National Repository of Grey Literature 17 records found  previous11 - 17  jump to record: Search took 0.01 seconds. 
Selected ecophysiological characteristics of the new invasive pests in agriculture.
HOUFKOVÁ, Kateřina
The aim of this thesis was to gather and review information on biology and ecophysiology of four invasive species that are considered to be important pests in agriculture. Following species were chosen for the review: Tuta absoluta, Epitrix spp., Ostrinia nubilalis and Diabrotica virgifera virgifera. Experimental part of the thesis consists of ecophysiological and survival experiments conducted on one of the selected species ? Diabrotica virgifera virgifera. The influence of temperature and photoperiod on egg diapause termination was tested in the laboratory. A comparison of adulta survival on three different diets is also included.
Population dynamics of the spruce bark beetle (\kur{Ips typographus (L.)}) at selected localities in the Bohemian Forest
DAVÍDKOVÁ, Markéta
The aim of this thesis was to monitor the population dynamics and the reproductive status of the spruce bark beetle, Ips typographus (L.), at three localities of different elevation. I focused mainly on following aspects: number of sister broods per generation and per vegetation season, rate of development in the first generation and swarming readiness in diapausing and post-diapausing adults.
Cold resistance of the water cricket Velia caprai: the influence of acclimation age class and food availability on the supercooling point
NOVOTNÁ, Iveta
Recently, the cold resistance becomes a common topic in scientific articles. If we focus on order Heteroptera, we can find a lot of studies dealing with the cold resistance or with the supercooling point (SCP) and also with the factors that influence them. According to the general rule, the acclimation at low temperatures increases the cold resistance. Therefore, the main goal of this thesis is to find out, whether the acclimation also increases the cold resistance of the water cricket Velia caprai Tamanini, 1947 (Veliidae), with the intention to measure SCP of the water crickets depending on the acclimation temperature and the length of exposure. Due to the high mortality (the 284 individuals remained alive of total 1300) and due to the technical difficulties in measuring of SCP (measured only 36 individuals) it was necessary to modify the original goal of the thesis. The new goal was to test the influence of acclimation (during one month vs. one week) and the influence of different temperatures (0°C, 5°C, 10°C) on SCP of V. caprai. The individuals used for this measurement were collected during the year 2010 and in March 2011. The results of this thesis did not confirm the hypothesis that the acclimation at low temperatures increases the cold resistance. The individuals who were acclimated at a higher temperature have the values of SCP demonstrably lower than the individuals who were acclimated at low temperatures. The individuals who overwinter for the first time have arguably higher cold resistance than the individuals who overwinter for the second time. Probable cause of these results is the fact that the water cricket V. caprai does not start with diapause in the fall but it overwinters in quiescence.
Physiological mechanisms of aging in maless of model insect species
PROVAZNÍK, Jan
Trade-off between reproduction and longevity is a widely accepted fact, yet proximate mechanisms are scarcely understood. In this work I tested differences in lifespan between diapause and non-diapause males of a model insect, the linden bug Pyrrhocoris apterus. Also the role of juvenile hormone in regulation of longevity and immunity (measured by relative phenoloxidase activity) was assessed. In addition to that, I examined if juvenile hormone is the mediator of reduction in longevity induced by mating.
The energetic state of the spruce bark beetle (\kur{Ips typographus} (L.)): Implications for winter survival
BARTOŠOVÁ, Eva
The thesis deals with characterisation and changes of energetic status in the spruce bark beetle, Ips typographus, during pre-diapause, diapause and post-diapause quiescence.
Molecular and environmental factors connected to diapause and aging in insect
ZDECHOVANOVÁ, Lenka
Current models state that insect peripheral oscillators are directly responsive to light, while mammalian peripheral clock genes are coordinated by a master clock in the brain via intermediate factors, possibly hormonal. We show that the expression levels of two circadian clock genes, period (per) and Par Domain Protein 1 (Pdp1) in the peripheral tisue of an insect model species are inversely affected by contrasting photoperiods. The effect of photoperiod on per and Pdp1 mRNA levels was found to be mediated by the juvenile hormone. Our results provide the first experimental evidence for hormonal regulation of circadian clock gene expression in insects.
Physiological and molecular adaptations during diapause development and overwintering in a heteropteran bug, Pyrrhocoris apterus
BOROVANSKÁ, Michaela
In this thesis I present complex experimental data on the physiological and molecular adaptations during diapause development and overwintering in a linden bug, Pyrrhocoris apterus (Heteroptera, Pyrrhocoridae). I focus on adjustments of the enzymatic complement, which is involved in the biosynthesis of cryoprotectants, and heat shock proteins, which are expressed in response to temperature stress.

National Repository of Grey Literature : 17 records found   previous11 - 17  jump to record:
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