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Why aggregate?Gillmeister, Andrea Brigitta January 1999 (has links)
No description available.
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Exploring the Role of the Foraging Gene on Egg-laying Preferences in Drosophila melanogasterMcConnell, Murray 23 August 2011 (has links)
Egg-laying decisions can have significant fitness consequences. In female Drosophila melanogaster, egg-laying involves foraging-like behaviour. Natural allelic variation in foraging (for) underlies the rover/sitter foraging behaviour polymorphism found in D. melanogaster. for encodes a cGMP-dependent protein kinase (PKG) where rovers have higher for-PKG transcript levels and PKG activity than sitters. Interestingly, the orthologue of for in nematodes (egl-4) affects both egg-laying and foraging behaviours. When given a choice between low- and high-nutrient patches, rovers preferentially lay more eggs on the low-nutrient patches while sitters and a sitter mutant prefer high-nutrient patches. Using the neuronal driver elav-GAL4, rover-like preferences were rescued in sitter flies. Compared to sitters, rovers have higher fitness on a sub-optimal substrate which may explain the observed egg-laying preferences. By studying the link from genes to behaviour, this study provides insight to the evolutionary basis and maintenance of behaviour.
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Exploring the Role of the Foraging Gene on Egg-laying Preferences in Drosophila melanogasterMcConnell, Murray 23 August 2011 (has links)
Egg-laying decisions can have significant fitness consequences. In female Drosophila melanogaster, egg-laying involves foraging-like behaviour. Natural allelic variation in foraging (for) underlies the rover/sitter foraging behaviour polymorphism found in D. melanogaster. for encodes a cGMP-dependent protein kinase (PKG) where rovers have higher for-PKG transcript levels and PKG activity than sitters. Interestingly, the orthologue of for in nematodes (egl-4) affects both egg-laying and foraging behaviours. When given a choice between low- and high-nutrient patches, rovers preferentially lay more eggs on the low-nutrient patches while sitters and a sitter mutant prefer high-nutrient patches. Using the neuronal driver elav-GAL4, rover-like preferences were rescued in sitter flies. Compared to sitters, rovers have higher fitness on a sub-optimal substrate which may explain the observed egg-laying preferences. By studying the link from genes to behaviour, this study provides insight to the evolutionary basis and maintenance of behaviour.
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The oviposition behaviour of Pieris rapae : a study in the ecological interpretation of insects' egg distributions / by Penelope M. IvesIves, Penelope Margaret January 1974 (has links)
1 v. (various paging) : ill. ; 27 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Zoology, University of Adelaide, 1975
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The oviposition behaviour of Pieris rapae : a study in the ecological interpretation of insects' egg distributions /Ives, Penelope Margaret. January 1974 (has links) (PDF)
Thesis (Ph.D.) -- Dept. of Zoology, University of Adelaide, 1975.
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Investigating morphometrics, movement and oviposition in the Lissotriton and Triturus newtsJohnson, Lisa January 2015 (has links)
This thesis focuses on the UK pond newts, the smaller bodied species known as Lissotriton newts and the larger Triturus. The primary aims were to identify and address gaps in the current Tritus/Lissotriton literature; to provide a more complete understanding of this group as many assumptions about morphology and physiology exist untested, for example that larger/fatter females will lay more eggs. Specifically for Lissotriton helveticus, many assumptions are based on the similarly sized Lissotriton vulgaris, potentially missing any species specific differences. A further focus of the work was to provide a clearer view over the whole breeding season; using measures of condition over a season and egg-laying.
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Exploiting early herbivory-induced defense traits in Zea species for the management of Chilo partellus in East Africa / Daniel Munyao MutyambaiMutyambai, Daniel Munyao January 2014 (has links)
Maize, a genetically diverse crop, is the third largest cereal crop in the world and the
most important staple cereal in sub-Saharan Africa, supplying 50% of the calorie intake
in this region. The stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is a
key constraint to cereal production in most resource-poor smallholder farming systems
in sub-Saharan Africa causing crop losses accruing up to 88%. Previous studies have
shown that feeding by herbivorous insects induces maize to emit volatiles attractive to
natural enemies. However, these antagonists are recruited when damage has already
been inflicted on the plant. Recent investigations revealed that egg deposition can
induce maize landraces of Mesoamerican origin to emit volatiles attractive to C.
partellus parasitoids, a trait previously reported to be absent in maize hybrids. However,
genotypic variation in this indirect defence trait within maize varieties adapted to local
agroclimatic conditions and the effect of processes such as domestication and breeding
on this trait are not known. Moreover, it is not known whether maize varieties
possessing this indirect defence trait can directly deter further herbivore colonization
and constitutively suppress the herbivore‟s larval development or whether they can
induce the same defence trait in neighbouring unattacked plants. This study sought to
fill these knowledge gaps with the aim of exploiting these plant defence traits in the
development of ecologically sound crop protection strategies. Experiments were
conducted in which headspace volatile samples were collected from plants of wild,
landrace and hybrid maize with and without C. partellus eggs. Chemical analyses were
done using gas chromatography (GC), coupled GC-mass spectrometry (GC-MS) and
coupled GC-Electroantenography (GC-EAG). Behavioural bioassays were done using
egg (Trichogramma bournieri Pintureau (Hymenoptera: Trichogrammatidae)) and larval
(Cotesia sesamiae Cameron (Hymenoptera: Braconidae)) parasitoids in a 4-arm
olfactometer using volatiles collected from the plants. Moreover, C. partellus larval
preference, growth and development as well as subsequent oviposition behaviour of
gravid C. partellus moths on these plants were determined. Behavioural assays showed
that both T. bournieri and C. sesamiae preferred volatiles from four of the five wild
teosinte species, five landraces and one of two maize hybrids exposed to egg
deposition. Similarly, volatiles collected from unoviposited maize landrace plants
exposed to oviposited landrace maize plants emitting oviposition-induced volatiles, were
attractive to both egg and larval parasitoids. Moreover, maize varieties emitting these
oviposition-induced volatiles deterred further herbivore colonization and suppressed
larval development. Volatile analysis by GC and GC-MS revealed marked increases in
volatile emission as well as qualitative changes in the odour blends in four wild types,
five landraces and one hybrid, following stemborer oviposition. Coupled GC-EAG
analysis of attractive samples revealed that C. sesamiae was responsive to (E)-2-
hexenal, (Z)-3-hexen-1-ol, nonane, 6-methyl-5-heptene-2-one, α-pinene, myrcene,
limonene, (E)-4,8-dimethyl-1,3,7-nonatriene, decanal, 3,4-dimethylacetophenone and
(E)-β-farnesene. Results from this study provide insights into tritrophic interactions thus
paving the way for designing novel and ecologically sound pest management strategies
through breeding crops with this novel oviposition-induced defence trait. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
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Exploiting early herbivory-induced defense traits in Zea species for the management of Chilo partellus in East Africa / Daniel Munyao MutyambaiMutyambai, Daniel Munyao January 2014 (has links)
Maize, a genetically diverse crop, is the third largest cereal crop in the world and the
most important staple cereal in sub-Saharan Africa, supplying 50% of the calorie intake
in this region. The stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is a
key constraint to cereal production in most resource-poor smallholder farming systems
in sub-Saharan Africa causing crop losses accruing up to 88%. Previous studies have
shown that feeding by herbivorous insects induces maize to emit volatiles attractive to
natural enemies. However, these antagonists are recruited when damage has already
been inflicted on the plant. Recent investigations revealed that egg deposition can
induce maize landraces of Mesoamerican origin to emit volatiles attractive to C.
partellus parasitoids, a trait previously reported to be absent in maize hybrids. However,
genotypic variation in this indirect defence trait within maize varieties adapted to local
agroclimatic conditions and the effect of processes such as domestication and breeding
on this trait are not known. Moreover, it is not known whether maize varieties
possessing this indirect defence trait can directly deter further herbivore colonization
and constitutively suppress the herbivore‟s larval development or whether they can
induce the same defence trait in neighbouring unattacked plants. This study sought to
fill these knowledge gaps with the aim of exploiting these plant defence traits in the
development of ecologically sound crop protection strategies. Experiments were
conducted in which headspace volatile samples were collected from plants of wild,
landrace and hybrid maize with and without C. partellus eggs. Chemical analyses were
done using gas chromatography (GC), coupled GC-mass spectrometry (GC-MS) and
coupled GC-Electroantenography (GC-EAG). Behavioural bioassays were done using
egg (Trichogramma bournieri Pintureau (Hymenoptera: Trichogrammatidae)) and larval
(Cotesia sesamiae Cameron (Hymenoptera: Braconidae)) parasitoids in a 4-arm
olfactometer using volatiles collected from the plants. Moreover, C. partellus larval
preference, growth and development as well as subsequent oviposition behaviour of
gravid C. partellus moths on these plants were determined. Behavioural assays showed
that both T. bournieri and C. sesamiae preferred volatiles from four of the five wild
teosinte species, five landraces and one of two maize hybrids exposed to egg
deposition. Similarly, volatiles collected from unoviposited maize landrace plants
exposed to oviposited landrace maize plants emitting oviposition-induced volatiles, were
attractive to both egg and larval parasitoids. Moreover, maize varieties emitting these
oviposition-induced volatiles deterred further herbivore colonization and suppressed
larval development. Volatile analysis by GC and GC-MS revealed marked increases in
volatile emission as well as qualitative changes in the odour blends in four wild types,
five landraces and one hybrid, following stemborer oviposition. Coupled GC-EAG
analysis of attractive samples revealed that C. sesamiae was responsive to (E)-2-
hexenal, (Z)-3-hexen-1-ol, nonane, 6-methyl-5-heptene-2-one, α-pinene, myrcene,
limonene, (E)-4,8-dimethyl-1,3,7-nonatriene, decanal, 3,4-dimethylacetophenone and
(E)-β-farnesene. Results from this study provide insights into tritrophic interactions thus
paving the way for designing novel and ecologically sound pest management strategies
through breeding crops with this novel oviposition-induced defence trait. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
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An individual based population study of an insect herbivore (Urophora jaceana) and its host plant (Centaurea nigra)Paul, Roger Philip January 1997 (has links)
No description available.
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Transmission of La Crosse Virus in Southwest Virginia: Role of Accessory Vectors, Microfilarial Coinfection and Canine SeroprevalenceTroyano, Nancy Michelle 02 June 2009 (has links)
Southwest Virginia has recently become an emerging focus of activity for La Crosse (LAC) virus, a mosquito-transmitted arbovirus in the California serogroup of Bunyaviruses. In 2005 and 2006, ovitrap surveys were conducted to access the spatiotemporal oviposition activity of LAC virus vectors Aedes triseriatus, Ae. albopictus and Ae. japonicus across a wide region of southwest Virginia. Egg abundance and oviposition patterns of these vectors were significantly different across the three study areas. The primary LAC virus vector, Ae. triseriatus, was collected in the greatest abundance from all three areas, and favored forested habitats. Aedes albopictus was the second most abundant species collected, and was found to favor urban environments. Aedes japonicus also has a preference for urban habitats, and is actively expanding its range throughout southwest Virginia.
Dogs were used to determine their efficacy as sentinels for assessing the distribution of LAC virus in southwest Virginia. Canine serum samples were tested using plaque reduction neutralization (PRNT) assays. Of the 436 collected canine serum samples, 21 (4.8%) were positive for LAC virus antibodies. LAC virus seroprevalence was evident in dogs from each study region, including areas where LAC virus human cases and LAC virus positive mosquito isolates have not been reported. As a result, this study provided documentation of horizontal transmission of LAC virus throughout southwest Virginia, demonstrating that dogs make useful sentinels for assessing the distribution of LAC virus in an area.
The final objective examined the effects of coinfection with D. immitis microfilariae and LAC virus in three species of Aedes mosquitoes. No significant differences were found between mosquitoes fed dually infected bloodmeals (i.e. D. immitis microfilariae and LAC virus) and those fed bloodmeals containing LAC virus only. A follow-up study found low mosquito midgut penetration rates by D. immitis, despite using biologically significant doses of microfilariae. Failure to demonstrate enhancement of LAC virus in vector mosquitoes suggests that D. immitis does not have a significant impact on LAC virus epidemiology in areas where these organisms co-exist. / Ph. D.
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