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Longest Distance (longest + distance)
Selected AbstractsAssociations between host migration and the prevalence of a protozoan parasite in natural populations of adult monarch butterfliesECOLOGICAL ENTOMOLOGY, Issue 2 2000Sonia M. Altizer Summary 1. Monarch butterflies Danaus plexippus (L.) (Lepidoptera: Nymphalidae) are susceptible to infection by the obligate protozoan parasite Ophryocystis elektroscirrha (McLaughlin and Myers) (Apicomplexa: Neogregarinida). Because monarchs form resident and migratory populations in different parts of the world, this host,parasite system provides the opportunity to examine how variation in parasite prevalence relates to host movement patterns. 2. Parasite prevalence was evaluated using 14 790 adult monarchs captured between 1968 and 1997. Comparison of three populations in North America indicated that parasite prevalence is associated negatively with host dispersal distances. A continuously breeding, nonmigratory population in southern Florida showed high prevalence (over 70% heavily infected). The western population migrates moderate distances to overwintering sites on the Pacific Coast and has intermediate prevalence (30% heavily infected). The eastern migratory population, which travels the longest distance to Mexican overwintering sites, has exhibited less than 8% infection throughout the past 30 years. 3. Variation in parasite loads within North American migratory populations was investigated to determine whether the prevalence of heavy infection and average parasite loads declined during migration or overwintering. Average parasite loads of summer-breeding adults in western North America decreased with increasing distance from overwintering sites. This suggests that heavily infected monarchs are less likely to remigrate long distances in spring. No differences in the frequency of heavily infected adults were found among eastern or western North American monarchs throughout the overwintering period, however, suggesting that this parasite does not affect overwintering mortality. 4. Changes in the prevalence of monarchs with low parasite loads demonstrate that spore transfer occurs during migration and overwintering, possibly when adult butterflies contact each other as a result of their clustering behaviour. 5. This study of geographical and temporal variation in O. elektroscirrha among populations of D. plexippus demonstrates the potential role of seasonal migration in mediating interactions between hosts and parasites, and suggests several mechanisms through which migratory behaviour may influence parasite prevalence. [source] Determination of the optimal cut-off value for the [13C]-urea breath test based on a Helicobacter pylori -specific polymerase chain reaction assayJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2000Haruhiko Yoshida Abstract Background: This study was conducted to determine the optimal cut-off value and breath sample collection time for the [13C]-urea breath test based on the assessment of Helicobacter pylori status with a gastric juice-based polymerase chain reaction (PCR) assay. Methods and Results: A total of 104 patients took 100 mg [13C]-urea orally and breath samples were collected at 5, 10, 20, 30 and 60 min. The increment of 13CO2: 12CO2 ratio from the baseline (,13C) was measured using a laser spectroanalyser. The PCR assay was positive in 63 and negative in 41 patients. The optimal cut-off value of ,13C was calculated for each sample collection time so that the distance from the geometric mean value among Helicobacter pylori -positive patients and that from the arithmetic mean value among negative patients were simultaneously maximized. The cut-off value of 2.7, at 20 min had the longest distance, being separated by 3.16 SD from the two mean values. Using this cut-off value, the urea breath test showed 100% specificity and 98% sensitivity for the diagnosis of Helicobacter pylori infection. [source] Influence of day length, ambient temperature, and seasonality on daily travel distance in the Yunnan snub-nosed monkey at Jinsichang, Yunnan, ChinaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2009Ren Baoping Abstract This article examines the effect of ambient temperature, day length, weather conditions, and seasonality on daily path length (DPL) of a free-ranging group of Yunnan snub-nosed monkeys (Rhinopithecus bieti) using an auto-released GPS collar. Data were collected from December 17, 2003 to October 22, 2004 at Laojunshan in northwestern Yunnan province, China. The average DPL of the monkey group was 909±472,m (n=291), with the shortest distance being 180,m and the longest distance 3,626,m. Ambient temperature and day length were found to affect DPL. Both factors were positively correlated with DPL, which means that the monkey group traveled greater distances on longer and warmer days. At the study site, three distinct seasons were identified, and DPL did not vary significantly across these periods. The time of sunrise was not correlated with DPL. Nevertheless, we sometimes observed the group starting its daily trip later on cloudy days than on sunny days. Furthermore, weather conditions (e.g. rainy, cloudy, and sunny) did not influence the average DPL of the study group. Overall we found that the primary factors affecting DPL in R. bieti were day length and ambient temperature, especially daily highest temperature. Am. J. Primatol. 71:233,241, 2009. © 2008 Wiley-Liss, Inc. [source] Presupuesto de Tiempo del Chancho Cariblanco (Tayassu pecani) en un Bosque Húmedo de Costa Rica,BIOTROPICA, Issue 1 2002Mariana Altrichter ABSTRACT The diurnal time budget of four herds of white,lipped peccaries (Tayassu pecari) was studied using direct observation. The study took place from July 1996 to April 1997 in Corcovado National Park, southwestern Costa Rica. We predicted that time budget would be diagnostic of peccaries' welfare regarding food abundance. We considered that a decrease in time spent resting and in social interactions would be indicative of nutritional stress. Peccaries spent 34 percent (±1.7) of their daytime eating, 33 percent (±1.8) moving, 28 percent (±2.3) resting, 3 percent (±0.25) in social interactions, and 2.6 percent (±1.4) in other activities. The time spent resting decreased as the time spent moving and eating increased during the months of fruit scarcity. There were no differences among habitats in the proportion of time used for each activity. In the wet season, peccaries spent more time eating than in the dry season, probably because of the considerable time allocated to rooting. The monthly variation in time spent on social interactions and the frequency of agonistic interactions seemed to be related to breeding rather than fruit availability. While in the study area, peccaries traveled the longest distance in October, which coincided with the lowest fruit availability. In mid,November, the radio,marked herds left the study area and returned in January. Analyses of the peccaries' time budget suggest that fruit scarcity at die end of the wet season affected the peccaries' behavior and probably induced them to travel long distances in search of food. RESUMES Se estudió el presupuesto de tiempo diurno de cuatro manadas de chanchos cariblancos Tayassu pecari mediante observación directa desde Julio de 1996 hasta abril de 1997, en el Parque Nacional Corcovado, suroeste de Costa Rica. Se predijo que el presupuesto de tiempo puede ser usado como diagnóstico del bienestar de los chanchos en cuanto a abundancia de alimento, bajo el supuesto de que una disminución del tiempo invertido en el descanso y en las interacciones sociales seria indicativa de estres alimenticio. Los chanchos invirtieron 34 por ciento (±1.7) de su tiempo diurno en alimentación, 33 por ciento (±1.8) en desplazamiento, 28 por ciento (±2.3) en descanso, 3 por ciento (±0.2) en interacciones sociales y 2.6 por ciento (±1.4) en otras actividades. El tiempo dedicado al descanso disminuyó a medida que aumentaron las proporciones de tiempo dedicadas al desplazamiento y a la alimentación en los meses de menor disponibilidad de frutos. La proporción de tiempo usada para cada actividad no difirió signifi-cativamente entre los diferentes hábitats. En la época húmeda, los animales invirtieron más tiempo en la alimentación que en la época seca, probablemente debido a la gran proporción de tiempo que dedicaron a escarbar. La variación mensual del tiempo invertido en las interacciones sociales y la frecuencia de interacciones agonisticas se relacionaron mas con la época reproductiva que con la disponibilidad de frutos. Las distancias recorridas por los chanchos que pudieron medirse fueron mayores en octubre, coincidiendo con la menor disponibilidad de frutos. A mediados de noviembre las manadas marcadas dejaron el área de estudio y regresaron a principios de enero. El análisis del presupuesto de tiempo sugiere que la escasez de frutos al final de la época húmeda afecta el comportamiento de los chanchos y probablemente los incita a desplazarse distancias largas en busca de alimento. [source] | ||||||||||