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Abstract Female ability to exploit conspecifics in reproduction may have unusual expressions. I studied the reproductive behaviour of the golden egg bug (Phyllomorpha laciniata; Heteroptera, Coreidae) experimentally in the field and in the laboratory. Female golden egg bugs lay their eggs mainly on the backs of conspecific males and other females. Non-parental eggs are often carried. Occasionally, the eggs are laid on the food plant (Paronychia spp; Polycarpea, Caryophyllaceae) of the species but typically, those eggs survive poorly due to egg parasitism and predation. I explored the dependence of female reproduction on conspecific presence and encounter rate. I also studied female current reproductive state (which depends on if she has recently oviposited) in relation to her activity as well as male choice of a female. Female bugs preferred to oviposit on conspecifics when presented with a choice between a bug and a food plant. When alone females often did not lay eggs. Increased encounter rate with others increased female egg laying rate. Survival of carried eggs among bugs did not vary significantly although males received more eggs than females. Females with high current fecundity (mature eggs accumulated to reproductive tract) were more active than females with lower current fecundity (recently oviposited). Females with high current fecundity seemed to search for conspecifics to lay eggs on. Males also preferred to court females with high current fecundity. These females were more likely to oviposit immediately after mating, lowering the risk of female remating before oviposition. To conclude, conspecifics are important egg-laying substrates for female golden egg bugs. Conspecific availability affects female egg laying and the rate of egg production in short term. In particular, males are necessary for egg-laying females and they typically receive unrelated eggs when they court females. Sexual interactions resulting from female polyandry are crucial factors that maintain female egg laying on the backs of males and other females in the unique reproductive system of the golden egg bug.

<p>One of the outstanding goals of neuroscience is to understand how neural circuits are assembled to produce context appropriate behavior. In an ever changing environment, it is critical for animals to be able to flexibly respond to different stimuli to optimize their behavioral responses accordingly. Oviposition, or the process of choosing where to lay eggs, is an important behavior for egg-laying animals, yet the neural mechanisms of this behavior are still not completely understood. Here, we use the genetically tractable organism, Drosophila melanogaster, to investigate how the brain decides which substrates are best for egg deposition. We show that flies prefer to lay eggs away from UV light and that induction egg-laying correlates with increased movement away from UV. Both egg-laying and movement aversion of UV are mediated through R7 photoreceptors, but only movement aversion is mediated through Dm8 amacrine neurons. We then identify octopaminergic neurons as being potential modulators of egg-laying output. Collectively, this work reveals new insights into the neural mechanisms that govern Drosophila egg-laying behavior.</p> / Dissertation

I investigated the maternal effects that take place in a joint-nesting bird: the smooth-billed ani. Female anis were shown to respond to increasing group size by increasing the number of eggs produced per capita, by tossing and burying more eggs per capita, and by taking longer to reach the dedicated incubation phase. These results support the hypothesis that females respond to increased egg laying competition by trying to skew the contents of the final incubated clutch of eggs in their own favor. I showed that in ani groups, yolk testosterone and estradiol deposited by females in eggs increased from early- to late-laid eggs. Increases in yolk steroid levels over the laying sequence may function to mitigate the disadvantage of being a later-hatched chick. This maternal influence may not be a mere reflection of a female's hormonal status as female plasma circulating levels of testosterone and estradiol did not vary in the same direction as yolk hormone profiles. I showed that yolk corticosterone levels, an indicator of maternal physiological stress, increased with laying order in multi-female groups, but not in single-female groups. Results suggest that laying females experience higher levels of stress in multifemale groups. The above results suggest that communal life in anis generates competition and egg production waste that likely reduces short-term per capita reproductive benefits. Female anis can vary egg quality via deposition of hormones in eggs, and also lay eggs of different sizes. I showed that circulating plasma testosterone levels were higher in nestlings with better begging abilities. Furthermore, nestlings hatched from eggs laid late in the laying sequence had better begging abilities. These results suggest that testosterone is an important controlling mechanism of begging behaviour, and that female testosterone depositions in eggs rave long lasting effects on offspring development and behavior. / Thesis / Doctor of Philosophy (PhD)

<p> Social learning, defined as learning from other individuals has been well studied in vertebrates and social insect species. I used fruit fly egg laying site selecting as a paradigm to test for social learning in a non-social insect. Focal females that experienced novel food together with mated females (models), who had laid eggs on that food, subsequently exhibited a stronger preference for laying eggs on that food over another novel food than focal females that experienced the same food alone. This socially influenced learning was also observed when focal females experienced both foods, one with mated models and their eggs and one alone. In contrast to the strong effect of a food with mated models and their eggs, neither a food with virgin models nor the aggregation pheromone (cVA) alone generated socially influenced learning. These results provide the first evidence for social learning about egg laying substrate in fruit flies. Further research utilizing fruit flies as a model system may help us gain a better understanding of the evolution and neurogenetics of social learning.</p> / Thesis / Master of Science (MSc)

Thesis (M.Dev.) --University of Limpopo, 2011 / Poverty among communities is not a static condition. There are many factors which contribute to its causes and depth. In South Africa, the economic gaps imposed by the previous apartheid government aggravated economic inequalities and caused considerable disparities, which resulted in the high unemployment rates. This led to a call for pro-active initiatives by post 1994 democratic government to remedy the living condition of the previously disadvantaged people. As part of its poverty relief drive, the South African government has embarked on a series of developmental initiatives to bring services to the poor and to reduce enormous prevailing backlogs, with the aim of increasing community participation and improving the lives of the poor. This study evaluates the egg layers project as a poverty alleviation effort within Blouberg Municipality of the Limpopo Province to respond to the prevailing poverty and underdevelopment among the poor communities. This study revealed from the observations, interviews conducted and questionnaires administrated to sampled beneficiaries of Blouberg Municipality who faces poverty. The study formulated strategies and made recommendations regarding the impact and implementation of the egg layers on poor people.

The aim of the thesis was comparing production parameters of laying hens breeding in different housing systems at a production enterprise, it means in enriched cages and aviary. There is used the laying hybrid ISA Brown for production consumer eggs. The achievement during 13months' cycle shown that in each laying month except 1st laying month the higher hen-day egg production was fond out by hens in enriched cages. The hen-egg production per month was higher in enriched cages too. The higher mortality was demonstrated by hens in aviary during all laying months. Both housing systems reached the highest mortality in the 13th laying month. The hens in aviary had higher feed consumption per egg during all months. Higher daily feed consumption was assigned by the hens in the aviary in the 1st, 2nd and 3rd month and from the 9th to the 13th laying month. In other laying months the hens in enriched cages had higher daily feed consumption. Feed costs formed the highest entry of total costs.

The aim is to determine the importance of photoperiod for oviposition of Peruphasma schultei. The theoretical part covers common description of the reproduction and embryonic development of phasmid. Included the climatic factors affecting physiological action and brief description of the biological clock of insects. Experimental individuals were are kept in three different photoperiods with constant temperature of 25 °C. Control and collection of eggs ran at intervals of two hours. It was shown the influence of photoperiod, time and their interaction on the number of eggs and imposed the difference in putting across time.