Search

Background Predators and fire shape ecosystems across the globe and these two forces can interact to impact prey populations. This issue is particularly pertinent in Australia where there is considerable scientific and public interest in the post-fire impacts of two invasive predators—the feral cat and red fox. It remains unclear, though, whether increased cat and fox activity in response to fire is a general phenomenon, or whether the responses are highly context-specific and not generalisable. Results We reviewed and analysed existing literature and found that a range of positive (e.g., increased activity in burnt areas), negative (decreased activity), and neutral responses have been recorded across different studies and locations. Mixed effects modelling revealed that positive responses to fire were more likely when areas were burnt more recently (shorter time since fire). The mean likelihood of increased activity by cats decreased from 41% at 0 months post-fire to 10% at 100 months post-fire, whereas the mean probability for foxes decreased from 53 to 10%. This suggests that there may be a critical time period immediately post-fire when prey are most vulnerable to elevated impacts of predators, and within which management interventions are likely to be most impactful. Conclusions Many of our findings can be identified as potential cases of either mechanistic or apparent context dependency (variation in recorded patterns due to observational and ecological factors). This provides a pathway for the design of future studies that will enhance our understanding of predator responses to fire, both in Australia and globally. Conservation policy and management will benefit from additional research spanning a greater range of ecosystems and fire events, along with a more comprehensive and nuanced interpretation of existing evidence.

[Background]: ‘Megafire’ is an emerging concept commonly used to describe fires that are extreme in terms of size, behaviour, and/or impacts, but the term’s meaning remains ambiguous. [Approach]: We sought to resolve ambiguity surrounding the meaning of ‘megafire’ by conducting a structured review of the use and definition of the term in several languages in the peer-reviewed scientific literature. We collated definitions and descriptions of megafire and identified criteria frequently invoked to define megafire. We recorded the size and location of megafires and mapped them to reveal global variation in the size of fires described as megafires. [Results]: We identified 109 studies that define the term ‘megafire’ or identify a megafire, with the term first appearing in the peer-reviewed literature in 2005. Seventy-one (~65%) of these studies attempted to describe or define the term. There was considerable variability in the criteria used to define megafire, although definitions of megafire based on fire size were most common. Megafire size thresholds varied geographically from > 100–100,000 ha, with fires > 10,000 ha the most common size threshold (41%, 18/44 studies). Definitions of megafire were most common from studies led by authors from North America (52%, 37/71). We recorded 137 instances from 84 studies where fires were reported as megafires, the vast majority (94%, 129/137) of which exceed 10,000 ha in size. Megafires occurred in a range of biomes, but were most frequently described in forested biomes (112/137, 82%), and usually described single ignition fires (59% 81/137). [Conclusion]: As Earth’s climate and ecosystems change, it is important that scientists can communicate trends in the occurrence of larger and more extreme fires with clarity. To overcome ambiguity, we suggest a definition of megafire as fires > 10,000 ha arising from single or multiple related ignition events. We introduce two additional terms – gigafire (> 100,000 ha) and terafire (> 1,000,000 ha) – for fires of an even larger scale than megafires., Threatened Species Recovery Hub; NSW Bushfire Risk Management Research Hub; Australian Wildlife Society; World Wildlife Fund

Applied ecology has traditionally approached management problems through a simplified, single-species lens. Repeated failures of single-species management have led us to a new paradigm - managing at the ecosystem level. Ecosystem management involves a complex array of interacting organisms, processes and scientific disciplines. Accounting for interactions, feedback loops and dependencies between ecosystem components is therefore fundamental to understanding and managing ecosystems. We provide an overview of the main types of ecosystem models and their uses, and discuss challenges related to modelling complex ecological systems. Existing modelling approaches typically attempt to do one or more of the following: describe and disentangle ecosystem components and interactions; make predictions about future ecosystem states; and inform decision making by comparing alternative strategies and identifying important uncertainties. Modelling ecosystems is challenging, particularly when balancing the desire to represent many components of an ecosystem with the limitations of available data and the modelling objective. Explicitly considering different forms of uncertainty is therefore a primary concern. We provide some recommended strategies (such as ensemble ecosystem models and multi-model approaches) to aid the explicit consideration of uncertainty while also meeting the challenges of modelling ecosystems.

Knowledge of how disturbances such as fire shape habitat structure and composition, and affect animal interactions, is fundamental to ecology and ecosystem management. Predators also exert strong effects on ecological communities, through top-down regulation of prey and competitors, which can result in trophic cascades. Despite their ubiquity, ecological importance and potential to interact with fire, our general understanding of how predators respond to fire remains poor, hampering ecosystem management. To address this important knowledge gap, we conducted a systematic review and meta-analysis of the effects of fire on terrestrial, vertebrate predators world-wide. We found 160 studies spanning 1978-2018. There were 36 studies with sufficient information for meta-analysis, from which we extracted 96 effect sizes (Hedges' g) for 67 predator species relating to changes in abundance indices, occupancy or resource selection in burned and unburned areas, or before and after fire. Studies spanned geographic locations, taxonomic families and study designs, but most were located in North America and Oceania (59% and 24%, respectively), and largely focussed on felids (24%) and canids (25%). Half (50%) of the studies reported responses to wildfire, and nearly one third concerned prescribed (management) fires. There were no clear, general responses of predators to fire, nor relationships with geographic area, biome or life-history traits (e.g. body mass, hunting strategy and diet). Responses varied considerably between species. Analysis of species for which at least three effect sizes had been reported in the literature revealed that red foxes Vulpes vulpes mostly responded positively to fire (e.g. higher abundance in burned compared to unburned areas) and eastern racers Coluber constrictor negatively, with variances overlapping zero only slightly for both species. Our systematic review and meta-analysis revealed strong variation in predator responses to fire, and major geographic and taxonomic knowledge gaps. Varied responses of predator species to fire likely depend on ecosystem context. Consistent reporting of ongoing monitoring and management experiments is required to improve understanding of the mechanisms driving predator responses to fire, and any broader effects (e.g. trophic interactions). The divergent responses of species in our study suggest that adaptive, context-specific management of predator-fire relationships is required.

Trophic interactions and disturbance events can shape the structure and function of ecosystems. However, the effects of drivers such as predation, fire and climatic variables on species distributions are rarely considered concurrently. We used a replicated landscape‐scale predator management experiment to compare the effects of red fox Vulpes vulpes control, time‐since‐fire, vegetation type and other environmental variables on native herbivore distributions. Occurrence data for four native herbivores and an invasive predator – the red fox – were collected from 240 sites across three baited (for lethal fox control) and three unbaited forest blocks (4659–9750 ha) in south‐western Victoria, Australia, and used to build species distribution models. The herbivore taxa were as follows: red‐necked wallaby Macropus rufogriseus, black wallaby Wallabia bicolour, grey kangaroo Macropus fuligenosus and Macropus giganteus and common brushtail possum Trichosurus vulpecula. Fox control and fire had little effect on herbivore occurrence, despite the literature suggesting it can influence abundance, while climate, proximity to farmland and topography were more influential. This may be because the region’s high productivity and agricultural pastures subsidise food resources for both predators and prey within the forest blocks and so dampen trophic interactions. Alternatively, these drivers may affect herbivore abundance, but not herbivore occurrence. Understanding the drivers of herbivore distributions is an important step in predicting the effects of herbivory on other species, particularly after management interventions such as predator control and prescribed burns.

Both fire and predators have strong influences on the population dynamics and behaviour of animals, and the effects of predators may either be strengthened or weakened by fire. However, knowledge of how fire drives or mediates predator-prey interactions is fragmented and has not been synthesised. Here, we review and synthesise knowledge of how fire influences predator and prey behaviour and interactions. We develop a conceptual model based on predator-prey theory and empirical examples to address four key questions: (i) how and why do predators respond to fire; (ii) how and why does prey vulnerability change post-fire; (iii) what mechanisms do prey use to reduce predation risk post-fire; and (iv) what are the outcomes of predator-fire interactions for prey populations? We then discuss these findings in the context of wildlife conservation and ecosystem management before outlining priorities for future research. Fire-induced changes in vegetation structure, resource availability, and animal behaviour influence predator-prey encounter rates, the amount of time prey are vulnerable during an encounter, and the conditional probability of prey death given an encounter. How a predator responds to fire depends on fire characteristics (e.g. season, severity), their hunting behaviour (ambush or pursuit predator), movement behaviour, territoriality, and intra-guild dynamics. Prey species that rely on habitat structure for avoiding predation often experience increased predation rates and lower survival in recently burnt areas. By contrast, some prey species benefit from the opening up of habitat after fire because it makes it easier to detect predators and to modify their behaviour appropriately. Reduced prey body condition after fire can increase predation risk either through impaired ability to escape predators, or increased need to forage in risky areas due to being energetically stressed. To reduce risk of predation in the post-fire environment, prey may change their habitat use, increase sheltering behaviour, change their movement behaviour, or use camouflage through cryptic colouring and background matching. Field experiments and population viability modelling show instances where fire either amplifies or does not amplify the impacts of predators on prey populations, and vice versa. In some instances, intense and sustained post-fire predation may lead to local extinctions of prey populations. Human disruption of fire regimes is impacting faunal communities, with consequences for predator and prey behaviour and population dynamics. Key areas for future research include: capturing data continuously before, during and after fires; teasing out the relative importance of changes in visibility and shelter availability in different contexts; documenting changes in acoustic and olfactory cues for both predators and prey; addressing taxonomic and geographic biases in the literature; and predicting and testing how changes in fire-regime characteristics reshape predator-prey interactions. Understanding and managing the consequences for predator-prey communities will be critical for effective ecosystem management and species conservation in this era of global change.

Biodiversity loss is driven by human behavior, but there is uncertainty about the effectiveness of behavior-change programs in delivering benefits to biodiversity. To demonstrate their value, the biodiversity benefits and cost-effectiveness of behavior changes that directly or indirectly affect biodiversity need to be quantified. We adapted a structured decision-making prioritization tool to determine the potential biodiversity benefits of behavior changes. As a case study, we examined two hypothetical behavior-change programs--wildlife gardening and cat containment--by asking experts to consider the behaviors associated with these programs that directly and indirectly affect biodiversity. We assessed benefits to southern brown bandicoot (Isoodon obesulus) and superb fairy-wren (Malurus cyaneus) by eliciting from experts estimates of the probability of each species persisting in the landscape given a range of behavior-change scenarios in which uptake of the behaviors varied. We then compared these estimates to a business-as-usual scenario to determine the relative biodiversity benefit and cost-effectiveness of each scenario. Experts projected that the behavior-change programs would benefit biodiversity and that benefits would rise with increasing uptake of the target behaviors. Biodiversity benefits were also predicted to accrue through indirect behaviors, although experts disagreed about the magnitude of additional benefit provided. Scenarios that combined the two behavior-change programs were estimated to provide the greatest benefits to species and be most cost-effective. Our method could be used in other contexts and potentially at different scales and advances the use of prioritization tools to guide conservation behavior-change programs.Proyección de los beneficios para la biodiversidad obtenidos de los programas de cambios de comportamiento de conservación Resumen La pérdida de la diversidad biológica es causada por el comportamiento humano, pero existe incertidumbre sobre la efectividad que tienen los programas de cambio de comportamiento para otorgar beneficios a la biodiversidad. Para demostrar el valor que poseen, los beneficios para la biodiversidad y la rentabilidad de los cambios de comportamiento que afectan directa o indirectamente a la biodiversidad necesitan ser cuantificados. Adaptamos una herramienta de priorización de toma de decisiones estructurada para determinar el potencial de los beneficios para la biodiversidad obtenidos de los cambios de comportamiento. Como estudio de caso, examinamos dos programas hipotéticos de cambio de comportamiento, la jardinería silvestre y la contención de gatos, mediante la petición a expertos de considerar los comportamientos asociados con estos programas que directa o indirectamente afectan a la biodiversidad. Evaluamos los beneficios para el bandicut café (Isoodon obeselus) y el reyezuelo supremo (Malurus cyaeneus) mediante la obtención de estimaciones de expertos de la probabilidad de que cada especie persista en el paisaje con una gama establecida de escenarios de cambios de comportamiento en los cuales la aceptación de los comportamientos varió. Después comparamos estas estimaciones con un escenario de situación normal para determinar el beneficio relativo para la biodiversidad y la rentabilidad de cada escenario. Los expertos proyectaron que los programas de cambio de comportamiento beneficiarían a la biodiversidad y que los beneficios aumentarían con la creciente aceptación de los comportamientos deseados. También se pronosticó que los beneficios se acumularían mediante comportamientos indirectos, aunque los expertos estuvieron en desacuerdo sobre la magnitud del beneficio adicional proporcionado. Se estimó que los escenarios que combinaron los dos programas de cambio de comportamiento proporcionarían el mayor beneficio para las especies y serían los más rentables. Nuestro método podría usarse en otros contextos y potencialmente a diferentes escalas y fomenta el uso de herramientas de priorización para orientar a los programas de cambios en el comportamiento de conservación.【摘要】人类行为驱动了生物多样性的丧失, 但通过行为改变项目使生物多样性获益的效果尚不明确。为证明行为改变项目的价值, 则需要定量评估直接或间接影响生物多样性的行为改变产生的生物多样性效益和成本效益。本研究采用一种结构化决策优先级工具, 确定了行为改变的潜在生物多样性效益。我们通过两个模拟的行为改变项目(野生动物园艺和家猫控制)作为案例研究, 要求专家评估与这些项目相关的直接及间接影响生物多样性的行为。我们通过向专家咨询在采取不同程度的行为改变所产生的一系列行为改变情景下每个物种在景观中续存的概率, 评估了行为改变对棕短鼻袋狸(Isoodon obesulus)和壮丽细尾鹩莺(Malurus cyaneus)的好处。接下来, 我们将这些估计情况与“一切照旧”的情景进行对比, 以确定每种情景的相对生物多样性效益和成本效益。根据专家预测, 行为改变项目将有益于生物多样性, 且随着人们对目标行为的接纳度增加, 生物多样性的效益也会提升。我们还预计生物多样性效益会通过间接行为得到累积, 尽管关于该额外效益程度的专家意见仍有分歧。此外, 我们估计在两种行为改变项目相结合的情景中, 物种获得的利益和成本效益都最高。我们的方法还可以用于其他背景或尺度, 以推动优先级工具在指导保护行为改变项目中的应用。【翻译: 胡怡思; 审校: 聂永刚】.

Threatened species managers are often required to make swift decisions in the face of considerable uncertainty. We tested a structured approach for evaluating conservation options for the critically endangered orange‐bellied parrot. The Orange‐bellied Parrot Recovery Team provides advice to government agencies to inform the allocation of a limited number of captive‐bred birds to different release scenarios. Using a structured expert elicitation approach, we determined that scenarios where more fledglings were released were more cost‐effective compared to other options. Following this finding in 2019, the recovery team adjusted plans and allocated additional birds to fledgling release, a response that contributed to an increase in wild birds migrating in 2020 and 2021. The challenges facing orange‐bellied parrot conservation, including limitations in animals, time and resources, and high uncertainty, are common for threatened species recovery programs. Here we show that a structured process can help managers grapple with these complex trade‐offs to make timely decisions.

Earth’s rapidly warming climate is propelling us towards an increasingly fire-prone future. Currently, knowledge of the extent and characteristics of animal mortality rates during fire remains rudimentary, hindering our ability to predict how animal populations may be impacted in the future. To address this knowledge gap, we conducted a global systematic review of the direct effects of fire on animal mortality rates, based on studies that unequivocally determined the fate of animals during fire. From 31 studies spanning 1984–2020, we extracted data on the direct impacts of fire on the mortality of 31 species from 23 families. From these studies, there were 43 instances where direct effects were measured by reporting animal survival from pre- to post-fire. Most studies were conducted in North America (52%) and Oceania (42%), focused largely on mammals (53%) and reptiles (30%), and reported mostly on animal survival in planned (82%) and/or low severity (70%) fires. We found no studies from Asia, Europe, or South America. Although there were insufficient data to conduct a formal meta-analysis, we tested the effect of fire type, fire severity, animal body mass, ecological attributes, and class on survival. Only fire severity affected animal mortality, with a higher proportion of animals being killed by high than low severity fires. Recent catastrophic fires across the globe have drawn attention to the plight of animals exposed to wildfire. Yet, our systematic review suggests that a relatively low proportion of animals (mean predicted mortality [95% CI] = 3% [1–9%]) are killed during fire. However, our review also underscores how little we currently know about the direct effects of fire on animal mortality, and highlights the critical need to understand the effects of high severity fire on animal populations.

The conservation profession is increasingly seeking effective ways to reduce societal impact on biodiversity, including through targeted behavior change interventions. Multiple conservation behavior change programs exist, but there is also great uncertainty regarding which behaviors are most strategic to target. Behavioral prioritization is a tool that has been used effectively to support behavior change decision‐making in other environmental disciplines and more recently for a small sub‐set of biodiversity behavior change challenges. Here, we use behavioral prioritization to identify individual behaviors that could be modified to achieve biodiversity benefits in the state of Victoria, Australia. We use an adapted nominal group technique method to identify potential biodiversity behaviors and, for each behavior, estimate the corresponding plasticity (or capacity for change) and positive impact on biodiversity outcomes. We elicited 27 behaviors that individuals could undertake to benefit or reduce their negative impact on biodiversity. This list was then used to prioritize 10 behaviors as determined by their likely effect(s) on biodiversity, plasticity, and current prevalence in Victoria. We take a first step in outlining a list of behaviors that can direct Victorian decision‐makers toward increasing positive and reducing negative impacts of society on biodiversity, guide motivated individuals to reduce their own biodiversity footprint, and more broadly, develop a behavior change research agenda for behaviors most likely to benefit biodiversity.

Citizen science can play an important role in school science education. Citizen science is particularly relevant to addressing current societal environmental sustainability challenges, as it engages the students directly with environmental science and gives students an understanding of the scientific process. In addition, it allows students to observe local representations of global challenges. Here, we report a citizen science programme designed to engage school‐age children in real‐world scientific research. The programme used standardized methods deployed across multiple schools through scientist–school partnerships to engage students with an important conservation problem: habitat for pollinator insects in urban environments. Citizen science programmes such as the programme presented here can be used to enhance scientific literacy and skills. Provided key challenges to maintain data quality are met, this approach is a powerful way to contribute valuable citizen science data for understudied, but ecologically important study systems, particularly in urban environments across broad geographical areas.

Feral cats (Felis catus) have devastated wildlife globally. In Australia, feral cats are implicated in most recent mammal extinctions and continue to threaten native species. Cat control is a high-profile priority for Australian policy, research and management. To develop the evidence-base to support this priority, we first review information on cat presence/absence on Australian islands and mainland cat-proof exclosures, finding that cats occur across >99.8% of Australia's land area. Next, we collate 91 site-based feral cat density estimates in Australia and examine the influence of environmental and geographic influences on density. We extrapolate from this analysis to estimate that the feral cat population in natural environments fluctuates between 1.4 million (95% confidence interval: 1.0–2.3 million) after continent-wide droughts, to 5.6 million (95% CI: 2.5–11 million) after extensive wet periods. We estimate another 0.7 million feral cats occur in Australia's highly modified environments (urban areas, rubbish dumps, intensive farms). Feral cat densities are higher on small islands than the mainland, but similar inside and outside conservation land. Mainland cats reach highest densities in arid/semi-arid areas after wet periods. Regional variation in cat densities corresponds closely with attrition rates for native mammal fauna. The overall population estimate for Australia's feral cats (in natural and highly modified environments), fluctuating between 2.1 and 6.3 million, is lower than previous estimates, and Australian feral cat densities are lower than reported for North America and Europe. Nevertheless, cats inflict severe impacts on Australian fauna, reflecting the sensitivity of Australia's native species to cats and reinforcing that policy, research and management to reduce their impacts is critical.

Applied ecology has traditionally approached management problems through a simplified, single-species lens. Repeated failures of single-species management have led us to a new paradigm - managing at the ecosystem level. Ecosystem management involves a complex array of interacting organisms, processes and scientific disciplines. Accounting for interactions, feedback loops and dependencies between ecosystem components is therefore fundamental to understanding and managing ecosystems. We provide an overview of the main types of ecosystem models and their uses, and discuss challenges related to modelling complex ecological systems. Existing modelling approaches typically attempt to do one or more of the following: describe and disentangle ecosystem components and interactions; make predictions about future ecosystem states; and inform decision making by comparing alternative strategies and identifying important uncertainties. Modelling ecosystems is challenging, particularly when balancing the desire to represent many components of an ecosystem with the limitations of available data and the modelling objective. Explicitly considering different forms of uncertainty is therefore a primary concern. We provide some recommended strategies (such as ensemble ecosystem models and multi-model approaches) to aid the explicit consideration of uncertainty while also meeting the challenges of modelling ecosystems.

Interactions between threatening processes and their effects on biodiversity are a major focus of ecological research and management. Threat interactions arise when threats or their effects co‐occur spatially and temporally. Whether the associations between threats are coincidental or causally linked is poorly understood, but has fundamental impacts on how, when and where threats should be managed. We propose that examining threat co‐occurrence, supplemented by experiments and triangulation of evidence, can help identify when and where threats interact causally, informing pressing biodiversity management goals. Using case studies, we demonstrate how co‐occurring and interacting threats can be visualized as networks (threat webs) and how this could guide conservation interventions at local, regional and global scales. Synthesis and applications. Recognizing that threats co‐occur and interact as networks, and are potentially driven by multiple agents (e.g. other threats, shared environmental drivers), helps us understand their dynamics and impacts on ecosystems. This greater understanding can help facilitate more targeted, efficient and effective environmental management.

A key challenge in conservation is the efficient allocation of limited resources to maximise benefits for biodiversity. Decision-support tools that account for landscape heterogeneity are needed to identify spatially-explicit actions that will achieve the greatest biodiversity benefits with available resources. We developed a raster-based, landscape-scale, spatial conservation action planning tool (SCAP) that offers significant advances for prioritising local and regional scale conservation actions in heterogenous landscapes. The SCAP tool was developed for the state of Victoria, Australia, to integrate heterogeneity of landscapes, species distributions, threats, and management costs and benefits across the state. We used empirical data to derive current and pre-European settlement distributions for 4400 native terrestrial species, and developed spatially explicit models of 19 threats to biodiversity. We coupled structured expert-elicitation techniques with machine learning to map the expected benefits to species, and the implementation costs, of 17 management actions – alone and in combination. We then ranked location-specific actions by their cost-effective contribution to an overall objective of minimizing the risk of species loss in Victoria over the next 50 years, using a modified implementation of the Zonation conservation planning framework. The SCAP tool provides decision makers with a transparent decision-support tool for identifying the cost-effective management actions at scales relevant to management.

The specificity of gonadotropin binding was studied in fresh and frozen human corpora lutea. Ovine, bovine, and porcine luteinizing hormone (LH) competed with 125 I-labeled human LH ( 125 I-hLH) and 125 I-labeled human chorionic gonadotropin ( 125 I-hCG) for binding to tissue receptors in homogenates of human corpora lutea frozen for 3 to 12months. In contrast, oLH, bLH, and pLH competed minimally for 125 I-hLH and 125 I-hCG binding sites in homogenates of fresh human corpora lutea. Ovine follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) did not compete in homogenates of fresh or frozen tissue. Competition of oLH and hCG for 125 I-hCG binding sites at several dose levels in a homogenate of a fresh corpus luteum was studied. One hundred micrograms of oLH and ten nanograms of hCG gave an equivalent competition—a 10,000-fold difference in competitive potency. Only hCG competed with 125 I-hCG for binding when the competition of oLH, bLH, pLH, oFSH, oTSH, hCG and hCG subunits, and hCG were compared at the 10-μg level in a homogenate of fresh human corpus luteum. The binding of 125 I-labeled homologous human hormones by the corpus luteum was examined in a limited fashion. 125 I-Prolactin did not bind to preparations of fresh stroma from a patient with polycystic ovaries nor did it bind to three separate preparations of fresh corpora lutea which did bind 125 I-hCG. 125 I-hTSH did not show significant binding to a fresh human corpus luteum preparation which did bind 125 I-hCG. These studies indicate that the gonadotropin receptor of the fresh human corpus luteum possesses a unique species specificity and illustrate the importance of working with human corpora lutea in their most native state.

Homogenates of human corpora lutea specifically bound 125 I-human luteinizing hormone (HLH). This binding was proportional to tissue (receptor) concentration and the receptor was saturable. Binding of 125 I-HLH was markedly reduced at 4° C. or in the presence of 10 I.U. human chorionic gonadotropin (HCG) or 2.4 I.U. of HLH (LER-907). LH from other species (ovine, bovine, and porcine) as well as other trophic hormones tested did not compete with 125 I-HLH. Specific binding of 125 I-ovine or 125 I-bovine LH could not be demonstrated. An apparent dissociation constant (Kd) of ∼3 and ∼9 × 10 −9 M was observed for two corpora lutea (Day 28 and Day 16) with lactoperoxidase labeled 125 I-HLH. In examining 125 I-HLH binding from over thirty corpora lutea from different times of the menstrual cycle, it was concluded that midluteal phase corpora lutea bound more 125 I-HLH than did older or younger corpora lutea. Day 14 corpora lutea and aged corpora lutea did not specifically bind 125 I-HLH. Ovarian stromal tissue failed to specifically bind 125 I-HLH, even when derived from ovaries that yielded corpora lutea which did bind 125 I-HLH. These results indicate that the human corpus luteum possesses a specific LH receptor. This receptor appears to require a conformation thus far found only in HLH and HCG.

• The diagnosis of pheochromocytoma during pregnancy has rarely been made correctly prior to delivery, only 42 cases having been reported. Antepartum diagnosis markedly decreases the maternal and fetal mortality. We report a case of pheochromocytoma manifesting during the third trimester of pregnancy. Preoperative control of blood pressure with phenoxybenzamine and phentolamine therapy was carried out. Simultaneous cesarean section and excision of the tumor resulted in a healthy mother and newborn infant. We review the perioperative and intraoperative management of patients with a pheochromocytoma during pregnancy. ( Arch Surg 115:1224-1225, 1980)