Our research examined the time of conception of fallow deer in the DALERD South Plains Forestry Private Limited Company’s Gyulai Forestry Area. We collected data from pregnant females who had been shot in the hunting season. At the time of evisceration the uterus was removed and dissected; and sex and body weight of embryos were recorded. We were able to collect and analyze 149 samples for our study. Based on the sex and body weight of embryos, we calculated the fertilization date for each animal
within our sample group. There were no significant statistical differences found between mean fertilization dates of adult does and yearlings (t = –0.72, p = 0.47). The mean fertilization date of does (with a gestation period of 231.5 days) was October 25th (SD = 13.82, n = 120); whereas, for yearlings this date was October 24th (SD = 12.97; n = 29). Based on embryonic development, results showed that in the population we examined, 2 % of females were impregnated in December, 1.3 % in September (at the end of September), 24.2 % in November and the majority, 72.5 % were fertilized in October.
The pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae), is a well-studied species in terms of its colour polymorphism, where it occurs as two distinct colour morphs, red and green. It is proposed that the occurrence and maintenance of this polymorphism is an adaptive response to environmental factors, in particular natural enemies and host plant quality. We hypothesized that these adaptations are directly mirrored in the energy reserves accumulated by the different colour morphs during their pre-adult stages and reflect their specialization for particular ecological roles. We quantitatively measured the different energy reserves of red and green pea aphids and found that the total energy reserves of these morphs did not differ. Interestingly, these reserves were made up of different components in the red and green colour morphs. There was a higher percentage content of water-soluble carbohydrates and lipids in the red clones and higher percentage content of protein in green clones. These finding are in accordance with green clones being more fecund than red ones and needing more protein for reproduction than red clones, which produce more winged offspring when crowded or in response to the presence of natural enemies and so, need more lipids and carbohydrates to fuel their walking and flight. Apparently, different colour morphs are physiologically specialized to adjust their energy reserves in relation to their specific ecological adaptations and maximize their fitness in terms of dispersal, reproduction, defense and survival., Seyed Mohammad Ahsaei ... []., and Obsahuje seznam literatury
It is argued in this paper that the diversity of plant life histories in the Arctic is much greater than indicated by general descriptions in the literature. Three basic types of life cycle are suggested as a fundamental trait-based framework for exploring the diversity of plant life histories in the Arctic: (i) annual, (ii) non-clonal perennial and (iii) clonal perennial. An overview of current understanding of traits of arctic plant life histories is provided within this framework. Based on the overview it is concluded that (i) there is a substantial diversity of plant life histories in the Arctic, and (ii) there is no single life-history trait that is specific for arctic plants. Furthermore, it is proposed that because arctic environments differ in many respects from other environments, unique combinations of life-history traits are selected among arctic plants. Consequently, arctic plants should express a unique spectrum of life histories. It is also recognized that there are large gaps in the knowledge on arctic plant life-history traits and that fine-tuned trait–habitat relationships may be offset by historical, biogeographical or ecological factors, which may hamper analyses of life history–habitat relationships. On the other hand, it may be rewarding in terms of an improved understanding of functional and evolutionary responses of arctic plants to climate and other environmental changes to identify potential life history syndromes (strategies) among them.
German cockroaches spend most of the day in aggregations within shelters, which they leave in nocturnal foraging trips; cockroaches are rarely seen outside shelters during daylight hours. However, when population density exceeds shelter availability, diurnal aggregations form in exposed, unsheltered locations. To determine if shelter availability affects fitness of B. germanica, we reared cohorts of nymphs in laboratory arenas with or without shelters, and measured reproduction and longevity of tagged adults. When shelters were available in arenas, nymphs developed faster, adults gained more body mass, and females produced more fertile oothecae than when arenas lacked shelters. Therefore, shelter alone has a significant positive effect on growth and reproduction of B. germanica, and reducing or eliminating shelters should affect population growth of B. germanica in residential and industrial settings. and César Gemeno, Gregory M. Williams, Coby Schal.
The duration of development, reproduction and longevity of Gastrophysa viridula (DeGeer) was measured at constant temperatures and a long day photoperiod. At 18, 21.5, 25, and 28°C the average duration of development of the egg, larval and pupal stages and total development time (28.2, 21.6, 16.1, 15.0 days) decreased with temperature but the proportion of time spent in the egg, larval and pupal stages did not significantly change with temperature. Total development required 304.6 day degrees above the lower development threshold of 7.1°C. Pre-adult mortality and the rate of oviposition increased, and the duration of oviposition decreased with increasing temperature. Net reproduction rate Ro decreased (from 157 female eggs at 18°C to 75 female eggs at 28°C) and mean generation time T also decreased (from 45.5 days at 18°C to 24.1 days at 28°C) with increasing temperature. The intrinsic rate of population increase rm increased with temperature (from 0.111 at 18°C to 0.179 at 28°C). On a physiological time scale the average generation time T was 496 day degrees.
At emergence females of Trichogramma had a lot of mature eggs in their ovaries, but some delayed parasitization or refused to parasitize a laboratory host. The effect of constant and alternating temperatures on the percentage of Trichogramma buesi females parasitizing Sitotroga cerealella eggs and the duration of the pre-parasitization period were investigated. The temperature dependencies of the rate of preimaginal development, pre-emergence survival, number of eggs laid daily, and total lifetime fecundity were also determined. As the temperature was increased from 12 to 35°C, the median pre-oviposition period decreased from 5 days to 3 h, with maximum values of 24 and 1.5 days, respectively. The rate of induction of parasitization (reciprocal of duration of the pre-parasitization period of the females that parasitized) increased with temperature like the rate of preimaginal development and average number of eggs laid daily by a parasitizing female. Total cumulative percentage of parasitizing females reached a maximum (ca 60%) at temperatures of 25-30°C, while at 12 and 35°C, respectively, 25 and 50% of females parasitized the S. cerealella eggs. Average lifetime fecundity and pre-emergence survival showed a similar dependence on temperature. The influence of the thermorhythm (25°C for 4 h and 15°C for 20 h) was strongly dependent on its position within the photoperiod. When thermophase coincided with photophase, the percentage of females that parasitized was close to that recorded at a constant temperature of 25°C. But when the high temperature pulse coincided with the dark period, the percentage of parasitizing females was the same as at 15°C. Thus, the temperature dependence of ethogenesis (supposedly, an increase in motivation to parasitize or search for a host) in Trichogramma females was similar to that of morphogenesis, although the reaction to alternating temperatures may have been complicated by interaction with the light : dark regime.
A relict population of Isoëtes echinospora Durieu survived a thirty-year period of severe acidification and high concentrations of phytotoxic aluminium (Al) in Plešné Lake (Bohemian Forest, Czech Republic). The population consisted of only adult plants. Sporeling survival and age structure were examined during the population recovery in 2004–2008. Laboratory experiments were conducted to assess the effect of various pH values (4–8) and Al concentrations (0–1000 µg·l–1) on sporeling development. The responses of the sporelings to the experimental treatments were evaluated and compared with those observed in the lake. The experiments showed that an Al concentration higher than 300 µg·l–1, and high acidity (pH 4), inhibit sporeling growth, in particular resulted in a pronounced reduction in absorptive organs (macrogametophyte rhizoids, roots and root hairs). With increasing concentrations of Al and at pH 4, the ratio of the below-ground to above-ground sporeling biomass decreased to less than 1. The responses of the lake sporelings, rooting in the upper sediment layer, were similar to those exposed to 100–300 µg·l–1 of Al in the laboratory, and reflected the Al toxicity of the lake water. The quillworts at Plešné Lake survived because adult plants can tolerate these adverse conditions and are very long-lived. The population recovered when the pH of the water increased to over 5 and the Al concentration decreased to below 300 µg·l–1.
Isoëtes echinospora, a submerged aquatic quillwort, is native in northern latitudes and a rare glacial relict in mountain lakes in temperate Central Europe. A relic population of this quillwort in the Plešné jezero lake has recovered recently from a 30-year period of failure to reproduce caused by acidification. Early ontogenetic stages of the quillwort are considered to be the most vulnerable to environmental changes. Therefore, the objective of this study was to investigate the phenology of germination of I. echinospora. In a two-year experiment, we examined the time course of germination of micro- and macrospores and establishment of sporelings under (i) natural in situ conditions in the Plešné jezero lake and (ii) at various temperatures (6–17 °C) in the laboratory. We developed a mathematical model that describes the temperature-specific temporal changes in the early ontogeny of I. echinospora. Our experiments clearly show that spores do not germinate at once but gradually over time if exposed to favourable temperatures. Generally, percentage germination tended to increase during the course of a season under most temperature regimes but was inhibited at the lowest temperature. With increasing temperature, microspores germinated earlier and more successfully than macrospores, as described by the model. Sporelings also developed faster at the higher temperature. However, the highest temperature used in the experiments (17 °C) desynchronized the phenology of germination in I. echinospora as it resulted in the two types of spore not being available for fertilization at the same time. Thus, climate change might affect interactions between temperature and the phenology of quillwort reproduction and threaten the survival of this species in Central Europe.
There are 20 endemic genera of mosses and three of liverworts in North America, north of Mexico. All are monotypic except Thelia, with three species. General ecology, reproduction, distribution and nomenclature are discussed for each genus. Distribution maps are provided. The Mexican as well as Neotropical genera of bryophytes are also noted without detailed discussion.
Anthropogenic environmental pollutants affect many physiological, biochemical, and endocrine actions as reproduction, metabolism, immunity, behavior and as such can interfere with any aspect of hormone action. Microbiota and their genes, microbiome, a large body of microorganisms, first of all bacteria and co-existing in the host´s gut, are now believed to be autonomous endocrine organ, participating at overall endocrine, neuroendocrine and immunoendocrine regulations. While an extensive literature is available on the physiological and pathological aspects of both players, information about their mutual relationships is scarce. In the review we attempted to show various examples where both, endocrine disruptors and microbiota are meeting and can act cooperatively or in opposition and to show the mechanism, if known, staying behind these actions., Richard Hampl, Luboslav Stárka., and Obsahuje bibliografii