Information use in anurans: how conspecifics and predators influence reproductive decisions

The choice of breeding habitat is integral to offspring survival and reproductive success, and can ultimately influence species distributions and population dynamics. Many factors are likely involved in location and evaluation of habitat, including biotic factors such as the presence of conspecifics and predators. Increasingly, organisms in a variety of taxa have been found to incorporate information on conspecifics and predators in their habitat selection decisions, but the degree to which this occurs in anuran amphibians is still not well-known. My research sought to first synthesize our current understanding of how conspecifics and predators influence reproductive decisions in anurans by reviewing the literature on this topic. Through experimental studies, I then examined how conspecific cues in the form of chorus sounds influenced breeding habitat selection in seven species of anurans (wood frog, Lithobates sylvaticus; Cope’s gray treefrog, Hyla chrysoscelis; American toad, Anaxyrus americanus; green frog, Lithobates clamitans; spring peeper, Pseudacris crucifer; Mexican spadefoot, Spea multiplicata; and Arizona treefrog, Hyla wrightorum). I then further examined how the presence of conflicting cues, in this case conspecific cues and predators, influenced breeding habitat selection in a single anuran species (western chorus frog, Pseudacris triseriata). A review of over 40 studies examining the influence of conspecifics, heterospecifics and/or predators on temperate and tropic anuran reproductive decisions found that in the majority of cases (75%), individuals avoid depositing offspring in sites with predators and conspecifics or heterospecifics. From my own experiments in Illinois, Indiana, and Arizona, I found that some species were attracted to breeding ponds with conspecific chorus sounds (Cope’s gray treefrog and Mexican spadefoot), while others showed weak or no response to conspecifics (wood frog, American toad, green frog, spring peeper, Arizona treefrog). Response was not predictably correlated with particular life history traits, but the tendency to breed in more seasonal or temporary ponds was a characteristic of the two species that did respond more strongly to conspecific cues. Regarding the influence of predator cues on breeding pond selection of western chorus frogs, chorus frogs exhibited predator avoidance at the Illinois field site but did not vary their behavior at the Indiana field site when presented with both predators and conspecific egg-mass cues. My results provide support for the idea that some species of anurans can and do use conspecific social information in locating and selecting breeding habitat, but that social information use may vary by breeding ecology, landscape matrix, and environmental characteristics

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Evaluation of Conspecific Attraction as a Management Tool across Several Species of Anurans

Amphibian populations are declining worldwide, with habitat loss and alteration being a primary driver of many declines. Management strategies to mitigate these declines include translocation and creation or restoration of breeding habitats, yet these techniques are not always effective. We examined whether conspecific attraction—a management tool frequently used in avian conservation—would be similarly valuable in management and conservation of anuran amphibians (i.e., frogs and toads). We broadcast conspecific chorus sounds at unoccupied, artificial breeding ponds for six anuran species across three field sites. We documented when frogs arrived at each pool and when eggs were laid. We compared differences in number of pools found with adults and egg masses between playback and control pools and examined latency to first colonization. We found that Mexican spadefoots colonized playback ponds faster and more often than control ponds, while Cope’s gray treefrogs, Arizona treefrogs, green frogs, spring peepers, and wood frogs exhibited weak or non-existent responses. We discuss why breeding ecology may influence tendency to exhibit conspecific attraction and how this behavior could be used in amphibian management and conservation