Givaudan-Roure Lecture - Association for Chemoreception Sciences

53 Poster [ ] Olfaction: Animal Behavior
AESTHETASCS, THE OLFACTORY SENSILLA, ARE
MEDIATORS OF CHEMOSENSORY ACTIVATION OF
ANTENNULAR FLICKING IN THE SPINY LOBSTER,
PANULIRUS ARGUS
Daniel P.C. 1 1Biology, Hofstra University, Hempstead, NY
Lobster antennules bear a number of different sensilla sensitive to
odorants. We have found that two antennular behaviors, grooming
(Wroblewska et al., Chem. Senses 27:769-778, 2002) and flicking (Fox
et al. Chem. Senses 28:555, 2003), are mediated by aesthetascs and/or
asymmetric setae located in the “tuft” region of the lateral flagellum.
Flicking also requires “non-tuft” setae scattered across the lateral and
medial flagella. Schmidt et al. (this meeting) have found through
ablation experiments that grooming is solely activated by asymmetric
setae. The present study used similar techniques to determine the
relative importance of aesthetascs and asymmetric setae to activation of
flicking behavior. Two groups of lobsters were sham-ablated by
removing a row of guard setae and then tested for antennular responses
to L-glutamate (the major chemical stimulus eliciting grooming), and
squid extract (concentration). This was followed by either ablation of
asymmetric setae (N=8) or ablation of aesthetascs (N=6) after which the
behavioral assay was repeated. Lobsters with asymmetric setae
removed no longer groomed in response to glutamate but showed no
reduction in flick rate to squid extract compared to their responses to
the same odorants following sham ablation. In contrast, lobsters with
aesthetascs removed showed no reduction in grooming to glutamate but
no longer increased flick rates to squid extract. These results, along
with those from the earlier study, suggest that olfactory and
nonolfactory pathways are utilized in eliciting flicking behavior in
which processing occurs via the olfactory lobes and the lateral
antennular neuropils.
54 Poster [ ] Olfaction: Animal Behavior
BEHAVIORAL DISCRIMINATION OF AMINO ACIDS IN
ZEBRAFISH (DANIO RERIO)
Valentincic T. 1, Miklavc P. 1 1Department of Biology, University of
Ljubljana, Ljubljana, Slovenia
Based on the dissimilar patterns of glomerular activation during
amino acid stimulation in recent calcium-imaging studies in zebrafish
(Friedrich and Korsching, 1997), it is possible, but previously untested,
that this species is capable of discriminating behaviorally different
amino acids. As performed in catfish, olfactory discrimination was
studied by conditioning zebrafish with a food reward that was presented
90 seconds after the conditioning amino acid solution was injected into
the aquarium. Tests for discrimination began after ~50 conditioning
sessions. Conditioned zebrafish, which associated a specific amino acid
odor with a food reward, searched for food longer and more intensely
(measurements of the swimming path by video-tracking or counting the
turns >90 degrees during 90 seconds) than after stimulation with a nonconditioned
amino acid. We used 3x10-5M L-Ala, L-Val and L-Arg,
respectively, as conditioning stimuli and the following as test stimuli:
Gly, L-Ala, L-Ser, L-Phe, L-Tyr, L-Trp, L-His, L-Asn, L-Val, L-Ile, L-
Leu, L-Met, L-Arg, L-Lys, L-Glu, L-Asp, L-Pro and D-Ala . With the
exception of the L-Val conditioning stimulus and the L-Ile test
stimulus, zebrafish discriminated all the conditioning stimuli from the
test stimuli. Our results clearly indicated that the amino acids that
previously showed similar glomerular activity patterns (e.g. L-Val and
L-Ile), were not discriminated behaviorally by zebrafish, but those in
which the glomerular activation patterns were distinct were readily
discriminated.
Friedrich, R.W. and Korsching, S., 1997. Combinatorial and
chemotopic odorant coding in the zebrafish olfactory bulb visualised by
optical imaging. Neuron 18:737-752.
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55 Poster [ ] Olfaction: Animal Behavior
OLFACTORY COMMUNICATION: EVOLVING NEW BLENDS
AND NOVEL PREFERENCES
Vickers N.J. 1, Hillier K. 1, Groot A. 2, Gould F.L. 2 1Biology, University
of Utah, Salt Lake City, UT; 2Entomology, North Carolina State
University, Raleigh, NC
Male moths are often extremely sensitive and narrowly tuned to the
blend of components emitted by conspecific females. The sexual
communication channel is therefore under strong stabilizing selective
pressure. How then do new female blends and male preferences evolve?
Two closely related moth species, Heliothis virescens and Heliothis
subflexa, can be hybridized under laboratory conditions in order to
study the genetic basis of behavior and olfactory characteristics that
accompany species divergence. Males of these two species prefer
qualitatively distinct blends that include either Z9-14:Ald (H. virescens)
or Z9-16:Ald (H. subflexa). In addition, H. subflexa males require Z11-
16:OH. These behavioral preferences are correlated with the specificity
of olfactory receptor neurons and central interneurons arborizing within
the glomeruli of the male-specific macroglomerular complex. Wind
tunnel studies have shown that Z9-14:Ald/Z9-16:Ald preference
segregates in a 1:1 ratio in backcross males. Preliminary genetic (QTL)
analyses have revealed that this trait is associated with a single
autosomal chromosome suggesting that a major gene may control this
phenotype, perhaps coupled to the expression of odorant receptors.
Other divergent characters in this system, such as Z11-16:OH-agonism
and Z11-16:OAc-antagonism, may involve odorant receptors but also
likely involve shifts in the glomerular targets of receptor axons and
interpretation of olfactory information by higher brain centers.
Supported by NSF IBN-9905683 to NJV.
56 Poster [ ] Olfaction: Animal Behavior
OLFACTORY RECOGNITION IN CANINES
Puchalski D. 1, Leitch A. 1, Hornung D. 1 1Biology Department, St.
Lawrence University, Canton, NY
The overall objective of this work was to assess the specificity of the
olfactory cues that canines use when identifying humans. That is, once
a dog is trained to identify the smell of a human (the target), will the
dog be confused by the smell of the target´s siblings or by the smell of
other people who use the target´s soap or deodorant? A 1-year-old
golden retriever was trained to pick her owner´s scent out of three
possible choices. After a trial had been initiated by “go” the dog would
smell each of three boxes containing T-shirts impregnated with human
scent. The target was randomly assigned to one of the boxes. The boxes
were constructed such that the dog could not use visual cues. The dog
signaled recognition of the target´s smell by a sit/stay response. The
dog was trained to correctly identify the target over 90% of the time.
When there was no target present the dog would repeatedly sample the
three boxes and 80% of the time give no recognition signal. The dog
was rewarded only for correct target responses. Probe trials consisting
of the scent of the target´s siblings or of the scent of other humans who
had used the soap and/or deodorant of the target were inserted into the
testing sessions. There was no reward given during a probe trial. The
dog gave the recognition response more often to the smell of the
target´s siblings as compared to the smell of non-related humans.
Likewise the dog gave the recognition response more often when nonrelated
humans used either the soap or deodorant of the target. These
results suggest that both genetic factors (such as HLA typing) and
added smells (such as soap) may have some bearing on canine olfactory
recognition of humans.