Describing predation patterns and especially estimating kill and consumption rates is essential for understanding the functional responses of predators. An understanding of the carrying capacity of ...the landscape, based on prey availability, also helps to formulate recovery plans for persecuted species. We studied the feeding behavior of the Persian leopard (Panthera pardus saxicolor) in Tandoureh National Park (355 km2) in northeastern Iran, near the Turkmenistan border. Between September 2014 and May 2017, we collared and monitored 6 adult leopards (5 males and 1 female) using GPS-satellite Iridium collars. We investigated 310 clusters of fixes as likely to be kill sites. In total, 130 kills were identified to species, suggesting a mean kill rate of approximately 3.3 ± 0.3 (SE) kills/month per adult male leopard, which is higher than reported by most previous studies. The leopards varied considerably in the time they spent outside the national park; only 1 individual appeared to subsist mainly by raiding livestock. The availability of medium-sized ungulates at adequate densities is likely to be important for future leopard conservation efforts. The management of problem individuals also may promote coexistence of humans and leopards, even in prey-rich areas.
The fear induced by predators on their prey is well known to cause behavioural adjustments by prey that can ripple through food webs. Little is known, however, about the analogous impacts of humans ...as perceived top predators on the foraging behaviour of carnivores. Here, we investigate the influence of human-induced fear on puma foraging behaviour using location and prey consumption data from 30 tagged individuals living along a gradient of human development. We observed strong behavioural responses by female pumas to human development, whereby their fidelity to kill sites and overall consumption time of prey declined with increasing housing density by 36 and 42%, respectively. Females responded to this decline in prey consumption time by increasing the number of deer they killed in high housing density areas by 36% over what they killed in areas with little residential development. The loss of food from declines in prey consumption time paired with increases in energetic costs associated with killing more prey may have consequences for puma populations, particularly with regard to reproductive success. In addition, greater carcass availability is likely to alter community dynamics by augmenting food resources for scavengers. In light of the extensive and growing impact of habitat modification, our study emphasizes that knowledge of the indirect effects of human activity on animal behaviour is a necessary component in understanding anthropogenic impacts on community dynamics and food web function.
(F.) (Diptera: Syrphidae) is the most abundant syrphid fly which is distributed worldwide and is the sole predator of aphids. Therefore, the present study was conducted to evaluate the predation rate ...and functional response of
against the cabbage aphid,
(L.). The experiment was carried out under laboratory conditions at 25 ± 2°C with 60-70% relative humidity. The results revealed that age-specific net predation rate (
) increased after the 4th day and a peak was recorded on the 10th day of pivotal age in the third larval instar. The stable host kill rate and finite host kill rate of
were 18.63 and 21.07, respectively, against the
and predicted that a mean of 20.78 aphids was needed for
to produce one offspring. A negative linear coefficient (
< 0) indicated the type II functional response for all larval instars of
against the
. At higher prey density, the prey consumption was significantly at par with second and third instar larvae of
as the prey consumption was increased with increasing the prey density, which then decreased after attaining the upper asymptote (76.40 and 81.40% consumption, respectively). The Roger's predator random equation for type II functional response was fitted to estimate attack rate (
) and handling time (
). The maximum prey consumption was recorded for third instar of
with a higher attack rate (0.336 h
) and lower handling time (0.514 h) against
, followed by the second and first instar. Thus, it is concluded that the third larval instar of
was the voracious feeder and used as an efficient biocontrol agent in the IPM programme.
Mycoplasma gallisepticum is one of the most important pathogens that cause chronic respiratory disease in chicken. This study investigated the antibacterial activity of doxycycline against M. ...gallisepticum strain S6. In static time-killing studies with constant antibiotic concentrations 0-64 minimum inhibitory concentration (MIC), M. gallisepticum colonies were quantified and kill rates were calculated to estimate the drug effect. The half-life of doxycycline in chicken was 6.51 ± 0.63 h. An in vitro dynamic model (the drug concentrations are fluctuant) was also established and two half-lives of 6.51 and 12 h were simulated. The samples were collected for drug concentration determination and viable counting of M. gallisepticum. In static time-killing studies, doxycycline produced a maximum antimycoplasmal effect of 5.62log10 (CFU/mL) reduction and the maximum kill rate was 0.11 h(-1). In the in vitro dynamic model, doxycycline had a mycoplasmacidal activity in the two regimens, and the maximum antimycoplasmal effects were 4.1 and 4.75log10 (CFU/mL) reduction, respectively. Furthermore, the cumulative percentage of time over a 48-h period that the drug concentration exceeds the MIC (%T > MIC) was the pharmacokinetic-pharmacodynamic index that best correlated with antimicrobial efficacy (R (2) = 0.986, compared with 0.897 for the peak level divided by the MIC and 0.953 for the area under the concentration-time curve over 48 h divided by the MIC). The estimated %T > MIC values for 0log10 (CFU/mL) reduction, 2log10 (CFU/mL) reduction and 3log10 (CFU/mL) reduction were 32.48, 45.68, and 54.36%, respectively, during 48 h treatment period of doxycycline. In conclusion, doxycycline shows excellent effectiveness and time-dependent characteristics against M. gallisepticum strain S6 in vitro. Additionally, these results will guide optimal dosing strategies of doxycycline in M. gallisepticum infection.
•Snow leopards chose wild ungulates even in landscapes dominated by livestock.•Snow leopards appeared to kill livestock opportunistically.•Adult males killed more livestock and were more vulnerable ...to retaliatory killing.•Avoiding rugged pastures and minimizing stragglers will reduce livestock losses.•Snow leopards removed much more prey than previous estimates of kill rates suggest.
Livestock predation is an important cause of endangerment of the snow leopard (Panthera uncia) across its range. Yet, detailed information on individual and spatio-temporal variation in predation patterns of snow leopards and their kill rates of livestock and wild ungulates are lacking.
We collared 19 snow leopards in the Tost Mountains, Mongolia, and searched clusters of GPS positions to identify prey remains and estimate kill rate and prey choice.
Snow leopards killed, on average, one ungulate every 8days, which included more wild prey (73%) than livestock (27%), despite livestock abundance being at least one order of magnitude higher. Predation on herded livestock occurred mainly on stragglers and in rugged areas where animals are out of sight of herders. The two wild ungulates, ibex (Capra ibex) and argali (Ovis ammon), were killed in proportion to their relative abundance. Predation patterns changed with spatial (wild ungulates) and seasonal (livestock) changes in prey abundance. Adult male snow leopards killed larger prey and 2–6 times more livestock compared to females and young males. Kill rates were considerably higher than previous scat-based estimates, and kill rates of females were higher than kill rates of males. We suggest that (i) snow leopards prey largely on wild ungulates and kill livestock opportunistically, (ii) retaliatory killing by livestock herders is likely to cause greater mortality of adult male snow leopards compared to females and young males, and (iii) total off-take of prey by a snow leopard population is likely to be much higher than previous estimates suggest.
Multi-channel defect detection in epitaxial SiC layers is used to detect and classify various extended defects. The effects of the killer defect category are analyzed on hundreds of production diode ...and MOSFET wafers. Invariably, the number of these killer defects sets the yield entitlement for each wafer, and electrically, they fall into a few expected failure bins depending on their position on the die. A variety of non-killer defects like Bar Stacking Faults (BSFs), V-type defects, isolated micro-pipe related bumps, stacking faults, scratches and deep pits are identified in over thousand die each, and their effect on fully fabricated diode and MOSFET products are determined at wafer sort. A very high percentage of the die containing these non-killer defects pass all electrical tests including the rigorous Unclamped Inductive Switching (UIS) testing. Specifically, a population of electrically passing die, containing BSFs, are identified and packaged for High Temperature Reverse Bias (HTRB) tests. Every BSF containing die passes both forward and reverse 1000-hour HTRB drift tests.
Abstract
Mexican gray wolf (
Canis lupus baileyi
) reintroduction began in 1998 in Arizona, USA, with 11 individuals initially; wolves from this population dispersed into New Mexico, USA, the ...following year. Numbers of wolves have steadily increased (≥241 individuals in Dec 2022) and the size of the recovery area has expanded in both states. Understanding kill rates is fundamental to the recovery and management of Mexican wolves to properly maintain a healthy and sustainable population of wolves and their prey species. We used global positioning system (GPS) cluster analysis to locate kill sites and estimate kill rates on native ungulate prey taken in the recovery area by 10 Mexican wolf groups during winter (15 Feb–15 Mar) and 8 wolf groups during summer (15 Jun–15 Jul) in 2015–2017. Elk (
Cervus canadensis
) composed 94% of the native ungulates documented at Mexican wolf kill sites (
n
= 139); the remaining 6% were mule deer (
Odocoileus hemionus; n
= 9). Two‐thirds of all wolf‐killed native ungulates were elk calves. We estimated kill rates as ungulate biomass killed/wolf/day. From combined results for all years, we estimated that each Mexican wolf killed on average 9.0 ± 5.4 kg (±95% CI) of ungulate biomass per day during winter and 7.8 ± 6.2 kg during the summer. Our estimates of kill rates could be overestimated if Mexican wolves obtained a substantial amount of their biomass from scavenging, particularly during 4 months of hunting seasons (Sep–Dec) not captured in winter and summer. Using data from the first 2 years of the study (2015, 2016), we developed a logistic regression model to predict probability of an elk kill occurring at a GPS cluster as a function of hours spent by a collared wolf at that GPS cluster and size of the wolf group. Applying this model to the final year of the study (2017) resulted in similar numbers of predicted (
n
= 16.1 and 27.2 in winter and summer, respectively) and observed numbers (
n
= 15 and 26) of elk kills. Additionally, the demographic composition of the 2017 elk kills closely matched that of the previous 2 years. The results of this study indicate similar predation patterns of Mexican wolves to those of wolves in northern locations and can help wildlife managers plan for potential effects from a larger population of wolves across a broad area in Arizona and New Mexico.
This study was conducted to generate basic pharmacodynamic information on the relationship between antibiotic concentrations and the growth of rapidly growing mycobacteria (RGM), and thereby ...contribute to a better understanding of current and future drug regimens for diseases caused by RGM.
Type strains of Mycobacterium abscessus and Mycobacterium fortuitum were used; the MICs of cefoxitin, amikacin, moxifloxacin, linezolid and clarithromycin were determined by broth microdilution. Time-kill assays were performed, exposing the bacteria to 2-fold concentrations from 0.25 to 32 times the MIC at 30°C for 120 h. The sigmoid maximum effect (Emax) model was fitted to the time-kill curves data.
The highest killing of M. abscessus was observed between 24 and 72 h; amikacin had the highest Emax (0.0427 h(-1)), followed by clarithromycin (0.0231 h(-1)) and cefoxitin (0.0142 h(-1)). For M. fortuitum, between 3 and 24 h, amikacin also showed the highest Emax (0.1933 h(-1)). There were no significant differences between the Hill's slopes determined for all the antibiotics tested against M. abscessus or M. fortuitum (P = 0.2213 and P = 0.2696, respectively).
The total effect observed for all antibiotics was low and primarily determined by the Emax and not by the Hill's slope. The limited activity detected fits well with the poor outcome of antibiotic treatment for disease caused by RGM, particularly for M. abscessus. An evaluation of drug combinations will be the next step in understanding and improving current treatment standards.
Understanding the ecological roles of species that influence ecosystem processes is a central goal of ecology and conservation biology. Eastern coyotes (Canis latrans) have ascended to the role of ...apex predator across much of eastern North America since the extirpation of wolves (Canis spp.) and there has been considerable confusion regarding their ability to prey on ungulates and their ecological niche relative to wolves. Eastern wolves (C. lycaon) are thought to have been the historical top predator in eastern deciduous forests and have previously been characterized as deer specialists that are inefficient predators of moose because of their smaller size relative to gray wolves (C. lupus). We investigated intrinsic and extrinsic influences on per capita kill rates of white-tailed deer (Odocoileus virginianus) and moose (Alces alces) during winter by sympatric packs of eastern coyotes, eastern wolves, and admixed canids in Ontario, Canada to clarify the predatory ability and ecological roles of the different canid top predators of eastern North America. Eastern coyote ancestry within packs negatively influenced per capita total ungulate (deer and moose combined) and moose kill rates. Furthermore, canids in packs dominated by eastern coyote ancestry consumed significantly less ungulate biomass and more anthropogenic food than packs dominated by wolf ancestry. Similar to gray wolves in previous studies, eastern wolves preyed on deer where they were available. However, in areas were deer were scarce, eastern wolves killed moose at rates similar to those previously documented for gray wolves at comparable moose densities across North America. Eastern coyotes are effective deer predators, but their dietary flexibility and low kill rates on moose suggest they have not replaced the ecological role of wolves in eastern North America.
PDF
