Behavioural ecology of New Zealand invasive rodents (Rattus norvegicus and Mus musculus) : implications for rodent control : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland, New Zealand

Biological invasions are natural phenomena that have occurred throughout the natural history of earth. The highly negative context of the term biological invasion is associated with the fact that many modern invasive processes are anthropogenically driven. Indeed, human affiliated invasions are among the primary drivers of the current biodiversity crises. Murid rodents (Rodentia: Muridea) of the genus Rattus and Mus have become among the worst vertebrate invasive species and apart from man are the most widespread mammals on earth. Invasive rodents have severe and negative effects on human health, agricultural systems, and natural environments. The practice of rodent control is extensive and substantial attempts are made to decrease rodents’ severe impacts on the environment. However, although these attempts are largely successful, there are still issues in the control of invasive rodents and new methodologies, whether at a macro or micro scale are actively pursued. Behavioural conservation attempts to understand and improve conservation processes and practices through the study of animal behaviour. Indeed, it is becoming increasingly apparent that the behaviour of animals can be a strong tool for conservation. The control of invasive species has the goal of reducing predatory or competition pressure on species of conservation concern and advocates for behavioural conservation acknowledge the importance of behavioural studies of invasive species that can directly benefit or inform control measures. In this thesis, I explore several aspects of behavioural ecology in the Norway rat R. norvegicus and the house mouse, M. musculus, with the overarching aim of informing and improving rodent control. I conducted a series of laboratory and field experiments focused on rodent behaviour and pest control. 1) I tested whether laboratory rats can act as effective lures for wild Norway rats and hence overcome the problem of rats avoiding food baits. This field experiment was based on the highly social behaviour exhibited by this species. I found that live traps containing live lures were significantly more effective than those with food baits at capturing wild Norway rats. In a second series of tests, I found that live lures were more efficient than food baits at attracting rats to kill traps. A study of radio-collared rats released onto a rat-free island produced inconclusive but promising results on the potential of live lures to be used to control incursions. I suggest that the use of laboratory rats as lures should be considered as an additional tool for use in future pest control management plans for invasive Norway rats. 2) I used Y-maze laboratory experiments to examine the attractiveness of urine from mice fed high and low protein diets to male and female wild mice, whether the protein content of the diet of mice affected their response and the strength of attraction of wild mice towards wild and laboratory live lure conspecifics of the opposite sex. I found that mice preferred to spend more time close to urine from donors that had eaten a high protein diet, that mouse strain did not affected conspecific attraction and that males were more active than females toward the urine of the opposite sex. These results may have implications for improving mouse capture and control. 3) I assessed the impacts of mammalian odours (specific direct cues of predation or competition) and illumination intensity (a general indirect cue of predation) on the foraging of free-ranging mice that are naïve to mammalian predators, using feeding trials in the field. Here I found that phases of the moon, but not odour, had significant effects on mouse foraging behaviour. I suggest that repeating the study over multiple lunar cycles is required to confirm this influence and, if confirmed, recommend coordinating management efforts according to the phases of the moon to improve mouse bait take and reduce bait wastage. 4) I tested for the responces of rat-naïve mice to scent cues from rats, which are competitors and potential predators in laboratory experiments, in a Y-maze apparatus. Mice behaviours revealed unexpected differences in male and female responces to rat scent. Male mice showed preference to control over rat scented food trays, while females were indiference in their preferation or even prefered rat scented food trays over control ones. These sex-based differences can suggest that males and females might be under different evolutionary pressures in regard to novel scents. 5) I looked at macronutrient selection in wild caught mice, under controlled laboratory conditions. I found that mice consumed more of diets with a high carbohydrate/protein ratio, but were highly generalist and opportunistic feeders, in general prioritising energy over macronutrients. These results demonstrate that the pattern of macronutrient selection is sensitive to ecological circumstances, and associates an opportunistic strategy with successful invasion by a small mammal in a temperate environment. The understanding and improvement of conservation practices directly through the study of animal behavioural processes is an emerging and rapidly growing science, but relatively little attention is given to the benefits that we can draw from incorporating and understanding of invasive species behaviour into their control. To maintain an effective and continuous control of invasive species, managers need comprehensive knowledge of the behaviour of the species they target. This can be achieved only through targeted behavioural research of invasive species that is directed at improving pest control. In this thesis I have attempted to do just this

A Conserved Mechanism Controls Translation of Rubisco Large Subunit in Different Photosynthetic Organisms

We previously proposed a mechanism for control of Rubisco expression and assembly during oxidative stress in Chlamydomonas reinhardtii. The N terminus of the large subunit (LSU) comprises an RNA recognition motif (RRM) that is normally buried in the protein, but becomes exposed under oxidizing conditions when the glutathione pool shifts toward its oxidized form. Thus, de novo translation and assembly of Rubisco LSU stop with similar kinetics and the unpaired small subunit (SSU) is rapidly degraded. Here we show that the structure of the N-terminal domain is highly conserved throughout evolution, despite its relatively low sequence similarity. Furthermore, Rubisco from a broad evolutionary range of photosynthetic organisms binds RNA under oxidizing conditions, with dissociation constant values in the nanomolar range. In line with these observations, oxidative stress indeed causes a translational arrest in land plants as well as in Rhodospirillum rubrum, a purple bacterium that lacks the SSU. We highlight an evolutionary conserved element located within α-helix B, which is located in the center of the RRM and is also involved in the intramolecular interactions between two LSU chains. Thus, assembly masks the N terminus of the LSU hiding the RRM. When assembly is interrupted due to structural changes that occur under oxidizing conditions or in the absence of a dedicated chaperone, the N-terminal domain can become exposed, leading to the translational arrest of Rubisco LSU. Taken together, these results support a model by which LSU translation is governed by its dimerization. In the case that regulation of type I and type II Rubisco is conserved, the SSU does not appear to be directly involved in LSU translation

A Proposed Mechanism for the Inhibitory Effects of Oxidative Stress on Rubisco Assembly and Its Subunit Expression

In Chlamydomonas reinhardtii, a light-induced oxidative stress shifts the glutathione pool toward its oxidized form, resulting in a translational arrest of the large subunit (LSU) of Rubisco. We show here that the translational arrest of LSU is tightly coordinated with cessation of Rubisco assembly, and both processes take place after a threshold level of reactive oxygen species is reached. As a result, the small subunit is also eliminated by rapid degradation. We previously showed that the amino terminus of the LSU could bind RNA in a sequence-independent manner, as it shares a structural similarity with the RNA recognition motif. This domain becomes exposed only under oxidizing conditions, thus restricting the RNA-binding activity. Here we show that in vitro, thiol groups of both subunits become oxidized in the presence of oxidized glutathione. The structural changes are mediated by oxidized glutathione, whereas only very high concentrations of H(2)O(2) confer similar results in vitro. Changes in the redox state of the LSU thiol groups are also observed in vivo, in response to a physiological light shock caused by transfer of cells from low light to high light. We propose that during a photooxidative stress, oxidation of thiol groups occurs already in nascent LSU chains, perhaps hindering their association with chaperones. As a result, their RNA recognition motif domain becomes exposed and will bind any RNA in its vicinity, including its own transcript. Due to this binding the ribosome stalls, preventing the assembly of additional ribosomes on the transcript. Polysome analysis using Suc gradients indeed shows that the rbcL RNA is associated with the polysomal fraction at all times but shifts toward fractions that contain smaller polysomes and monosomes during oxidative stress. Thus, translational arrest of the LSU most likely occurs at a postinitiation stage

The Influence of Human Infrastructure on Mammal Community Composition - Lessons Learned from Israel’s National Biodiversity Monitoring Program

Anthropogenic activity may cause changes in species assemblages and affect top-down and bottom-up processes. As part of Hamaarag's National Terrestrial Biodiversity Monitoring Program, camera traps were used to collect data on multiple large mammal species. The data was used to unfold new insights on changes in large mammal densities, distribution, and species assemblages in relation to proximity to human infrastructure (settlements and agriculture). Eleven ecological units along Israel’s steep climatic gradient were monitored , from north to south: herbaceous and dwarf scrubland, planted conifer forest in the Mediterranean zone (Judean Highlands, Mt. Carmel, Galilee), Mediterranean Maquis (Judean Highlands, Mt. Carmel, Galilee), Mediterranean-desert transition zone, planted conifer forests in the arid zone, Negev highland desert and Arava arid desert. Nine cameras were placed for 10 consecutive days at 80 plots across Israel, during two monitoring cycles (2012-2014 and 2015-2016), resulting in 720 camera traps pr. monitoring cycle and over 14,000 camera nights. To estimate species densities in relation to spatial predictors while accounting for imperfect detection, encounter data on 13 mammal species were fitted to individual species N-mixture models. Species estimations were thereafter used in non-metric multidimensional scaling (NMDS) based on Bray-Curtis dissimilarity, to evaluate dissimilarity in species assemblages among ecological units and proximity to anthropogenic activity. Mammal species varied in their response to anthropogenic infrastructure: Generalist meso-canid species (golden jackal and red fox) and omnivorous wild boars were found in extreme large numbers near anthropogenic infrastructure, while species such as the endangered mountain gazelle and Dorcas gazelle, were negatively affected by human activity. Extreme over abundant meso-carnivores populations in mosaic landscapes, such as Israel’s northern Mediterranean region, may push sensitive prey species to small isolated patches surrounded by humans and predators, while in southern arid areas, expansion of agriculture and settlements may further increase meso-carnivores populations affecting the ability of prey species to occupy and use such areas. Bino G, Dolev A, Yosha D, et al (2010) Abrupt spatial and numerical responses of overabundant foxes to a reduction in anthropogenic resources. J Appl Ecol 47:1262–1271. doi: 10.1111/j.1365-2664.2010.01882.x Manor R, Saltz D (2005) Effects of human disturbance on use of space and flight distance of mountain gazelles. 69:1683–1690. Shamoon H, Saltz D, Dayan T (2017) Fine-scale temporal and spatial population fluctuations of medium sized carnivores in a Mediterranean agricultural matrix. Landsc Ecol 32:1243–1256. doi: 10.1007/s10980-017-0517-8peerReviewe

Effect of Weed Management on the Parasitoid Community in Mediterranean Vineyards

Enriching agroecosystems with non-crop vegetation is a popular strategy for conservation biocontrol. In vineyards, the effects of specific seeded or planted cover crops on natural enemies are well-studied, whereas conserving spontaneously developing weeds received less attention. We compared parasitoid communities between matched pairs of vineyard plots in northern Israel, differing in weed management practices: “herbicide”, repeated herbicide applications vs. “ground cover”, maintaining resident weeds and trimming them when needed. Using suction sampling, we assessed the parasitoids’ abundance, richness, and composition during three grape-growing seasons. Ground cover plots had greater parasitoid abundances and cumulative species richness than herbicide-treated plots, possibly because of their higher vegetation cover and richness. Dominant parasitoid species varied in their magnitude and direction of response to weed management. Their responses seem to combine tracking of host distributions with attraction to additional vegetation-provided resources. Parasitoid community composition was mildly yet significantly influenced by weed management, while season, year, and habitat (weeds vs. vine) had stronger effects. Vineyard weeds thus support local biocontrol agents and provide additional previously demonstrated benefits (e.g., soil conservation, lower agrochemical exposure) but might also attract some crop pests. When the benefits outweigh this risk, weed conservation seems a promising step towards more sustainable agricultural management.This research was funded by the Israel Open Lands Foundation, the Tabor Winery and the Nekudat Chen Foundation.info:eu-repo/semantics/publishedVersio