Good Bugs Gone Bad

[Mona Miller]

Good Bugs Gone Bad
By Doug Stewart
Introduced into this country to control pests, these insects now wreak havoc of their own
https://secure.nwf.org/nationalwildlife ... &issueID=6

[Mona Miller]

http://en.wikipedia.org/wiki/Harmonia_axyridis
"Background This species was possibly established as the result of
introductions into the United States in an attempt to control the spread of
aphids. Whatever the source, in the last two decades, this insect has spread
throughout the United States and Canada and has been a prominent factor in
controlling aphid populations. However, many people now view this species as
a nuisance, partly due to their tendency to overwinter indoors and the
unpleasant odor and stain left by their bodily fluid when frightened or
squashed. It is also currently increasing in Europe to the detriment of
indigenous species, due to its voracious appetite which enables them to
out-compete and even eat other lady beetles, as it also does in the United
States."

Be careful that you know what you are identifying. You don't want to
destory the native ladybugs. And, many website are encouraging the
relocation of the asian ladybug, but apparently they are relocating
themselves in large numbers.

[Mona Miller]

http://www.invasive.org/hostrange/ch2.pdf
CHAPTER 2. THE EFFECTS OF COMPSILURA CONCINNATA,
AN INTRODUCED GENERALIST TACHINID, ON NON-TARGET
SPECIES IN NORTH AMERICA: A CAUTIONARY TALE
J. S. Elkinton and G. H. Boettner
Deptartment of Plant, Soil and Insect Science: Division of Entomology,
University of Massachusetts, Amherst, MA 01003 USA
elkinton@ent.umass.edu
INTRODUCTION
Classical biological control has long been a principal weapon in the worldwide effort to combat
the devastating effects of invasive species. Classical biological control involves locating natural
enemies of invasive species in their native range and releasing them in the newly invaded habitat.
The premise of classical biological control is that invasive species out-compete native species
and become major pest problems in large part because they have become isolated from the
suite of natural enemies that keep them in check in their native habitat. There have been many
successes worldwide in the classical biological control of both invasive weeds and invasive
arthropods. The advantages of classical biological control over any other approach are obvious
and well known: the control exerted is typically permanent; it requires little or no further
intervention; it is thus highly cost effective compared to mechanical removal or use of chemical
pesticides, which must typically be applied repeatedly and are often infeasible in forests or
other natural habitats.
Classical biological control of invasive weeds has had a long history of evaluating the host
range of candidates for introduction. The obvious reason is that herbivorous natural enemies
might become important pests of agricultural crops or other beneficial plants. In contrast, traditionally
there has been little concern about the potential impacts on non-target native insects
that might be caused by the introduced natural enemies of invasive arthropods. Indeed, the
ability of natural enemies to attack native non-target species was viewed by many as a positive
attribute (e.g., Culver, 1919; Webber and Schaffner, 1926). Native species might be pests in their
own right, or, at the very least, they might provide a host reservoir that would maintain high
densities of the natural enemy when densities of the target insect were low.
Until recently, there was little or no evidence that arthropod predators or parasitoids introduced
as biological control agents against other invasive arthropods had had any important
deleterious effects on non-target species. As a result, several authors have concluded that the
technique is generally safe and unlikely to have significant effects on non-target organisms
(Coulson et al., 1991; Godfray, 1995). However, as pointed out by Howarth (1991), “absence
of evidence is not evidence of absence” of such effects. In the last few years, several studies have
elucidated negative impacts by a number of introduced agents (e.g. Obrycki et al., 2000;
Henneman and Marmot, 2001). Here we review our work on this topic focusing on the nontarget
effects of the generalist tachinid parasitoid Compsilura concinnata (Meigen), which was
introduced to North America in 1906 primarily to control the gypsy moth, Lymantria dispar
L. We have shown that this species is probably having a severe impact on a number of our
native giant silk moths (Saturniidae) (Boettner et al., 2000), which include our largest and most
showy native Lepidoptera.

http://www.entomology.wisc.edu/mbcn/kyf609.html
Know Your Friends
The tachinid fly Compsilura concinnata is a parasitoid of gypsy moth and other imported pests, such as satin moth and brown-tail moth. It was one of more than 45 species of natural enemies introduced for control of gypsy moth over a period of over 50 years, beginning in 1906. This native European species is highly polyphagous and has been reared from more than 200 host species in the United States. Some are pests such as forest tent caterpillar, but many are non-pest species in the families Nymphalidae (brushfooted butterflies) or Saturniidae (giant silkworms).