Host selection in phytophagous insects: a new explanation for learning in adults

Insect learning can change the preferences an egg laying female displays towards different host plant species. Current hypotheses propose that learning may be advantageous in adult host selection behaviour through improved recognition, accuracy or selectivity in foraging. In this paper, we present a hypothesis for when learning can be advantageous without such improvements in adult host foraging. Specifically, that learning can be an advantageous strategy for egg laying females when larvae must feed on more than one plant in order to complete development, if the fitness of larvae is reduced when they switch to a different host species. Here, larvae benefit from developing on the most abundant host species, which is the most likely choice of host for an adult insect which increases its preference for a host species through learning. The hypothesis is formalised with a mathematical model and we provide evidence from studies on the behavioural ecology of a number of insect species which demonstrate that the assumptions of this hypothesis may frequently be fulfilled in nature. We discuss how multiple mechanisms may convey advantages in insect learning and that benefits to larval development, which have so far been overlooked, should be considered in explanations for the widespread occurrence of learning.

A general model for host plant selection in phytophagous insects

We develop a general theoretical framework for exploring the host plant selection behaviour of herbivorous insects. This model can be used to address a number of questions, including the evolution of specialists, generalists, preference hierarchies, and learning. We use our model to: (i) demonstrate the consequences of the extent to which the reproductive success of a foraging female is limited by the rate at which they find host plants (host limitation) or the number of eggs they carry (egg limitation); (ii) emphasize the different consequences of variation in behaviour before and after landing on (locating) a host (termed pre- and post-alighting, respectively); (iii) show that, in contrast to previous predictions, learning can be favoured in post-alighting behaviour--in particular, individuals can be selected to concentrate oviposition on an abundant low-quality host, whilst ignoring a rare higher-quality host; (iv) emphasize the importance of interactions between mechanisms in favouring specialization or learning.

Intra-specific variation for host plant use in Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae) : implications for management

The polyphagous moth Helicoverpa armigera (Hübner) is one of the world's most important agricultural pests. A number of existing approaches and future designs for management of H. armigera rely on the assumption that moths do not exhibit either genetically and/or non-genetically based variation for host plant utilization. We review recent empirical evidence demonstrating that both these forms of variation influence host plant use in this moth. The significance of this variation in H. armigera in relation to current and future pest management strategies is examined. We provide recommendations on future research needs and directions for sustainable management of H. armigera, under a framework that includes consideration of intra-specific variation for host use relevant in this and other similar pest species.

How host plant variability influences the advantages to learning : a theoretical model for oviposition behaviour in Lepidoptera

Learning can allow individuals to increase their fitness in particular environments. The advantage to learning depends on the predictability of the environment and the extent to which animals can adjust their behaviour. Earlier general models have investigated when environmental predictability might favour the evolution of learning in foraging animals. Here, we construct a theoretical model that predicts the advantages to learning using a specific biological example: oviposition in the Lepidoptera. Our model includes environmental and behavioural complexities relevant to host selection in these insects and tests whether the predictions of the general models still hold. Our results demonstrate how the advantage of learning is maximised when within-generation variability is minimised (the local environment consists mainly of a single host plant species) and between-generation variability is maximised (different host plant species are the most common in different generations). We discuss how our results: (a) can be applied to recent empirical work in different lepidopteran species and (b) predict an important role of learning in lepidopteran agricultural pests.

Host location behaviour in the desert caterpillar, Heliothis punctifera

The host location behaviour of foraging caterpillars has received little attention, despite the wealth of theoretical and empirical studies that have been directed at this behavioural trait in adult Lepidoptera. Here, we study caterpillars of the moth Heliothis punctifera Walker (Lepidoptera: Noctuidae), which inhabits the arid inland desert areas of Australia. Caterpillars of this species consume many flowerheads before completing development and can be observed moving across the sand in search of new hosts. Consequently, if host location behaviour favours attraction to certain plant species, it might be expected to influence the distribution and abundance of caterpillars in the field. We present field data showing that H. punctifera caterpillars are unevenly distributed throughout mixed patches of two of its host species, with a higher abundance on Senecio gregorii F. Muell., the annual yellow top, compared to Myriocephalus stuartii (F. Muell. & Sond.) Benth., the poached egg daisy (both Asteraceae). Using laboratory studies, we test whether this distribution may, in part, be due to host location behaviour of caterpillars. Our results show that caterpillars exhibit a preference for locating S. gregorii in their pre- and post-contact foraging behaviour. In addition, our results provide evidence that feeding history plays a role in host location behaviour in this insect. We propose that key features of the desert environment and the ecology of H. punctifera would favour adaptations to host location behaviour by immatures.

Can mechanism help explain insect host choice?

Evolutionary theory predicts that herbivorous insects should lay eggs on plants in a way that reflects the suitability of each plant species for larval development. Empirical studies, however, often fail to find any relationship between an adult insect’s choice of host–plant and offspring fitness, and in such cases, it is generally assumed that other ‘missing’ factors (e.g. predation, host–plant abundance, learning and adult feeding sites) must be contributing to overall host suitability. Here, I consider an alternative theory – that a fitness cost inherent in the olfactory mechanism could constrain the evolution of insect host selection. I begin by reviewing current knowledge of odour processing in the insect antennal lobe with the aid of a simple schematic: the aim being to explain the workings of this mechanism to scientists who do not have prior knowledge in this field. I then use the schematic to explore how an insect’s perception of host and non-host odours is governed by a set of processing rules, or algorithm. Under the assumptions of this mechanistic view, the perception of every plant odour is interrelated, and seemingly bad host choices can still arise as part of an overall adaptive behavioural strategy. I discuss how an understanding of mechanism can improve the interpretation of theoretical and empirical studies in insect behaviour and evolution.

Mathematical modelling of tumour growth and interaction with host tissue and the immune system

In this thesis, three mathematical models describing the growth of solid tumour incorporating the host tissue and the immune system response are developed and investigated. The initial model describes the dynamics of the growing tumour and immune response before being extended in the second model by introducing a time-varying dendritic cell-based treatment strategy. Finally, in the third model, we present a mathematical model of a growing tumour using a hybrid cellular automata. These models can provide information to pre-experimental work to assist in designing more effective and efficient laboratory experiments related to tumour growth and interactions with the immune system and immunotherapy.

Developing and sustaining successful mentoring relationships

As mentor teachers hold the balance of power in the relationship, how do they build and sustain positive mentor-mentee relationships? This study involved eleven pairs of mentors and mentees (n=22) with audio-recorded interviews to explore their relationships, mentors’ support and mentors’ expectations for mentees’ involvement in the school. Findings suggested ways to build and sustain mentoring relationships (e.g., professionalism, respect, and support). Indeed, support in providing information for planning, access to resources, two-way dialoguing with feedback and reflections, and establishing safe, risk-taking environments to trial and evaluate newly-learnt teaching practices were considered as a ways to build and sustain relationships.

The role of customer gratitude in strengthening seller-buyer relationships

Despite its emphasis on relationships between buyers and sellers, and the effect of emotion on behaviours, marketing literature has not yet investigated customer gratitude as an element of relational exchange. Gratitude is a significant component of personal relationships and may offer important insights into how perceptions of relationship marketing investments impact customer trust in, satisfaction with and affective commitment to a seller. In addition, customer gratitude may provide a more complete explanation of how marketing investments work. Consequently, this research contributes to marketing literature by investigating customer gratitude as a mediating mechanism in the relationship between customer perceptions of relationship marketing investments and customer trust in, satisfaction with and affective commitment to the seller: all dimensions of relationship quality.

The institutional limits to, and possibility of, understanding young people diagnosed with 'mental disorders', within inclusive teacher-student relationships

A persistent pattern of exclusion of young people with ‘mental disorders’ from school systems, despite the best intentions of schools and teachers, has prompted a call for a more reflexive understanding of their behaviours. This thesis, by describing how institutionally recognised ways of understanding can result in otherwise avoidable moral collisions and exclusion, produces new insights into the nature and processes of understanding required to promote inclusion. These insights were produced through an intensive qualitative examination of a violent classroom episode, identifying key points in the interaction that could make the difference between misrecognition and recognition, turning exclusion into inclusion.

Study protocol : establishing good relationships between patients and health care providers while providing cardiac care. Exploring how patient-clinician engagement contributes to health disparities between indigenous and non-indigenous Australians in South Australia

Abstract Background: Studies that compare Indigenous Australian and non-Indigenous patients who experience a cardiac event or chest pain are inconclusive about the reasons for the differences in-hospital and survival rates. The advances in diagnostic accuracy, medication and specialised workforce has contributed to a lower case fatality and lengthen survival rates however this is not evident in the Indigenous Australian population. A possible driver contributing to this disparity may be the impact of patient-clinician interface during key interactions during the health care process. Methods/Design: This study will apply an Indigenous framework to describe the interaction between Indigenous patients and clinicians during the continuum of cardiac health care, i.e. from acute admission, secondary and rehabilitative care. Adopting an Indigenous framework is more aligned with Indigenous realities, knowledge, intellects, histories and experiences. A triple layered designed focus group will be employed to discuss patient-clinician engagement. Focus groups will be arranged by geographic clusters i.e. metropolitan and a regional centre. Patient informants will be identified by Indigenous status (i.e. Indigenous and non-Indigenous) and the focus groups will be convened separately. The health care provider focus groups will be convened on an organisational basis i.e. state health providers and Aboriginal Community Controlled Health Services. Yarning will be used as a research method to facilitate discussion. Yarning is in congruence with the oral traditions that are still a reality in day-to-day Indigenous lives. Discussion: This study is nestled in a larger research program that explores the drivers to the disparity of care and health outcomes for Indigenous and non-Indigenous Australians who experience an acute cardiac admission. A focus on health status, risk factors and clinical interventions may camouflage critical issues within a patient-clinician exchange. This approach may provide a way forward to reduce the appalling health disadvantage experienced within the Indigenous Australian communities. Keywords: Patient-clinician engagement, Qualitative, Cardiovascular disease, Focus groups, Indigenous

Utility of COI, CAD and morphological data for resolving relationships within the genus Sarcophaga (sensu lato) (Diptera: Sarcophagidae) : a preliminary study

Currently there are ~3000 known species of Sarcophagidae (Diptera), which are classified into 173 genera in three subfamilies. Almost 25% of sarcophagids belong to the genus Sarcophaga (sensu lato) however little is known about the validity of, and relationships between the ~150 (or more) subgenera of Sarcophaga s.l. In this preliminary study, we evaluated the usefulness of three sources of data for resolving relationships between 35 species from 14 Sarcophaga s.l. subgenera: the mitochondrial COI barcode region, ~800. bp of the nuclear gene CAD, and 110 morphological characters. Bayesian, maximum likelihood (ML) and maximum parsimony (MP) analyses were performed on the combined dataset. Much of the tree was only supported by the Bayesian and ML analyses, with the MP tree poorly resolved. The genus Sarcophaga s.l. was resolved as monophyletic in both the Bayesian and ML analyses and strong support was obtained at the species-level. Notably, the only subgenus consistently resolved as monophyletic was Liopygia. The monophyly of and relationships between the remaining Sarcophaga s.l. subgenera sampled remain questionable. We suggest that future phylogenetic studies on the genus Sarcophaga s.l. use combined datasets for analyses. We also advocate the use of additional data and a range of inference strategies to assist with resolving relationships within Sarcophaga s.l.

Integrating early childhood teachers into long day care : building respectful relationships

Amongst the current reforms in early childhood in Australia is the requirement for four year university degree-qualified teachers to be employed to provide a kindergarten program for four-year-old children in the year prior to school entry. The possibility for long day care to provide a funded kindergarten program, with an early childhood teacher (ECT) presents a change for the field. With this change come challenges, though also opportunities to think in new and different ways about what long day care and working in long day care might look like.

Child-related factors that influence teacher-child relationships using an Australian national sample

This study assessed the extent to which child-related factors had an impact on teacher-child relationships in Australian childcare settings. Analyses used data from Growing Up in Australia: The Longitudinal Study of Australian Children (LSAC). The sample consisted of 1577 two to three year old children (M= 33.9 months, SD=2.93; 51.5% male). Two separate hierarchical multiple regression analyses were conducted to examine the relation between teachers’ perceptions of their relationships with children and (a) gender, (b), indigenous status, (c), language background other than English, (d), socio-economic position, (e) special health care needs, (f) expression and receptive language concerns, (g) psychosocial competence and problems and (h) temperament factors (approach, persistence and reactivity). Results indicated that special health care needs, receptive language concerns and all three temperament scales (approach, persistence and reactivity) significantly predicted conflict in teacher-child relationships. Close relationships were predicted by being female, indigenous status, higher socio-economic position, not having a special health care need and no expressive language concerns.

Role salience and support as moderators of demand/conflict relationships in China

This study examined the effects of role demand on both work–family conflict and family–work conflict, and the moderating effects of role salience and support on these relationships. Based on 391 dual-career (managerial and blue-collar employees) couples from a Taiwanese company in China, the results of this survey study showed clear gender differences in the patterns of relationships observed. For men, the most important demands that negatively impacted on work–family conflict were frequency of overtime and frequency of socializing for work purposes (yingchou), and supervisory support buffered the negative impact of frequent overtime. For women however, strong supervisory support and low work role salience were more important for reducing work–family conflict, and there was no significant main effect found for any of the role demand factors. Furthermore, women with high work role salience were more likely to feel the impact of yingchou on work–family conflict. In the family domain, the most influential demand for men was hours spent on household tasks, but for women, it was the frequency of family-related leave. Interestingly, males reported higher family role salience than females and spouse support intensified rather than buffered the positive impact of hours spent on household tasks on family–work conflict for males.