Biology Reference
In-Depth Information
(
Hoover et al. 2011
). The body contents of the infected larvae become liquefied,
and the body bursts, releasing millions of infective virus particles. By contrast,
healthy gypsy moth larvae hide in crevices or even climb down the tree to the
soil to avoid bird predation during the day. The cause of change in behavior was
identified as due to a gene in the baculovirus (ecdysteroid uridine 5
′
-diphos-
phate-glucosyltransferase) that encodes an enzyme that inactivates the molt-
ing hormone of gypsy moth larvae.
Hoover et al. (2011)
inoculated gypsy moth
larvae with genetically modified virus containing or lacking the virus gene. As
expected, deletion of the gene from the virus eliminated the climbing behav-
ior of the larvae and rescue of the gene (adding the gene or gene product)
restored the climbing behavior. This behavior was termed an “extended pheno-
type” because the gene in one organism (the parasite) had a phenotypic effect
on another (the host).
Sharon et al. (2010)
found that gut bacteria played a role in mating prefer-
ence of
D. melanogaster
reared on different media. A population of
D. mela-
nogaster
was divided and part was reared on a molasses medium and the
other on a starch medium. When the populations were mixed, flies reared on
molasses preferred to mate with other molasses flies and vice versa. The mat-
ing preference occurred after only one generation and was maintained for
37 generations. Antibiotic treatment eliminated the preference, indicating
that microbes were responsible. The authors suggest the mating preferences
were caused by the bacteria “changing the levels of cuticular hydrocarbon sex
pheromones.”
As noted in Chapter 4, the facultative symbiont
Hamiltonella defensa
affects
the defensive behavior of the pea aphid (
Dion et al. 2011
). Aphids containing
H. defensa
are protected against parasitoids and, as a result, the infected aphids
spend less time being aggressive against the parasitoids and exhibit fewer
escape behaviors. This change in behavior benefited both the aphid and the
symbiont because the aphid was able to feed and survive at a greater rate than
uninfected aphids.
11.7 Human Neurodegenerative Diseases and Addictions
in
Drosophila
Drosophila
is perhaps unique among eukaryotes in the variety and level of
sophistication that can be applied to understand its neurobiology and behavior.
As a result,
Drosophila
is being studied to gain knowledge about various neu-
rodegenerative diseases in humans (
Mutsuddi and Nambu 1998, Andretic et al.
1999, Feany 2000, Fortini and Bonini 2000
).
