Flower colour and size signals differ depending on geographical location and altitude region.

Bees are major pollinators of angiosperms and have phylogenetically conserved colour vision but differ in how various key species use achromatic information that is vital for both flower detection and size processing. We modelled green contrast and colour contrast signals from flowers of different countries where there are well established differences in availability of model bee species along altitudinal gradients. We tested for consistency in visual signals as expected from generalization in pollination principles using phylogenetically informed linear models. Patterns of chromatic contrast, achromatic green contrast and flower size differed among the three floras we examined. In Nepal there is a significant positive correlation between flower size and colour contrast in the subalpine region, but a negative correlation at the lower altitudes. At high elevations in Norway, where pollinators other than bees are common, flower size was positively correlated with colour contrast. At low and medium altitudes in Norway and in Australia, we did not observe a significant relationship between size and colour contrast. We thus find that the relationship between size, green and colour contrast cannot be generalized across communities, thus suggesting that flower visual signal adaptations to local pollinators are not limited to chromatic contrast.

Rewardlessness in orchids: how frequent and how rewardless?

About one-third of orchid species are thought to offer no floral reward and therefore attract pollinators through deception. Statements of this idea are common in the botanical literature, but the empirical basis of the estimate is rarely mentioned. We traced citation pathways for the one-third estimate in a sample of the literature and found that the paths lead to empirical foundations that are surprisingly narrow. Moreover, recent measurements have detected minute quantities of sugar available to insect visitors in some orchids thought to be rewardless, raising the possibility of a pollination strategy that is largely deceitful but different to absolute rewardlessness. The orchids are a well-studied group and there is no doubt that rewardlessness is common in the family. However, greater empirical effort is needed to verify rewardlessness in orchids and to explore geographic and environmental variation in the proportion of rewardless species.

Colour evolution within orchids depends on whether the pollinator is a bee or a fly.

Orchids are a classic angiosperm model for understanding biotic pollination. We studied orchid species within two species-rich herbaceous communities that are known to have either hymenopteran or dipteran insects as the dominant pollinators, in order to understand how flower colour relates to pollinator visual systems. We analysed features of the floral reflectance spectra that are significant to pollinator visual systems and used models of dipteran and hymenopteran colour vision to characterise the chromatic signals used by fly-pollinated and bee-pollinated orchid species. In contrast to bee-pollinated flowers, fly-pollinated flowers had distinctive points of rapid reflectance change at long wavelengths and a complete absence of such spectral features at short wavelengths. Fly-pollinated flowers also had significantly more restricted loci than bee-pollinated flowers in colour space models of fly and bee vision alike. Globally, bee-pollinated flowers are known to have distinctive, consistent colour signals. Our findings of different signals for fly pollination is consistent with pollinator-mediated selection on orchid species that results from the distinctive features of fly visual systems.

Publisher Correction: GloPL, a global data base on pollen limitation of plant reproduction.

J. H. Burns was omitted in error from the author list of the original version of this Data Descriptor. This omission has now been corrected in both the HTML and PDF versions.

GloPL, a global data base on pollen limitation of plant reproduction.

Plant reproduction relies on transfer of pollen from anthers to stigmas, and the majority of flowering plants depend on biotic or abiotic agents for this transfer. A key metric for characterizing if pollen receipt is insufficient for reproduction is pollen limitation, which is assessed by pollen supplementation experiments. In a pollen supplementation experiment, fruit or seed production by flowers exposed to natural pollination is compared to that following hand pollination either by pollen supplementation (i.e. manual outcross pollen addition without bagging) or manual outcrossing of bagged flowers, which excludes natural pollination. The GloPL database brings together data from 2969 unique pollen supplementation experiments reported in 927 publications published from 1981 to 2015, allowing assessment of the strength and variability of pollen limitation in 1265 wild plant species across all biomes and geographic regions globally. The GloPL database will be updated and curated with the aim of enabling the continued study of pollen limitation in natural ecosystems and highlighting significant gaps in our understanding of pollen limitation.

Floral colours in a world without birds and bees: the plants of Macquarie Island.

We studied biotically pollinated angiosperms on Macquarie Island, a remote site in the Southern Ocean with a predominately or exclusively dipteran pollinator fauna, in an effort to understand how flower colour affects community assembly. We compared a distinctive group of cream-green Macquarie Island flowers to the flora of likely source pools of immigrants and to a continental flora from a high latitude in the northern hemisphere. We used both dipteran and hymenopteran colour models and phylogenetically informed analyses to explore the chromatic component of community assembly. The species with cream-green flowers are very restricted in colour space models of both fly vision and bee vision and represent a distinct group that plays a very minor role in other communities. It is unlikely that such a community could form through random immigration from continental source pools. Our findings suggest that fly pollination has imposed a strong ecological filter on Macquarie Island, favouring floral colours that are rare in continental floras. This is one of the strongest demonstrations that plant-pollinator interactions play an important role in plant community assembly. Future work exploring colour choices by dipteran flower visitors would be valuable.

The palmar metric: A novel radiographic assessment of the equine distal phalanx.

Digital radiographs are often used to subjectively assess the equine digit. Recently, quantitative and objective radiographic measurements have been reported that give new insight into the form and function of the equine digit. We investigated a radio-dense curvilinear profile along the distal phalanx on lateral radiographs we term the Palmar Curve (PC) that we believe provides a measurement of the concavity of the distal phalanx of the horse. A second quantitative measurement, the Palmar Metric (PM) was defined as the percent area under the PC. We correlated the PM and age from 544 radiographs of the distal phalanx from the left and right front feet of various breed horses of known age, and 278 radiographs of the front feet of Quarter Horses. The PM was negatively correlated with age and decreased at a rate of 0.28 % per year for horses of various breeds and 0.33 % per year for Quarter Horses. Therefore, veterinarians should be aware of age related change in the concave, parietal solar aspect of the distal phalanx in the horse.

Clinical investigation of an outbreak of alveolitis and asthma in a car engine manufacturing plant.

BACKGROUND: Exposure to metal working fluid (MWF) has been associated with outbreaks of extrinsic allergic alveolitis (EAA) in the USA, with bacterial contamination of MWF being a possible cause, but is uncommon in the UK. Twelve workers developed EAA in a car engine manufacturing plant in the UK, presenting clinically between December 2003 and May 2004. This paper reports the subsequent epidemiological investigation of the whole workforce. The study had three aims: (1) to measure the extent of the outbreak by identifying other workers who may have developed EAA or other work-related respiratory diseases; (2) to provide case detection so that those affected could be treated; and (3) to provide epidemiological data to identify the cause of the outbreak. METHODS: The outbreak was investigated in a three-phase cross-sectional survey of the workforce. In phase I a respiratory screening questionnaire was completed by 808/836 workers (96.7%) in May 2004. In phase II 481 employees with at least one respiratory symptom on screening and 50 asymptomatic controls were invited for investigation at the factory in June 2004. This included a questionnaire, spirometry and clinical opinion. 454/481 (94.4%) responded and 48/50 (96%) controls. Workers were identified who needed further investigation and serial measurements of peak expiratory flow (PEF). In phase III 162 employees were seen at the Birmingham Occupational Lung Disease clinic. 198 employees returned PEF records, including 141 of the 162 who attended for clinical investigation. Case definitions for diagnoses were agreed. RESULTS: 87 workers (10.4% of the workforce) met case definitions for occupational lung disease, comprising EAA (n = 19), occupational asthma (n = 74) and humidifier fever (n = 7). 12 workers had more than one diagnosis. The peak onset of work-related breathlessness was Spring 2003. The proportion of workers affected was higher for those using MWF from a large sump (27.3%) than for those working all over the manufacturing area (7.9%) (OR = 4.39, p<0.001). Two workers had positive specific provocation tests to the used but not the unused MWF solution. CONCLUSIONS: Extensive investigation of the outbreak of EAA detected a large number of affected workers, not only with EAA but also occupational asthma. This is the largest reported outbreak in Europe. Mist from used MWF is the likely cause. In workplaces using MWF there is a need to carry out risk assessments, to monitor and maintain fluid quality, to control mist and to carry out respiratory health surveillance.

Social group size, potential sperm competition and reproductive investment in a hermaphroditic leech, Helobdella papillornata (Euhirudinea: Glossiphoniidae).

Social group size may affect the potential for sperm competition, and this in turn may favour ontogenetic adjustments in testicular mass according to the likely requirements for sperm and spermatophore production. In a number of comparative analyses of testis mass among vertebrate species that differ in mating system or social organization, increasing potential for sperm competition is associated with larger testis size. Intraspecific phenotypic plasticity should be able to produce the same pattern if social group size is heterogenous and reflects differing degrees of average sperm competition, but this intraspecific effect is less well studied. We tested the effect of social groups on both male and female investment in the simultaneously hermaphroditic leech, Helobdella papillornata. Leeches were placed in groups of one, two, four or eight. Sexual investment at the onset of reproductive maturity was quantified as the total testisac volume for male function and total egg volume for female function. We found that testisac volume (statistically adjusted for body size) showed a significant increase with increasing group size. Total egg volume (also adjusted for body size) was unaffected by group size. Our findings indicate adaptive developmental plasticity in male gonad investment in response to the potential for sperm competition.

Epidemiology of MRSA: the North/South study of MRSA in Ireland 1999.

The North/South Study of methicillin-resistant Staphylococcus aureus (MRSA) in Ireland, 1999, includes a joint review of the epidemiology of MRSA across both jurisdictions on the island of Ireland. Data were gathered on all MRSA cases identified in laboratories in Northern Ireland (the North) and in the Republic of Ireland (the South) over a two-week period. The prevalence rate per 100000 population was 11.4 in the North and 14.0 in the South, with a marked variation across geographical regions. MRSA cases were located throughout hospitals and the community, were slightly more common in males than females, and occurred in all age groups, especially in the elderly. The majority of cases were inpatients in acute hospitals and were distributed across all types of wards. Most cases were colonized with MRSA but 5% of cases in the North and 10% in the South had invasive infection. Invasive infection was associated with intravascular lines and invasive procedures/surgery. Continuous surveillance is recommended to monitor the epidemiology of MRSA and the effectiveness of control measures.

Control and the prevention of methicillin-resistant Staphylococcus aureus in hospitals in Ireland: North/South Study of MRSA in Ireland 1999.

As part of an all-island survey of methicillin-resistant Staphylococcus aureus (MRSA) in the Republic of Ireland (the South), where there is a mixed public and private healthcare system, and Northern Ireland (the North), where the healthcare system is part of the UK National Health Service, a questionnaire was circulated to all participating hospitals on measures routinely taken to control MRSA. Response rates were 100% in the North and 89% in the South. Over 70% of hospitals screened particular groups of patients on admission to hospital. Ninety-five percent of hospitals in the North and 88% in the South attempted to eradicate MRSA from carriage sites. Most hospitals attempted to isolate or cohort positive patients. About a quarter of hospitals in both parts of Ireland screened new healthcare workers for the presence of MRSA. Terminal decontamination of the environment after the discharge of a patient positive for MRSA was the norm in over 90% of hospitals, however, 6% of hospitals in the South used inappropriate disinfectants for MRSA. All hospitals in the North, but a minority (41%) in the South, had written antibiotic prescribing policies, but only 65% of hospitals in the South had access to an infection control committee, acute hospitals having greater access than district hospitals. The prevention and control of spread of MRSA remains a major challenge in the North and in the South. Although most hospitals in the North and in the South implemented current recommended guidelines on the control of MRSA in hospitals, there was some variability that may be resource related. Policies need to be reviewed in the light of the changing epidemiology of MRSA.

MRSA bacteraemia: North/South Study of MRSA in Ireland 1999.

Retrospective aggregate data on all Staphylococcus aureus isolates recovered from blood cultures during 1998 were collected in both jurisdictions on the island of Ireland, Northern Ireland (North) and the Republic of Ireland (South), as part of the North/South Study of MRSA in Ireland 1999. A postal questionnaire was used to gather the data, and all diagnostic microbiology laboratories in the North and 98% of laboratories in the South participated. S. aureus bacteraemia occurred at rates of 20.4 per 100,000 population in the North and 24.5 per 100,000 in the South (missing data from one laboratory). In the North, 22% of patients who had blood cultures positive for S. aureus had methicillin-resistant S. aureus (MRSA) and 25% of S. aureus isolates were MRSA (some patients had more than one isolate). In the South, 31% of patients who had blood cultures positive for S. aureus had MRSA and 36% of S. aureus isolates were MRSA. There was a marked variation in rates between different regions. The percentage of patients with blood cultures positive for S. aureus that had MRSA was considerably lower in the North (22%) than in the South (31%), and in both jurisdictions was lower than that found in England and Wales in 1999 (37%). It is recommended that data on S. aureus bacteraemia and methicillin-resistance rates (already available in many laboratories) are gathered at regional and national level for the surveillance of antimicrobial resistance.

Methicillin-resistant Staphylococcus aureus: laboratory detection methods in use in the Republic of Ireland and Northern Ireland.

There is no universally agreed laboratory protocol for the detection of methicillin-resistant Staphylococcus aureus (MRSA) and hence a variety of approaches are used. As part of an all-island survey of MRSA in the Republic of Ireland (the South) and Northern Ireland (the North), a questionnaire was circulated to 14 participating laboratories in the North and 49 in the South, to determine the methods used to isolate MRSA from clinical specimens, identify S. aureus and test for susceptibility to methicillin. Almost two-thirds (64%) of laboratories in the North but only 16% of laboratories in the South use enrichment culture. There is heavy reliance on commercial kits to confirm the identification of S. aureus in the South but all laboratories in the North use the staphylocoagulase test. More than 90% of all laboratories use a disc method for susceptibility testing and 71% of laboratories in the North supplement this with the E-test; however, a range of methicillin disk concentrations are in use. There is a need to review current laboratory methods used to detect MRSA, with follow-up audit on their implementation. Additional resources may be needed in some laboratories to comply with revised guidelines, and reference facilities are required to assess new commercially available techniques and to confirm the identification of unusual or difficult strains.

Correlated response of autogeny to selection for adult starvation resistance in the blowfly, Lucilia cuprina.

We withheld sucrose from adults in three lineages of Lucilia cuprina, producing a four-fold greater mortality than in control lineages, in order to impose direct selection for carbohydrate starvation resistance. The frequency of autogeny (maturation of eggs in the absence of adult protein feeding) increased as a correlated response by an average of 4.9 to 9.2% per generation in three lineages subjected to starvation over five generations. The frequency of autogeny fluctuated but did not display a significant net change in three control lineages. Autogeny in L. cuprina seems to behave as a threshold trait, with a continuous, genetically-based underlying disposition producing discrete phenotypes. The heritability of autogeny in our laboratory lineages was estimated to be 0.09 to 0.39, 0.04 to 0.36, and -0.08 to 0.30 (95% confidence intervals). Despite the potential for autogeny to evolve and despite protein limitation of female fecundity in Australian populations of L. cuprina, the trait is rare or absent in the field. Genetic variation for autogeny may be maintained, but at sub-threshold levels, by nutrient availability in the field, while trade-offs associated with autogeny probably limit the net fitness benefit of the trait and prevent the evolution of a noticeable frequency of autogenous females.

Foraging behaviour of Atta cephalotes (leaf-cutting ants): an examination of two predictions for load selection.

Two mechanisms have been proposed to explain how colony-level foraging performance of leaf-cutting ants can be maximized when workers harvest leaf fragments of a size that does not maximize their individual performance. Each mechanism predicts that ants will adjust the size of leaf fragments between starting a foraging bout and establishing full traffic between the nest and foraging site, but the two models predict shifts in opposite directions. I examined fragment sizes at the start of daily foraging in five field colonies of Atta cephalotes in Costa Rica and detected an obvious shift in only one case. More shifts were detected when the small and large ends of the worker body size range were considered separately, but the direction was inconsistent among colonies. I also examined the role of returning laden workers in recruitment of nestmates by intercepting all laden workers for the first 2 h of foraging, and measuring the effect on the arrival of recruits at the foraging site. In two cases, the flow of recruits was not diminished by the interception of returning workers. The results suggest that neither mechanism correctly and consistently accounts for load size selection by leaf-cutting ants. Copyright 2000 The Association for the Study of Animal Behaviour.

Experimental adenovirus hemorrhagic disease in yearling black-tailed deer.

An apparently novel adenovirus was associated with an epizootic of hemorrhagic disease that is believed to have killed thousands of mule deer (Odocoileus hemionus) in California (USA) during 1993-1994. A systemic vasculitis with pulmonary edema and hemorrhagic enteropathy or a localized vasculitis associated with necrotizing stomatitis/pharyngitis/glossitis or osteomyelitis of the jaw were common necropsy findings in animals that died during this epizootic. Six black-tailed yearling deer (O. hemionus columbianus) were inoculated with purified adenovirus isolated from a black-tailed fawn that died of acute adenovirus hemorrhagic disease during the epizootic. Three of six inoculated deer also received intramuscular injections of dexamethasone sodium phosphate every 3 days during the study. Eight days post-inoculation, one deer (without dexamethasone) developed bloody diarrhea and died. Necropsy and histopathologic findings were identical to lesions in free-ranging animals that died of the natural disease. Hemorrhagic enteropathy and pulmonary edema were the significant necropsy findings and there was microscopic vascular damage and endothelial intranuclear inclusion bodies in the vessels of the intestines and lungs. Adenovirus was identified in necrotic endothelial cells in the lungs by fluorescent antibody staining, immunohistochemistry and by transmission electron microscopy. Adenovirus was reisolated from tissues of the animal that died of experimental adenovirus hemorrhagic disease. Similar gross and microscopic lesions were absent in four of six adenovirus-inoculated deer and in the negative control animal which were necropsied at variable intervals during the 14 wk study. One deer was inoculated with purified adenovirus a second time, 12 wk after the first inoculation. Fifteen days after the second inoculation, this deer developed severe ulceration of the tongue, pharynx and rumen and necrotizing osteomyelitis of the mandible which was associated with vasculitis and thrombosis of adjacent large vessels and endothelial intranuclear inclusions. Transmission electron microscopy demonstrated adenovirus within the nuclei of vascular cells and immunohistochemistry demonstrated adenovirus antigen within tonsilar epithelium and in rare vessels.

Phenological aspects of male and female function in hermaphroditic plants.

We present a model of plant sexual allocation that takes account of the timing of male and female function when resources take the form of a rate-limited photosynthetic "income" rather than a resource "pool." The model suggests that investment in male function imposes an opportunity cost with respect to female allocation by diverting resources from further vegetative growth that could have fueled later fruit and seed maturation. The optimal sex allocation predicted by the model is more female biased than the allocation expected if a plant instantaneously divides a common pool of reproductive resources. If fruiting tissue is photosynthetic, the optimal allocation is even more female biased. Temporal factors may help account for the frequently observed female bias in carbon allocation. Although the phenological factors that affect reproduction are certain to vary among species depending on their morphology, physiology, and habitat, such factors may frequently be important, and future studies of plant sex allocation would profit from explicit and detailed attention to the timing of reproductive events.