59 research outputs found
The Trout-food insects of Tasmania: Part II--A monograph of the mayflies of Tasmania
The paper forms Part II. of the' Trout-food Insects of Tasmania,'
and is intended to be read with Part I., in which Atalophlebia australis
(Walker), the long-lost genotype of the genus Atalophlebia,
was fully discussed and described. Part II. is a Monograph of the
Mayflies of Tasmania, as far as at present known
The biological control of noxious weeds
R.M. Johnston was honoured in a lecture read by R.J Tilyard in which it was claimed that the most striking achievement of that time was the immense
field of research covered by the biologists of that time.
The great credit of inaugurating work on the biological
control of Noxious Weeds must be given to that extremely
progressive body, the Hawaiian Sugar Planters Association,
and their very capable entomologists.
The plant Lantana camara, originally
introduced about the year 1860 as an ornamental
shrub, soon began to take possession of large areas of land in
the various islands of the Hawaiian group, just as it has done
over large tracts of similar land in the warmer portions of
Eastern Australia.
The well-known entomologist Koebele,
while collecting in Mexico in 1898, noticed that the seeds of
this planrt in its native state were damaged by insects which
bred in them. This suggested to him the idea that the profuse
seeding of the plant might be checked, or even completely
prevented, if these insects could be firmly established
on the weed lantana in the Hawaiian Islands. Four years
later, his idea having been officially approved, he again
visited Mexico, and this time made a thorough study of all
the insects that feed on lantana. More than twenty different
species of these were shipped back to the Chief Entomologist,
Perkins, in Honolulu, and eight of these were soon successfully
established on the island of Oahu, of which Honolulu is the capital. Of these the most important were the species
that prevent the seeding of the plant. The larvae of an
Agromyzid fly, Agromyza lantanae proved to be the most
effective of these; it attacks the berries before they are
mature, and causes them to shrivel up, destroying the seeds
within them.
The Butterfly
larvae feed chiefly on the fiowers, and are therefore also of
great value in preventing the formation of the fruit.
The result of these introductions was a very marked
decrease in the amountof infestation by lantana in the drier
parts of the islands. With the aid of some judicious mechanical
clearing, these parts have now been rendered safe for all
time from being overrun by this dangerous weed
Ethics review: 'Living wills' and intensive care â an overview of the American experience
Withdrawal and limitation of life support in the intensive care unit is common, although how this decision is reached can be varied and arbitrary. Inevitably, the patient is unable to participate in this discussion because their capacity is limited by the nature of the illness and the effects of its treatment. Physicians often discuss these decisions with relatives in an attempt to respect the patient's wishes despite evidence suggesting that the relatives may not correctly reflect the patient's desires. Advance decisions, commonly known as 'living wills', have been proposed as a way of facilitating the maintenance of an individual's autonomy when they become incapacitated. Others have argued that legalising advance decisions is euthanasia by the back door. In October 2007 in England and Wales, advance decisions will become legally binding as part of the 2005 Mental Capacity Act. This has been the case in the USA for many years. The purpose of the present review is to examine the published literature regarding the effect of advance decisions in relation to the provision of adult critical care
The evolution of the class Insecta
The subject of this paper is one which is admittedly
full of difficulty, yet at the same time one of the profoundest
interest, viz., the Evolution of the Insects as a Class from
some ancestral type which was not an Insect, but something
more primitive in its general structure. In attempting
this task, I must first of all classify and pass in review
the various theories that have been advanced by famous
Zloologists or entomologists to account for the origin of
this Class, admittedly the highest development within the
Phylum Arthropoda. Each main hypothesis will be examined
on its merits and tested as to its validity. Having carried
out this task, I then propose to state the position as it
appears to me and to offer a new theory which attempts
to embrace all the known facts of the case
The trout-food insects of Tasmania. Part. I; A study of the genotype of the Mayfly genus Atalophlebia and its life history
The study of the more important insects which serve as food for trout in any given country is, in these days of applied science, an indispensable preliminary to a full understanding of the methods by which a successful and permanent trout-fishery can be maintained in that country. For many years I have been interested in those groups of aquatic insects which are of most importance as trout-food. But I have never found, anywhere in Australia, any public realisation of their economic importance, and thus it comes about that even to-day, when scientific ideas have penetrated further into the public mind than ever before, it still remains impossible for any work on such insects to be carried out officially. The alternatives are, either to leave the subject alone and let the knowledge gained die with one, or to work at the subject slowly in oneâs spare time, in the hope that something of value may come out of it in time to save the inland fisheries of Australia from deterioration due to lack of scientific knowledge
The Earliest Evidence of Holometabolan Insect Pupation in Conifer Wood
Background: The pre-Jurassic record of terrestrial wood borings is poorly resolved, despite body fossil evidence of insect diversification among xylophilic clades starting in the late Paleozoic. Detailed analysis of borings in petrified wood provides direct evidence of wood utilization by invertebrate animals, which typically comprises feeding behaviors.\ud
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Methodology/Principal Findings: We describe a U-shaped boring in petrified wood from the Late Triassic Chinle Formation of southern Utah that demonstrates a strong linkage between insect ontogeny and conifer wood resources. Xylokrypta durossi new ichnogenus and ichnospecies is a large excavation in wood that is backfilled with partially digested xylem, creating a secluded chamber. The tracemaker exited the chamber by way of a small vertical shaft. This sequence of behaviors is most consistent with the entrance of a larva followed by pupal quiescence and adult emergence â hallmarks of holometabolous insect ontogeny. Among the known body fossil record of Triassic insects, cupedid beetles (Coleoptera: Archostemata) are deemed the most plausible tracemakers of Xylokrypta, based on their body size and modern xylobiotic lifestyle.\ud
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Conclusions/Significance: This oldest record of pupation in fossil wood provides an alternative interpretation to borings once regarded as evidence for Triassic bees. Instead Xylokrypta suggests that early archostematan beetles were leaders in exploiting wood substrates well before modern clades of xylophages arose in the late Mesozoic
At last, a Pennsylvanian stem-stonefly (Plecoptera) discovered
<p>Abstract</p> <p>Background</p> <p>Stem-relatives of many winged insect orders have been identified among Pennsylvanian fossils (Carboniferous Period). Owing to their presumed 'basal' position in insect phylogeny, stoneflies were expected to occur at this period. However, no relative has ever been designated convincingly.</p> <p>Results</p> <p>In this paper, we report specimens belonging to a new fossil insect species collected from the Tupo Formation (Pennsylvanian; China). The wing venation of <it>Gulou carpenteri </it><b>gen. et sp. nov</b>. exhibits character states diagnostic of the order Plecoptera, but lack character states shared by unequivocal representatives of the order. Derived from this identification, the delimitation of the fossil species is ascertained based on comparison of several extant stonefly species. This comparative analysis allowed a trait present in <it>G. carpenteri </it><b>gen. et sp. nov</b>., but rarely occurring in extant species, to be documented and highlighted as atavistic. Affinities of taxa formerly proposed as putative stem-stoneflies are reconsidered in the light of the new discovery.</p> <p>Conclusions</p> <p><it>Gulou carpenteri </it><b>gen. et sp. nov</b>. is considered the only genuine Plecoptera reported from the Pennsylvanian. Continuing efforts on the systematics of Pennsylvanian winged insects indicate a fauna more diverse than previously appreciated. It suggests that insects already had a long, yet undocumented, history by this time.</p
Phylogeographic Analysis Elucidates the Influence of the Ice Ages on the Disjunct Distribution of Relict Dragonflies in Asia
Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata
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