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PubMed2003

Problematising depression: young people, mental health and suicidal behaviours.

The published literature provides strong evidence for connections between mental health issues, such as depression, and suicidal behaviours. However, in spite of this, no investigations to date have explored young people's perceptions of the interconnections between depression, and suicidal behaviours. This article presents discussive analyses of discussions of the contributions of depression to their suicidal behaviours of young people in New Zealand. Two dominant discourses of depression emerged: a medicalised discourse, and a moral discourse. The medicalised discourse was accessible to the majority of participants, and constructed depression as a disease. This discourse prioritised the voices of health professionals and suggested that depression was difficult to resist. The moral discourse was an alternative to the medicalised discourse, and constructed young people who experienced depression and suicidal behaviours as failures. Both discourses were informed by a mechanistic cause-and-effect relationship between depression and suicidal behaviours: attempting suicide was seen as an inevitable outcome of experiencing depression, and suicidal behaviours were inevitably undertaken by young people who were depressed. Resistance to either of these dominant discourses was problematic, and was best articulated during discussions of the stigma associated with mental ill-health and depression.

Adult↗
PubMed1997

Urban small area variation in adolescents' health behaviour.

Our previous study indicated that region plays a relatively small role in adolescents' health behaviour. Here, the regional patterning of health behaviour is studied further by shifting the focus to small areas. First, we test whether small area socioeconomic, demographic and housing characteristics correlate with health behaviour. The analysis then turns to the relationship between these characteristics and their individual level correlates. We wish to ascertain if behaviour is related to small area characteristics similarly for both genders and for adolescents' socioeconomic characteristics. The Adolescent Health and Lifestyle Survey data from 1989-1995 (16- and 18-year-olds, n = 1048, response rate 71%) were linked with data describing 33 subareas of Helsinki, the capital of Finland. Smoking, alcohol use, abstention from dietary fat and physical activity were used as lifestyle indicators. Gender apparently influences the extent to which the area plays a role. Logistic regression demonstrated that prolonged unemployment predicted low prevalence of abstention from dietary fat (traditional dietary patterns) among girls and heavy drinking among boys. High total rate of unemployment predicted lower physical activity among girls. Also owner-occupied housing correlated positively with girls' physical activity. Although the individual level socioeconomic characteristics were not as strongly related to health behaviour as the small area factors, a low level of education predicted smoking and alcohol use and, among girls, decreased physical activity. We conclude that small area characteristics, especially the level of unemployment of the area, may be even more strongly related to health behaviour than individual socioeconomic characteristics.

Adolescent↗
PubMed2001

Pain self-efficacy beliefs and pain behaviour. A prospective study.

This study examined the relationship between pain self-efficacy beliefs and a range of pain behaviours, as measured by the pain behaviour questionnaire (PBQ), using a prospective design. A heterogeneous sample of 145 chronic pain patients completed sets of questionnaires on four occasions over a nine-month period. Multiple hierarchical regression analyses revealed that the subjects' confidence in their ability to perform a range of tasks despite pain (assessed at baseline), was predictive of total pain behaviour and avoidance behaviour over the nine-month study period. This finding was particularly significant because the analyses controlled for the possible effects of pain severity (at each measurement occasion), pain chronicity, age, gender, physical disability, depression, neuroticism and catastrophising. These findings suggest that pain self-efficacy beliefs are an important determinant of pain behaviours and disability associated with pain, over and above the effects of pain, distress and personality variables. In particular, higher pain self-efficacy beliefs are predictive of reduced avoidance behaviours over an extended period.

Activities of Daily Living↗
PubMed1998

Multimodal cognitive-behavioural treatment for workers with chronic spinal pain: a matched cohort study with an 18-month follow-up.

An outpatient multimodal cognitive-behavioural treatment program (MMCBT) for chronic spinal pain was evaluated during an 18-month follow-up period. The treatment included a 1-day course for the patients' work supervisors. The aim of the study was to evaluate the long-term effect of the treatment program as well as the effect of a work supervisor-training program on the patients' return to work. The design was a matched cohort study with four repeated measures. Two groups of subjects suffering from non-specific spinal pain (treatment group n=67, no treatment control group n=29) were assessed with regard to pain intensity, sick-leave, pain coping ability and behavioural changes at work and in personal life. Recordings on supervisors attending the course and changes of supervisory behaviour were also obtained. The results show a significant between group difference in pain intensity and perceived pain coping ability at work, favouring the MMCBT group. Further, the MMCBT intervention enhances self-reported behavioural changes in areas within the subjects' own control. There is not sufficient statistical support to accept the assumption of MMCBT being superior in reducing sick-leave, either with or without the education of supervisors. Even when supervisors changed their behaviour as reported by the patient, no significant effect was found on patients' return to work. In conclusion, the MMCBT do not seem to be effective in reducing sick-leave compared to no treatment, but the MMCBT program is superior in decreasing pain intensity, enhancing self-reported behavioural changes in personal life and improving pain coping ability at work.

Adult↗
PubMed2000

Intrathecally administered spermine produces the scratching, biting and licking behaviour in mice.

Intrathecal (i.t.) administration of spermine (0.1-10000 fmol), an endogenous polyamine, produced the behavioural response mainly consisting of biting and/or licking of the hindpaw along with a slight hindlimb scratching directed toward the flank in mice, which peaked at 5-15 min and almost disappeared at 30 min after an injection. The behaviour induced by spermine (10 pmol) was dose-dependently inhibited by intraperitoneal injection of morphine (0.125-0.5 mg/kg). The characteristic behaviour was also inhibited dose-dependently by i.t. co-administration of ifenprodil (62.5-4000 pmol), a competitive antagonist of the polyamine recognition site on N-methyl-D-aspartate (NMDA) receptor ion-channel complex, and D(-)-2-amino-5-phosphonovaleric acid (D-APV) (0.5-2 nmol) and 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) (7. 8-500 pmol), the competitive NMDA receptor antagonists, and (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,b]cycloheptene-5, 10-imine hydrogen maleate (MK-801) (0.5-4 nmol), an NMDA ion-channel blocker, but not by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist. Both (2S, 3S)-[cis-2-(diphenylmethyl)-N-[(2-methoxyphenyl)-methyl]-1-azabicy clo [2.2.2]octane-3-amine] (CP-96,345), a non-peptidic neurokinin-1 (NK-1) receptor antagonist, and CP-96,344, its inactive 2R,3R enantiomer, inhibited spermine-induced behavioural response in a dose-dependent manner. However, [Tyr(6), D-Phe(7), D-His(9)]-substance P(6-11) (sendide) and [D-Phe(7), D-His(9)]-substance P(6-11), the selective antagonists for NK-1 receptors, were without affecting spermine-induced behaviour. These results indicate that spermine-induced behaviour is mediated through the polyamine recognition site on NMDA receptor ion-channel complex without the involvement of substance P system in the mouse spinal cord.

Aggression↗
PubMed1997

Contrasting effects of excitotoxic lesions of the prefrontal cortex on the behavioural response to D-amphetamine and presynaptic and postsynaptic measures of striatal dopamine function in monkeys.

The effects of excitotoxic lesions of the prefrontal cortex on behavioural, neurochemical and molecular indices of dopamine function in the caudate nucleus were studied in the marmoset. The lesion, which encompassed both the lateral and orbital regions of prefrontal cortex, made the animals more sensitive to the performance disrupting effects of the dopamine releasing drug, D-amphetamine, in a variation of the object retrieval task. Specifically, following drug administration, the lesioned marmosets were less able to gain access to food reward in the minimum number of responses. Analysis of the nature of the errors suggested that the deficit was not due to inhibition of a prepotent response as the lesioned monkeys were just as likely to make a detour reach to the unopened side of the box as a direct "line-of-sight" reach into the unopened front of the box. Rather, the data indicated a general disorganization of behaviour. The enhanced behavioural responsiveness to manipulations increasing presynaptic dopamine function was accompanied by neurochemical changes indicating a reduced responsiveness, as revealed by in vivo microdialysis. Thus, in lesioned animals, whilst there were no effects on baseline levels of extracellular dopamine in dorsolateral caudate, evoked release, both to systemic D-amphetamine and to a local depolarizing pulse of potassium ions, was attenuated. These opposite effects of the prefrontal cortex lesion on behavioural and neurochemical indices of striatal dopamine function occurred in the absence of any changes in striatal dopamine receptors of the D1 and D2 subtype, as determined both by radioligand binding assays and measurements of messenger RNA using in situ hydridization techniques. These data provide further insight into the interactions between prefrontal cortex and striatal dopamine function in the non-human primate. In particular, when taken in the light of our previous studies they indicate that following prefrontal manipulations, concurrence between behavioural and neurochemical indices of striatal dopamine function depends, critically, on the behavioural task. These findings are discussed with respect to the growing body of evidence implicating abnormalities in frontostriatal neurotransmission in complex disorders such as schizophrenia.

Analysis of Variance↗
PubMed1998

Forebrain expression of c-fos due to active maternal behaviour in lactating rats.

To reveal brain sites simultaneously active during the expression of maternal behaviour in lactating rats, we used immunocytochemical visualization of the nuclear protein product Fos of the immediate-early gene c-fos as a marker of neuronal activity. After a 48 h separation from their litter, day 7 postpartum dams received a 1 h period of physical interaction with pups either capable or incapable of suckling, inaccessible pups in a wire-mesh box, an empty box, or no stimulation. Physical interaction with pups elicited high levels of pronurturant maternal behaviour (retrieval, licking, mouthing), and suckling elicited nursing behaviour as well. Exposure to the box, with or without pups, elicited high levels of investigatory sniffing, self-grooming, and general activity. Distal stimulation from pups did not differentially activate Fos in any of 20 sites, including olfactory-processing structures such as the piriform cortex and medial amygdala. Physical interaction with pups, with or without suckling, elicited higher levels of Fos-immunoreactive nuclei than that of other conditions in numerous sites, including many previously implicated in maternal behaviour (medial preoptic nucleus, nucleus accumbens, lateral septum, lateral habenula, and the bed nucleus of the stria terminalis). Similar group patterns of Fos expression also occurred in sites not previously implicated in maternal behaviour (somatosensory cortex and paraventricular thalamic nucleus). Interaction with nonsuckling pups elicited the highest levels of Fos in the cortical amygdala, whereas suckling did not activate higher Fos than nonsuckling interaction in any site included in this report, including hypothalamic nuclei involved in lactation (paraventricular, supraoptic, and arcuate). There was little or no Fos in cingulate cortex, olfactory tubercle, medial septum, medial habenula, or ventromedial hypothalamus. These data suggest that trigeminal stimuli received by lactating rats during the performance of pronurturant maternal behaviour promote cellular activity resulting in neuronal expression of c-fos in many forebrain sites including the medial preoptic nucleus, several sites connected with it that are part of the mesotelencephalic dopamine system, and in the somatosensory cortex. In contrast, in these forebrain sites suckling does not elicit greater levels of Fos than that seen in nonsuckled rats and distal stimuli from pups are ineffective in increasing Fos levels compared with non-stimulated controls.

Animals↗
PubMed1997

Glial cell line-derived neurotrophic factor attenuates behavioural deficits and regulates nigrostriatal dopaminergic and peptidergic markers in 6-hydroxydopamine-lesioned adult rats: comparison of intraventricular and intranigral delivery.

The effects of intranigrally- or intraventricularly-administered glial cell line-derived neurotrophic factor were tested on low dose (0.05 mg/kg) apomorphine-induced rotations and tyrosine hydroxylase activity in the substantia nigra and striatum of stable 6-hydroxydopamine-lesioned rats. In addition, we determined if 6-hydroxydopamine lesions in the absence or presence of treatment affected neuropeptide (substance P, met-enkephalin, dynorphin) content in the striatum. Glial cell line-derived neurotrophic factor, when administered intranigrally, prevented apomorphine-induced rotational behaviour for 11 weeks following a single injection. In comparison, intraventricularly-administered glial cell line-derived neurotrophic factor produced a transient reduction in rotational behaviour that lasted for two to three weeks following a single injection. We also show that rotational behaviour is reduced following each subsequent intraventricular injection of glial cell line-derived neurotrophic factor given every six weeks, a time-point when baseline rotation deficits were re-established. Intranigrally- or intraventricularly-administered glial cell line-derived neurotrophic factor significantly reduced weight gain in all 6-hydroxydopamine-lesioned rats in this study. Following behavioural analysis where a confirmed improvement of behaviour was established, tissues were dissected for neurochemical analysis. In lesioned rats with intranigral injections of administered glial cell line-derived neurotrophic factor, significant increases of nigral, but not striatal tyrosine hydroxylase activity were measured. Additionally, 6-hydroxydopamine lesions significantly increased striatal dynorphin (61-139%) and met-enkephalin (81-139%), but not substance P levels. In these rats, intranigrally-administered glial cell line-derived neurotrophic factor injections reversed lesion-induced increases in nigral dynorphin A levels and increased nigral dopamine levels, but did not alter nigral met-enkephalin or substance P levels nor striatal dopamine levels. In lesioned rats with intraventricular injections of glial cell line-derived neurotrophic factor, tyrosine hydroxylase ispilateral to the lesion was increased in the substantia nigra, but not in the striatum. Intraventricularly-administered glial cell line-derived neurotrophic factor did not reverse lesion-induced increases in nigral dynorphin A or met-enkephalin levels nor did glial cell line-derived neurotrophic factor affect substance P levels in the striatum. These results suggest that in an animal model of Parkinson's disease, the neurotrophic factor glial cell line-derived neurotrophic factor reverses behavioural consequences of 6-hydroxydopamine administration, an effect that may involve both dopaminergic and peptidergic neurotransmission.

Animals↗
PubMed1998

Behavioural, neurochemical and neuroanatomical effects of chronic postnatal N-nitro-L-arginine methyl ester treatment in neonatal and adult rats.

In the present study we evaluated the consequences of interference with nitric oxide synthesis during development on brain function and behaviour in later life. Rat pups received a daily injection of the nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME, 25 mg/kg, s.c.) from postnatal day 0 to 24. At postnatal day 8 L-NAME-treated rats had enlarged and heavier stomachs, while body weights appeared to be reduced. The stomachs were not affected in size and weight anymore at postnatal day 24, whereas the body weights were still reduced by the L-NAME treatment, although they soon recovered after termination of the treatment. At four months-of-age, rats were tested in non-cognitive (open field) and cognitive (Morris water escape, two-way active avoidance) tasks. Open field behaviour of adult rats postnatally treated with L-NAME was not affected. In the water escape task there were no differences between the saline and L-NAME-treated rats in spatial discrimination learning and spatial reversal learning. Furthermore, postnatal L-NAME treatment did not have an effect on the acquisition of the two-way active avoidance task. Subsequently, we tested rat pups during the L-NAME treatment at postnatal day 19 through 24 in the open field and the two-way active avoidance task. L-NAME treatment appeared to increase the behavioural activity in the open field. There was no difference in behaviour in the active avoidance task between saline and L-NAME-treated rats. Biochemical and immunocytochemical studies showed that at postnatal day 8 the basal cyclic GMP level was reduced, while the cyclic GMP formation due to incubation with the nitric oxide donor sodium nitroprusside appeared to be increased in the hippocampus, striatum and frontal cortex of L-NAME-treated rats. Hence, nitric oxide synthase was inhibited whereas the soluble guanylyl cyclase activity may be increased in sensitivity. At postnatal day 24 basal cyclic GMP levels and nitric oxide-mediated cyclic GMP formation in the brain structures of L-NAME-treated rats had normal values again. Taken together, the findings of this study suggest that postnatal inhibition of nitric oxide synthase has profound neurochemical effects during development and may have short-lasting effects on non-cognitive behaviour, but it does not affect behaviour and brain function in later life.

Animals↗
PubMed2001

Simultaneous nutritional cognitive--behavioural therapy in obese patients.

The most important problem in cognitive-behavioural therapies for obese patients is to initiate weight loss without reinforcing the eating-behavioural disorders. We propose to assess the cognitive-behavioural therapy in obese patients suffering from eating disorders with and without combining a nutritional approach based on fat information. The patients (n = 60) have followed a group treatment of 12 weekly cognitive-behavioural therapy sessions with or without a combined nutritional approach mainly focused on fat restriction. The scores for depression (P < 0.01), anxiety (P < 0.01) and eating disorders (P < 0.001) are significantly and similarly improved with both types of treatments. The mean weight loss is significant (P < 0.001) only after a combined nutritional cognitive-behavioural approach. The Eating Disorders Inventory (EDI) subgroup 'Drive for thinness' remains only in a combined therapy (ANOVA P < 0.01), which could explain the weight loss that only occurs in this group. Finally, the association between a cognitive-behavioural therapy and a nutritional learning process improves the anxiety and depression related to eating disorders as well as the weight loss.

Adult↗
PubMedDate not supplied

Prevalence of psychiatric symptoms in adults with mental retardation and challenging behaviour.

The relation between psychiatric symptoms and different types of challenging behaviour in adults with mental retardation was investigated, using an instrument designed for use by non-specialist informants. A sample of 165 persons with mental retardation was surveyed for the presence of psychiatric symptoms, level of mental retardation, and self-injurious and other types of challenging behaviour. Challenging behaviour was associated with increased prevalence of psychiatric symptoms, especially anxiety and psychosis, less with hypomania, and not with depression. No association between anxiety and self-injurious behaviour was found. An association between psychiatric symptoms and challenging behaviour on a group level is an initial step towards understanding causes of challenging behaviour. Issues remain, like how causation takes place on an individual level, and the nature of psychiatric disorders in persons with severe and profound mental retardation.

Adult↗
PubMed2004

Frequency of newborn behaviours associated with neonatal abstinence syndrome: a hospital-based study.

OBJECTIVES: To determine the frequency of neonatal abstinence syndrome (NAS) among unselected term newborns, using newborn behaviour data only. METHODS: This hospital-based prospective exploratory study used clinical observations of newborn behaviours, mothers' observations of their newborns, and newborn chart data to determine the prevalence of suspected and confirmed cases of NAS in a convenience sample of unselected term newborns "rooming in" with their mothers in a large central city acute-care referral hospital. Over a 4-month period, 824 out of 1008 newborns were observed at between 8 and 30 hours of life by specially trained nurse observers. Behaviours recorded and their weighting were adapted from the Neonatal Abstinence Scoring System (NASS) by Finnegan and Kaltenbach. Newborns with scores of 5 or greater and "suspect for NAS" were referred to their physicians for confirmation or refutation of the clinical findings. The prevalence of "suspect for NAS" and confirmed NAS, as well as of individual neonatal behaviours, was calculated. RESULTS: Thirty-one (3.8%) of 824 term "rooming in" newborns were identified with findings suggestive of NAS. Four newborns were positively identified as having NAS and treated. The identification was confirmed by post hoc affirmation of maternal drug use. Individual behaviours occurring in 10% or more of newborns included excessive sneezing, nasal stuffiness, unsustained suck, tremor, and abnormal nipple latch. CONCLUSIONS: Clinical observation of newborn behaviour may identify NAS. Further studies are recommended to correlate this methodology with laboratory findings, as are more in-depth maternal questionnaires concerning use of mood-altering substances. The prevalence of NAS is likely underestimated because of early hospital discharge. A coordinated system of early identification and infant-specific assessment and treatment, both in hospital and following discharge home, is advocated.

Alberta↗
PubMed1993

Breathing patterns of monozygous twins during behavioural tasks.

To better understand behavioural and genetic influences upon breathing, the breathing patterns of 8 pairs of monozygous (MZ) twins were measured under 4 behavioural conditions; relaxed without standardisation; eyes closed; eyes open; and reading. Breathing was quantified by inspiratory and expiratory durations (TI, TE), tidal volume (VT) and derived variables. Airflow shape was normalised and quantified using 8 dimensions. Reading caused breathing to increase by > 500 ml/min compared to the other four conditions. Differences in breathing between combinations of two conditions were compared by testing whether the differences within an individual were smaller than the differences between random pairs of individuals from the same 16 subjects. For almost all respiratory variables, and whatever the behavioural condition, there were highly significant similarities within an individual (p < 0.00025 on 32/80 comparisons). Under each condition, the differences within MZ twin-pairs were compared to the differences within random-pairs from the same subject population. There were highly significant similarities within twin-pairs for the airflow shape across all conditions. However, TI, TE and VT failed to consistently show significant similarities within twin pairs. Hence, an individual's airflow shape appears to be a fundamental characteristic which is conserved when behavioural condition and level of ventilation changes. Further, MZ twins have similar airflow shapes--whatever the behavioural situation. Hence, behavioural influences upon airflow shape act upon monozygous twin pairs in similar ways, or such influences were negligible under the conditions of the present study.

Adolescent↗
PubMed1999

Development of lateralized behaviour in the human fetus from 12 to 27 weeks' gestation.

Handedness is the most prominent manifestation of behavioural lateralization in the human population. However, little is known about its ontogeny. This study examined the prenatal development of behavioural lateralization by observing, longitudinally, the occurrence of left- and right-arm movements in 17 human fetuses at 3-week intervals from 12 to 27 weeks gestational age. Fetuses exhibited significantly more right-arm movements than left-arm movements at every gestational age. Throughout all periods of observation, 83.3% of fetuses showed more right-arm than left-arm movements. The number of arm movements observed peaked at 15 to 18 weeks' gestation and declined rapidly in mid-gestation. The occurrence of laterality in early gestation indicates that asymmetric behaviour is probably under muscular or spinal, rather than cortical, control and points to a 'genetic' origin for such behaviour. The presence of lateralized motor behaviour in early gestation suggests it may have a potential causative role for subsequent lateralized behaviour and asymmetric brain development.

Adult↗
PubMed2006

Performance and behaviour of calves reared in groups or individually following an enhanced-growth feeding programme.

Nineteen calves were reared in individual pens (IP), and twenty calves were grouped in four pens of five calves each (GP) to study the effects of grouping on behaviour and performance. All calves were on an enhanced-growth feeding programme and had unlimited access to starter. Total dry matter intake (DMI) body weight (BW), serum urea, non-esterified fatty acid (NEFA), cortisol, insulin, and glucose concentrations, and immune response to vaccination were measured. Behaviour patterns categorized as: non-nutritive oral behaviour, cross-sucking, inter-sucking, and self-grooming, were monitored 20 min following the morning and afternoon milk replacer consumption, and at the same times after weaning. There were no differences in final BW and starter DMI between treatments. The decrease of average daily gain (ADG) during the week following weaning was more pronounced in GP than in IP calves. Serum NEFA concentration increased at the beginning of the study in IP calves but serum urea concentrations were greater in GP than in IP calves the week after weaning. Self-grooming increased in both treatments throughout the study but GP calves increased non-nutritive oral behaviour and decreased cross-sucking and inter-sucking behaviours throughout the study. Rearing calves in groups following an enhanced-growth feeding programme did not increase starter intake. Furthermore, cross-sucking and inter-sucking behaviours in calves reared in groups did not seem to cause increased metabolic or immunological distress.

Animal Feed↗
PubMed1998

Evolution and phylogeny of behavioural manipulation of insect hosts by parasites.

The literature contains many examples of changes induced by parasites in the behaviour and/or other phenotypic traits of insects. From an evolutionary perspective, the nature of these changes is usually difficult to assess. Parasite-induced changes in host behaviour can be adaptations of either host or parasite, or they can be mere pathological consequences of infection. Of the many criteria and experimental tests necessary to distinguish between adaptations and non-selected consequences, two are particularly important: the demonstration of fitness benefits for either host or parasite associated with the behavioural change, and the elucidation of the proximate mechanism responsible for the behavioural change. Another approach can serve to identify adaptive changes in behavior: mapping specific behavioural alterations on a phylogeny of either hosts or parasites. The usefulness of this approach is illustrated with two examples, acanthocephalan-cockroach associations and insect-fungus associations. The adaptive nature of parasite-induced behavioural changes will always be difficult to evaluate because they are the product of two distinct but interacting genotypes. However, experimental and phylogenetic approaches can provide valuable insights into the evolutionary history of insect-parasite interactions.

Acanthocephala↗
PubMed1994

Physiological analyses of host-finding behaviour in trematode cercariae: adaptations for transmission success.

Physiological analyses of the behaviour of several cercarial species which actively find and invade their hosts have revealed very complex sequences of behaviour patterns and responses to very different stimuli from the environment and the host. A result of these physiological studies is that the behaviour patterns of each of the species investigated are surprisingly individual. The behavioural patterns of host-finding of those species analysed in some detail reveal profound adaptations to maximize transmission success. This can be demonstrated for movement patterns during swimming, for responses to environmental conditions such as gravity, light and temperature, for responses to stimuli emanating from the host such as shadows, water turbulence and chemical compounds and especially for the responses after contact with the host. The behaviour patterns can be interpreted as adaptations to: (1) dispersal by leaving the habitat of the snail intermediate host and distribution within the area; (2) long survival by energy saving swimming behaviour, by avoiding responses to inappropriate stimuli, by selecting favourable microhabitats and probably by avoiding predation; (3) finding and invading particular host types by selecting microhabitats frequented by the hosts and responding to sequences of specific stimuli emanating from the hosts.

Adaptation, Physiological↗
PubMed2006

The virus infecting the parasitoid Leptopilina boulardi exerts a specific action on superparasitism behaviour.

Parasites often induce behavioural changes in their host. However, it is not necessarily easy to determine whether these changes are representative of an adaptation of the parasite (parasite manipulation), an adaptive response of the host or a side-effect of infection. In a solitary parasitoid of Drosophila larvae (Leptopilina boulardi), viral particles (LbFV) modify the host acceptance behaviour of infected females by increasing their tendency to superparasitize. This behavioural alteration allows for the horizontal transmission of the virus within superparasitized Drosophila larvae. To add support for or against the 'manipulation hypothesis', we investigated whether other behavioural components of the parasitoid are affected by viral infection, and whether other forms of horizontal transmission exist. Neither the ability of females to locate host kairomones nor their daily rhythm of locomotor activity was affected by viral infection. However, infected females showed a lower rate of locomotor activity, suggesting a physiological cost of infection. The searching paths of females were also unaffected. Males from infected and uninfected lines showed the same ability to locate females'sexual pheromones. Moreover, alternative modes of horizontal transmission (through food consumption and/or contact with the same Drosophila larvae) did not lead to viral contamination of the parasitoid. The overall specificity of behavioural alteration and of viral horizontal transmission is consistent with the hypothesis that the virus manipulates the behaviour of the parasitoid.

Animals↗