Analysis of the feeding behaviour of the mosquito Culex pipiens L. (Diptera: Culicidae) in relation to West Nile virus

The goal ofthis literature review is to inform the reader on several aspects of West Nile Virus (WNV) transmission by its mosquito vector, Culex pipiens and to elucidate how Cx. pipiens and WNV are intertwined. The first few sections of the literature review describe the life cycle and blood feeding behaviours ofmosquitoes so that baseline data ofmosquito biology are established. In addition to explaining how and why a mosquito blood feeds, the section on "Blood Meal Analysis" describes the different methods for determining the vertebrate source of mosquito blood meals and a brief history of these testing methods. Since this thesis looks at the feeding behaviour of Cx. pipiens, it is important to know how to determine what they are feeding upon. Discussion on other mosquito-borne diseases related to WNV gives a broader perspective to the thesis, and examines other diseases that have occurred in Ontario in the past. This is followed by background information on WNV and theories on how this virus came to North America and how it relates to Cx. pipiens. The final sections discuss Cx. pipiens and give background information to how this species of mosquito exists and behaves within North America.

Non-D9-tetrahydrocannabinol phytocannabinoids stimulate feeding in rats

Cannabinoid type 1 receptor-mediated appetite stimulation by D9tetrahydrocannabinol (D9THC) is well understood. Recently, it has become apparent that non-D9THC phytocannabinoids could also alter feeding patterns. Here, we show definitively that non-D9THC phytocannabinoids stimulate feeding. Twelve male, Lister-Hooded rats were prefed to satiety prior to administration of a standardized cannabis extract or to either of two mixtures of pure phytocannabinoids (extract analogues) comprising the phytocannabinoids present in the same proportions as the standardized extract (one with and one without D9THC). Hourly intake and meal pattern data were recorded and analysed using two-way analysis of variance followed by one-way analysis of variance and Bonferroni post-hoc tests. Administration of both extract analogues significantly increased feeding behaviours over the period of the test. All three agents increased hour-one intake and meal-one size and decreased the latency to feed, although the zero-D9THC extract analogue did so to a lesser degree than the high-D9THC analogue. Furthermore, only the analogue containing D9THC significantly increased meal duration. The data confirm that at least one non-D9THC phytocannabinoid induces feeding pattern changes in rats, although further trials using individual phytocannabinoids are required to fully understand the observed effects.

Cannibalistic feeding of larval Trichogramma carverae parasitoids in moth eggs

Wasps of the genus Trichogramma parasitise the eggs of Lepidoptera. They may deposit one or many eggs in each host. Survival is high at low density but reaches a plateau as density increases. To reveal the mechanism by which excess larvae die we chose a lepidopteran host that has flattened, transparent eggs and used video microscopy to record novel feeding behaviours and interactions of larval Trichogramma carverae (Oatman and Pinto) at different densities. Single larvae show a rapid food ingestion phase, followed by a period of extensive saliva release. Ultimately the host egg is completely consumed. The larva then extracts excess moisture from the egg, providing a dry environment for pupation. When multiple larvae are present, the initial scramble for food results in the larvae consuming all of the egg contents early in development. All larvae survive if there is sufficient food for all to reach a threshold developmental stage. If not, physical proximity results in attack and consumption of others, continuing until the surviving larvae reach the threshold stage beyond which attacks seem to be no longer effective. The number of larvae remaining at the end of rapid ingestion dictates how many will survive to emerge as adults.

Beliefs about infant regulation, early infant behaviors and maternal postnatal depressive symptoms

Background: Young infants may have irregular sleeping and feeding patterns. Such regulation difficulties are known correlates of maternal depressive symptoms. Parental beliefs regarding their role in regulating infant behaviours also may play a role. We investigated the association of depressive symptoms with infant feeding/sleeping behaviours, parent regulation beliefs, and the interaction of the two. Method: In 2006, 272 mothers of infants aged up to 24 weeks completed a questionnaire about infant behaviour and regulation beliefs. Participants were recruited from general medical practices and child health clinics in Brisbane, Australia. Depressive symptomology was measured using the Edinburgh Postnatal Depression Scale (EPDS). Other measures were adapted from the ALSPAC study. Results: Regression analyses were run controlling for partner support, other support, life events, and a range of demographic variables. Maternal depressive symptoms were associated with infant sleeping and feeding problems but not regulation beliefs. The most important infant predictor was sleep behaviours with feeding behaviours accounting for little additional variance. An interaction between regulation beliefs and sleep behaviours was found. Mothers with high regulation beliefs were more susceptible to postnatal depressive symptoms when infant sleep behaviours were problematic. Conclusion: Mothers of young infants who expect greater control are more susceptible to depressive symptoms when their infant presents challenging sleep behaviour.

Trophic role of small cetaceans and seals in Irish waters

Understanding the role of marine mammals in specific ecosystems and their interactions with fisheries involves, inter alia, an understanding of their diet and dietary requirements. In this thesis, the foraging ecology of seven marine mammal species that regularly occur in Irish waters was investigated by reconstructing diet using hard parts from digestive tracts and scats. Of the species examined, two (striped and Atlantic white-sided dolphin) can be considered offshore species or species inhabiting neritic waters, while five others usually inhabit more coastal areas (white-beaked dolphin, harbour porpoise, harbour seal and grey seal); the last species studied was the bottlenose dolphin whose population structure is more complex, with coastal and offshore populations. A total of 13,028 prey items from at least 81 different species (62 fish species, 14 cephalopods, four crustaceans, and a tunicate) were identified. 28% of the fish species were identified using bones other than otoliths, highlighting the importance of using all identifiable structures to reconstruct diet. Individually, each species of marine mammal presented a high diversity of prey taxa, but the locally abundant Trisopterus spp. were found to be the most important prey item for all species, indicating that Trisopterus spp. is probably a key species in understanding the role of these predators in Irish waters. In the coastal marine mammals, other Gadiformes species (haddock, pollack, saithe, whiting) also contributed substantially to the diet; in contrast, in pelagic or less coastal marine mammals, prey was largely comprised of planktivorous fish, such as Atlantic mackerel, horse mackerel, blue whiting, and mesopelagic prey. Striped dolphins and Atlantic white-sided dolphins are offshore small cetaceans foraging in neritic waters. Differences between the diet of striped dolphins collected in drift nets targeting tuna and stranded on Irish coasts showed a complex foraging behaviour; the diet information shows that although this dolphin forages mainly in oceanic waters it may occasionally forage on the continental shelf, feeding on available prey. The Atlantic white-sided dolphin diet showed that this species prefers to feed over the continental edge, where planktivorous fish are abundant. Some resource partitioning was found in bottlenose dolphins in Irish waters consistent with previous genetic and stable isotope analysis studies. Bottlenose dolphins in Irish waters appears to be generalist feeders consuming more than 30 prey species, however most of the diet comprised a few locally abundant species, especially gadoid fish including haddock/pollack/saithe group and Trisopterus spp., but the contribution of Atlantic hake, conger eels and the pelagic planktivorous horse mackerel were also important. Stomach content information suggests that three different feeding behaviours might occur in bottlenose dolphin populations in Irish waters; firstly a coastal behaviour, with animals feeding on prey that mainly inhabit areas close to the coast; secondly an offshore behaviour where dolphins feed on offshore species such as squid or mesopelagic fish; and a third more complex behaviour that involves movements over the continental shelf and close to the shelf edge. The other three coastal marine mammal species (harbour porpoise, harbour seal and grey seal) were found to be feeding on similar prey and competition for food resources among these sympatric species might occur. Both species of seals were found to have a high overlap (more than 80%) in their diet composition, but while grey seals feed on large fish (>110mm), harbour seals feed mostly on smaller fish (<110mm), suggesting some spatial segregation in foraging. Harbour porpoises and grey seals are potentially competing for the same food resource but some differences in prey species were found and some habitat partitioning might occur. Direct interaction (by catch) between dolphins and fisheries was detected in all species. Most of the prey found in the stomach contents from both stranded and by catch dolphins were smaller sizes than those targeted by commercial fisheries. In fact, the total annual food consumption of the species studied was found to be very small (225,160 tonnes) in comparison to fishery landings for the same area (~2 million tonnes). However, marine mammal species might be indirectly interacting with fisheries, removing forage fish. Incorporating the dietary information obtained from the four coastal species, an ECOPATH food web model was established for the Irish Sea, based on data from 2004. Five trophic levels were found, with bottlenose dolphins and grey and harbour seals occurring at the highest trophic level. A comparison with a previous model based on 1973 data suggests that while the overall Irish Sea ecosystem appears to be “maturing”, some indices indicate that the 2004 fishery was less efficient and was targeting fish at higher trophic levels than in 1973, which is reflected in the mean trophic level of the catch. Depletion or substantial decrease of some of the Irish Sea fish stocks has resulted in a significant decline in landings in this area. The integration of diet information in mass-balance models to construct ecosystem food-webs will help to understand the trophic role of these apex predators within the ecosystem.

Neuromotor tolerability and behavioural characterisation of cannabidiolic acid, a phytocannabinoid with therapeutic potential for anticipatory nausea

Rationale: Anticipatory nausea (AN) is a poorly controlled side-effect experienced by chemotherapy patients. Currently, pharmacotherapy is restricted to benzodiazepine anxiolytics, which have limited efficacy, significant sedative effects, and induce dependency. The non-psychoactive phytocannabinoid, cannabidiolic acid (CBDA), has shown considerable efficacy in pre-clinical AN models, however determination of its neuromotor tolerability profile is crucial to justify clinical investigation. Provisional evidence for appetite-stimulating properties also requires detailed investigation. Objectives: To assess the tolerability of CBDA in locomotor activity, motor coordination and muscular strength tests, and additionally for ability to modulate feeding behaviours. Methods: Male Lister hooded rats administered CBDA (0.05-5 mg/kg; p.o.) were assessed in habituated open field (for locomotor activity), static beam and grip strength tests. A further study investigated whether these CBDA doses modulated normal feeding behaviour. Finally, evidence of anxiolytic-like effects in the habituated open field prompted testing of 5 mg/kg CBDA for anxiolytic-like activity in unhabituated open field, light/dark box and novelty-supressed feeding (NSF) tests. Results: CBDA had no adverse effects upon performance in any neuromotor tolerability test, however anxiolytic-like behaviour was observed in the habituated open field. Normal feeding behaviours were unaffected by any dose. CBDA (5 mg/kg) abolished the increased feeding latency in the NSF test induced by the 5-HT1AR antagonist, WAY-100,635, indicative of anxiolytic-like effects, but had no effect on anxiety-like behaviour in the novel open field or light/dark box. Conclusions: CBDA is very well tolerated and devoid of the sedative side-effect profile of benzodiazepines, justifying its clinical investigation as a novel AN treatment.

Water chemistry, and body temperature, swimming depth and stomach contents of Arctic char (Salvelinus alpinus) in inner Frobisher Bay, Canada

The influence of salinity, temperature and prey availability on the marine migration of anadromous fishes was determined by describing the movements, habitat use and feeding behaviours of Arctic char (Salvelinus alpinus). The objectives were to determine whether char are restricted to the upper water column of the inter-/subtidal zones due to warmer temperatures. Twenty-seven char were tracked with acoustic temperature/pressure (depth) transmitters from June to September, 2008/2009, in inner Frobisher Bay, Canada. Most detections were in surface waters (0-3 m). Inter-/subtidal movements and consecutive repetitive dives (maximum 52.8 m) resulted in extreme body temperature shifts (-0.2-18.1 °C). Approximately half of intertidal and subtidal detections were between 9-13 °C and 1-3 °C, respectively. Stomach contents and deep diving suggested feeding in both inter-/subtidal zones. We suggest that char tolerate cold water at depth to capture prey in the subtidal zone, then seek warmer water to enhance feeding/digestion physiology.

Foraging behaviour of Helicoverpa armigera first instar larvae on crop plants of different developmental stages

Understanding how insect pests forage on their food plants can help optimize management strategies. Helicoverpa armigera (Hubner) (Lep., Noctuidae) is a major polyphagous pest of agricultural crops worldwide. The immature stages feed and forage on crops at all stages of plant development, damaging fruiting and non-fruiting structures, yet very little is known about the influence of host type or stage on the location and behaviour of larvae. Through semi-continuous observation, we evaluated the foraging (movement and feeding) behaviours of H. armigera first instar larvae as well as the proportion of time spent at key locations on mungbean [Vigna radiata (L.) Wilczek] and pigeon pea [Cajanus cajan (L.) Millspaugh] of differing developmental stages: seedling- and mature (flowering/pod fill)-stage plants. Both host type and age affected the behaviour of larvae. Larvae spent more time in the upper parts of mature plants than on seedlings and tended to stay at the top of mature plants if they moved there. This difference was greater in pigeon pea than in mungbean. The proportion of time allocated to feeding on different parts of a plant differed with host and age. More feeding occurred in the top of mature pigeon pea plants but did not differ between mature and seedling mungbean plants. The duration of key behaviours did not differ between plant ages in either crop type and was similar between hosts although resting bouts were substantially longer on mungbeans. Thus a polyphagous species such as H. armigera does not forage in equivalent ways on different hosts in the first instar stage.

Parenting behaviours and maternal infant-feeding practices in first-time Australian mothers

Introduction: There is emerging evidence that parenting style and early feeding practices are associated with child intake, eating behaviours and weight status. The aim of this cross sectional study was to examine the relationships between general maternal parenting behaviour and feeding practices and beliefs. Methods: Participants were 421 first-time mothers of 9-22 week old healthy term infants (49% male, mean±sd age 19±4 weeks) enrolled in the NOURISH trial. At baseline mothers self-reported their parenting behaviours (self-efficacy, warmth, irritability) and infant-feeding beliefs using questions from the Longitudinal Study of Australian Children and the Infant Feeding Questionnaire (Baughcum, 2001), respectively. Multivariable regression analyses were used with feeding practices (four factors) as the dependent variables, Independent variables were maternal BMI, weight concern, age, education level perception of infant weight status, feeding mode (breast vs formula) and infant gender, age and weight gain z-score. Results: Parenting behaviours partly were associated with feeding beliefs (adjusted R2 =0.21-0.30). Higher maternal parenting self-efficacy was inversely associated with concerns that the baby would become underweight (p=0.006); become overweight (p<0.001); and lack of awareness of infant hunger/satiety cues (p<0.001). Higher maternal irritability was positively associated with lack of awareness of cues (p<0.05). Maternal warmth was not associated with any feeding beliefs. Infant weight- gain (from birth) z-score and age, maternal BMI and education level and mothers’ perception of infant weight status and feeding mode were covariates. Conclusions: These findings suggest strategies to improve early feeding practices need to be address broader parenting approaches, particularly self-efficacy and irritability.

Associations between parenting behaviours and feeding beliefs of first-time Australian mothers in the NOURISH obesity prevention trial

Purpose: Parenting style and early feeding practices have been linked to child intake, eating behaviour and weight status. The purpose of this study was to examine associations between general maternal parenting behaviours and feeding beliefs in Australian mothers of 11-17 month-old children. Methods: This cross-sectional analysis included 223 first-time mothers and their children (49% male, mean age 14 [sd 1] months) enrolled in the control group of the NOURISH trial. Mothers self-reported their feeding beliefs and parenting behaviours (overprotection, irritability, warmth, autonomy-encouraging) using modified questions from the Infant Feeding Questionnaire (Baughcum, 2001) and the Longitudinal Study of Australian Children. Multiple regression analyses were conducted, using feeding beliefs (four factors) as dependent and parenting behaviours as independent variables while adjusting for child gender, age, weight-for-age z-score and maternal age, education level, feeding mode (breast vs. non-breast), and perception of own pre-pregnancy and child weight status. Results/Findings: Two of four parenting behaviours were significantly associated with feeding beliefs. Maternal warmth was inversely associated with concerns that the child would become underweight (β=-0.156, p=0.022) and positively associated with mothers’ awareness of child’s hunger/satiety cues (β=0.303, p<0.001). Mothers’ overprotection was positively associated with concerns that the child would become underweight (β=0.213, p=0.001); become overweight (β=0.174, p=0.005); and mother’s responsive feeding (β=0.135, p=0.057). Weight-for-age z-score, mothers’ perception of their child and own weight status, education, feeding mode, and child’s age were significant covariates. Conclusions: Feeding occurs within the broader parenting context. Improving early feeding beliefs and practices may require addressing mother’s approaches to parenting, especially warmth and overprotection.

Caries and its association with infant feeding and oral health-related behaviours in 3-4-year-old Brazilian children

Objectives: To investigate the relationships between socio-demographic factors, infant feeding habits, oral hygiene and the prevalence and patterns of caries in Brazilian 3-4-year-olds. Methods: Systematic random sampling was used to select children enrolled in municipal nurseries in Araraquara, Brazil, in 1998. Clinical examinations were carried out by one examiner using dmft and dmfs indices and WHO criteria. Questionnaires for information related to the socio-demographic background, oral hygiene and dietary history of the children were completed by their mothers. Results: Caries was seen in 46% of the children; 17% of them had the more extensive pattern involving molars and incisors. Social class, mother's education, and age at which breast-feeding terminated showed statistically significant associations with caries. Feeding bottles with added sugars were still being given to 80% of the children. When the significant variables were taken into account only age at which breast-feeding terminated showed a significant relationship to the pattern of disease. Children who were never breast-fed or were breast-fed beyond the age of 24 months had a higher prevalence of the more extensive pattern of caries. Conclusions: The association between the length of time a mother breast-feeds and extensive caries should be a consideration in any local infant feeding policies or health promotion strategies. The duration for appropriate breast- or bottle-feeding should be emphasised.

Sibling eating behaviours and differential child feeding practices reported by parents

The purpose of this study was to investigate the intra-familial relationships between parental reports of feeding practices used with siblings in the same family, and to evaluate whether differences in feeding practices are related to differences in siblings' eating behaviours. Eighty parents of two sibling children completed measures assessing their feeding practices and child eating behaviours. Parents reported using greater restrictive feeding practices with children who were fussier and desired to drink more than their sibling. Parents reported using more pressure to eat with siblings who were slower to eat, were fussier, emotionally under-ate, enjoyed food less, were less responsive to food, and were more responsive to internal satiety cues. Restriction and pressure to eat appear to be part of the non-shared environment which sibling children experience differently. These feeding practices may be used differently for children in the same family in response to child eating behaviours or other specific characteristics.

Stability and continuity of parentally reported child eating behaviours and feeding practices from 2 to 5 years of age

Previous research suggests that many eating behaviours are stable in children but that obesigenic eating behaviours tend to increase with age. This research explores the stability (consistency in individual levels over time) and continuity (consistency in group levels over time) of child eating behaviours and parental feeding practices in children between 2 and 5 years of age. Thirty one participants completed measures of child eating behaviours, parental feeding practices and child weight at 2 and 5 years of age. Child eating behaviours and parental feeding practices remained stable between 2 and 5 years of age. There was also good continuity in measures of parental restriction and monitoring of food intake, as well as in mean levels of children's eating behaviours and BMI over time. Mean levels of maternal pressure to eat significantly increased, whilst mean levels of desire to drink significantly decreased, between 2 and 5 years of age. These findings suggest that children's eating behaviours are stable and continuous in the period prior to 5 years of age. Further research is necessary to replicate these findings and to explore why later developmental increases are seen in children's obesigenic eating behaviours. © 2011 Elsevier Ltd.