Biodiversity is declining at unprecedented rates worldwide due largely to land use change and abnormal disturbance events. The high species diversity and endemicity found in California’s coastal sage ...scrub (CSS) are especially at risk from urban development and ongoing disturbance. However, several CSS plant species have disturbance adaptations which may allow them to serve as vital resources for insect pollinators when native plant diversity is threatened. Common fiddleneck (Boraginaceae;
Amsinckia menziesii
var.
intermedia
) is one of the first annual forbs to germinate in CSS and as a result, it occurs in high density patches in early spring which temporarily creates a near monoculture. Although fiddleneck is a prominent CSS plant, particularly in areas that have experienced a disturbance event, its larger ecological role is not well explored. Therefore, we monitored ten sites across a disturbance gradient for two spring seasons to assess the composition of plant-pollinator networks in fiddleneck-dominated plots. We found fiddleneck supported a diverse pollinator community with 68% of recorded taxa visiting fiddleneck. The plants most frequently visited included two native annual forbs (common fiddleneck and
Phacelia distans)
and two invasive annual forbs (
Erodium cicutarium
and
Brassica tournefortii)
. Increased mean precipitation resulted in increased plant abundance but decreased native pollinator diversity. Additionally, plant-pollinator networks changed over time; the number of links per species increased throughout the season but did not differ among disturbance types. Despite the numerical dominance of fiddleneck, CSS supported a diversity of pollinator taxa and exhibited complex plant-pollinator networks across the disturbance gradient.
Hummingbirds utilize visual cues to locate flowers, but little is known about the role olfaction plays in nectar foraging despite observations that hummingbirds avoid resources occupied by certain ...insects. We investigated the behavioral responses of both wild and captive hummingbirds to olfactory cues of hymenopteran floral visitors, including native wood ants (
Formica francoeuri
), invasive Argentine ants (
Linepithema humile
), and European honeybees (
Apis mellifera
). We demonstrate for the first time that hummingbirds use olfaction to make foraging decisions when presented with insect-derived chemical cues under field and aviary conditions. Both wild and captive hummingbirds avoided foraging on feeders with defensive chemicals of
F. francoeuri
and aggregation pheromones of
L. humile
, but showed no response to honeybee cuticular hydrocarbons. Our experiments demonstrate the importance of olfaction in shaping hummingbird foraging decisions.
Significance statement
Recent reviews reveal that avian olfaction is not just limited to vultures and a few taxa. We demonstrate that a very charismatic group, hummingbirds, avoid defensive and aggregatory chemical cues from insects present at nectar resources. Olfactory cues can provide critical information about the presence and potential threat of insect floral visitors. This study raises new questions about the underrated importance of olfaction in avian foraging and specifically, hummingbird foraging.
To compare the accuracy of doppler ultrasound (DOP) and pulse oximeter plethysmography (POP) in the measurement of systolic arterial pressure (SAP) to invasive blood pressure (IBP) in anesthetized ...dogs.
40 client-owned healthy dogs > 10 kg.
Dogs were anesthetized for surgical procedures in dorsal recumbency. Invasive blood pressure was measured from a dorsal pedal artery. DOP and POP device probes were placed over the median caudal artery with a flow-occluding cuff for noninvasive blood pressure measurement. Systolic arterial pressure measured by DOP, loss of pulse oximeter plethysmograph (POPL), and return of pulse oximeter plethysmograph (POPR) were compared to SAP measured by IBP. A linear mixed model was used to determine correlation. Bland-Altman analyses were performed to determine bias, SD, and limits of agreement. The accuracy of DOP and POP was compared to IBP across different tensive states.
Conditional R2 values for DOP, POPL, and POPR versus IBP were 0.92, 0.85, and 0.87, respectively (all P < .001). The biases for DOP, POPL, and POPR compared to IBP were +7.6 ± 13.1, +3.9 ± 14.4, and +8.6 ± 15.2 mm Hg (bias ± SD), respectively. Limits of agreement (lower, upper) were (-18.1, +33.3), (-24.3, +32.1), and (-21.2, +38.4) mm Hg for DOP, POPL, and POPR, respectively. DOP and POP overestimated SAP during hypotension (SAP < 90 mm Hg), DOP to a lesser magnitude.
DOP measured from the median caudal artery may be acceptable for SAP measurement in dorsally recumbent, healthy anesthetized dogs > 10 kg. POP was determined an unacceptable method.
Summary
Corydalis pseudobarbisepala Fedde is described and illustrated. The species is at present known only from two mountains in west central Sichuan Province in the Republic of China, and has not ...been reported from its type location for 100 years.
We estimate hybridization rates among hummingbirds using nearly a million banding records from the United States and Canada. Annually from 2006 to 2019, an average of 44,600 individual hummingbirds ...and 14 hybrids were banded. Nearly all reports of hybrids come from localities west of the Mississippi, where multiple species breed in sympatry, whereas only Ruby-throated Hummingbird (Archilochus colubris) breeds east of the Mississippi. Adult male hybrids comprise 62% of all hybrids banded, a significantly greater fraction than “regular” adult males, which are 29% of all birds banded (excluding Ruby-throated Hummingbird). We infer that this excess of adult male hybrids is caused by ascertainment bias: banders more often misidentify female hybrids as parental species because females mostly lack species-specific showy sexual ornaments of male hummingbirds, making them harder to identify, rather than Haldane's rule of reduced survivorship of the heterogametic sex. Also influencing the apparent hybridization rate are banders, a few of whom seek out or avoid hybrids. After considering these biases, the data suggest that, in areas of the United States and Canada with >1 species, approximately 1 hummingbird in a thousand (0.1%) is an F1 hybrid. LAY SUMMARY Nearly a million hummingbirds have been banded in the United States and Canada since 1960. West of the Mississippi, roughly, 0.1% of wild hummingbirds are F1 hybrids. This estimate excludes birds from hybrid zones. More adult male hybrids are reported than adult female hybrids. This is due to ascertainment bias: banders misidentify hybrid females more often than hybrid males.
Social wasps play critical ecological roles in an ecosystem, providing a diversity of services and some disservices. Yellowjacket wasps (Vespula spp.) in particular are well known for shaping ...arthropod communities via predation and competition for resources. In part due to their sociality and large colony sizes, Vespula can have a profound ecological impact on local communities. Such effects can be magnified when colonies exhibit a perennial life history, in which a colony will overwinter, persist for more than one year, and become orders of magnitude larger in size compared to typical annual colonies. Despite growing interest in the factors that influence colony success, we currently lack the ability to predict when yellowjackets may have a high-abundance or outbreak year. This highlights the need for a critical understanding of the phenological patterns of foraging activity, colony distribution, and senescence. Here, we quantify the seasonal activity and foraging rates of 123 colonies of the western yellowjacket, V. pensylvanica, in its native range over 4 consecutive years. Average colony longevity was about 1 month longer than previously reported for this species, and colonies with later peaks in activity and higher average traffic rates persisted longer into the winter. Longer-lived colonies tended to cluster together within a year, but not between years. We found 3 perennial colonies (2.4% of all colonies), and they exhibited tenfold higher peak traffic rates compared to annual colonies. By identifying temporal and spatial patterns in survivorship and colony longevity, we gain insight into the factors associated with prolonged survival time and increased likelihood of overwintering in yellowjacket wasps.
Background Patients who exceed their expected length of stay in the hospital come at a cost to stakeholders in the healthcare sector as bed spaces are limited for new patients, nosocomial infections ...increase and the outcome for many patients is hampered due to multimorbidity after hospitalization. Objectives This paper develops a technique for predicting Extended Length of Hospital Stay (ELOHS) at preadmission and their risk factors using hospital data. Methods A total of 91,468 records of patient's hospital information from a private acute teaching hospital were used for developing a machine learning algorithm relaying on Recursive Feature Elimination with Cross-Validation and Extra Tree Classifier (RFECV-ETC). The study implemented Synthetic Minority Oversampling Technique (SMOTE) and tenfold cross-validation to determine the optimal features for predicting ELOHS while relying on multivariate Logistic Regression (LR) for computing the risk factors and the Relative Risk (RR) of ELOHS at a 95% confidence level. Results An estimated 11.54% of the patients have ELOHS, which increases with patient age as patients < 18 years, 18-40 years, 40-65 years and greater than or equal to 65 years, respectively, have 2.57%, 4.33%, 8.1%, and 15.18% ELOHS rates. The RFECV-ETC algorithm predicted preadmission ELOHS to an accuracy of 89.3%. Age is a predominant risk factors of ELOHS with patients who are > 90 years--PAG (> 90) {RR: 1.85 (1.34-2.56), P: < 0.001} having 6.23% and 23.3%, respectively, higher likelihood of ELOHS than patient 80-90 years old--PAG (80-90) {RR: 1.74 (1.34-2.38), P: < 0.001} and those 70-80 years old--PAG (70-80) {RR: 1.5 (1.1-2.05), P: 0.011}. Those from admission category--ADC (US1) {RR: 3.64 (3.09-4.28, P: < 0.001} are 14.8% and 70.5%, respectively, more prone to ELOHS compared to ADC (UC1) {RR: 3.17 (2.82-3.55), P: < 0.001} and ADC (EMG) {RR: 2.11 (1.93-2.31), P: < 0.001}. Patients from SES (low) {RR: 1.45 (1.24-1.71), P: < 0.001)} are 13.3% and 45% more susceptible to those from SES (middle) and SES (high). Admission type (ADT) such as AS2, M2, NEWS, S2 and others {RR: 1.37-2.77 (1.25-6.19), P: < 0.001} also have a high likelihood of contributing to ELOHS while the distance to hospital (DTH) {RR: 0.64-0.75 (0.56-0.82), P: < 0.001}, Charlson Score (CCI) {RR: 0.31-0.68 (0.22-0.99), P: < 0.001-0.043} and some VMO specialties {RR: 0.08-0.69 (0.03-0.98), P: < 0.001-0.035} have limited influence on ELOHS. Conclusions Relying on the preadmission assessment of ELOHS helps identify those patients who are susceptible to exceeding their expected length of stay on admission, thus, making it possible to improve patients' management and outcomes. Keywords: Extended length of hospital stay, Recursive feature elimination, Extra tree classifier, Multivariate logistic regression, Admission risk
Hummingbirds compete with other floral visitors for access to floral resources (nectar). Several hummingbird species, including Anna's (Calypte anna), Black-chinned (Archilochus alexandri), Allen's ...(Selasphorus sasin), and Costa's (Calypte costae) hummingbirds, make extensive use of non-native plants of urban areas of Southern California. Exploitation of urban ornamentals may expose hummingbirds to increased interactions with invasive Argentine ants (Linepithema humile), which are also frequently found foraging on flowers in such habitats. Here, we investigated the mechanisms by which hummingbirds interact with invasive ants at nectar resources in a series of aviary and wild experiments. When given a choice, hummingbirds avoided flowers and feeders with ants in or feeding at a sucrose solution. We identified specific ant-derived cues (visual, tactile, and gustatory) which are sufficient to elicit changes in bird foraging. Tactile and gustatory cues appeared to play the strongest role in mediating interactions with Argentine ants, with visual cues alone not enough to deter hummingbirds from feeding at sugar resources with ants. Our experiments provide support for interference competition at floral resources, where ants limit the birds' access to flowers and feeders.
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