Consequences of toxic secondary compounds in nectar for mutualist bees and antagonist butterflies

Attraction of mutualists and defense against antagonists are critical challenges for most organisms and can be especially acute for plants with pollinating and non?pollinating flower visitors. Secondary compounds in flowers have been hypothesized to adaptively mediate attraction of mutualists and defense against antagonists, but this hypothesis has rarely been tested. The tissues of milkweeds (Asclepias spp.) contain toxic cardenolides that have long been studied as chemical defenses against herbivores. Milkweed nectar also contains cardenolides, and we have examined the impact of manipulating cardenolides in nectar on the foraging choices of two flower visitors: generalist bumble bees, Bombus impatiens, which are mutualistic pollinators, and specialist monarch butterflies, Danaus plexippus, which are herbivores as larvae and ineffective pollinators as adults. Although individual bumble bees in single foraging bouts showed no avoidance of cardenolides at the highest natural concentrations reported for milkweeds, a pattern of deterrence did arise when entire colonies were allowed to forage for several days. Monarch butterflies were not deterred by the presence of cardenolides in nectar when foraging from flowers, but laid fewer eggs on plants paired with cardenolide?laced flowers compared to controls. Thus, although deterrence of bumble bees by cardenolides may only occur after extensive foraging, a primary effect of nectar cardenolides appears to be reduction of monarch butterfly oviposition.The Templeton Foundation and National Science Foundation DEB-1513839 provided financial support

The Effects of Host Plant Species and Plant Quality on Growth and Development in the Meadow Spittlebug (Philaenus spumarius) on Kent Island in the Bay of Fundy

Philaenus spumarius (Meadow Spittlebug, Homoptera: Cercopoidea) is a cosmopolitan generalist insect that feeds on a wide repertoire of host plants in the field. We studied density and growth of Meadow Spittlebugs on a range of host plants on Kent Island, a boreal island in the Bay of Fundy, NB, Canada. The highest spittlebug densities were on Cirsium arvense (Canadian Thistle), although spittlebugs had larger body sizes on Solidago rugosa (Rough-stemmed Goldenrod) and Anaphalis margaritacea (Pearly Everlasting). We fertilized plots of Rough-stemmed Goldenrod in the field over 3 weeks to examine the effects of plant quality on development of Meadow Spittlebugs. Following fertilization, there were fewer nymphs present in fertilized plots than in unfertilized plots, indicating faster nymph maturation to adulthood on fertilized plants. This study offers an initial report of the host plants used by Meadow Spittlebugs in northeastern boreal habitat, variation in density and performance of the species on a range of host plants, and the effects of plant fertilization on spittlebug life history

Self-management : keeping it simple with “Flo”

Background: Living with and managing a long-term condition are complex processes that are further compounded by a range of medical and psychosocial factors. The size and scale of long-term conditions in the UK is vast, with strategic drivers seeking to find innovative ways to managing this problem. Methods: This project introduced Simple Telehealth “Florence,” a software-based short message service texting system to monitor a variety of conditions, such as diabetes, hypertension, and wounds, initially in one region of the East Midlands, England, UK. This article discusses the findings from our patient and staff evaluations of using the system. In total, 37 patients across four conditions, diabetes, chronic obstructive pulmonary disease, hypertension, and Asperger’s syndrome, evaluated the study and this exercise involved 33 nurses in teams across three locations over a 6-month period. Evaluation was made using a simple, self-completed questionnaire and analysis of qualitative comments. Results: The majority of patients find the service easy to use, reassuring, and reducing the number of contacts they had with their doctor. The results also show that staff did notice a reduction in consultation time, highlighting the potential of the system to save time; the majority viewed it as a support to existing approaches aimed at the management of long-term conditions. Discussion: This study adds to the growing body of evidence that supports community nurses through the use of innovative ways to assess, support, and monitor long-term conditions. It also offers insight into the experience of patients and staff working together in one region of England, UK. Recommendations: Embedding Simple Telehealth “Florence” as an option within primary care services in the UK is hereby proposed. This would add to the range of options and therapeutic approaches available through modern Telehealth. Keywords: self-management, simple telehealth, Flo, patient experience, community nurs

When to approach novel prey cues? Social learning strategies in frog-eating bats

Animals can use different sources of information when making decisions. Foraging animals often have access to both self-acquired and socially acquired information about prey. The fringe-lipped bat, Trachops cirrhosus, hunts frogs by approaching the calls that frogs produce to attract mates.We examined howthe reliability of self-acquired prey cues affects social learning of novel prey cues. We trained bats to associate an artificial acoustic cue (mobile phone ringtone) with food rewards. Bats were assigned to treatments in which the trained cue was either an unreliable indicator of reward (rewarded 50% of the presentations) or a reliable indicator (rewarded 100% of the presentations), and they were exposed to a conspecific tutor foraging on a reliable (rewarded 100%) novel cue or to the novel cue with no tutor. Bats whose trained cue was unreliable and who had a tutor were significantly more likely to preferentially approach the novel cue when compared with bats whose trained cue was reliable, and to bats that had no tutor. Reliability of self-acquired prey cues therefore affects social learning of novel prey cues by frog-eating bats. Examining when animals use social information to learn about novel prey is key to understanding the social transmission of foraging innovations. © 2013 The Author(s) Published by the Royal Society

Controls on the Silicon Isotope Composition of Diatoms in the Peruvian Upwelling

The upwelling area off Peru is characterized by exceptionally high rates of primary productivity, mainly dominated by diatoms, which require dissolved silicic acid (dSi) to construct their frustules. The silicon isotope compositions of dissolved silicic acid (δ 30 Si dSi ) and biogenic silica (δ 30 Si bSi ) in the ocean carry information about dSi utilization, dissolution, and water mass mixing. Diatoms are preserved in the underlying sediments and can serve as archives for past nutrient conditions. However, the factors influencing the Si isotope fractionation between diatoms and seawater are not fully understood. More δ 30 Si bSi data in today’s ocean are required to validate and improve the understanding of paleo records. Here, we present the first δ 30 Si bSi data (together with δ 30 Si dSi ) from the water column in the Peruvian Upwelling region. Samples were taken under strong upwelling conditions and the bSi collected from seawater consisted of more than 98% diatoms. The δ 30 Si dSi signatures in the surface waters were higher (+1.7‰ to +3.0‰) than δ 30 Si bSi (+1.0‰ to +2‰) with offsets between diatoms and seawater (Δ 30 Si) ranging from −0.4‰ to −1.0‰. In contrast, δ 30 Si dSi and δ 30 Si bSi signatures were similar in the subsurface waters of the oxygen minimum zone (OMZ) as a consequence of a decrease in δ 30 Si dSi . A strong relationship between δ 30 Si bSi and [dSi] in surface water samples supports that dSi utilization of the available pool (70 and 98%) is the main driver controlling δ 30 Si bSi . A comparison of δ 30 Si bSi samples from the water column and from underlying core-top sediments (δ 30 Si bSi_ sed. ) in the central upwelling region off Peru (10°S and 15°S) showed good agreement (δ 30 Si bSi_ sed. = +0.9‰ to +1.7‰), although we observed small differences in δ 30 Si bSi depending on the diatom size fraction and diatom assemblage. A detailed analysis of the diatom assemblages highlights apparent variability in fractionation among taxa that has to be taken into account when using δ 30 Si bSi data as a paleo proxy for the reconstruction of dSi utilization in the region

Nonresponse Error in Mail Surveys: Top Ten Problems

Conducting mail surveys can result in nonresponse error, which occurs when the potential participant is unwilling to participate or impossible to contact. Nonresponse can result in a reduction in precision of the study and may bias results. The purpose of this paper is to describe and make readers aware of a top ten list of mailed survey problems affecting the response rate encountered over time with different research projects, while utilizing the Dillman Total Design Method. Ten nonresponse error problems were identified, such as inserter machine gets sequence out of order, capitalization in databases, and mailing discarded by postal service. These ten mishaps can potentiate nonresponse errors, but there are ways to minimize their frequency. Suggestions offered stem from our own experiences during research projects. Our goal is to increase researchers' knowledge of nonresponse error problems and to offer solutions which can decrease nonresponse error in future projects

Controls on Dissolved Silicon Isotopes along the US GEOTRACES Eastern Pacific Zonal Transect (GP16)

The distribution of dissolved silicon isotopes (δ30Si) was examined along the US GEOTRACES East Pacific Zonal Transect (GP16) extending from Peru to Tahiti (10°S and 15°S latitude). Surface waters in the subtropical gyre displayed high δ30Si due to strong utilization of silicic acid (DSi). In contrast, surface waters close to the Peruvian coast where upwelling prevailed were less depleted and only moderately fractionated. δ30Si of water masses along the transect were compared with the results of an Optimum Multiparameter Analysis that quantified the fractional contributions of endmember water masses in each sample. Strong admixture of intermediate waters obscured the expected heavy isotopic signatures of Subantarctic Mode Water and Antarctic Intermediate Water. Isotope values were nearly homogenous below 2000 m (Average: +1.3 ± 0.1 ‰, 1 s.d.) despite the 25 μmol kg‐1 range in the DSi content among water masses. This homogeneity confirms prior observations and model results that predict nearly constant δ30Si values of +1.0 to +1.2 ‰ for Pacific deep waters with [DSi] > 100 μmol kg‐1. Waters above the East Pacific Rise (EPR) influenced by hydrothermal activity showed a small increase in [DSi] together with dissolved iron, but overall stations close to the EPR were slightly depleted in [DSi] (3 to 6 μmol kg‐1) with no significant shift in δ30Si compared to adjacent waters. Hydrothermal [DSi] appears to precipitate within the conduit of the EPR or upon contact with cold seawater resulting in a negligible influence of hydrothermal fluids on δ30Si in deep water. Key Points Surface waters have a large range in dissolved silicon isotopes covering nutrient‐rich coastal upwelling to oligotrophic waters Deep water masses with DSi concentrations > 100 μmol kg‐1 show homogenous silicon isotope signatures despite up to 25 μmol kg‐1 differences in [DSi] Hydrothermal fluids have a negligible effect on Si isotope distributions in the deep Pacifi

Spontaneous Discharge Patterns in Cochlear Spiral Ganglion Cells Prior to the Onset of Hearing in Cats

Spontaneous neural activity has been recorded in the auditory nerve of cats as early as 2 days postnatal (P2 ), yet individual auditory neurons do not respond to ambient sound levels below 90–100 dB SPL until about P10. Significant refinement of the central projections from the spiral ganglion to the cochlear nucleus occurs during this neonatal period. This refinement may be dependent on peripheral spontaneous discharge activity. We recorded from single spiral ganglion cells in kittens aged P3 to P9. The spiral ganglion was accessed via the round window through the spiral lamina. A total of 112 ganglion cells were isolated for study in 9 animals. Spike rates in neonates were very low, ranging from 0.06 to 56 sp/s with a mean of 3.09 +/- 8.24 sp/s. Ganglion cells in neonatal kittens exhibited remarkable repetitive spontaneous bursting discharge patterns. The unusual patterns were evident in the large mean interval coefficient of variation (CVi = 2.9 +/-1.6) and burst index of 5.2 +/- 3.5 across ganglion cells. Spontaneous bursting patterns in these neonatal mammals were similar to those reported for cochlear ganglion cells of the embryonic chicken suggesting this may be a general phenomenon that is common across animal classes. Rhythmic spontaneous discharge of retinal ganglion cells has been shown to be important in the development of central retinotopic projections and normal binocular vision (Shatz, 1996, Proc Natl Acad Sci 93). Bursting rhythms in cochlear ganglion cells may play a similar role in the auditory system during pre-hearing periods. Originally published in Journal of Neurophysiology Vol. 98, No. 4 200

Factors Related to Youth Living with HIV Delaying Access to Care: The Role of Positive and Negative Social Network Influences on Health Seeking Behaviors

To explore factors related to youths’ delay in seeking care after an HIV diagnosis. Multivariate analyses were performed on 347 participants who were selected from a sample of 351 adolescents participating in a 1994-1996 survey among youth in four U.S. metropolitan cities. Key findings were that participants with prosocial peer behaviors took longer (34 days) to seek care than youth with poorer social engagement and excessive fibbing delayed seeking care (23 days). Potentially important findings suggest being female, older, having close peer networks, conduct problems, and certain housing settings may delay seeking care. Multivariate regression analyses indicate that later entry into medical care was observed among those with close social networks and behavioral characteristics related to delinquency