Biology Reference
In-Depth Information
11.6 Symbionts and Insect Behavior 502
11.7 Human Neurodegenerative Diseases and Addictions in
Drosophila
503
11.8 High-Throughput Ethomics 506
11.9 Systems Genetics of Complex Traits in
Drosophila
506
11.10 Social Behavior in Bees and Ants
507
11.11 Conclusions 508
References Cited
509
11.1 Overview
The study of insect behavior involves the analysis of any and all activities per-
formed by an insect in relation to its surrounding environment. Behavior
genetics is the study of the underlying hereditary basis of the behavior. For
many years, Mendelian genetic analyses were conducted on a few traits deter-
mined by one or a few genes, or quantitative-genetic methods were used for
traits determined by “many” genes. The sequencing of whole genomes and the
use of molecular-genetic methods are revolutionizing the genetic analysis of
insect behavior. However, one caveat should be recognized, based on a recent
discovery about the discrepancy between behavior in the laboratory and in the
field by the well-studied
Drosophila melanogaster
: the behavior you evaluate in
the laboratory should be tested under conditions approaching the natural envi-
ronment as much as possible or erroneous conclusions could be reached.
Circadian behaviors, mating behavior, and learning in
Drosophila
have
been dissected with the tools of molecular genetics and inter- and intraspe-
cific comparisons can be made of the DNA sequences associated with these
behaviors. The circadian clock of
Drosophila
involves several genes, including
period
+
(
per
+
). Mutants of
period
+
influence activity patterns and other circa-
dian rhythms, as well as altering song cycles in courting males. The
per
+
locus
has been cloned and sequenced in
D. melanogaster
and
D. simulans
. After the
per
+
gene of
D. simulans
was inserted by
P
-element-mediated transformation
into a strain of
D. melanogaster
that is arrhythmic, transgenic
D. melanogaster
males produced song cycles like those of
D. simulans
. As few as four amino
acids may account for the differences in song rhythm determined by the
per
+
locus. The
timeless
+
,
doubletime
+
,
cycle
+
,
cryptochrome
+
, and
Clock
+
genes are
involved in the circadian clock. The clock involves transcription of the
per
+
and
tim
+
genes, followed by production of the PER and TIM proteins and subsequent
negative feedback on self-transcription. Degradation of proteins then releases
the negative feedback, allowing a new round of transcription, resulting in oscil-
lations of RNA and protein.
