On the failure of two butterfly species to respond to the presence of conspecific eggs prior to oviposition

Abstract. 1. The eggs of Euptychiine butterflies are laid singly, but their distributions tend to be contagious. However, these insects do not discriminate between egg-laden and egg-free plants.
2. Response to conspecific eggs is not part of the mechanism responsible for clumped egg distribution.     

Habitat preferences of the noisy miner (Manorina melanocephala) – a propensity for prime real estate?

This study investigated habitat characteristics that have been postulated to influence the occurrence of noisy miners (Manorina melanocephala Family Meliphagidae). It builds on an earlier study that identified corners along remnant edges as important predictors of the presence of noisy miners in large blocks of remnant vegetation (>300 ha). Six habitat characteristics were recorded at 39 corner sites within the box‐ironbark region of Victoria. We failed to detect any significant effect of the density of understorey vegetation on the likelihood of noisy miners occupying a site, but this might have been an artefact of prolonged drought conditions. The most powerful predictors of the presence of noisy miners at remnant corners were found to be soil type and the proportion of canopy trees at a site that were yellow gum (Eucalyptus leucoxylon), with noisy miners being associated with deeper, more fertile soils and higher proportions of yellow gums present. As yellow gum is a prolific and reliable nectar producer, the inherent productivity of a site might be more important in determining the attractiveness of a site to noisy miners than structural attributes like the presence or absence of an understorey. Noisy miners are sedentary colonial birds that occupy year‐round territories, often at high densities. Sites capable of supporting such high density occupation year‐round might be limited to the most productive sites within the landscape. This productivity hypothesis has potentially profound implications for other woodland avifauna, as noisy miners might be excluding other woodland birds from some of the most fertile components of the landscape; components that are already rare in the box‐ironbark region due preferential clearing for agriculture at the time of settlement.     

Further evidence that resistance in raspberry to the virus vector aphid, Amphorophora idaei, is related to the chemical composition of the leaf surface

In an approach to understand the mechanism(s) of resistance in raspberry to infestation by the aphid Amphorophora idaei, progeny plants segregating for the A. idaei resistance gene, A₁₀, were bioassayed and dichloromethane extracts from the leaf surface were examined by capillary column gas chromatography (GC). No single GC peak was detected that was present in only the resistant progeny plants. Nevertheless, thirteen compounds present in all samples were quantified and identified by mass spectrometry. They were of four major classes; straight chain hydrocarbons, acetic acid esters of long chain alcohols, tocopherols and triterpenoid compounds, including α and β amyrin. Several of these compounds were not recorded previously in raspberry leaves. Linear discriminant analysis, applied to the standardised chromatographic data in an attempt to relate chemical composition to resistance, successfully partitioned 24 of the 26 plants into resistant and susceptible types as determined by bioassay. These data provide further evidence that resistance in raspberry to A. idaei is related to the chemical composition of the leaf surface.     

DESMOGRAPTUS MICRONEMATODES, A SILURIAN DENDROID GRAPTOLITE, AND ITS ULTRASTRUCTURE

Abstract:  Desmograptus  micronematodes from Thornton quarry, Cook County, Illinois, USA, remarkably preserved in relief and encased in pyrite, is described. The internal details of the thecae, and of the stolon system, examined using the SEM, allow the reconstruction of the growth of a stipe. The stolons and stolonal nodes are formed of a dense crassal fabric, and are surrounded by a loose fabric of three-dimensional fibrils. The nodes have a complex structure of three boxes with proximal and distal nozzles. The base of a bitheca, and the base of each autothecal cup, has a central nozzle surrounded by a unique honeycomb fabric. The ultrastructure of the cortical fibrils, with their clockwise striations, is similar to that in Dendrograptus , and may be universal in the graptolites. The nodes of the stolon system appear identical to those of Acanthograptus and other dendroids, but differ from those of the extant hemichordate Rhabdopleura , which have only a diaphragm, and lack box structures.     

Convergent body flattening in a clade of tropical rock-using lizards (Scincidae: Lygosominae)

The repeated occurrence of similar morphologies in organisms from similar habitats provides good evidence of convergent selection, and convergent patterns of evolutionary change. In lizards, a flattened morphology has often been noted; however, whether this trait is convergent in specific habitats has never been tested using phylogenetic methods. The present study examined patterns of morphological convergence in 18 species of tropical Lygosomine skinks from three broad habitat categories (generalist, leaf litter-dwelling, and rock-using species). In general, although there where relatively few morphological differences of species from different habitats, phylogenetic analyses revealed that rock-using species have consistently and repeatedly evolved a dorsoventrally flattened head and body. The adaptive basis of this flattened morphology is consistent with both biomechanical predictions of performance (e.g. climbing locomotion) and ecology (e.g. use of rock crevices, camouflage) of species that occupy rocky habitats.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 399–411.     

Know thy enemy: Behavioural response of a native mammal (Rattus lutreolus velutinus) to predators of different coexistence histories

Abstract Predation is recognized as a major selective pressure influencing population dynamics and evolutionary processes. Prey species have developed a variety of predator avoidance strategies, not least of which is olfactory recognition. However, within Australia, European settlement has brought with it a number of introduced predators, perhaps most notably the red fox (Vulpes vulpes) and domestic cat (Felis catus), which native prey species may be unable to recognize and thus avoid due to a lack of coexistence history. This study examined the response of native Tasmanian swamp rats (Rattus lutreolus velutinus) to predators of different coexistence history (native predator‐ spotted‐tail quoll (Dasyurus maculatus), domestic cats and the recently introduced red fox). We used an aggregate behavioural response of R. l. velutinus to predator integumental odour in order to assess an overall behavioural response to predation risk. Rattus lutreolus velutinus recognized the integumental odour of the native quoll (compared with control odours) but did not respond to either cat or fox scent (compared with control odur). In contrast, analyses of singular behaviours resulted in the conclusion that rats did not respond differentially to either native or introduced predators, as other studies have concluded. Therefore, measuring risk assessment behaviours at the level of overall aggregate response may be more beneficial in understanding and analysing complex behavioural patterns such as predator detection and recognition. These results suggest that fox and cat introductions (and their interactive effects) may have detrimental impacts upon small native Tasmanian mammals due to lack of recognition and thus appropriate responses.