Alarm Calls Research Articles

Monitoring of pyrethroid resistance in Aedes aegypti: first report of double and triple kdr mutations in Buenos Aires Province

BackgroundDengue is an emerging disease in Argentina due to the colonization of Aedes aegypti, the mosquito vector. Buenos Aires Province is the biggest and most populated district in Argentina, suffering dengue outbreaks of growing magnitude. During epidemic periods, pyrethroid insecticides are used in this country to control adult mosquitoes. Pyrethroid resistance in dengue vectors has been reported worldwide, making it necessary to implement resistance management strategies. The voltage-gated sodium channel is the target site of pyrethroids. Mutations in the gene encoding this protein, called kdr mutations, are usually the molecular cause of pyrethroid resistance in insects. In Ae. aegypti from the Americas, three kdr substitutions were described: V410L, V1016I, and F1534C. The diagnostic of kdr mutations is recommended for the early detection of pyrethroid resistance as well as the consequent planning of evidence-based control policies.MethodsWe distributed ovitraps across 16 localities in Buenos Aires Province, collecting 22,123 eggs. A total of 522 mosquitoes were genotyped in positions 1016 and 1534 of voltage-gated channel using multiplex high-resolution melting and/or TaqMan probe methods. A subset of 449 samples was also genotyped by a singleplex high-resolution melting method developed ad hoc and/or Sanger sequencing.ResultsWe have documented, for the first time to our knowledge in the central region of Argentina, the presence of the 1016Ikdr + 1534Ckdr allele. Additionally, our study reports the first identification of the V410L mutation in central Argentina. These results underscore a growing trend of pyrethroid resistance in Ae. aegypti, fueled by the widespread use of these insecticides.ConclusionsWe detected 1016Ikdr + 1534Ckdr and 410Lkdr mutations in central Argentina for the first time and improved the processivity and accuracy of kdr genotyping methods. The results are both a tool for resistance monitoring and a sign of alarm to direct efforts towards finding sustainable methods for vector control to complement or replace pyrethroids. Joint efforts between academia and authorities to develop and implement public policies for vector control are a productive way to transfer scientific results for their application in public health.Graphical

Cancer cachexia and weight loss before CAR T-cell therapy for lymphoma are independently associated with poor outcomes

AbstractChimeric antigen receptor (CAR) T-cell therapy has transformed the care of lymphoma, yet many patients relapse. Several prognostic markers have been associated with CAR T-cell outcomes, such as tumor burden, response to bridging chemotherapy, and laboratory parameters at the time of lymphodepletion or infusion. The effect of cancer cachexia and weight loss before CAR T cells on toxicity and outcomes is not well understood. Here, we present a retrospective single-institution cohort study of 259 patients with lymphoma treated with CAR T cells between 2017 and 2023. We observed that patients with >5% decrease in their body mass index in the 3 months preceding CAR T-cell treatment (weight loss group; all meeting one of the commonly accepted definitions of cancer cachexia) had higher disease burden and inflammatory parameters (C-reactive protein, ferritin, interleukin-6, and tumor necrosis factor α) at the time of lymphodepletion and CAR T-cell infusion. Patients with weight loss experienced higher rates of grade 3+ neurotoxicity and early hematotoxicity, but those effects were not seen upon multivariable adjustment. However, in both univariate and multivariable analysis, patients with weight loss had worse response rates, overall survival, and event-free survival, indicating that weight loss is an independent poor prognostic factor. Our data suggest that weight loss in the 3 months preceding CAR T-cell therapy represents a worrisome “alarm signal” and a potentially modifiable factor, alongside tumor burden and inflammation, and warrants further investigation in patients treated with CAR T-cell therapy.

Design, Synthesis, Anti-inflammatory Evaluation and In silico Molecular Docking of Novel Furan-based Derivatives as Potential TNF-α Production Inhibitors

Introduction: Inflammation is the first response and an alarming signal for the onset of chronic disease. Most of the anti-inflammatory drugs available in the market are reported to have undesirable gastrointestinal toxicities. Therefore, it is of urgent significance to develop anti-inflammatory drugs with low toxicity and good efficacy. Methods: We created a targeted scaffold based on a literature review by combining the different structural characteristics of furan and benzyl amides into a single pharmacophore. A series of eighteen furanbased derivatives (1-18) were designed, synthesized for in vitro and in vivo anti-inflammatory activity. The characterization of synthesized compounds was elucidated by techniques like 1H-NMR, 13C-NMR, FT-IR and MS. Results: The synthetic compounds were examined through molecular docking studies on TNF-α for probable binding mode and interactions with hydrophilic and hydrophobic pocket of TNF-α in comparison to standard drug (Indomethacin). Conclusion: When compared to the standard treatment, compounds 18, 15 and 9 displayed a remarkable inhibitory effect on the production of TNF-α and in vivo inflammatory activity with no damage to stomach and reduction of LPO. The compounds 18, 15 and 9 might be a good consideration for potential antiinflammatory agents.

Why is the quality of revision so low? Attempts to explain and tackle the situation

ABSTRACT Empirical studies on revision quality show that the added value of revision is often low, or even nonexistent. Revisers tend to miss many problems, make unnecessary changes and sometimes introduce errors into the draft translation. This alarming but scientifically-grounded picture calls for explanations and solutions. The aim of this article is to understand the situation and come up with potential solutions by drawing upon a large interview study that was carried out in various settings, mostly in translation teams. One factor is that revision is difficult for professional translators, as shown through nine difficulties cited by participants in the interviews, including limiting the number of changes and staying focused on the task. The poor results observed in empirical studies may also stem from poor training or the lack of supervision of revisers. As for solutions, in addition to promoting training and supervision, this article also advocates for advisory revision and oral revision, instead of corrective, written revision.

Design and Implementation of Eight-Way Call System Based on Digital Integrated Circuits

This paper introduces the construction of an eight-channel call system using medical callers. The circuit enables the call signal to be sent to the 74HC148 priority encoder for encoding if any of the channels make a call. The encoded signal is processed by the 74LS283 and then output from the 74LS373 latch to the 4511BD decoding and driving circuit. The output of the decoding and driving circuit is displayed on the display circuit, showing the number of the channel that made the call. Meanwhile, the control signal triggers a monostable oscillator circuit composed of a 555 timer, which generates a temporary stable output signal with a pulse width of about 2s. The pulse signal drives a multivibrator circuit composed of a 555 timer, which causes the LED to work and output an alarm signal. The alarm state can be eliminated manually by pressing a key.

Pair‐Coordinated Calling: Eurasian Magpies Respond Differently to Simulated Intruder Pairs That Overlap or Alternate Their Calls

ABSTRACTAnimal vocalisations are widely used to signal strength or motivation of a caller in competitive interactions, such as in territorial defence. Substantial understanding of signalling functions in territorial conflicts is based on singing by male songbirds. Yet, in many species, both pair members call during territorial conflicts, as well as in predator‐induced situations, leading to complex signalling interactions in which calls overlap or alternate. This raises the question as to whether or not variation in how individuals in pairs time their calls is perceived as meaningful by receivers. Here, we tested with playback experiments whether Eurasian magpies (Pica pica), a species producing alarm calls (so‐called chatter calls) in territorial defence, respond stronger to simulated pair‐intruders who overlap their calls with each other than to those who alternate them. Magpies emitted a significantly longer first chatter calls in response to playback with overlapping calls but chattered significantly sooner and approached the loudspeakers significantly more closely in response to playbacks of alternating (and therefore longer) call sequences. These findings exemplify that the timing of calls by pair members matters, but in more complex ways than we predicted. The overlapping playback appeared to trigger a longer yet later initial chatter response and a weaker approach response, suggesting that the different ways in which magpies respond reflect different levels of arousal or defence strategies. The results may also reflect uncertainty by receivers due to a potential mismatch between signalled and perceived information: While overlapping calls may signal high arousal by both callers, a longer alternating sequence could be perceived as a more aroused longer signal. These findings expand on classical experiments on call function, suggesting that pairs can vary the message by coordinating their alarm calls in different ways, similar to how duetting pairs time their song contributions in advertisement signalling.

A survey of practice patterns and adherence to national and international guidelines on the management of Helicobacter pylori infection among gastroenterologists and gastroenterology fellows in India.

Patients and primary care providers alike benefit greatly from the expertise of gastroenterologists when it comes to managing Helicobacter pylori (H. pylori) infection. However, information on gastroenterologists' practices in the management of H. pylori infection is scarce in this part of the world. This study aimed at evaluating the practice patterns of gastroenterologists and gastroenterology fellows in India. This was a cross-sectional questionnaire-based survey of gastroenterologists and gastroenterology fellows working in India. Total 207 gastroenterologists and 53 fellows filled out the questionnaire. Responses were received from all around India. Approximately 70% of respondents perceive H. pylori to be a gastric pathogen, while 20% regard it as a commensal bacterium. While the proportion of respondents who chose a test and treat method (34.6%) for uninvestigated dyspepsia without alarm symptoms was comparable to empirical proton pump inhibitor (PPI) therapy (38.8%), about one-fifth chose a scope and treat strategy in this setting. Even in the absence of alarm signs, more than half of respondents (61.5%) preferred endoscopic biopsy to detect H. pylori. While rapid urease testing (RUT) was the preferred modality (80%) for detecting H. pylori, about one-third preferred single-site RUT (from the antrum). Only 40% followed the Updated Sydney protocol, while performing biopsies and a majority (78.8%) are unable to discontinue PPIs before testing for H. pylori. PPI-clarithromycin-based triple treatment was the preferred regimen (67%) for first-line eradication, while nearly a quarter of respondents did not utilize bismuth due to concerns about adverse effects. The survey reveals a lack of adherence to the currentH. pylori guidelines for diagnosis, testing and treatment among gastroenterologists and gastroenterology fellows in India. It is vital that scientific societies simplify guidelines, investigate challenges to their effective implementation and execute targeted interventions to increase adherence.

Respiratory failure and rhabdomyolysis caused by severe hypokalemia in a young female with hypertension: a rare critical condition in primary aldosteronism

BackgroundThe two classic manifestations of primary aldosteronism are hypertension and hypokalemia. However, acute respiratory failure due to hypokalemia in primary hyperaldosteronism is rare.Case presentationThe patient was a 27-year-old female who presented with drowsiness and weakness in all extremities. She had been diagnosed with hypertension three years prior, with irregular follow-up, and had a history of preeclampsia one year later. She exhibited high blood pressure and severe hypokalemia (2 mEq/L), leading to respiratory depression and impending respiratory arrest. Consequently, the patient was intubated and transferred to the intensive care unit (ICU). She also developed rhabdomyolysis. Blood pressure tests, including hormonal tests (aldosterone: 13.2 ng/dL, plasma renin activity: 0.32 ng/mL/h), were conducted. Due to the high aldosterone-renin ratio, an abdominopelvic computed tomography (CT) scan was performed. The CT scan revealed a 14 × 12 mm round mass with a washout value above 60%, consistent with an adrenal adenoma, leading to a diagnosis of primary aldosteronism. The patient was discharged after stabilization, and one and a half months after ICU admission, a laparoscopic left adrenalectomy was successfully performed without post-operative complications. Histopathology showed encapsulated hypertrophy of the adrenal cortex with a predominance of large clear cells, confirming the diagnosis of adrenal adenoma. At the most recent follow-up, the patient had normal potassium levels, was normotensive without any medications, and exhibited no alarming signs or symptoms.ConclusionRespiratory depression to the extent of impending respiratory failure and rhabdomyolysis as a result of hypokalemia in primary aldosteronism are extremely rare. In this patient, who developed respiratory depression due to resistant hypokalemia, timely investigation of secondary causes and diagnosis of adrenal adenoma were crucial. The surgery provided definitive treatment for the patient’s blood pressure and prevented the recurrence of life-threatening complications.

Sparrowhawk imitation or convergent alarm signal? A new hypothesis for bubbling call of cuckoos with empirical testing

Abstract Alarm calls in bird vocalizations serve as acoustic signals announcing danger. Owing to the convergent evolution of alarm calls, some bird species can benefit from eavesdropping on certain parameters of alarm calls of other species. Vocal mimicry, displayed by many bird species, aids defense against predators and may help brood parasites during parasitism. In the coevolutionary dynamics between brood parasites, such as the common cuckoo (Cuculus canorus), and their hosts, female cuckoo vocalizations can induce hosts to leave the nest, increasing the probability of successful parasitism and reducing the risk of host attacks. Such cuckoo calls were thought to mimic those of the sparrowhawk. However, owing to their similarity to alarm calls, we propose a new hypothesis: female cuckoos cheat their hosts by mimicking the parameters of the host alarm call. In this study, we tested this new hypothesis and the sparrowhawk mimicry hypothesis simultaneously by manipulating the syllable rate in male and female common cuckoo vocalizations and playing them in front of the host Oriental reed warbler (Acrocephalus orientalis) for examination. The results indicate that similar to a normal female cuckoo call, a female call with a reduced syllable rate prompted the hosts to leave their nests more frequently and rapidly than male cuckoo calls. Additionally, the male cuckoo calls with increased syllable rate did not prompt the host to leave their nests more frequently or quickly compared with the male cuckoo calls with a normal syllable rate. Our results further confirm that female common cuckoos mimic the vocalizations of Eurasian sparrowhawks, reveal the function mechanisms underlying such mimicry, and support the theory of imperfect mimicry.

The Role of (E)-β-Farnesene in Tritrophic Interactions: Biosynthesis, Chemoreception, and Evolution.

(E)-β-farnesene (EBF) stands out as a crucial volatile organic compound, exerting significant influence on the complex interactions between plants, aphids, and predator insects. Serving as an alarm signal within aphids, EBF is also emitted by plants as a defense mechanism to attract aphid predators. This review delves into EBF sources, functions, biosynthesis, detection mechanisms, and its coevolutionary impacts on aphids and insect predators. The exploration underscores the need to comprehend the biophysical and structural foundations of EBF receptors in aphids, emphasizing their role in unraveling the intricate patterns and mechanisms of interaction between EBF and target receptors. Furthermore, we advocate for adopting structure-based or machine-learning methodologies to anticipate receptor-ligand interactions. On the basis of this knowledge, we propose future research directions aiming at designing, optimizing, and screening more stable and efficient active odorants. A pivotal outcome of this comprehensive investigation aims to contribute to the development of more effective aphid-targeted control strategies.

Costly calling: Marmots who alarm call at higher rates are less likely to survive the summer and live shorter lives

Abstract Emitting alarm calls may be costly, but few studies have asked whether calling increases a caller’s risk of predation and survival. Since observing animals calling and being killed is relatively rare, we capitalized on over 24,000 h of observations of marmot colonies and asked whether variation in the rate that yellow-bellied marmots (Marmota flaviventer) alarm called was associated with the probability of summer mortality, a proxy for predation. Using a generalized mixed model that controlled for factors that influenced the likelihood of survival, we found that marmots who called at higher rates were substantially more likely to die over the summer. Since virtually all summer mortality is due to predation, these results suggest that calling is indeed costly for marmots. Additionally, the results from a Cox survival analysis showed that marmots that called more lived significantly shorter lives. Prior studies have shown that marmots reduce the risk by emitting calls only when close to their burrows, but this newly quantified survival cost suggests a constraint on eliminating risks. Quantifying the cost of alarm calling using a similar approach in other systems will help us better understand its true costs, which is an essential value for theoretical models of calling and social behavior.

7876 Complex Complications of Thionamide Therapy in One Patient: Methimazole-Induced Agranulocytosis and PTU-Induced ANCA-Vasculitis

Abstract Disclosure: E. Zweibach: None. A. Chang: None. Introduction: Thionamides, including methimazole and propylthiouracil (PTU), are essential for treating Graves' disease but can cause serious side effects such as agranulocytosis and ANCA-vasculitis. Although agranulocytosis itself is quite uncommon, the incidence of ANCA vasculitis is even more infrequent, making combination of conditions particularly exceptional. We present a unique case of a Graves' disease patient who suffered both complications: agranulocytosis due to methimazole and ANCA vasculitis from PTU, with successful resolution of both the clinical signs and laboratory findings following drug discontinuation. Case: 61-year-old female with a history of Graves' disease previously managed with methimazole but discontinued due to agranulocytosis, presented with lower extremity swelling, atrial fibrillation with RVR, and high output cardiac failure. Laboratory tests showed hyperthyroidism (TSH 0.008, Free T4 3.07), leading to a diagnosis of thyroid storm. Patient was started on PTU inpatient and discharged with this medication to home. Eight months later, the patient developed alarming signs including gross hematuria, oral ulcers, widespread muscle pain, found to have AKI with Cr of 2.79 and hospitalized for further eval. While hospitalized, the patient was found to have a range of complications including leukopenia with normal granulocyte count, anemia, AKI, proteinuria, and microscopic hematuria. Rheumatological evaluation showed +ANA and a high ANCA titer >1:1280, along with elevated levels of MPO and PR-3, and reduced complement levels. These symptoms and laboratory findings led to a diagnosis of ANCA vasculitis induced by PTU, resulting in the cessation of this medication. Following the discontinuation of PTU there was a notable improvement with normalization of serum Cr and resolution of proteinuria within 1.5 months. Concurrently, MPO and PR-3 levels began to decrease, and her hematological abnormalities resolved. During this period, her Free T4 levels gradually increased, leading to the administration of radioactive iodine for the treatment of her Graves' disease. Discussion: This case underscores the complexities in treating a patient with Graves' disease highlighting the unpredictable and severe side effects of antithyroid drugs like agranulocytosis and ANCA vasculitis. We report the first documented case of sequential thionamide-induced complications: agranulocytosis with methimazole, followed by ANCA vasculitis with propylthiouracil. Although both can arise from immune responses to these medications, they are distinct in their pathophysiology and are not associated with one another. The unpredictable nature of these side effects complicates prevention. Educating patients to promptly report any unusual symptoms and immediate medical intervention with drug discontinuation are key to managing these adverse reactions effectively. Presentation: 6/1/2024

Coping strategies of intensive care units nurses in alarm management: a qualitative research study

BackgroundIntensive care units are critical environments where various alarm systems play a pivotal role in patient monitoring and safety. Alarm fatigue can lead to slower response times and missed alarms, compromising patient safety and increasing stress and burnout among intensive care unit nurses. Understanding how intensive care unit nurses respond to and manage these alarms is crucial in evaluating their impact on patient care and nursing well-being.MethodsThis descriptive qualitative study explored the experiences of intensive care unit nurses in alarm management. Conducted in the medical and surgical intensive care units of a Northern Taiwan medical center, the study involved 15 nurses. Semi-structured interviews were utilized to investigate the working experiences of ICU nurses in alarm management and to identify their coping strategies for dealing with the constant inundation of medical device alarms. The interviews were transcribed, and content analysis was applied to identify key themes in the responses.ResultsThe study revealed five main themes in intensive care unit nurses’ strategies for managing alarms: (1) Mastering alarm signals and acting; (2) Team monitoring for life preservation; (3) Enhancing senses and distinguishing carefully; (4) Learning from the lessons of incidents for vigilant reflection; and (5) Detach alarms’ influence on daily life. These coping strategies are effective in alarm management, safeguarding patients’ lives, enhancing the serenity of the clinical environment, and mitigating the physical and mental exhaustion caused by alarm fatigue.ConclusionsIntensive Care Unit nurses develop various coping strategies to manage medical device alarms, based on their experience. These strategies are crucial in maintaining patient safety and reducing nurse alarm fatigue. They can also be used for nursing education and clinical training.

Prevalence and Profile of Tapentadol Use in Patients Visiting a Drug De-addiction Center in Kashmir

Background: Misuse of prescription opioids has been a hazard lately with tapentadol being a recent addition to the list. Tapentadol is a schedule H1 opioid (Drugs and Cosmetics Rules, India), approved for the management of moderate-to-severe acute and chronic pain. Aims and Objectives: We examined the prevalence of tapentadol use among patients attending the Drug De-addiction Center, Government Medical College, Srinagar, Kashmir, along with their sociodemographic and clinical profiles. Materials and Methods: It was a cross-sectional study. Patients who reported current tapentadol use were included in the study. Results: In a span of 4 months, a total of 104 patients using tapentadol were seen. Our study mostly consisted of young, unmarried males. More than half of our study participants had concurrent opioid dependence. In our study, no participant had ever injected tapentadol. Conclusion: Tapentadol is becoming infamous as a cheap and ready-to-available drug, replacing other opioids during their nonavailability. This should be a potentially alarming sign for drug control authorities. As such, its sale and supply should be well regulated.

Examining Brain Activity Responses during Rat Ultrasonic Vocalization Playback: Insights from a Novel fMRI Translational Paradigm.

Despite decades of preclinical investigation, there remains limited understanding of the etiology and biological underpinnings of anxiety disorders. Sensitivity to potential threat is characteristic of anxiety-like behavior in humans and rodents, but traditional rodent behavioral tasks aimed to assess threat responsiveness lack translational value, especially with regard to emotionally valenced stimuli. Therefore, development of novel preclinical approaches to serve as analogues to patient assessments is needed. In humans, the fearful face task is widely used to test responsiveness to socially communicated threat signals. In rats, ultrasonic vocalizations (USVs) are analogous social cues associated with positive or negative affective states that can elicit behavioral changes in the receiver. It is therefore likely that when rats hear aversive alarm call USVs (22 kHz), they evoke translatable changes in brain activity comparable with the fearful face task. We used functional magnetic resonance imaging in male and female rats to assess changes in BOLD activity induced by exposure to aversive 22 kHz alarm calls emitted in response to threatening stimuli, prosocial (55 kHz) USVs emitted in response to appetitive stimuli, or a computer-generated 22 kHz tone. Results show patterns of regional activation that are specific to each USV stimulus. Notably, limbic regions clinically relevant to psychiatric disorders (e.g., amygdala, bed nucleus of the stria terminalis) are preferentially activated by either aversive 22 kHz or appetitive 55 kHz USVs. These results support the use of USV playback as a promising translational tool to investigate affective processing under conditions of distal threat in preclinical rat models.

Direct and indirect effects of copepod grazers on community structure

Abstract Ecological theory and empirical research show that both direct lethal effects and indirect non-lethal effects can structure the composition of communities. While the direct effects of grazers on marine phytoplankton communities are well studied, their indirect effects are still poorly understood. Direct and indirect effects are inherently difficult to disentangle in plankton food webs. In this study we evaluate the indirect effects of copepod grazers on community function and structure using isolated chemical alarm signals, copepodamides. We expose intact summer and spring communities to direct grazing from copepods, or to chemical alarm cues without the presence of grazers in controlled experiments. The effects of direct grazing on ecosystem function were moderate in both experiments as indicated by levels of chlorophyll and primary production. Indirect and direct effects resulted in changes in the composition of both the eukaryote and prokaryote communities as shown by metabarcoding of 18S and 16S rRNA. Size structure analysis suggests that direct grazing and copepodamide exposure both favoured smaller organisms (< 10–15 μm) corroborating the size-structuring effect of copepod grazers. We conclude that the well-established effect of copepods on phytoplankton communities results from a combination of direct and indirect effects. This is a first attempt to isolate indirect effects of copepods on community structure and the results suggest that a full mechanistic understanding of the structuring effect of copepods will require insights to both direct and indirect effects of consumers as demonstrated for other ecosystems components.

Prevention, detection and management of adverse events of third-space endoscopy.

Third space endoscopy (TSE) or sub-mucosal endoscopy using a mucosal flap valve (SEMF) enables the endoscopist to operate in the deeper layers of the gastrointestinal tract or gain access to the mediastinal/peritoneal cavity for natural orifice transoral endoscopic surgery (NOTES). TSE procedures are essentially endoscopic surgical procedures with a variable learning curve. Adverse events (AEs) during TSE are specific and follow a certain pattern across the spectrum of TSE procedures. These can be broadly categorized according to either type of AE, time of presentation relative to the procedure or according to degree of severity. Three major categories of AEs encountered during TSE include insufflation related AEs, mucosal injuries (MIs) and bleeding. Other relevant AEs include infectious complications, aspiration pneumonia, post-procedural chest/abdominal pain, atelectasis, cardiac arrhythmias, pleural effusion and pulmonary embolism. Reported incidence of AEs during TSE procedures varies according to the type and complexity of procedure. Acquaintance regarding potential risk factors, technical tips and precautions, alarm signs for early recognition, assessment of degree of severity, morphological characterization of AEs and finally, expeditious selection of appropriate management strategy are crucial and imperative for successful clinical outcomes. The current review discusses the current evidence and practical guidelines for prevention, early detection and management of TSE-related AEs.

Context or arousal? Function of drumming in Mongolian gerbils (Meriones unguiculatus)

Drumming is a non-vocal auditory display producing airborne as well as seismic vibrations by tapping body extremities on a surface. It is mostly described as an alarm signal but is also discussed to signal dominance or mating quality. To clarify the function of drumming in Mongolian gerbils (Meriones unguiculatus), we compared the occurrence of drumming during predator, opposite-sex and same-sex encounters. We tested 48 captive Mongolian gerbils (Meriones unguiculatus) in three experiments. In predator experiments, subjects were exposed alone or with their cagemate to aerial and terrestrial predator dummies. In social encounter experiments, familiar and unfamiliar male–female dyads and same-sex dyads were confronted. For the same-sex encounters, a dominance index was calculated for each subject based on the number of won and lost conflicts. Drumming and drumming-call combinations were counted, and a multi-parametric sound analysis was performed. In all experiments drumming and drumming-call combinations occurred. In predator experiments, more subjects drummed when confronted with the predator stimulus than in the habituation phase. In social encounter experiments, more subjects drummed when facing an unfamiliar than a familiar conspecific. In addition, the accompanying call type and body posture of the sender differed between experiments. Thus, we suggest that whereas drumming signals an increased arousal state of the sender, the accompanying call type and the body posture signal context specific information.

Grasshoppers do not flee from their alarmed predators but from non-alarmed ones.

Alarm calls produced by basal prey have a well-known informative value. In multi-predator communities, mesopredators, when faced with top predators, may emit alarm calls that could inform basal prey about their lowered predation risk. To test this unexplored possibility, we conducted one field and one mesocosm experiment in which we simulated alarm and non-alarm calls from little owls (Athene noctua) as mesopredators and measured their effects on grasshoppers as prey of little owls but not of top predators. In the field experiment, we found that grasshopper species were significantly more abundant in patches where we simulated either the presence of scared little owls (alarm treatment) or no owls (control treatment) compared to patches where the presence of non-scared little owls (non-alarm treatment) was simulated. In the mesocosm experiment, locusts (Locusta migratoria) moved significantly more to exposed areas when we simulated the presence of scared little owls (alarm treatment) or of a granivorous bird (control treatment), while they moved to sheltered areas when we simulated the presence of non-scared owls (non-alarm treatment). These results show that prey could cue on predators' calls to assess their predation risk and make decisions, revealing unprecedented potential ecological consequences of alarm calls in invertebrate communities.

Alarm calls of sagebrush converge when herbivory is high.

Herbivory is a major threat to virtually all plants, so adaptations to avoid herbivory will generally be selected. One potential adaptation is the ability to 'listen in' on the volatile cues emitted by plants that are experiencing herbivory and to then respond by ramping up defences. The nature of these volatile cues is poorly understood. Sagebrush (Artemisia tridentata) plants that were exposed to cues of experimentally damaged neighbours experienced less herbivory; this induction was most effective if emitter and receiver plants had similar volatile emission profiles, termed chemotypes. Previously, we observed that sagebrush populations that were in locations with high herbivory exhibited little diversity of volatiles compared to populations with low herbivory. Several hypotheses could produce this correlation. High risk of herbivory could have selected for individuals that converged on a common 'alarm cue' that all individuals would respond to. In this case, individuals of locally rare chemotypes that were less able to eavesdrop would experience more damage than common chemotypes when herbivores were abundant. Alternatively, low chemotypic diversity could allow higher levels of damage to plants. In this case, rare chemotypes would experience less damage than common chemotypes. We examined the chemotypes of sagebrush individuals from multiple sites and found that rare chemotypes experienced more damage than common chemotypes when herbivores were abundant. This pattern was seen among sites and among years with different densities of herbivores. This result is consistent with the hypothesis that herbivory selects for individuals that are effective communicators and shapes the communication system.