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311.
Kimberly L. VanderWaal Edward R. Atwill Stacie Hooper Kelly Buckle Brenda McCowan 《Behavioral ecology and sociobiology》2013,67(12):1951-1959
Although pathogen transmission dynamics are profoundly affected by population social and spatial structure, few studies have empirically demonstrated the population-level implications of such structure in wildlife. In particular, epidemiological models predict that the extent to which contact patterns are clustered decreases a pathogen’s ability to spread throughout an entire population, but this effect has yet to be demonstrated in a natural population. Here, we use network analysis to examine patterns of transmission of an environmentally transmitted parasite, Cryptosporidium spp., in Belding’s ground squirrels (Spermophilus beldingi). We found that the prevalence of Cryptosporidium was negatively correlated with transitivity, a measure of network clustering, and positively correlated with the percentage of juvenile males. Additionally, network transitivity decreased when there were higher percentages of juvenile males; the exploratory behavior demonstrated by juvenile males may have altered the structure of the network by reducing clustering, and low clustering was associated with high prevalence. We suggest that juvenile males are critical in mediating the ability of Cryptosporidium to spread through colonies, and thus may function as “super-spreaders.” Our results demonstrate the utility of a network approach in quantifying mechanistically how differences in contact patterns may lead to system-level differences in infection patterns. 相似文献
312.
313.
Tuan T. Cao Kelly M. Hyland Alana Malechuk Lee A. Lewis Stanley S. Schneider 《Behavioral ecology and sociobiology》2009,63(4):521-529
Communication signals used in animal social interactions are frequently performed repetitively, but the function of this repetition
is often not well understood. We examined the effects of signal repetition by investigating the behavior of worker honey bees
that received differing numbers of vibration signals in established and newly founded colonies, which could use signal repetition
differently to help adjust task allocations to the labor demands associated with the different stages of colony development.
In both colony types, more than half of all monitored workers received more than one vibration signal, and approximately 12%
received ≥5 signals during a given 20-min observation period. Vibrated recipients exhibited greater activity and task performance
than same-age non-vibrated controls at all levels of signal activity. However, vibrated workers showed similar levels of task
performance, movement rates, cell inspection rates, and trophallactic exchanges regardless of the number of signals received.
Thus, the repeated performance of vibration signals on individual bees did not cause cumulative increases in the activity
of certain workers, but rather may have functioned to maintain relatively constant levels of activity and task performance
among groups of recipients. The established and newly founded colonies did not differ in the extent to which individual workers
received the different numbers of vibration signals or in the levels of activity stimulated by repeated signals. Previous
work has suggested that compared to established colonies, newly founded colonies have a greater number of vibrators that perform
signals on a greater proportion of the workers they contact. Taken in concert, these results suggest that vibration signal
repetition may help to adjust task allocations to the different stages of colony development by helping to maintain similar
levels of activity among a greater total number of recipients, rather than by eliciting cumulative effects that cause certain
recipients to work harder than others. 相似文献
314.
Phylogeny, niches, and relative abundance in natural communities 总被引:3,自引:0,他引:3
Community structure refers to the number of species in a community and the pattern of distribution of individuals among those species. We use a novel way of representing community structure to show that abundance within closely related pairs of co-occurring tree species in a highly diverse Mexican forest is more equitable than is abundance within more distantly related pairs. This observation is at odds with the fundamental assumption of neutral models of community structure, i.e., that species are interchangeable. The observed patterns suggest niche apportionment, in which interaction is focused pairwise between congeners but falls away from the phylogenetic structure above the genus level. Thus niche processes may significantly affect community structure through regulating relative abundance in a substantial proportion of species, which in turn potentially enhances community stability. One such mechanism of stable coexistence has already been shown to be active in this forest. 相似文献
315.
Widespread contribution of methane-cycle bacteria to the diets of lake profundal chironomid larvae 总被引:1,自引:0,他引:1
Reports of unexpectedly 13C-depleted chironomid larvae in lakes have led to an hypothesis that significant transfer of detrital organic matter to chironomid larvae may occur via methane-cycle bacteria. However, to date little is known of how such transfer might vary across species and lakes. We gathered data from 87 lakes to determine how widespread this phenomenon might be and to define boundaries for its likely magnitude. Carbon stable isotope values of chironomid larvae varied greatly between taxa. Very marked 13C-depletion was evident only in certain taxa, especially Chironomus plumosus, C. anthracinus, and C. tenuistylus, all characteristic of eutrophic or dystrophic lakes and known to be tolerant of low oxygen conditions. Furthermore, marked 13C-depletion was only found in larvae from lakes in which late-summer hypolimnetic oxygen depletion near the sediment surface was below an apparent threshold concentration of 2-4 mg O2/L. Similarly, application of a two-source mixing model suggested that methanotrophic bacteria made the greatest contribution to profundal chironomid growth (0-70% of larval carbon) when the late-summer oxygen concentration dropped below approximately 2 mg O2/L. Our study demonstrates that methane-derived carbon is an important, but often neglected, contribution to the flux of carbon through the food webs of many productive or dystrophic lakes. 相似文献
316.
Kelly M. Proffitt Robert A. Garrott Jay J. Rotella 《Behavioral ecology and sociobiology》2008,62(10):1679-1687
The Trivers–Willard model predicts that in polygynous species, superior-quality females will maximize their fitness by producing
male offspring. Using a sample of 1,780 Weddell seal (Leptonychotes weddellii) pups recorded over 31 years, we investigated relationships between offspring sex ratio and maternal age, reproductive experience,
an index of maternal lifetime reproductive output, and annual environmental variations. We found evidence that females with
higher index of lifetime reproductive output were more likely to produce male than female offspring but found only weak evidence
that large-scale environmental variations influenced sex ratios. Our results suggest that mothers manipulate offspring sex
to maximize their own fitness, and inherent maternal quality may influence offspring sex. These findings support the Trivers–Willard
sex-allocation model.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
317.
Francisco Luiza Flavia Veiga do Amaral Crispim Bruno Spósito Juliana Caroline Vivian Solórzano Julio César Jut Maran Nayara Halimy Kummrow Fábio do Nascimento Valter Aragão Montagner Cassiana Carolina De Oliveira Kelly Mari Pires Barufatti Alexeia 《Environmental science and pollution research international》2019,26(24):24581-24594
Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is... 相似文献
318.
319.
Peter Schlesinger Carlos L. Muñoz Brenes Kelly W. Jones Lee A. Vierling 《Journal of Land Use Science》2017,12(1):36-54
Strategic planning to increase forest cover in Central American transboundary areas of the Mesoamerican Biological Corridor requires understanding land-cover and land-use change trends and drivers. We estimated forest cover change from remotely sensed land-cover and land-use classifications from 1986, 2001, and 2010, in the tri-national Trifinio Region, bordering El Salvador, Guatemala, and Honduras. Our analysis spanned subnational, national, regional, and protected border areas. We determined correlations with direct drivers of deforestation, developing a multilevel linear regression model. Higher population density significantly correlated with deforestation; coffee, agroforestry, and pasture replaced forests. The tri-national park retained forests compared to neighboring areas, but additionality requires more research. The literature on drivers suggests similar processes and factors in other tropical regions. Forest cover governance efficacy is highly variable. Results indicate relationship between governance and forest cover though more comprehensive understanding of this complex region is needed to determine their causality. 相似文献
320.