# Browse results

## You are looking at 1 - 10 of 312 items for :

• Biology
• Just Published
• Search level: All
Clear All

## Abstract

The anatomical structure of the bamboo stem is characterized by vascular bundles comprising the xylem, phloem, and sclerenchyma fibrous sheaths as well as parenchymatous ground tissue in which the vascular bundles are embedded. The composition of the stem is the main factor influencing the anatomical characteristics of circular bamboo, which shows considerable variation in the radial direction. However, most species of Chimonobambusa have square stems. Here, we tested the hypothesis that circumferential variation exists in the cross-sectional anatomy of this species. We analysed fibre morphology and the cross-sectional structural characteristics of vascular bundles of Chimonobambusa quadrangularis (Fenzi) Makino and their associated circumferential and radial variation in cross-sections. Microscopic observations were conducted to identify, measure, and compare fibre morphology and the structural characteristics of vascular bundles, including both circumferential and radial anatomical variation. Vascular bundles occurred as undifferentiated, semi-differentiated, and open types in the radial direction with no changes in the circumferential direction. The average length, width, and ratio of fibre length to width were 1463.6 μm, 12.3 μm and 119.3 in the corner region, and 1452.7 μm, 12.8 μm, and 111.3 in the side region, and there were significant circumferential and radial differences in length, width, and the ratio of fibre length to width ($p<0.001$). The circumferential variation in density of vascular bundles, the ratio of fibre length to width, radial to tangential diameter ratio of vascular bundles, and the proportion of sclerenchyma were greater in the corner regions than the side regions. The variation in fibre width and the proportion of parenchyma were greater in the corner regions than in the side regions. The density of vascular bundles and proportions of sclerenchyma were greater in the outer stem compared to the inner stem, whereas the length, width, and ratio of fibre length to width were greatest in the centre compared to the inner and outer zones. Circumferential variation of the density of vascular bundles, fibre length and fibre width occurred in the central and outer stem zones. These findings confirm that there are significant anatomical variations in both the circumferential and radial directions and provide a scientific basis for the rational use of Chimonobambusa quadrangularis.

In: IAWA Journal
Author: K.C. Burns

## Abstract

I observed a wild kākā (Nestor meridionalis) excavate a piece of deadwood from the branch it was perched on and carry it to a new position immediately above a perched predatory falcon (Falco novaeseelandiae). It then raised its head upwards, and in a single downward motion with its head, released the piece of wood towards the falcon below. The piece of wood stuck the falcon in the back, which immediately took flight and disappeared from view. I conclude my description of this anecdotal observation of anti-predatory tool use with caveats and alternative interpretations.

In: Behaviour

## Abstract

Male infanticide has been reported in wide range of mammalian taxa however it remains very rare in even-toed ungulates where it was documented in two species only. Among six hypotheses explaining this phenomenon, the sexual selection hypothesis is supported by the largest evidence in mammals. Here, we report the first case of male infanticide in sika deer (Cervus nippon) which occurred at Ostrava Zoo. At the end of rutting season, new male had been joined with two pregnant females that successfully gave birth and reared offspring in his presence then. However, in the next season, the same male attacked and killed his own newborn female offspring. Since this male was separated from the herd for most of the time in the rut, we argue that he could be confused about paternity. Therefore, this case of infanticide might be driven by the same mechanism as that which is in line with the sexual selection hypothesis. In addition, based on our evidence we cannot reject the social pathology hypothesis as an alternative explanation.

In: Behaviour
Authors: Le T. Ho and Frank M. Thomas

## Abstract

Wood density constitutes an integrative trait of water relations and growth. We compared the recently developed blue intensity (BI) method, which has only rarely been applied to tropical conifers, for determining wood density with anatomical analyses in studying the three rarely investigated palaeotropical pine species Pinus kesiya, P. dalatensis and P. krempfii, which co-occur in South-Central Vietnam, but differ in their distribution areas. For species comparisons, we also calculated the hydraulic conductivity of the xylem with the Hagen-Poiseuille equation and the water potential causing 50% loss of hydraulic conductivity ($Ψ50$) based on the anatomical analyses. We hypothesized (i) that the BI values are correlated with the cell wall fractions, the calculated hydraulic conductivity and the $Ψ50$ values; and (ii) that the wider occurrence of P. kesiya, which also can grow at drier sites, is reflected by higher wood density, lower hydraulic conductivity, lower (more negative) $Ψ50$ values and a smaller variation in the wood anatomical features across the years compared to the other two species. In agreement to our hypotheses, the results of the BI and the anatomical method were closely correlated, especially for sapwood, and P. kesiya exhibited features that are related to the growth at drier sites and to a higher tolerance towards drought: higher wood density and cell wall:lumen area ratios of its smaller xylem conduits, lower calculated hydraulic conductivity and more negative $Ψ50$ values. The BI method is well suitable for determining the wood density in tropical conifers. As a fast and inexpensive method, it may be used for initial screening woody species for their water transport capacity and drought resistance.

In: IAWA Journal

## Abstract

Scent marks are an important means of transmitting information between rodents, and they can be produced from several body sources. Previous studies have shown that scents from multiple sources can convey the same information; female meadow voles, for example, have three scent sources that communicate sex. However, possessing three separate sources that convey the same information is likely costly due to the metabolic energy required to produce these signals and the increased chance that eavesdropping individuals may intercept information present in these signals. In this study, we investigated if these scent sources could communicate other information, in addition to scent donor sex, by determining if male meadow voles could distinguish scent marks taken from different sources of a single female scent donor. This was accomplished with a habituation-test method, that allowed us to compare how male meadow voles differently investigate scent from a familiar and novel source of a female scent donor. Male meadow voles could distinguish between faeces and urine scent marks of a female, but could only distinguish mouth from urine and faeces scent marks when first familiarized with mouth scent marks. Our findings suggest that mouth, urine, and faeces scent marks of female meadow voles produce both redundant and distinct information. The overlap in information between scent marks produced from separate sources may be needed to provide social context, which allows receiving individuals to accurately weigh the tradeoffs associated with responding to an olfactory cue. While this overlap in information remains costly, this cost may be minimized by the different fade-out times of scent marks from distinct body sources, which may limit the amount of time information in a scent mark is available to a time period where this information is socially relevant.

In: Behaviour
In: IAWA Journal

## Abstract

Leptohyphes Eaton is one of the most species-rich American genera in Ephemeroptera, with 45 valid species distributed from south-central USA to Patagonia. Most species are distributed in central and northern Andes. Nymphs are frequent and abundant in mountain streams. We present a parsimony-based morphological phylogeny for the genus. Specific geographic records were studied using Hovenkamp’s protocol (barrier biogeography). Leptohyphes was recovered as a monophyletic group. The most ancient disjunction found in Leptohyphes separated Tepui-area from the rest of the Americas. Other interesting vicariant events were found, including the separation of eastern Atlantic mountains (Mata Atlantica) from the Andes; oriental and occidental slopes of the Andes; northern from central Andes; and northern Andes from Central and North America. An ancient tropical South American origin for the genus is supported, with a more recent diversification due to Andean orogeny. Clades and terminals reaching North America include few independent events of more recent range expansions.

In: Insect Systematics & Evolution
Brill's Biology E-Books Online, Collection 2000-2006 is the electronic version of the book publication program of Brill in the field of Biology from 2000-2006.

Coverage: Botany, Carcinology, Entomology, Nematology, Perception and Behaviour, Zoology in general
This E-Book Collection is part of Brill's Biology E-Books Online Collection.
The title list and free MARC records are available for download here.