Olfactory Ability Research Articles

Brain anatomy of the marine isopod Saduria entomon Linnaeus, 1758 (Valvifera, Isopoda) with special emphasis on the olfactory pathway.

Representatives of at least six crustacean taxa managed to establish a terrestrial life style during their evolutionary history and the Oniscidea (Isopoda) are currently held as the most successfully terrestrialized malacostracan crustaceans. The brain architecture of terrestrial isopods is fairly well understood and studies on this field suggest that the evolutionary transition from sea to land in isopods coincided with a considerable size reduction and functional loss of their first pair of antennae and associated brain areas. This finding suggests that terrestrial isopods may have no or poor abilities to detect volatile substances but that their chemosensory ecology is most likely restricted to contact chemoreception. In this study, we explored how the brain of a marine isopod and particularly its olfactory system compares to that of terrestrial relatives. Using histochemical and immunohistochemical labeling, brightfield and confocal laser-scan microscopy, we show that in the marine isopod Saduria entomon aesthetascs on the first pair of antennae provide input to a well defined deutocerebrum (DC). The deutocerebral chemosensory lobes (DCL) are divided into spherical neuropil compartments, the olfactory glomeruli (og). Secondary processing areas in the lateral protocerebrum (lPC) are supplied by a thin but distinct projection neuron tract (PNT) with a contralateral connection. Hence, contrary to terrestrial Isopoda, S. entomon has at least the neuronal substrate to perceive and process olfactory stimuli suggesting the originally marine isopod lineage had olfactory abilities comparable to that of other malacostracan crustaceans.

Sensory Systems and Environmental Change on Behavior during Social Interactions

The impact of environmental conditions for transmitting sensory cues and the ability of crayfish to utilize olfaction and vision were examined in regards to social interactive behavior. The duration and intensity of interactions were examined for conspecific crayfish with different sensory abilities. Normally, vision and chemosensory have roles in agonistic communication ofProcambarus clarkii; however, for the blind cave crayfish (Orconectes australis packardi), that lack visual capabilities, olfaction is assumed to be the primary sensory modality. To test this, we paired conspecifics in water and out of water in the presence and absence of white light to examine interactive behaviors when these various sensory modalities are altered. For sighted crayfish, in white light, interactions occurred and escalated; however, when the water was removed, interactions and aggressiveness decreased, but, there was an increase in visual displays out of the water. The loss of olfaction abilities for blind cave and sighted crayfish produced fewer social interactions. The importance of environmental conditions is illustrated for social interactions among sighted and blind crayfish. Importantly, this study shows the relevance in the ecological arena in nature for species survival and how environmental changes disrupt innate behaviors.

Olfactory Discrimination Ability of Asian Elephants (Elephas maximus) for Structurally Related Odorants

Using a food-rewarded two-choice instrumental conditioning paradigm, we assessed the ability of Asian elephants, Elephas maximus, to discriminate between 2 sets of structurally related odorants. We found that the animals successfully discriminated between all 12 odor pairs involving members of homologous series of aliphatic 1-alcohols, n-aldehydes, 2-ketones, and n-carboxylic acids even when the stimuli differed from each other by only 1 carbon. With all 4 chemical classes, the elephants displayed a positive correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length. The animals also successfully discriminated between all 12 enantiomeric odor pairs tested. An analysis of odor structure-activity relationships suggests that a combination of molecular structural properties rather than a single molecular feature may be responsible for the discriminability of enantiomers. Compared with other species tested previously on the same sets of odor pairs (or on subsets thereof), the Asian elephants performed at least as well as mice and clearly better than human subjects, squirrel monkeys, pigtail macaques, South African fur seals, and honeybees. Further comparisons suggest that neither the relative nor the absolute size of the olfactory bulbs appear to be reliable predictors of between-species differences in olfactory discrimination capabilities. In contrast, we found a positive correlation between the number of functional olfactory receptor genes and the proportion of discriminable enantiomeric odor pairs. Taken together, the results of the present study support the notion that the sense of smell may play an important role in regulating the behavior of Asian elephants.

Olfactory ability to detect ovulatory cues: A function of biological sex, sexual orientation, or both?

For two decades, psychologists studying ovulation have successfully employed a series of “T-shirt studies” supporting the hypothesis that men can detect when a woman is most fertile based on olfactory detection of ovulatory cues. However, it is not known whether the ability to detect female fertility is primarily a function of biological sex, sexual orientation, or a combination of both. Using methodologies from previous T-shirt studies, we asked women not using hormonal contraceptives to wear a T-shirt for three consecutive nights during their follicular (ovulatory) and luteal (non-ovulatory) phases. Male and female participants of differing sexual orientations then rated the T-shirts based on intensity, pleasantness, and sexiness. Heterosexual males were the only group to rate the follicular T-shirts as more pleasant and sexy than the luteal T-shirts. Near-significant trends also indicated that heterosexual men and non-heterosexual women consistently ranked the T-shirts, regardless of menstrual stage, to be more intense, pleasant, and sexy than did non-heterosexual men and heterosexual women. Recommendations for future research, including suggestions for methodological changes, are discussed.

Effects of protein restriction during gestation and lactation on cell proliferation in the hippocampus and subventricular zone: Functional implications. Protein restriction alters hippocampal/SVZ cell proliferation

There is no consensus about the effects of protein restriction on neurogenesis and behavior. Here, for the first time, we evaluated the effects of protein restriction during gestation and lactation, on the two major neurogenic regions of the adult brain, the subgranular zone (SGZ) of the hippocampal dentate gyrus and the subventricular zone (SVZ), simultaneously. We also assessed different types of behavior relevant to each region. After mating, pregnant Wistar rats were divided into a control group (CG) that received a normal diet (20% protein); and a protein-restriction group (PRG) that received a low-protein diet (8% protein). After birth, the same diets were provided to the mother and pups until weaning, when some rats were analyzed and others received a normal-protein diet until adulthood. Different sets of rats were used for cellular and behavioral studies in juvenile or adult age. Brains were processed for immunohistochemistry anti-BrdU, anti-Ki67, or anti-pHisH3. Juvenile and adult rats from distinct litters also underwent several behavioral tests. Our data show that early protein restriction results in a reduction of hippocampal progenitors and deficits in object recognition during adult life. Moreover, longer periods of immobility in the tail suspension and in the forced swimming tests revealed that PRG rats show a depressive behavior at 21 days of age (P21) and in adulthood. Furthermore, we suggest that despite the reduced number/proliferation of neural stem cells (B and/or E cells) in SVZ there is a compensatory mechanism in which the progenitors (types C and A cells) proliferate in a higher rate, without affecting olfactory ability in adulthood.

Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers

Using a food-rewarded two-choice instrumental conditioning paradigm we assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs. The results demonstrate that the fur seals as a group were able to discriminate between the optical isomers of carvone, dihydrocarvone, dihydrocarveol, menthol, limonene oxide, α-pinene, fenchone (all p<0.01), and β-citronellol (p<0.05), whereas they failed to distinguish between the (+)- and (-)-forms of limonene, isopulegol, rose oxide, and camphor (all p>0.05). An analysis of odor structure-activity relationships suggests that a combination of molecular structural properties rather than a single molecular feature may be responsible for the discriminability of enantiomeric odor pairs. A comparison between the discrimination performance of the fur seals and that of other species tested previously on the same set of enantiomers (or subsets thereof) suggests that the olfactory discrimination capabilities of this marine mammal are surprisingly well developed and not generally inferior to that of terrestrial mammals such as human subjects and non-human primates. Further, comparisons suggest that neither the relative nor the absolute size of the olfactory bulbs appear to be reliable predictors of between-species differences in olfactory discrimination capabilities. Taken together, the results of the present study support the notion that the sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals.

Consequences of Evolution

We hypothesize that if otitis media is most likely primarily a human disease due to consequences of evolution, rhinosinusitis may also be limited to humans for similar reasons. If otitis media, with its associated hearing loss, occurred in animals in the wild, they probably would have been culled out by predation. Similarly, if rhinosinusitis occurred regularly in animals, they likely would have suffered from severely decreased olfactory abilities, crucial for predator avoidance, and presumably would likewise have been selected against evolutionarily. Thus, both otitis media and rhinosinusitis-common conditions particularly in infants and young children-appear to be essentially human conditions. Their manifestation in our species is likely due to our unique evolutionary trajectory and may be a consequence of adaptations, including adaptations to bipedalism and speech, loss of prognathism, and immunologic and environmental factors.

Olfactory Abilities and Psychopathy: Higher Psychopathy Scores Are Associated with Poorer Odor Discrimination and Identification

Olfactory processing is known to involve the orbitofrontal cortex (OFC). The OFC is also believed to function less effectively in individuals scoring higher in psychopathic personality traits. In this study, we examined whether poorer olfactory discrimination and identification—taken as an indicator of OFC integrity—was associated with the degree of presence of psychopathic traits in a community sample. Seventy-nine non-criminal participants completed the Self-Report Psychopathy scale and a standardized measure of olfactory ability, the Sniffin’ Sticks, measuring odor threshold, identification, and discrimination. Consistent with predictions, we found a relationship between psychopathy and olfactory discrimination and identification but not odor threshold, even after controlling for gender, age, empathy, smoking status, and craniofacial surgery/injury. These findings suggest that brain areas subserving higher olfactory processes—identification and discrimination—are somehow less efficient in individuals who score higher on psychopathic traits. In particular, we suggest that this relates to processing within the orbitofrontal cortex.

Olfactory ability and object memory in three mouse models of varying body weight, metabolic hormones, and adiposity

Physiological and nutritional state can modify sensory ability and perception through hormone signaling. Obesity and related metabolic disorders present a chronic imbalance in hormonal signaling that could impact sensory systems. In the olfactory system, external chemical cues are transduced into electrical signals to encode information. It is becoming evident that this system can also detect internal chemical cues in the form of molecules of energy homeostasis and endocrine hormones, whereby neurons of the olfactory system are modulated to change animal behavior towards olfactory cues. We hypothesized that chronic imbalance in hormonal signaling and energy homeostasis due to obesity would thereby disrupt olfactory behaviors in mice. To test this idea, we utilized three mouse models of varying body weight, metabolic hormones, and visceral adiposity — 1) C57BL6/J mice maintained on a condensed-milk based, moderately high-fat diet (MHF) of 32% fat for 6months as the diet-induced obesity model, 2) an obesity-resistant, lean line of mice due to a gene-targeted deletion of a voltage-dependent potassium channel (Kv1.3-null), and 3) a genetic model of obesity as a result of a gene-targeted deletion of the melanocortin 4 receptor (MC4R-null). Diet-induced obese (DIO) mice failed to find a fatty-scented hidden peanut butter cracker, based solely on olfactory cues, any faster than an unscented hidden marble, initially suggesting general anosmia. However, when these DIO mice were challenged to find a sweet-scented hidden chocolate candy, they had no difficulty. Furthermore, DIO mice were able to discriminate between fatty acids that differ by a single double bond and are components of the MHF diet (linoleic and oleic acid) in a habituation–dishabituation paradigm. Obesity-resistant, Kv1.3-null mice exhibited no change in scented object retrieval when placed on the MHF-diet, nor did they perform differently than wild-type mice in parallel habituation–dishabituation paradigms of fatty food-related odor components. Genetically obese, MC4R-null mice successfully found hidden scented objects, but did so more slowly than lean, wild-type mice, in an object-dependent fashion. In habituation–dishabituation trials of general odorants, MC4R-null mice failed to discriminate a novel odor, but were able to distinguish two fatty acids. Object memory recognition tests for short- and long-term memory retention demonstrated that maintenance on the MHF diet did not modify the ability to perform these tasks independent of whether mice became obese or were resistant to weight gain (Kv1.3-null), however, the genetically predisposed obese mice (MC4R-null) failed the long-term object memory recognition performed at 24h. These results demonstrate that even though both the DIO mice and genetically predisposed obese mice are obese, they vary in the degree to which they exhibit behavioral deficits in odor detection, odor discrimination, and long-term memory.

Implicit olfactory abilities in traumatic brain injured patients

To investigate implicit olfactory abilities in a group of anosmic traumatic brain injured (TBI) patients, an olfactomotor priming paradigm was administered. A group of matched normosmic/mildly microsmic TBI patients and a group of neurologically healthy participants served as controls. For all the groups, an interference effect was evident on the peak velocity of grip aperture when participants grasped a large target preceded by a “small” odor. The present results suggest that some form of implicit olfactory processing is preserved in TBI patients even when diagnosed as anosmic on the basis of explicit olfactory testing.

Associative olfactory learning of the red dwarf honey bee Apis florea

Apis florea has a wide distribution in southeast Asia, where it is the dominant honey bee species. It is an excellent colonizer, suggesting advanced behavioral plasticity. Using the proboscis extension response (PER) conditioning method, we investigated A. florea associative olfactory learning ability and compared it to the learning performances of Apis mellifera. A. florea workers reacted to pure odorant (conditioned stimulus) only when it was delivered in paired associations with sucrose rewards (unconditioned stimulus), and discriminated between a rewarded and unrewarded odor. Moreover, A. florea levels of acquisition in olfactory associative learning were higher in our study than those of A. mellifera, and they showed better retention of learning after 24 h than A. mellifera. Our results show that A. florea can be studied using PER procedures, enlarging the scope for future comparative studies of associative olfactory learning ability in bees.

Autism-relevant social abnormalities and cognitive deficits in engrailed-2 knockout mice.

ENGRAILED 2 (En2), a homeobox transcription factor, functions as a patterning gene in the early development and connectivity of rodent hindbrain and cerebellum, and regulates neurogenesis and development of monoaminergic pathways. To further understand the neurobiological functions of En2, we conducted neuroanatomical expression profiling of En2 wildtype mice. RTQPCR assays demonstrated that En2 is expressed in adult brain structures including the somatosensory cortex, hippocampus, striatum, thalamus, hypothalamus and brainstem. Human genetic studies indicate that EN2 is associated with autism. To determine the consequences of En2 mutations on mouse behaviors, including outcomes potentially relevant to autism, we conducted comprehensive phenotyping of social, communication, repetitive, and cognitive behaviors. En2 null mutants exhibited robust deficits in reciprocal social interactions as juveniles and adults, and absence of sociability in adults, replicated in two independent cohorts. Fear conditioning and water maze learning were impaired in En2 null mutants. High immobility in the forced swim test, reduced prepulse inhibition, mild motor coordination impairments and reduced grip strength were detected in En2 null mutants. No genotype differences were found on measures of ultrasonic vocalizations in social contexts, and no stereotyped or repetitive behaviors were observed. Developmental milestones, general health, olfactory abilities, exploratory locomotor activity, anxiety-like behaviors and pain responses did not differ across genotypes, indicating that the behavioral abnormalities detected in En2 null mutants were not attributable to physical or procedural confounds. Our findings provide new insight into the role of En2 in complex behaviors and suggest that disturbances in En2 signaling may contribute to neuropsychiatric disorders marked by social and cognitive deficits, including autism spectrum disorders.

Learning Impairment in Honey Bees Caused by Agricultural Spray Adjuvants

BackgroundSpray adjuvants are often applied to crops in conjunction with agricultural pesticides in order to boost the efficacy of the active ingredient(s). The adjuvants themselves are largely assumed to be biologically inert and are therefore subject to minimal scrutiny and toxicological testing by regulatory agencies. Honey bees are exposed to a wide array of pesticides as they conduct normal foraging operations, meaning that they are likely exposed to spray adjuvants as well. It was previously unknown whether these agrochemicals have any deleterious effects on honey bee behavior.Methodology/Principal FindingsAn improved, automated version of the proboscis extension reflex (PER) assay with a high degree of trial-to-trial reproducibility was used to measure the olfactory learning ability of honey bees treated orally with sublethal doses of the most widely used spray adjuvants on almonds in the Central Valley of California. Three different adjuvant classes (nonionic surfactants, crop oil concentrates, and organosilicone surfactants) were investigated in this study. Learning was impaired after ingestion of 20 µg organosilicone surfactant, indicating harmful effects on honey bees caused by agrochemicals previously believed to be innocuous. Organosilicones were more active than the nonionic adjuvants, while the crop oil concentrates were inactive. Ingestion was required for the tested adjuvant to have an effect on learning, as exposure via antennal contact only induced no level of impairment.Conclusions/SignificanceA decrease in percent conditioned response after ingestion of organosilicone surfactants has been demonstrated here for the first time. Olfactory learning is important for foraging honey bees because it allows them to exploit the most productive floral resources in an area at any given time. Impairment of this learning ability may have serious implications for foraging efficiency at the colony level, as well as potentially many social interactions. Organosilicone spray adjuvants may therefore contribute to the ongoing global decline in honey bee health.

Kin recognition and inbreeding avoidance in wild birds: the first evidence for individual kin-related odour recognition

Identification of family members plays a primary role in the evolution of social behaviours such as nepotism, altruism and mate choice. The process is particularly important for philopatric species in which the encounter rate of kin-related conspecifics is high. Olfactory-based recognition of individual kin has been identified in most species, with the exception of birds; historically, birds were thought to have poor olfactory abilities, so the use of olfactory cues was ruled out a priori. Here, we show that European storm petrels, Hydrobates pelagicus, are able to distinguish kin from nonkin odours. Using special cotton swabs, like those used in forensic police procedures, we offered birds a binary choice in a Y-maze. Birds significantly preferred odours of unrelated individuals. Olfactory imprinting on a ‘family olfactory template’ or self-referent phenotype matching may be the mechanism underlying this effect. This choice behaviour may allow these highly philopatric birds to avoid inbreeding and select an appropriate mate. Our results suggest that sophisticated olfactory communication is relevant in birds, and leads to important behavioural traits such as philopatry.

Diet‐Induced Obesity Resistance of Kv1.3−/− Mice is Olfactory Bulb Dependent

Gene-targeted deletion of the voltage-gated potassium channel, Kv1.3 (Kv1.3-/-), increases olfactory sensitivity and discriminatory ability, and causes resistance to diet-induced obesity (DIO) in mice. The present study aimed to determine whether the enhanced olfactory ability of the Kv1.3-/- mouse contributes to the resistance to DIO. Kv1.3+/+ and Kv1.3-/- mice were subject to bilateral olfactory bulbectomy (OBX) or sham surgery at 9 weeks of age and placed on either a control chow diet or a 32% moderately high-fat diet (MHF). Caloric and water intake, locomotor activity and oxygen consumption were monitored after 5 weeks of diet treatment. At the end of 26 weeks of diet treatment, fat pad weight and blood chemistry were evaluated. Kv1.3+/+ mice exhibited a significant increase in weight, adiposity, fasting glucose and fasting leptin in response to the MHF-diet, with or without OBX. When treated with a MHF-diet, Kv1.3-/- mice gained significantly less weight than Kv1.3+/+ mice and exhibited a significant increase in light phase metabolism. OBX of Kv1.3-/- mice prevented the resistance to DIO and concomitant up-regulation of light phase metabolism at the same time as decreasing dark phase metabolism and total energy expenditure. These findings suggest that pathways activated in Kv1.3-/- that increased energy expenditure and led to resistance to DIO are olfactory bulb dependent. Thus, these findings add to a growing body of evidence suggesting that the olfactory system can modulate the pathways involved in the regulation of energy balance.

Temporal variation of flower scent in Silene otites (Caryophyllaceae): a species with a mixed pollination system

Floral scent composition and emission are often related to olfactory abilities, preferences and activity times of pollinating agents. However, most studies have focused on species with one pollinator type, and little is known about species with mixed pollination systems. We investigated the temporal variation in flower visitor activity and flower scent emission of Silene otites (Caryophyllaceae), a species regarded as being nocturnal and pollinated by moths and mosquitoes. We found, however, that S. otites is not only visited at night by moths and mosquitoes, but also by a wide range of day-active insects. Furthermore, both the intensity and composition of floral scent change during the course of the day. Total scent emission reached its maximum in the early hours of the night when compounds known to be attractants for moths and/or mosquitoes, such as lilac aldehyde, benzaldehyde, phenylacetaldehyde and 2-phenylethanol, dominated the scent. However, although less intensive, emission continued during the day. In the early morning, α-pinene, hotrienol, 2-phenylethanol and δ-3-carene were the dominant scent compounds. (E)-β-Ocimene, hotrienol and benzyl alcohol contributed proportions of at least 10% before midday when flies, such as syrphids, were abundant flower visitors, whereas linalool and hotrienol contributed to the scent with at least 10% each in the afternoon when bees also contributed to flower visits. We conclude that, in S. otites, the changing emission patterns are ‘in tune’ with the olfactory abilities, preferences and activity times of its day- and night-active potentially pollinating flower visitors. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 447–460.

Implicit olfactory processing attenuates motor disturbances in idiopathic Parkinson's disease

Many reports in the literature indicate that idiopathic Parkinson's disease (IPD) patients have substantial olfactory dysfunctions even before motor symptoms become evident. It has not yet been clarified, however, if some form of implicit olfactory processing is preserved in this population. An olfactory visuomotor priming paradigm, which detects implicit olfactory processing in neurologically healthy participants, was utilized to investigate motor control in relation to olfactory signals in a group of IPD patients. Two control groups were also considered: 12 vascular Parkinson's disease (VPD) in whom normal olfactory abilities are typically reported and 12 neurologically healthy participants. All of the participants were asked to perform reach-to-grasp movements toward large or small targets following olfactory cues delivered by a computer-controlled olfactometer. The odor was either ‘size’ congruent with the target (e.g., strawberry or apple, respectively) or incongruent (e.g., apple or strawberry, respectively). A bend sensor glove (CyberGlove) was used to measure the hand kinematics. Facilitation effects were noted in all the groups with regard to movement time. If a congruent rather than an incongruent odor was delivered, the movement time of the reach-to-grasp was shortened and facilitation effects in maximum grip amplitude were noted in both the IPD and the VPD groups. The maximum grip amplitude was smaller when no odor, as compared to a congruent odor, was delivered. The present results suggest that implicit olfactory processing affects motor control in IPD patients favoring less severe bradykinesia and hand movement hypometria. Once confirmed, these findings could be useful when rehabilitation strategies are being hypothesized for these patients.

Comparison of subjective olfaction ratings in patients with and without olfactory disorders

Olfactory dysfunction is common. The reliability of self-assessment tools for smell testing is still controversial. This study aimed to provide new data about the accuracy of olfactory self-assessment compared with a standardised smell test. Prospective, controlled, cohort study of patients with olfactory disorders and healthy controls. Ninety-six patients with a smell deficit and 71 controls were asked to rate their sense of smell on a visual analogue scale. Their olfactory abilities were also evaluated with the Sniffin' Sticks tests. The whole cohort showed a significant correlation between visual analogue scale smell scores and Sniffin' Sticks total scores. This correlation was also significant in the patient group, but not in the control group. These results were independent of olfactory deficit aetiology and subject age. Self-assessment of olfaction is only a reliable indicator in smell-impaired patients, not in healthy controls. For an accurate assessment of olfaction, reliable, standardised tests are needed.

Variation in Attraction to Host Plant Odors in an Invasive Moth Has a Genetic Basis and is Genetically Negatively Correlated with Fecundity

Lepidopteran insects are major pests of agricultural crops, and mated female moths exploit plant volatiles to locate suitable hosts for oviposition. We investigated the heritability of odor-guided host location behavior and fecundity in the cosmopolitan oriental fruit moth Grapholita (Cydia) molesta, an oligophagous herbivore that attacks fruit trees. We used a full-sib/half-sib approach to estimate the heritability and the genetic correlation between these two traits. Results document a considerable genetic basis for olfactory attraction of females (h ( 2 ) = 0.37 ± 0.17) and their fecundity (h ( 2 ) = 0.32 ± 0.13), as well as a genetic trade-off between female attraction and fecundity (r ( g ) = -0.85 ± 0.21). These estimations were empirically corroborated by comparing two strains maintained in the laboratory for different numbers of generations. The long-term reared strain lost its olfactory discrimination ability but achieved significantly higher fecundity compared with the short-term reared strain. Our results highlight that genetic studies are relevant for understanding the evolution of odor-guided behavior in herbivore insects and for judging the promise of pest management strategies involving behavioral manipulation with plant volatiles.

Olfactory sensitivity in Kea and Kaka

The olfactory capabilities of birds have been vastly underestimated. We investigated the sense of smell of a captive group of New Zealand endemic parrots and found strong support for the hypothesis that both species can detect odour. Our aim was to assess whether Kea (Nestor notabilis) and Kaka (N. meridionalis) display varying behavioural responses to different types and concentrations of scent in comparison to controls. Video monitoring was used to measure parrot visits to scent stations compared with controls and to assess any tendency to explore novel odours. Although our sample sizes were small and individual responses varied, both species showed an ability to distinguish between scents and controls and to detect novel scents. We can conclude that both Kea and Kaka have functional olfactory abilities and we hypothesise that scent plays a significant role in their ecology.