Beaked whales respond to simulated and actual navy sonar

Beaked whales have mass stranded during some naval sonar exercises, but the cause is unknown. They are difficult to sight but can reliably be detected by listening for echolocation clicks produced during deep foraging dives. Listening for these clicks, we documented Blainville's beaked whales, Mesoplodon densirostris, in a naval underwater range where sonars are in regular use near Andros Island, Bahamas. An array of bottom-mounted hydrophones can detect beaked whales when they click anywhere within the range. We used two complementary methods to investigate behavioral responses of beaked whales to sonar: an opportunistic approach that monitored whale responses to multi-day naval exercises involving tactical mid-frequency sonars, and an experimental approach using playbacks of simulated sonar and control sounds to whales tagged with a device that records sound, movement, and orientation. Here we show that in both exposure conditions beaked whales stopped echolocating during deep foraging dives and moved away. During actual sonar exercises, beaked whales were primarily detected near the periphery of the range, on average 16 km away from the sonar transmissions. Once the exercise stopped, beaked whales gradually filled in the center of the range over 2-3 days. A satellite tagged whale moved outside the range during an exercise, returning over 2-3 days post-exercise. The experimental approach used tags to measure acoustic exposure and behavioral reactions of beaked whales to one controlled exposure each of simulated military sonar, killer whale calls, and band-limited noise. The beaked whales reacted to these three sound playbacks at sound pressure levels below 142 dB re 1 μPa by stopping echolocation followed by unusually long and slow ascents from their foraging dives. The combined results indicate similar disruption of foraging behavior and avoidance by beaked whales in the two different contexts, at exposures well below those used by regulators to define disturbance.     

N3-Arylmalonamides: A new series of thieno[3,2-b]pyridine based inhibitors of c-Met and VEGFR2 tyrosine kinases

A family of thieno[3,2-b]pyridine based small molecule inhibitors of c-Met and VEGFR2 were designed based on lead structure 2. These compounds were shown to have IC₅₀ values in the low nanomolar range in vitro and were efficacious in human tumor xenograft models in mice in vivo.     

A picornaviral loop-to-loop replication complex

Picornaviruses replicate their RNA genomes through a highly conserved mechanism that involves an interaction between the principal viral protease (3C^pro) and the 5′-UTR region of the viral genome. The 3C^pro catalytic site is the target of numerous replication inhibitors. This paper describes the first structural model of a complex between a picornaviral 3C^pro and a region of the 5′-UTR, stem-loop D (SLD). Using human rhinovirus as a model system, we have combined NMR contact information, small-angle X-ray scattering (SAXS) data, and previous mutagenesis results to determine the shape, position and relative orientation of the 3C^pro and SLD components. The results clearly identify a 1:1 binding stoichiometry, with pronounced loops from each molecule providing the key binding determinants for the interaction. Binding between SLD and 3C^pro induces structural changes in the proteolytic active site that is positioned on the opposite side of the protease relative to the RNA/protein interface, suggesting that subtle conformational changes affecting catalytic activity are relayed through the protein.     

Experimental field studies on predation and egg parasitism of rice brown planthopper in Indonesia

• 1 Egg parasitism and general predation are known to be important mortality factors in the population dynamics of rice brown planthopper (BPH) Nilaparvata lugens in tropical Asia, but previous studies have not attempted to quantify and compare them.
• 2 Field experiments in Java, Indonesia, are reported for 1993 and 1994. Plants previously infested with BPH eggs were put out in field cage‐enclosures, which, by means of different size mesh gauze covering, allowed either: (1) free access to all natural enemies, (2) access only to egg parasitoids, or (3) no access to any natural enemies.
• 3 After one BPH generation (30 days), numbers of adults and gravid females were counted for each treatment. In addition, plants were dissected to determine the numbers of eggs laid.
• 4 An additional treatment in which all natural enemies were excluded, but lycosid spiders were added, was used in 1994 experiments in an attempt to assess the effects of predators in the absence of egg parasitoids.
• 5 Numbers of BPH adults and eggs laid were highest when natural enemies were excluded and lowest when they had free access. Mortality due to egg parasitoids in the absence of predators was intermediate and significantly different to the two other treatments.
• 6 The effects of added predators in the absence of egg parasitoids gave variable results, but again clearly demonstrated the significance of egg parasitism in overall BPH mortality.
• 7 The conservation of BPH egg parasitoids should form an important element of any rice pest management programme in tropical Asia.

     

The palaearctic species ofBothriothorax (Hym., Encyrtidae) allied toB. paradoxus (Dalman)

Résumé Une espèce nouvelle deBothriothorax est décrite et une clef d'identification est donnée pour les espèces apparentées àB. paradoxus (Dalm.).      

Use of time‐at‐temperature data to describe dive behavior in five species of sympatric deep‐diving toothed whales

This paper develops and validates a method of using time‐at‐temperature (TAT) histograms from satellite transmitter tags to describe the dive activity patterns and approximate depth distributions of five deep‐diving toothed whale species in the northern Bahamas. TAT histograms represent a bandwidth‐conserving method of recovering a long‐term proxy record of dive activity. However, using temperature to interpret TAT on a scale of approximate depths required the complex estimation of TAT histogram bin boundary depths in a dynamic oceanographic region. Here we evaluated the relative performance of four interpolation methods and a global reanalysis data assimilation model in estimating climatological isotherm depth surfaces within our study area. TAT‐derived approximate time‐at‐depth (TAD) distributions aligned closely with directly observed TAD distributions from a smaller sample of depth‐recording satellite tags deployed on separate individuals of each species. TAT‐derived approximate depth distributions were also consistent with various published accounts for this suite of species. Estimating dive ranges and time budgets are important components of (1) understanding habitat overlap between species, (2) evaluating the potential role of these predators in meso‐ and bathypelagic ecosystems, and (3) assessing vulnerability and exposure to anthropogenic impacts.     

Developing indices of relative abundance for monitoring cave and ground wētā (Orthoptera) in southern beech forest,New Zealand

We sampled populations of forest-floor dwelling cave and ground wētā using footprint tracking tunnels and spotlight transect counts in southern beech forest, New Zealand. Samples were compared to estimates of wētā density based on mark–recapture estimates from 25?m² enclosures. Both activity indices captured variability in cave wētā in time and space, were strongly correlated with each other, and have the potential for monitoring cave wētā activity levels. Comparisons between indices and cave wētā density estimates were equivocal, as recapture rates were too low to calculate high-resolution density estimates. We also found that cave wētā counts had a curved relationship increasing with temperature, and a negative relationship with increasing shrub and woody debris cover. Based on these preliminary results, tracking tunnels could be a viable method of monitoring cave wētā as they appear more efficient than transect counts and are relatively inexpensive. However, further calibration trials are needed to determine if indices mirror robust population density estimates.     

Diversity and habitat relationships of hypogeous fungi. II. Factors influencing the occurrence and number of taxa

Fruit-bodies of hypogeous fungi were sampled over two seasons across 136 forested study sites representing a stratified sample of the climatic, geological and topographic features of far south-eastern mainland Australia. Two hundred and nine species, over three-quarters being undescribed, were recorded. Statistical models based on various environmental attributes measured for each site were developed for the occurrence of several common taxa. At a landscape scale, climatic factors such as mean minimum temperature of the coldest month and annual mean moisture index were important explanatory variables for most taxa examined, but the type of response varied. More locally, topographic position, soil fertility, time since last fire and micro-habitat structures such as the leaf litter layer and number of large fallen trees also influenced the distribution of taxa in different ways. A model was then developed for the number of fungal species occurring at each site. Important explanatory variables were type of substrate, topography and diversity of potential host eucalypt species. The utility of each model constructed needs evaluation by further sampling of hypogeous fungi. Possible implications of our findings for forest management are discussed. Further analyses of our existing data are also identified.