Population Differences In Response Research Articles

Population differences in responses to male hormonal contraception (lessons learned from the WHO-CONRAD phase III study)

Population differences in responses to male hormonal contraception (lessons learned from the WHO-CONRAD phase III study)

Population differences in responses to male hormonal contraception (lessons learned from the WHO-CONRAD phase III study)

Population differences in responses to male hormonal contraception (lessons learned from the WHO-CONRAD phase III study)

Patterns of Genetic Diversity and Gene Flow Associated With an Aridity Gradient in Populations of Common Mole-rats, Cryptomys hottentotus hottentotus.

Genetic adaptation is the change of a population toward a phenotype that best fits the present ecological conditions of the environment it inhabits. As environmental conditions change, allele frequencies shift, resulting in different populations of the same species possessing genetic variation and divergent phenotypes. Cooperatively breeding common mole-rats (Cryptomys hottentotus hottentotus) inhabit environments along an aridity gradient in South Africa, which provides an opportunity for local genetic adaptations to occur. Using one mitochondrial gene (cytochrome b) and 3,540 SNP loci across the whole genome, we determined the phylogenetic relationship, population structure and genetic diversity of five populations of C. h. hottentotus located along an aridity gradient. Mitochondrial data identified population-specific clades that were less distinct in the two mesic populations, potentially indicating historical or recent gene flow, or the retention of ancestral haplotypes. Arid and semi-arid populations formed a distinct cluster from the non-arid populations. Genetic diversity and gene flow were higher in arid-dwelling individuals, suggesting greater connectivity and interactions between colonies in arid regions in comparison to mesic ones. Using an Aridity Index, we determined that isolation by environment, rather than isolation by geographical distance, best explains the genetic distance between the populations. Further analyses using target loci may determine if there are differing underlying genetic adaptations among populations of C. h. hottentotus. These analyses could help unravel population differences in response to environmental factors within a subspecies of bathyergid mole-rat and determine the adaptive capacity of this small nonmigratory subterranean rodent species in response to aridification in the face of climate change.

Characterizing neural coding performance for populations of sensory neurons: comparing a weighted spike distance metrics to other analytical methods.

The identity of sensory stimuli is encoded in the spatio-temporal patterns of responses of the encoding neural population. For stimuli to be discriminated reliably, differences in population responses must be accurately decoded by downstream networks. Several methods to compare patterns of responses have been used by neurophysiologists to characterize the accuracy of the sensory responses studied. Among the most widely used analyses, we note methods based on Euclidean distances or on spike metric distances. Methods based on artificial neural networks and machine learning that recognize and/or classify specific input patterns have also gained popularity. Here, we first compare these three strategies using datasets from three different model systems: the moth olfactory system, the electrosensory system of gymnotids, and leaky-integrate-and-fire (LIF) model responses. We show that the input-weighting procedure inherent to artificial neural networks allows the efficient extraction of information relevant to stimulus discrimination. To combine the convenience of methods such as spike metric distances but leverage the advantages of weighting the inputs, we propose a measure based on geometric distances where each dimension is weighted proportionally to how informative it is. We show that the result of this Weighted Euclidian Distance (WED) analysis performs as well or better than the artificial neural network we tested and outperforms the more traditional spike distance metrics. We applied information theoretic analysis to LIF responses and compared their encoding accuracy with the discrimination accuracy quantified through this WED analysis. We show a high degree of correlation between discrimination accuracy and information content, and that our weighting procedure allowed the efficient use of information present to perform the discrimination task. We argue that our proposed measure provides the flexibility and ease of use sought by neurophysiologists while providing a more powerful way to extract relevant information than more traditional methods.

Edaphic ecotypic divergence in Senecio vulgaris and the evolutionary potential of predominantly self-fertilising species

ABSTRACT Background There is continued interest in ecotypic divergence because it is informative of local adaptation and can be an important step in speciation. Aim To investigate ecotypic divergence in a predominantly self-fertilising species, Senecio vulgaris, in response to variation in soil nitrogen (N) and phosphorus (P) concentrations. Methods Responses to increased N and P were compared among populations sampled from sand dune, bird sanctuary and garden habitats, containing soils of low, high and intermediate fertility, respectively. Responses were measured in terms of growth, with capitulum production and days to seed set recorded in some experiments. Results Population differences in response to increased N and P were detected and linked to differences in soil fertility among habitats. Thus, the sand dune population exhibited the lowest growth response to increased N and P concentrations, while a bird sanctuary population showed the greatest response to increased N supplied as either NaNO3, NH4NO3 or urea. Genetic variation in response to increased N was present in both of these populations. Conclusions The results indicate the presence of edaphic ecotypes in S. vulgaris, providing further evidence that questions the premise that self-fertilisation limits adaptation to environmental change and thus is an evolutionary dead-end.

Mental health consequences of the COVID-19 pandemic: Results from a large-scale population-based study in Israel

IntroductionContemporary evidence notes the COVID-19 pandemic greatly impacted the utilization of physical and mental health services worldwide. The present study was therefore designed to evaluate the changes in the utilization of mental health services during the first year of the COVID-19 pandemic compared to previous years as well as to estimate the moderating role age had on these changes. Materials and methodsPsychiatric data was collected from n = 928,044 individuals living in Israel. Rates of receipt of psychiatric diagnoses and purchases of psychotropic medication were extracted for the first year of the COVID-19 pandemic and for two comparison years. The odds of receiving a diagnosis or of purchasing a psychotropic medication during the pandemic were compared to control years using uncontrolled logistic regression models and controlled and logistic regression that accounted for differences between ages. ResultsThere was a general reduction of about 3–17% in the odds of receiving a psychiatric diagnosis or purchasing psychotropic medications during the pandemic year compared to control years. The bulk of tests conducted showed that reduction in the rates of receiving diagnoses and purchasing medications during the pandemic were evident or more profound in the older age groups. An analysis of a combined measure conclusive of all other measures revealed decreased rates of utilizing any service examined during 2020, with rates decreasing as age increases up to a decrease of 25% in the oldest age group (80–96). Discussion and conclusionChanges in utilization of mental health services reveal the interplay between psychological distress that has been documented to increase during the pandemic and people's reluctance to seek professional assistance. This appears to be especially prominent among the vulnerable elderly, who may have received even less professional help for their emerging distress. The results obtained in Israel are likely to be replicated in other countries as well, given the global impact of the pandemic on adults' mental health and individuals' readiness to utilize mental healthcare services. Future research on the long-term impact of the pandemic on utilization of mental healthcare services is warranted, with an emphasis on the response of different populations to emergency situations.

Early lateral root formation in response to calcium and nickel shows variation within disjunct populations of Arabidopsis lyrata spp. lyrata

Root architecture is important in nutrient uptake and avoidance of toxic compounds within the soil. Arabidopsis lyrata spp. lyrata has widespread distribution in disjunct environments that encounter unique stressors starting at germination. Five populations of A. lyrata spp. lyrata show local adaptation to Nickel (Ni) but cross-tolerance to variations in Calcium (Ca) concentration within the soil. Differentiation among the populations begins early in development and appears to impact timing of lateral root formation; therefore the purpose of the study was to understand changes in root architecture and root exploration in response to Ca and Ni within the first three weeks of growth. Lateral root formation was first characterized under one concentration of Ca and Ni. Lateral root formation and tap root length were reduced in all five populations in response to Ni compared to Ca, with the least reduction in the three serpentine populations. When the populations were exposed to a gradient (either Ca or Ni) there were differences in population response based on the nature of the gradient. Start side was the greatest determinant of root exploration and lateral root formation under a Ca gradient, while population was the greatest determinant of root exploration and lateral root formation under a Ni gradient. All populations exhibited about the same frequency of root exploration under a Ca gradient, while the serpentine populations exhibited much higher levels of root exploration under a Ni gradient compared to the two non-serpentine populations. Differences among populations in response to Ca and Ni demonstrate the importance of stress responses early in development, particularly in species that have widespread distribution among disparate habitats.

Estimating the impacts of climate change on the habitat suitability of common minke whales integrating local adaptation

Climate change is exerting unprecedented effects on the habitats of marine mammals. Common minke whales (Balaenoptera acutorostrata) have suffered immense harm from commercial whaling, and the recovery of this species is likely threatened by climate change. To better manage and conserve this species, it is important to predict its current habitat distribution and the potential change under future climate change scenarios. Such predictions are typically generated by species distribution models (SDMs), which construct a correlation between species occurrence data and its habitat environmental variables. SDMs are commonly constructed at the species level, assuming a homogenous response of the species to climatic variables across their entire geographic range. Spatially segregated populations from the same species inhabit distinct environments and gradually adapt to the local conditions, resulting in niche differentiation among populations. Species-level SDMs that ignore the effects of local adaptation mask differences in population responses to climate change and might present an unrealistic picture of potential species distributions. Based on morphological and genetic evidence, the common minke whale was divided into three populations: the North Atlantic population (NAP), Southern Hemisphere population (SHP) and North Pacific population (NPP); these populations inhabit isolated geographic areas with distinct environmental conditions. We quantified the realized niches of these populations and found evidence of significant ecological niche differentiation. We then constructed SDMs at the species and population levels and compared the predictions from these two types of models under different climate change scenarios. Both types of models projected similar change trends in species range, with a contraction of future suitable habitats for the NAP and SHP and an expansion for the NPP. However, the magnitudes of this change differed; the population-level model projected more optimistic results for the SHP and NAP, indicating less habitat loss. This study highlighted the importance of considering local adaptation when estimating the impact of climate change on species habitat suitability. These spatiotemporal predictions provide essential knowledge for designing climate-adaptive conservation and management strategies, such as the delimitation of mobile marine protected areas (MPAs).

Local environment prevails over population variations in growth-climate relationships of Pinus pinaster provenances

In view of the projected decrease in precipitation and increase in temperature, a better understanding on growth-climate responses in different populations of tree species is needed to improve and enhance the conservation and management strategies for major forest tree species. In this study, we assessed differences in growth traits (i.e., stem diameter, tree height, and stem radial growth) and analysed climate-growth relationships in five provenances of maritime pine (Pinus pinaster Ait.) grown in four replicated common gardens in Sardinia (Italy). Stem radial growth increased under a positive water balance in late winter and early spring. Conversely, high temperature and low precipitation in summer had a negative impact on stem radial growth. At age 40, none of the considered provenances (Portugal, Corsica, Tuscany, Sardinia-Telti, Sardinia-Limbara) showed a substantial advantage in more than one common garden site for tree height and stem diameter. Nevertheless, differences were found among common garden sites in terms of dendrometric parameters, stem radial growth, and growth-climate responses (including sensitivity to summer drought), suggesting a greater site dependent over tree growth. Although in juvenile stages the Portuguese provenance (in particular) showed greater growth than the Sardinian ones, this study showed that, with tree age, the differences among the five provenances tends to narrow. Therefore, irrespective of the seed source, tree growth patterns and growth-climate responses were similar at age 40. This result can be important for implementing forest management strategies to balance adaptation and mitigation potential of maritime pine plantations in harsh environmental conditions.

Efficacy and safety of oral semaglutide in Russian patients with type 2 diabetes: subgroup analysis of PIONEER 1, 2, 3 trials

INTRODUCTION. Glucagon-like peptide-1 receptor agonists (GLP-1 RA) are the treatment options with comprehensive action on different aspects of type 2 diabetes. Due to its peptide nature GLP-1 RAs, until recent time the delivery of these agents into patients’ organism was via injectable devices. In 2019, the first time in history oral semaglutide was registered based on the results of PIONEER clinical trial program, since 2021 this drug is available in Russia. However, the pathophysiology of type 2 diabetes and local treatment approaches may differ in different populations; this can lead to the differences in the efficacy and safety of newly registered drug. Therefore, it is necessary to evaluate the response in different populations. In this paper we report the result of subanalysis of efficacy and safety of oral semaglutide in Russian patients.OBJECTIVE. The aim of this analysis is to evaluate efficacy and safety of oral semaglutide in Russian patients, who participated in semaglutide clinical development program, as well as to evaluate consistency and applicability of the results obtained from global population in that program.MATERIALS AND METHODS. Patients from PIONEER 1, 2, 3 were included in the analysis: 150 patients from Russian, 1956 — the rest patients from these trials. Reductions in HbA1c and body weight were analyzed in both cohorts, and treatment differences were tested for interaction. Similarly, the rate of adverse events was analyzed.RESULTS. Reduction in HbA1c in oral semaglutide arms in both cohorts showed numerically similar and consistent result. Interaction test showed statistical difference in PIONEER 1 data (p=0.0268) — the effect was due to diminishing influence of substantial response in placebo arm in Russian cohort. In longer-term trials (PIONEER 2 and 3) this finding was not confirmed (p=0.7459 and p=0.4906, respectively). In regard to body weight reduction there were more numerically pronounced results in Russian cohort compared to global population; although statistical significance were not reached in any of the trial (p>0.05). There was lower rate of reported adverse events in Russian patients compared to the rest cohort.CONCLUSION. This analysis showed similar efficacy and safety of oral semaglutide in Russian patients compared to global population of patients from clinical program.

Characterization of patients with lung adenocarcinoma treated at a reference oncology center in northeastern Brazil and submitted to EGFR gene mutation research.

e20548 Background: Lung cancer has the highest incidence and mortality worldwide. In Brazil, it is the second most common, and individualized therapy, although more efficient than traditional chemotherapy, is still a challenge for health services, especially in developing countries, as socioeconomic disparities make access to genetic testing difficult or treatment. Thus, it is understood that greater knowledge about the genetic profile and therapeutic response of different populations can contribute to policy changes that guarantee expanded access to individualized therapy. Methods: the EGFR gene mutation status was correlated with clinical-epidemiological, socioeconomic, treatment, and survival parameters of patients with lung adenocarcinoma treated from 2014 to 2021 at an oncology referral center in northeastern Brazil. Data were obtained retrospectively from the patient's charts at the Hospital Haroldo Juaçaba/Instituto do Câncer do Ceará. The X²/Fisher and Log-Rank Mantel-Cox tests were used to associate clinical variables and overall survival curves. The Research Ethics Committee approved the research under protocol number 3.544.754. Results: 586 patients tested, 157 (26.8%) had an EGFR mutation, with exon 19 deletion (n = 83, 52.9%). the most frequent followed by L858R (n = 54, 34.4%) and others (n = 30, 12.8%). The EGFR mutation was inversely associated with smoking history (p < 0.001) and previous use of carboplatin plus paclitaxel (p < 0.001). The median overall survival was 33 (95%CI = 25-41) months, and the presence of a mutation was not associated with a worse outcome (p = 0.146). Interestingly, patients with sensitivity mutation who used gefitinib (64.1%) did not show a significant difference in overall survival (p = 0.218). However, when stratifying analyzes according to mutation type, it was observed that patients with exon 19 deletion treated with gefitinib had greater median overall survival (32, 95%CI = 27-37 months) than patients with this mutation not treated with gefitinib (median = 15, 95%CI = 2-25 months) (p < 0.001). Patients with the L858R type sensitivity mutation (p = 0.523) or other mutations (p = 0.439) did not experience significant benefits from gefitinib use. Conclusions: In the population studied, the exon 19 deletion was the most frequent and the only one associated with a substantial benefit from using gefitinib.

Comparison of cytokines levels among COVID-19 patients living at sea level and high altitude

BackgroundAt the end of 2019, a novel coronavirus denominated SARS-CoV-2 rapidly spread through the world causing the pandemic coronavirus disease known as COVID-19. The difference in the inflammatory response against SARS-CoV-2 infection among people living at different altitudes is a variable not yet studied.MethodsA descriptive cross-sectional study was performed in two Peruvian cities at different altitudes for comparison: Lima and Huaraz. Five important proinflammatory cytokines were measured including: IL-6, IL-2, IL-10, IFN-γ and TNF-α using ELISA assays.ResultsA total of 35 COVID-19 patients and 10 healthy subjects were recruited from each study site. The mean levels of IL-6 (p < 0.03) and TNF-α (p < 0.01) were significantly different among the study groups. In the case of IL-6, patients from Lima had a mean level of 16.2 pg/ml (healthy) and 48.3 pg/ml (COVID-19), meanwhile, patients from Huaraz had levels of 67.3 pg/ml (healthy) and 97.9 pg/ml (COVID-19). Regarding TNF-α, patients from Lima had a mean level of 25.9 pg/ml (healthy) and 61.6 pg/ml (COVID-19), meanwhile, patients from Huaraz had levels of 89.0 pg/ml (healthy) and 120.6 pg/ml (COVID-19). The levels of IL-2, IL-10 and IFN-γ were not significantly different in the study groups.ConclusionPatients with COVID-19 residing at high-altitude tend to have higher levels of inflammatory cytokines compared to patients living at sea level, particularly IL-6 and TNF-α. A better understanding of the inflammatory response in different populations can contribute to the implementation of therapeutic and preventive approaches. Further studies evaluating more patients, a greater variety of cytokines and their clinical impact are required.

Massive Ulva Green Tides Caused by Inhibition of Biomass Allocation to Sporulation.

The green seaweed Ulva spp. constitute major primary producers in marine coastal ecosystems. Some Ulva populations have declined in response to ocean warming, whereas others cause massive blooms as a floating form of large thalli mostly composed of uniform somatic cells even under high temperature conditions—a phenomenon called “green tide”. Such differences in population responses can be attributed to the fate of cells between alternative courses, somatic cell division (vegetative growth), and sporic cell division (spore production). In the present review, I attempt to link natural population dynamics to the findings of physiological in vitro research. Consequently, it is elucidated that the inhibition of biomass allocation to sporulation is an important key property for Ulva to cause a huge green tide.

Genetic Polymorphism of Drug Metabolic Gene CYPs, VKORC1, NAT2, DPYD and CHST3 of Five Ethnic Minorities in Heilongjiang Province, Northeast China.

IntroductionGenetic variability in genes encoding drug-metabolizing enzymes may contribute to the heterogeneity of drug responses in different populations. Extensive research in pharmacogenomics in major populations around the world provides us with a great deal of information about drug-related genetic polymorphisms.ObjectiveThe purpose of this study was to detect the genetic variation of drug-metabolism-related genes in the five ethnic minorities Daur, Hezhen, Ewenki, Mongolian and Manchu in China, and to analyze the distribution differences among ethnic groups.MethodsWe genotyped 32 SNPs of drug metabolism genes in 882 healthy Chinese volunteers from five ethnic groups. The genotype frequency and allele frequency of the five ethnic groups were calculated, and the different variants among the five ethnic groups were compared by chi-square test. Genetic parameters were analyzed using Popgene software. The genetic structure of five ethnic minorities was analyzed by principal component analysis, and compared with 26 populations.ResultsWe found that SNPs of genes related to drug metabolism existed diversity in different populations. Among them, rs8192766 and rs9419082 in CYP2E1 showed statistical differences between Daur and Manchu, and NAT2 rs1801280 showed statistical differences between Hezhen and Mongolian. In addition, the five populations we studied had the smallest differences with EAS populations. There was haplotype diversity in CHST3, VKORC1, CYP1A2 and CYP2E1 genes in the five ethnic minorities, and these haplotype polymorphisms were related to the use of corresponding drug doses. Cluster analysis shows that the five ethnic minorities in Heilongjiang Province are clustered together with the EAS populations.ConclusionThese results suggest that understanding the diversity of drug-related genetic markers is critical for individualized drug gene therapy programs in ethnic minorities in China as well as in populations highly mixed with these ethnic groups.

Structural and functional insights on vitamin D receptor and CYP24A1 deleterious single nucleotide polymorphisms: A computational and pharmacogenomics perpetual approach.

The development of chronic kidney disease (CKD) drugs remains a challenge due to the variations in the genes. The vitamin D receptor (VDR) and Cytochrome 24A1 (CYP24A1) genetic variants might affect the drug potency, efficacy and pathway. Here we have to analyse and determine the deleterious single-nucleotide polymorphisms (nsSNPs) of VDR and CYP24A1 genes and their different population's drug responses in different populations to understand the key role in CKD. Among that the large scale of nsSNP, we used certain computational tools that predicted six missense variants are observed to be significantly damaging effect and SNP variability with large differences in various populations. Molecular docking studies were carried out by clinical and our screened compounds to VDR and CYP24A1. Docking results revealed all the compounds have a good binding affinity (Score). The screened compounds (TCM_2868 and UNPD_141613) show good binding affinity when compared to known compounds. The QM/MM study revealed that the compounds have electron transfer ability and act as a donor/acceptor to mutated proteins. The structural and conformational changes of protein complexes were analysed by molecular dynamics study. Hence, this study helps to identify suitable drugs through drug discovery in CKD treatment. The abovementioned compounds have more binding affinity, efficacy, and potency of both wild and mutant of VDR and CYP24A1.

Sex distributions and growth response in different populations of catfish (Clarias gariepinus)

This study evaluated the gender ratio in Clarias gariepinus production from five different populations. 300 Juveniles fish each were sourced from five (5) fish farms. The fish were grouped based on the farms into five populations (i.e. treatments) and were replicated thrice with each replicate stocked with 100 fish in a square shaped experimental plastic tanks of 1m x 1m x 1m. Data obtained from the experiment were subjected to one-way analysis of variance. Significant differences (p&lt;0.05) were recorded in the values of final weight, mean weight gain, specific growth rate, percentage survival and daily growth rate. The male-female ratio showed that the females were more in number compared to their male counterpart. There was no significant difference in the number of males, number of females and weight of males across the populations. The female C. gariepinus in population 5 had the highest value (246.41±2.73g) of final weight while those in population 3 had the least value (205.95±13.17g) of weight. The fish in population 2 displayed a better growth curve compared to other populations while fish in population 3 displayed the least curve. The curve revealed that the fish grows at almost the same rate from day 0 to day 42 after which their growth pattern changed. This study showed that the number of female fish in any production outweighs the number of males.

Antibody response and therapy in COVID-19 patients: what can be learned for vaccine development?

The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions of people and caused tremendous morbidity and mortality worldwide. Effective treatment for coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 infection is lacking, and different therapeutic strategies are under testing. Host humoral and cellular immunity to SARS-CoV-2 infection is a critical determinant for patients’ outcomes. SARS-CoV-2 infection results in seroconversion and production of anti-SARS-CoV-2 antibodies. The antibodies may suppress viral replication through neutralization but might also participate in COVID-19 pathogenesis through a process termed antibody-dependent enhancement. Rapid progress has been made in the research of antibody response and therapy in COVID-19 patients, including characterization of the clinical features of antibody responses in different populations infected by SARS-CoV-2, treatment of COVID-19 patients with convalescent plasma and intravenous immunoglobin products, isolation and characterization of a large panel of monoclonal neutralizing antibodies and early clinical testing, as well as clinical results from several COVID-19 vaccine candidates. In this review, we summarize the recent progress and discuss the implications of these findings in vaccine development.

Immunogenetic and tolerance strategies against a novel parasitoid of wild field crickets.

Among the parasites of insects, endoparasitoids impose a costly challenge to host defenses because they use their host’s body for the development and maturation of their eggs or larvae, and ultimately kill the host. Tachinid flies are highly specialized acoustically orienting parasitoids, with first instar mobile larvae that burrow into the host’s body to feed. We investigated the possibility that Teleogryllus oceanicus field crickets employ postinfestation strategies to maximize survival when infested with the larvae of the parasitoid fly Ormia ochracea. Using crickets from the Hawaiian Islands of Kauai, where the parasitoid is present, and crickets from the Cook Islands (Mangaia), where the parasitoid is absent, we evaluated fitness consequences of infestation by comparing feeding behavior, reproductive capacity, and survival of males experimentally infested with O. ochracea larvae. We also evaluated mechanisms underlying host responses by comparing gene expression in crickets infested with fly larvae for different lengths of time with that of uninfested control crickets. We observed weak population differences in fitness (spermatophore production) and survival (total survival time postinfestation). These responses generally did not show an interaction between population and the number of larva hosts carried or by host body condition. Gene expression patterns also revealed population differences in response to infestation, but we did not find evidence for consistent differences in genes associated with immunity or stress response. One possibility is that any postinfestation evolved resistance does not involve genes associated with these particular functional categories. More likely, these results suggest that coevolution with the fly does not strongly select for either postinfestation resistance or tolerance of parasitoid larvae in male crickets.

Susceptibility of the bird cherry‐oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae), to four insecticides

AbstractThe bird‐cherry oat aphid (Rhopalosiphum padi) is a global pest, attacking most cereal crops including barley, wheat, oats and triticale. The aphids cause yield losses through direct feeding damage and the transmission of plant viruses. In Australia, feeding injury can reduce cereal yields by 6%, with the damage caused by aphid‐vectored viruses reducing the yield of cereal crops by up to 30%. Aphid control in these crops is achieved almost exclusively with insecticides, and there is growing concern surrounding insecticide resistance evolution in multiple aphid species. In this study, nine field populations of R. padi were collected from localities representing the major grain growing regions of Australia. Toxicity data against four insecticides (dimethoate, alpha‐cypermethrin, pirimicarb and imidacloprid) was generated for each aphid population. This revealed little differences in population responses for three of these insecticides. For alpha‐cypermethrin, a widely used insecticide in Australia, there were significant differences between several populations. These data will be important for future monitoring of insecticide responses of R. padi and highlight the impending pest management challenges growers could encounter in Australia.

Rejection of parasitic eggs by Yellow-bellied Prinias: importance of egg spot location

Characteristics of egg surfaces serve as recognition cues that allow avian hosts to detect and reject foreign eggs in brood parasitism. The blunt egg pole hypothesis suggests that the blunt egg pole is an essential signal in parasitic egg recognition. In the present study, eggs of Yellow-bellied Prinia (Prinia flaviventris) were painted with black spots at either the blunt or sharp egg pole to determine and compare the responses of different populations exposed to brood parasitism (parasitized population) or not (non-parasitized population). These results supported the above hypothesis and showed that the parasitized population displayed a higher rate of rejection of eggs with blunt pole-painted spots than with sharp pole-painted spots. In contrast, the non-parasitized population accepted all experimental eggs, which may be related to decreased egg recognition resulting from low exposure to brood parasitism.