Climate, size and flowering history determine flowering pattern of an orchid

The flowering pattern of plant species, including orchid species, may fluctuate irregularly. Several explanations are given in the literature to explain that pattern, including: costs associated with reproduction, herbivory effects, intrinsically triggered unpredictable variation of the system, and external conditions (i.e. weather). The influence of age is discussed, but is difficult to determine because relevant long-term field observations are generally absent in the literature. The influence of age, size, reproductive effort and climatic conditions on flowering variability of Himantoglossum hircinum are examined using data collected in a long-term project (1976–2001) in Germany. PCA and multiple regression analysis were used to analyse variability in flowering pattern over the years as a function of size and weather variability. We studied future size after flowering to quantify costs of reproduction. Flowering probability was strongly determined by plant size, while there was no significant influence of age class on flowering probability of the population. Costs associated with reproduction resulted in a decrease in plant size, causing reduced flowering probability of the plants in the following year. The weather explained about 50% of the yearly variation in the proportion of large plants and thus had an indirect, strong influence on the flowering percentage. We conclude that variability in flowering is caused mainly by the variability of weather conditions in the previous and current year, whereby reproductive effort causes further variability in flowering at the individual and, consequently, the population levels.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 511–526.     

Three Variable Arenopontia Species (Crustacea, Copepoda) from Panamá

Three species of the genus Arenopontia (Cylindropsyllidae) from the Pacific and Atlantic coast of Panamá are presented. Two of them are A. trisetosa Mielke and A. peteruxi Mielke, both of which were described for the first time from the Galápagos Islands. The third species is tentatively identified as A. gussoae Cottarelli previously reported from an interstitial habitat in Cuba.     

Side effects of atypical antipsychotics: a brief overview

This paper reviews the available evidence concerning the side effects of atypical antipsychotics, including weight gain, type II diabetes mellitus, hyperlipidemia, QTc interval prolongation, myocarditis, sexual side effects, extrapyramidal side effects and cataract. Some recommendations about how to prevent and manage these side effects are also provided. It is concluded that atypical antipsychotics do not represent a homogeneous class, and that differences in side effects should be taken into account by clinicians when choosing an antipsychotic for an individual patient.     

Amphiascus discrepans sp.n., a new benthic copepod (Crustacea) from lquique (Chile)

A new diosaccid copepod, Amphiascus discrepans sp.n., is described from the eulittoral zone of Playa Blanca, near Iquique (Chile). It differs from all presently known Amphiascus species in the characteristic structure of the female furca.     

Kinesis in Euplotes vannus-Ethological and Electrophysiological Characteristics of Chemosensory Behavior

ABSTRACT. Equally dispersed Euplotes vannus cells accumulate inside a drop of supernatant of a bacteria suspension that is surrounded by a reference solution. In the drop, frequencies of stops and backward jerks are tenfold increased. The sequences of directional changes and translocations prevent cells from leaving the chemostimulant region, as if they were trapped. This behavior is quickly induced after casual arrival in the drop and not by chemotactic influence over a larger distance. With intracellular recordings, we have found a K⁺ conductance decrease in chemically stimulated cells that prolongs the duration of spontaneously occurring depolarizations to 600-1,700 ms by delaying repolarization. The freely fluctuating membrane potential shifts to more depolarized levels, although the total potential range is expanded in the positive and negative direction by 5.5 and 3.8 mV, respectively. Chemosensory behavior is explained and discussed with respect to these electrophysiological events.     

Experimentally elevated testosterone levels enhance courtship behaviour and territoriality but depress acquired immune response in Red Bishops Euplectes orix

The immunocompetence handicap hypothesis (ICHH) posits that the hormone testosterone mediates a trade‐off between investment in reproduction and immunological condition. In this study, we tested the ICHH in the Red Bishop Euplectes orix, a polygynous weaverbird. Males of this strongly sexually dimorphic species show an elaborate courtship display to attract females and compete aggressively with other males for nesting sites in breeding colonies. We experimentally elevated testosterone levels in breeding male Red Bishops kept in an aviary with a subcutaneous implantation of testosterone‐releasing pellets. We then compared behaviour, development of territory size and immunological condition (as assessed through a white blood cell count) of the experimental group with a control group treated with placebos. In addition, we measured the primary and secondary response to phytohaemagglutinin (PHA) to investigate the effect of testosterone on both innate and acquired immunity. Males with elevated levels of testosterone enlarged their territories and conducted more courtship behaviour, while showing a decrease in health, expressed by an increased heterophil/lymphocyte ratio compared with the control group. Males of the control group showed an increase of the secondary response to PHA, as expected under the assumption that repeated exposure to an antigen enhanced the immune response due to acquired immunity. However, males with experimentally increased testosterone levels did not show such an enhanced immune response in the secondary PHA test (although sample size and power of the statistical tests were low), indicating that testosterone treatment might directly or indirectly suppress some component of the acquired immune response.     

Selection of a suitable cladoceran species for toxicity testing in turbid waters

Abstract Two Australian cladocerans, Moina australiensis Sars and a species of Ceriodaphnia, were evaluated as possible biological indicator organisms to assess the toxicity of irrigation supply and drainage water of the Murrumbidgee and Coleambally Irrigation Areas. M. australiensis, being large (～2000 μm) and orange, was initially chosen to overcome visibility problems in highly turbid Australian inland waters. However, the organism responded erratically in culture. Mortality was high and neonate production was unpredictable when cultured under recommended United States Environmental Protection Agency protocols. Attempts to improve culture performance by optimizing food (quality and quantity), water (control source, hardness, volume) and temperature were only marginally successful. Similar difficulties were not evident when Ceriodaphnia sp. was used as the test organism. Although Ceriodaphnia sp. is small (～1000 μm), grey and more difficult to see in turbid water its responses were more predictable and reliable than those of M. australiensis. Results of initial trials comparing the two organisms suggest that Ceriodaphnia sp. was a better test organism and more suited to local requirements.     

Ammonium Nutrition Enhances Chlorophyll and Glaucousness in Kohlrabi

Kohlrabi (Brassica oleracea var.gongylodes) plants were grownin the greenhouse under autumn conditions and fertilized eitherwith pellets containing nitrogen as 40% ammonium sulphate and60% urea or with nutrient solution containing nitrogen predominantlyas nitrate. Plants given nitrogen as ammonium ions developedglaucous leaves compared to those supplied with nitrate whichformed glossy leaves. Ammonium-induced glaucousness was theresult of a two-fold increase in the amount of epicuticularwax and a markedly altered fine structure. Leaves from ammoniumfertilized kohlrabi plants also showed a 21% increase in chlorophyllcontent together with a reduction in the chlorophyll a:b ratioand decreased ground state fluorescence compared to plants suppliedwith nitrate. Photosynthesis and stomatal transpiration wereunaffected by the form of supplied nitrogen. Brassica oleracea ; chlorophyll; chlorophyll fluorescence; epicuticular wax; glaucousness; photosynthesis; transpiration     

A Seventy-Year History of Trends in Yellowstone's Northern Elk Herd

ABSTRACT We analyzed counts of northern Yellowstone elk (Cervus elaphus) in Yellowstone National Park, Wyoming, USA, over 70 years to evaluate the effects of changing management on population trends. Population reduction efforts and hunter harvests during 1932–1968 removed 71,330 elk and decreased estimated abundance from 16,000 to 6,000 elk. Abundance increased to approximately 17,000 elk (λ = 1.19) when removals ceased and harvests were very small during 1969–1975. Moderate to liberal hunter harvests of antlerless elk outside the Park during 1976–2004 removed a relatively consistent proportion (26 ± 0.1 [SD]%) of females that migrated outside the park, mostly from prime-age (3–15 yr) classes with high reproductive value. Substantial winterkill was infrequent (1989, 1997), but it significantly reduced calf survival when it occurred. Wolves (Canis lupus) were reintroduced in 1995–1996 and rapidly increased in abundance (λ = 1.23) and distribution. Estimated wolf kill of elk now exceeds hunter harvest, but has a smaller effect on population dynamics because wolves concentrate on calves and older females (>14 yr) with low reproductive value. During 1995–2004, estimated abundance decreased from 23,000 to 12,000 elk. The recent ratio of wolves to elk is relatively low compared to the estimated equilibrium ratio, suggesting that the wolf population may yet increase in the future. Thus, reduction of harvests of prime-aged female elk to decrease removals of animals with high reproductive value and increase adult female survival appears essential. We analyzed the relative impact of removals by hunters and by wolves using Fisher's (1930) reproductive value and found that the impact of hunters is far more important than that by wolves, a finding of broad significance.