Pros and Cons of Biological Control
ABSTRACT This chapter will briefly review the positive aspects of biological control and will highlight a few examples. It will further
review negative aspects of biological control introductions. One of the examples where biological control led to detrimental
environmental effects was the introduction of the ladybeetle Harmonia axyridis, and this case will be outlined in more detail. This example will also be used to explore some of the population biology
mechanisms which can contribute to the net effects of introduced natural enemies. Finally, some information on recent developments
and improvements in risk assessment of biological control agents is provided.
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ABSTRACT: Reproductive potentials were compared for a large invasive lady beetle, sevenspotted lady beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae), and a set of four smaller native North American species that have been displaced from alfalfa, Medicago sativa L., fields in Utah. The invader rapidly attained predominance in these fields during years when aphid populations were high. In a laboratory experiment, females were provided with excess numbers of their principal prey in these fields, pea aphids, Acyrthosiphon pisum (Harris). Among the five species, both the number and total volume of eggs (number × mean egg volume) produced per day increased with increasing female size and were greatest for C. septempunctata. Rates of reproduction also increased with increasing female size within species. Similarly sized females of C. septempunctata and transverse lady beetle, Coccinella transversoguttata richardsoni (Brown), laid similar total volumes of eggs per day, but females of the invasive species had more ovarioles and laid larger numbers of individually smaller eggs. In summary, when feeding on abundant prey in a habitat in which it predominates, the invasive C. septempunctata gains reproductive advantage over native, North American lady beetles, from its large body size and its investment in many small eggs. The results support the generalization that high fecundity linked with large body size may often be one important factor that promotes the dominance of introduced species over native competitors in resource-rich environments.Annals of the Entomological Society of America 08/2010; 103(5):750-756. · 1.20 Impact Factor
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ABSTRACT: During 1994 -1999 several hundred thousands of Harmonia axyridis adults were released at various cultivations infested by aphids (citrus, vegetable and bean crops, maize, etc.) or in urban places on ornamental plants in central and southern Greece (mainly Attica and Peloponnessos region) as well as on several islands. During 1995-2007, samplings were conducted in some areas, in spring just before any new releases, in order to determine if H. axyridis overwintered in the field. In spring 1995 (the year that followed the first releases) as well in spring 1996-97 and 2000-07, no presence of H. axyridis was recorded in any of the orchards where the predator had been released. Only in spring 1998 and 1999 small colonies (
Analysis and Synthesis
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With 38 Figures and 19 Tables
ISBN-10 3-540-36919-8 Springer Berlin Heidelberg New York
ISBN-13 978-3-540-36919-6 Springer Berlin Heidelberg New York
Library of Congress Control Number: 2006934733
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University of Bern
Cover illustration:The cover drawing shows the global dimensions of three invasion his-
tories.(1) Imports of the first potato (Solanum tuberosum) from the Andean highlands
to Europe began around 1550. In the eighteenth century potatoes were brought to the
east coast of North America from where potato cultivation expanded to the west coast,
until potatoes came into contact with the native weed Solanum rostratum. From this
plant, the Colorado potato beetle (Leptinotarsa decemlineata) switched in 1859 to
Solanum tuberosum, reached via potato fields the east coast of North America, crossed
the Atlantic in 1874, and invaded Europe to East Asia. (2) The common water hyacinth
(Eichhornia crassipes),native to a small area in tropical South America,has been spread
into the tropical and subtropical areas of all continents.(3) In Brazil,cultivated European
honey bees (Apis mellifera) and African wild forms of the honey bee, were interbred.
Around 1956,colonies of the so-called Africanized honey bee escaped and these are cur-
rently spreading into North America.
Yet another book on “Biological Invasions”? It is true,the market already pro-
vides several recent works on this topic and, in the next few years, probably
many more will follow.There are,however,two important points which argue
in favour of the relevance and need of exactly this book.
Most books on biological invasions treat only a small part of the subject.
They cover either invasive plants or invasive pest arthropods,address invasive
species of a country,an island or a habitat,discuss the impact of alien species
on economy or evolution, or gather an impressive number of case studies.
This book is clearly different insofar that it attempts to cover all (or at least
most) of these undoubtedly very important topics.A joint effort of 42 special-
ists, it deals with plants and animals, includes both the terrestrial and the
aquatic environment,guides us from ecology via economy to socio-economy,
and comprises also administrative and management aspects.Our intention is
a strong focus on mechanisms and so,in the opening chapters we analyse the
main pathways of biological invasions and discuss the traits of good invaders.
The patterns of invasion and invasibility point to central aspects such as land
management,nitrogen pollution or climate change.A presentation of the eco-
logical impact of invasive species, based on striking case studies from major
ecosystems worldwide, also tackles the key question whether genetically
modified organisms may become invasive. This all includes relevant eco-
nomic and socio-economic facets. The closing chapters claim an enormous
current lack of preventive means,and demand more administrative and con-
trol measures as well as eradication programs.
This all leads to my second main point,of urgent need.We already live in a
global world,in which the globalizing process has started with full power only
a few decades ago.Still,the pace will increase considerably,and there will be
ever more people and goods moving from one point of the world to another.
This complete loss of biogeographical borders will lead to much more alien
species everywhere and an increasing number of these will become invasive.
Invasion biology,until recently known only to a few experts,is becoming ever