de reprovação de touros britânicos no exame andrológico

Background: The breeding soundness evaluation is a method that is based on the evaluation of all factors that contribute to the reproductive function in bull, basically is constituted by the general clinical examination, examination of internal and external genital system, measurement of scrotal circumference, semen physical and morphological evaluation and sexual behavior. Most progress in improving the reproductive efficiency can be made by estimating the fertility of the males and by careful selection of the bulls. Reproduction will continue to depend mainly on the ability to manage all available information. The aim of this study was to determine the main causes of failure in British bulls in the steps provided for breeding soundness evaluation, as well as demonstrate the importance of the behavior examination as a norm and not just as a complementary test.Materials, Methods & Results: This study consisted in evaluating the records of breeding soundness evaluation of 10,407 British breeds of bulls (Abeerden Angus, Red Angus, Hereford, Polled Hereford, Shorthorn and Devon) in the State of Rio Grande do Sul. The animals evaluated were grouped into two age classes: young bulls (two years) and adult bulls (three to ten years). Breeding soundness evaluation consisted of four steps: a general clinical examination, special clinical examination; seminal examination and behavior

Background: The breeding soundness evaluation is a method that is based on the evaluation of all factors that contribute to the reproductive function in bull, basically is constituted by the general clinical examination, examination of internal and external genital system, measurement of scrotal circumference, semen physical and morphological evaluation and sexual behavior. Most progress in improving the reproductive efficiency can be made by estimating the fertility of the males and by careful selection of the bulls. Reproduction will continue to depend mainly on the ability to manage all available information. The aim of this study was to determine the main causes of failure in British bulls in the steps provided for breeding soundness evaluation, as well as demonstrate the importance of the behavior examination as a norm and not just as a complementary test.Materials, Methods & Results: This study consisted in evaluating the records of breeding soundness evaluation of 10,407 British breeds of bulls (Abeerden Angus, Red Angus, Hereford, Polled Hereford, Shorthorn and Devon) in the State of Rio Grande do Sul. The animals evaluated were grouped into two age classes: young bulls (two years) and adult bulls (three to ten years). Breeding soundness evaluation consisted of four steps: a general clinical examination, special clinical examination; seminal examination and behavior