Allochthonous coarse particulate organic material in forest and pasture reaches of two south-eastern Australian streams

1. Terrestrial plant litter entering two forest and two pasture sites on upland streams in south-eastern Australia was measured over a 2-year period using traps suspended above the streams. Laterally transported terrestrial plant litter was also determined in one stream, but found to be only 10% of the total. 2. Litter accession to traps suspended above the stream was significantly lower at both forested sites than was litter fall in the adjacent riparian vegetation. 3. Litter input was high (600–700g DW m^?2yr^?1) and seasonal, with 30–50% of the annual total entering the stream during December—February (summer). However, seasonality was not as great as that recorded in Northern Hemisphere deciduous forest streams. 4. Leaves comprised the largest litter component, but represented a relatively smaller proportion of the litter than is usually the case in Northern Hemisphere deciduous forest streams; in contrast bark was a relatively large proportion of the litter. 5. At the sites flowing through pasture, litter accession was about two orders of magnitude lower than at the forested sites.     

Coccidia (Eimeria tachyglossi n. sp., E. echidnae n. sp., and Octosporella hystrix n. sp.) in the Echidna, Tachyglossus aculeatus (Monotremata: Tachyglossidae)

Oocysts of Octosporella hystrix n. sp., Eimeria tachyglossi n. sp., and E. echidnae n. sp. are described from the feces of the echidna Tachyglossus aculeatus (Monotremata: Tachyglossidae) from Australia. Eimeria tachyglossi has subspherical oocysts, 26.4 × 23.7 μm in size, with a single oocyst wall; no micropyle; four ellipsoidal sporocysts 13.2 × 9.7, slightly pointed at one end, each containing two sporozoites. Eimeria echidnae has subspherical oocysts, 19.4 × 17.8 in size, with a single oocyst wall; no micropyle; four ellipsoidal sporocysts 9.8 × 7.8, blunt at both ends, each containing two sporozoites. Octosporella hystrix has ovoid or subspherical oocysts 32.9 × 29.7 in size with a thick outer and thin inner oocyst wall; no micropyle; eight sporocysts spherical or slightly subspherical 11.3 × 11.2 each containing two sporozoites lying in embrace, with an extensive granular sporocyst residuum about the equator of the sporocyst. Endogenous stages considered to be of E. tachyglossi at least, were recognized in the lamina propria and epithelium on villi in the small intestine of three echidnas.     

The Role of Small Cardioactive Peptide, SCPB, in the Regulatory Responses of Terrestrial Slugs

The feeding motor program in Limax maximus is the neural correlateof feeding and consists of a discrete pattern of cyclical efferentactivity generated by the buccal ganglia in response to stimulationof chemosensory pathways. The small cardioactive peptide, SCP_B(10^–6 to 10^–9 M), increases the responsiveness ofthe FMP and the endogenous activity of specific feeding motoneuronssuch as the fast salivary burster. Stimulation of buccal neuron,B1, which contains SCP_B-like immunoreactive substance, similarlyincreases the activity of feeding motoneurons. Furthermore,both exogenous SCP_B and stimulation of Bl increase the contractileforce of the heart. Thus it appears that the peptidergic neuronBl is a multifunctional interneuron that is involved in thecontrol of both peripheral and central targets.     

Carboxylic Ester Hydrolases of Apple

p-Nitrophenyl esters of carboxylic acids (C₂–C₈) wereused to characterize the carboxylic ester hydrolases of peeltissue of apple (Malus domestica Borkh.). The paper presentsevidence for the presence of five ester hydrolases in the peeltissue which show differences in substrate specificity and molecularweight.     

Amphetamine Response in Rat after Dopamine Neurone Destruction

AMPHETAMINE increases spontaneous locomotor activity and induces stereotyped motor responses in rats. The magnitude of these two behavioural responses varies according to the dose and which optical isomer of the drug is used^1,2. Amphetamine is known to influence the uptake and release of catecholamines in the brain both in vitro³ and in vivo^4,5 and the finding that inhibition of catecholamine synthesis by α methyl-p-tyrosine abolishes the behavioural effect of the drug^6,7 suggests that a release of catecholamines may mediate these effects. The amine transmitters noradrenaline (NA) and dopamine (DA) are localized in different anatomical systems in the brain^8,9 and attempts have been made to correlate the specific behavioural effects of amphetamine with one or other of these aminergic systems. Taylor and Snyder, on the basis of comparisons of the potency of d- and l-amphetamine in behavioural and biochemical tests, suggested that a release of NA mediates the locomotor activity and DA the stereotypy responses. We have attempted to pursue these hypotheses with lesions to aminergic pathways.     

The effect of water colour on lake hydrodynamics: a modelling study

1. The one‐dimensional equation solver, PROgram for Boundary layers in the Environment, was used to simulate the temperature structure of Lake Erken, a medium‐sized Swedish lake, assuming differing extinction coefficients for a series of modelled years driven by observed meteorological data and by a set of idealized meteorological data. 2. Results suggested that, as expected, larger extinction coefficients initially led to surface waters becoming warmer. The reverse was true late in the summer, however, as the warming induced by greater absorption of solar radiation was outweighed by the cooling effects of entrained colder hypolimnetic water. 3. There was between a two‐ and fourfold inter‐annual variation in the effects on key physical lake parameters, induced by changing extinction coefficient, such as maximum heat flux, heat content and Schmidt stability. 4. The change in surface heat flux induced by a change in extinction coefficient was up to almost 50 W m⁻². 5. In the summer, changes in extinction coefficient from 0.5 to 0.2 m⁻¹ led to a dramatic shift in the duration of the stratified period as well as to enormous changes in Schmidt stability and hypolimnetic temperature. 6. Future changes to extinction coefficients of small and medium‐sized lakes are likely to have wide‐ranging effects on lake thermal structure and ecology.     

PROTEINS INVOLVED IN MEMBRANE TRANSPORT BETWEEN THE ER AND THE GOLGI APPARATUS: 21 PUTATIVE PLANT HOMOLOGUES REVEALED BY DBEST SEARCHING

Numerous proteins have been identified in yeast and mammalian cells which are involved in trafficking between the endoplasmic reticulum and the Golgi apparatus. A great number of partial cDNA sequences now available from the two major plant model species, Arabidopsis thaliana and Oryza sativa, makes it possible to identify putative plant homologues of known genes/proteins from non-plant species. The authors used this approach to screen the database of Expressed Sequence Tags (dbEST) in order to detect plant homologues of proteins involved in membrane transport between ER and Golgi. Availability of these partial sequences will facilitate the screening of cDNA and genomic libraries otherwise performed using heterologous probes derived from animal and yeast genes. As the plant Golgi complex differs in many respects from its mammalian and yeast counterparts, the dbEST clones found can be directly used for various functional assays (immunoprecipitation, two-hybrid analysis, transgenic plants etc.) to test the exact roles of the encoded proteins and identify their functional partners, some of which may be specific for plants.     

Hatching asynchrony and growth trade‐offs within domesticated and wild zebra finch,Taeniopygia guttata,broods

The Australian zebra finch, Taeniopygia guttata, is a widely used model organism, yet few studies have compared domesticated and wild birds with the aim of examining its relevance as an evolutionary model species. Domestic and wild broods hatch over approximately 4 and 2 days, respectively, which is important given that nestlings can fledge after as little as 12 days, although 16–18 days is common. We aimed to evaluate the extent to which the greater hatching asynchrony in domestic stock may effect reproductive success through greater variance in size hierarchies, variance in within‐brood growth rates, and partial brood mortality. Therefore, by simultaneously controlling brood sizes and experimentally manipulating hatching intervals in both domesticated and wild birds, we investigated the consequences of hatching intervals for fledging success and nestling growth patterns, as well as trade‐offs. Fledging success was similarly high in domestic and wild broods of either hatching pattern. Nonetheless, between‐brood analyses revealed that domestic nestlings had significantly higher masses, larger skeletal characters, and longer wings than their wild counterparts, although wild nestlings had comparable wing lengths at the pre‐fledging stage. Moreover, within‐brood analyses revealed only negligible differences between domestic and wild nestlings, and larger effects of hatching order and hatching pattern. Therefore, despite significant differences in the hatching intervals, and the ultimate size achieved by nestlings, the domestication process does not appear to have significantly altered nestling growth trade‐offs. The present study provides reassuring evidence that studies involving domesticated zebra finches, or other domesticated model organisms, may provide reasonable adaptive explanations in behavioural and evolutionary ecology. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 763–773.     

Evidence for mate‐encounter Allee effect in an invasive longhorn beetle (Coleoptera: Cerambycidae)

1. Limited empirical support is available for mate‐encounter Allee effects in invasive insects due to the logistical challenges of studying demographic trends in low‐density populations. 2. Traps baited with pheromone and spruce volatiles were used to monitor the abundance of female Tetropium fuscum F. (Coleoptera: Cerambycidae) at multiple sites in Nova Scotia in 2011 and 2012. Each female was dissected to determine the presence or absence of sperm in its spermatheca (mated or virgin female, respectively). 3. Both male and total T. fuscum abundance declined with increasing distance to the focal point of T. fuscum's invasion. Female mating probability declined with male abundance and with distance from the invasion focus, and mating probabilities were very low at the most peripheral sites. Difficulty in encountering mates may thus contribute to limiting the spread of T. fuscum. 4. The approach outlined here could be integrated into existing surveys of wood borers using traps baited with semiochemicals to improve our understanding of the role of the mate‐encounter Allee effect in invasion dynamics.     

Influence of simulated climate change and eutrophication on three‐spined stickleback populations: a large scale mesocosm experiment

1. Shallow lakes and their ectothermic inhabitants are particularly vulnerable to the effects of climatic warming. These impacts are likely to depend on nutrient loading, especially if the combination of warming and eutrophication leads to severe hypoxia. 2. To investigate effects of realistic warming and nutrient loading on a fish species with high tolerance of warming and hypoxia, we observed population changes and timing of reproduction of three‐spined sticklebacks in 24 outdoor shallow freshwater ecosystems with combinations of temperature (ambient and ambient +4 °C) and three nutrient treatments over 16 months. 3. Warming reduced stickleback population biomass by 60% (population size by 76%) and nutrient‐addition reduced biomass by about 80% (population size 95%). Nutrients and warming together resulted in extinction of the stickleback populations. These losses were mainly attributed to the increased likelihood of severe hypoxia in heated and nutrient‐addition mesocosms. 4. Warming of nutrient‐rich waters can thus have dire consequences for freshwater ectotherm populations. The loss even of a hardy fish suggests a precarious future for many less tolerant species in such eutrophic systems under current climate change predictions.