Invasive interactions: can Argentine ants indirectly increase the reproductive output of a weed?

The direct and indirect interactions of invasive ants with plants, insect herbivores, and Hemiptera are complex. While ant and Hemiptera interactions with native plants have been well studied, the effects of invasive ant–scale insect mutualisms on the reproductive output of invasive weeds have not. The study system consisted of Argentine ants (Linepithema humile), boneseed (Chrysanthemoides monilifera monilifera), and sap-sucking scale insects (Hemiptera: Saissetia oleae and Parasaissetia nigra), all of which are invasive in New Zealand. We examined the direct and indirect effects of Argentine ants on scale insects and other invertebrates (especially herbivores) and on plant reproductive output. Argentine ants spent one-third of their time specifically associated with scale insects in tending behaviours. The invertebrate community was significantly different between uninfested and infested plants, with fewer predators and herbivores on ant-infested plants. Herbivore damage was significantly reduced on plants with Argentine ants, but sooty mould colonisation was greater where ants were present. Herbivore damage increased when ants were excluded from plants. Boneseed plants infested with Argentine ants produced significantly more fruits than plants without ants. The increase in reproductive output in the presence of ants may be due to increased pollination as the result of pollinators being forced to relocate frequently to avoid attack by ants, resulting in an increase in pollen transfer and higher fruit/seed set. The consequences of Argentine ant invasion can be varied; not only does their invasion have consequences for maintaining biodiversity, ant invasion may also affect weed and pest management strategies.     

Gelatinous and soft-bodied zooplankton in the Northeast Pacific Ocean: Phosphorus content and potential resilience to phosphorus limitation

Hydrobiologia - Marine ecosystems on continental shelves face multiple challenges due to anthropogenic disturbances, many of which can change the seawater stoichiometry (C:N:P) and consequently...     

Effect of lithium on granulopoiesis in culture.

Lithium carbonate therapy is associated with polymorphonuclear leukocytosis. In vitro studies have shown that lithium ions stimulate formation of granulocytic colonies. In a study undertaken to determine how lithium acts, colony-forming cells uncontaminated by monocytes (which elaborate colony-stimulating factor [CSF] in vitro) were obtained by means of a two-step cell separation procedure. The effects of lithium on colony formation were then studied in (a) cultures stimulated by humoral CSF, (b) cultures in which monocytes were relied upon to synthesize CSF de novo and (c) unstimulated cultures. Lithium enhanced the action of CSF but did not stimulate colony formation in the absence of CSF. In monocyte-stimulated cultures, colony formation increased with lithium concentrations up to 1 mmol/L but this increase paralleled that in CSF-stimulated cultures and therefore was not due to increased CSF production by monocytes. At higher concentrations of lithium, colony formation decreased in the monocyte-stimulated cultures but increased in the CSF-stimulated cultures. A lithium concentration of 4 mmol/L gave the greatest enhancing effect on colony formation in CSF-stimulated cultures and a concentration greater than 1 mmol/L inhibited de novo synthesis of CSF by monocytes.     

Studies on Papanicolaou staining. III. Quantitative investigations of orangeophilia and cyanophilia

This paper provides data derived from the visible light absorbance spectra of Papanicolaou stained epithelial cells from the uterine cervix. Twenty-four types of spectra have been considered, namely, those derived from orangeophilic and cyanophilic nuclei and cytoplasms of superficial, intermediate, parabasal and dysplastic cells, and cells of carcinoma in situ and invasive carcinoma. Wavelengths of maximum absorbance and peak absorbances are tabulated. The proportions of bound orange G, eosin Y, aluminum-hematein and light green SF yellowish have been calculated. For the majority of cell types, dyebinding differences between orangeophilic and corresponding cyanophilic substrates were statistically significant. CIE coordinates were calculated from absorbance spectra; again differences between organeophilic and cyanophilic cells were statistically significant in most cases. Although the designation of cells as orangeophilic or cyanophilic is made on the basis of cytoplasmic coloration, the nucleus is also usually orangeophilic or cyanophilic. These nuclear differences are real and not due to the effects of over- and underlying cytoplasm.     

Comparison of micrometer‐ and scanning electron microscope‐based measurements of avian eggshell thickness

ABSTRACT The study of avian eggshell structure, including composition, pigmentation, thickness, and strength, has important ecological and economic implications. Previous investigators have used a variety of techniques to derive either direct measures or indirect estimates of eggshell thickness. Assessing the repeatability and method agreement of different techniques is necessary to permit comparison of eggshell thickness values from different studies on various genetic stocks, populations, and species. We recorded and analyzed measurements of eggshell thickness using two methods, micrometers and scanning electron microscopy (SEM), for several Palaeognathae and Neognathae taxa, including nonpasserines and passerines. Applying a tolerance‐interval approach, we found that repeatability of measurements for eggs with thinner shells (<300 μm, all Neognathae taxa) was worse than for eggs with thicker shells (Palaeognathae taxa), but was still statistically and biologically reasonable given that the relative magnitude of intramethod agreements was <11%. Our results support previous predictions that measurements made using a micrometer are comparable to those made using SEM. This finding is particularly important given the relative ease and cost efficiency of the micrometer method. Importantly, these new analyses can be used to validate the use of published data from previous studies of micrometer‐based eggshell thickness for both intra‐ and interspecific comparisons.