Responses of insects to recent climate change have been well documented in a number of taxa, but not in wasps. This study examined shifts in phenology of the two most important wasp species (Vespa crabro and Vespula germanica) in Poland over the last three decades. Both species showed similar temporal trends, advancing their phenology after the early 1980s, but this pattern was detected only for workers not for the appearance of queens. The appearance times for V. germanica were negatively related to mean April temperature, appearing earlier in years with warmer springs, and positively related to precipitation in April. The studied species advanced aspects of their phenology, but linking this to temperature was not achieved for V. crabro suggesting that we have to pay more attention to the life history traits of the study organisms.
The individual plant of Chinese ivy can produce three types of branches (creepy, climbing, and reproductive) during its development, which adapt to different environmental factors. An eco-physiological model was constructed to simulate leaf net photosynthetic rate (PN) of Chinese ivy (Hedera nepalensis var. sinensis) in subtropical evergreen broad-leaved forest based on leaf physiological and mathematical analysis. The model integrated the rate-limiting biochemical process of photosynthesis and the processes of stomatal regulation. Influence of environmental factors (solar radiation, temperature, CO2 concentration, vapour pressure deficit, etc.) on PN was also considered in our model; its parameters were estimated for leaves on three types of branch in the whole growing season. The model was validated with field data. The model could simulate PN of leaf on three types of branches accurately. Influence of solar radiation on leaf PN of three types of branches in different seasons was analyzed through the model with numerical analysis. and J. Yang ... [et al.].
Thermal stability of thylakoid membranes isolated from acclimated and non-acclimated wheat (Triticum aestivum L. cv. HD 2329) leaves under irradiation was studied. Damage to the photosynthetic electron transport activity was more pronounced in thylakoid membranes isolated from non-acclimated leaves as compared to thylakoid membrane isolated from acclimated wheat leaves at 35 °C. The loss of D1 protein was faster in non-acclimated thylakoid membrane as compared to acclimated thylakoid membranes at 35 °C. However, the effect of elevated temperature on the 33 kDa protein associated with oxygen evolving complex in these two types of thylakoid membranes was minimal. Trypsin digestion of the 33 kDa protein in the thylakoid membranes isolated from control and acclimated seedlings suggested that re-organisation of 33 kDa protein occurs before its release during high temperature treatment. and A. K. Singh, G. S. Singhal.
The survival of Encephalitozoon cuniculi Lcvaditi, Nicolau et Schoen, 1923 spores suspended in distilled water and exposed at defined temperatures was investigated. Infectivity of E. cuniculi spores was tested by inoculation of SCID mice. There was no marked loss of infectivity of spores stored at 4°C for two years or frozen at -12°C and -24°C for 1, 8, and 24 h. Although there was a remarkable loss of infectivity, spores remained infective after freezing at -70°C for 1 and 8 h. Heating at 60°C and 70°C for 5 min and 1 min, respectively, rendered the microsporidia non-infective. These findings demonstrate that E. cuniculi spores suspended in water can survive freezing temperatures but lost infectivity in water that reached a temperature of 60°C at 5 min.
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.
Encarsia bimaculata (Heraty & Polaszek) is an abundant parasitoid of Bemisia tabaci in southern China. The effects of constant temperatures on a range of life history traits, including development, survival of immatures, longevity and reproduction of adults, were studied in the laboratory. The developmental period from egg to adult ranged from 34.3 ± 0.4 d at 20°C to 8.7 ± 0.6 d at 32°C, A total of 181.4 ± 2.4 degree-days were required to complete development with a lower developmental threshold of 11.6 ± 0.3°C. The survivorship of E. bimaculata from 2nd instar to adult varied from 81.3 ± 1.7% at 20°C to 91.0 ± 1.8% at 26°C. Average adult female longevity was 8.4 ± 0.7 d at 20°C and 5.4 ± 0.4 d at 32°C, and daily production of offspring peaked at 29°C with 4.5 offspring per female. The maximum oviposition occurred three days after adult emergence at 23, 26, 29 and 32°C, and four days at 20°C. Total number of offspring produced per female varied from 24.3 ± 2.0 at 32°C to 29.3 ± 2.9 at 20°C. The maximum intrinsic rate of increase (rm) was 0.2163 ± 0.013 at 29°C, followed by 0.2062 ± 0.022 at 32°C. Results indicate that E. bimaculata reaches its maximum biological potential at temperatures ranging from 26°C to 32°C with 29°C being the optimal temperature.
A laboratory study was carried out to determine the effects and interactions of temperature, host deprivation and adult feeding on the longevity of the parasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae). The effect of body size was also examined. Large wasps (hind tibia length > 1.96 mm) lived significantly longer than smaller conspecifics (hind tibia length < 1.89 mm). Adults reared at 15°C lived longer regardless of whether supplied with hosts or food. Correspondingly, adults had a shorter life at 30°C. Honey-fed adults lived significantly longer than starved adults at all temperatures and irrespective of host presence, while access to hosts resulted in a decrease in longevity at all temperatures, regardless of food supply. The Weibull distribution was used to describe the age specific survival, which in V. canescens is of "Type I", as the risk of death increases with age. Despite the significant effect of host presence on survival it was less than either temperature or feeding. The interactions between feeding, host presence and temperature proved to be significant. The objective of the study was to improve the effectiveness of V. canescens as a biological control agent of stored product pests.
Chrococcoid cyanobacteria of the genus Synechococcus are the important component of marine and freshwater ecosystems. Picocyanobacteria comprise even 80% of total cyanobacterial biomass and contribute to 50% of total primary cyanobacterial bloom production. Chlorophyll (Chl) fluorescence and photosynthetic light response (P-I) curves are commonly used to characterize photoacclimation of Synechococcus strains. Three brackish, picocyanobacterial strains of Synechococcus (BA-132, BA-124, BA-120) were studied. They were grown under 4 irradiances [10, 55, 100, and 145 μmol(photon) m-2 s-1] and at 3 temperatures (15, 22.5, and 30°C). Photosynthetic rate was measured by Clark oxygen electrode, whereas the Chl fluorescence was measured using Pulse Amplitude Modulation fluorometer. Based on P-I, two mechanisms of photoacclimation were recognized in Synechococcus. The maximum value of maximum rate of photosynthesis (Pmax) expressed per biomass unit at 10 μmol(photon) m-2 s-1 indicated a change in the number of photosynthetic units (PSU). The constant values of initial slope of photosynthetic light response curve (α) and the maximum value of Pmax expressed per Chl unit at 145 μmol(photon) m-2 s-1 indicated another mechanism, i.e. a change in PSU size. These two mechanisms caused changes in photosynthetic rate and its parameters (compensation point, α, saturation irradiance, dark respiration, Pmax) upon the influence of different irradiance and temperature. High irradiance had a negative effect on fluorescence parameters, such as the maximum quantum yield and effective quantum yield of PSII photochemistry (φPSII), but it was higher in case of φPSII., S. Jodłowska, S. Śliwińska., and Obsahuje bibliografii
Differences in acclimation to elevated growth CO2 (700 µmol mol-1, EC) and elevated temperature (ambient +4 °C, ET) in successive leaves of wheat were investigated in field chambers. At a common measurement CO2, EC increased photosynthesis and the quantum yield of electron transport (Φ) early on in the growth of penultimate leaves, and later decreased them. In contrast, EC did not change photosynthesis, and increased Φ at later growth stages in the flag leaf. Contents of chlorophyll (Chl), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), and total soluble protein were initially higher and subsequently lower in penultimate than flag leaves. EC decreased RuBPCO protein content relative to soluble protein and Chl contents throughout the development of penultimate leaves. On the other hand, EC initially increased the RuBPCO:Chl and Chl a/b ratios, but later decreased them in flag leaves. In the flag leaves but not in the penultimate leaves, ET initially decreased initial and specific RuBPCO activities at ambient CO2 (AC) and increased them at EC. Late in leaf growth, ET decreased Chl contents under AC in both kinds of leaves, and had no effect or a positive one under EC. Thus the differences between the two kinds of leaves were due to resource availability, and to EC-increased allocation of resources to photon harvesting in the penultimate leaves, but to increased allocation to carboxylation early on in growth, and to light harvesting subsequently, in the flag leaves. and P. Pérez ... [et al.].
Daily emigrations of non-native age 0 and age 1 potamodromous (fluvial) rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta
were investigated in two Missouri River tributaries, USA over the period 1998-2002. The patterns of emigration for both age 0 and age 1 fish of both species were highly variable, sometimes showing bimodal (spring and fall) emigrations and other times less well defined patterns. Peak timing of age 0 emigration was also highly variable among years (up to 5 months) and more
variable than the timing of age 1 emigrations (more than two months). Emigrations were preferentially associated with increasing photoperiod before June 22, with water temperatures from 7.5 to 12.5 °C, and often followed sudden increases in stream discharge. More emigrations were associated with the new moon phase as opposed to the full moon phase. In an analysis of models of emigration (2 rivers × 2 species × 2 ages/species
× 31 model combinations for five categorical variables – year, temperature, discharge, moon phase, and photoperiod) using the information-theoretic approach, none of the models were especially effective at explaining emigrations; for the 16 models (i.e. the two with the lowest AIC per river, species and age), no corresponding multiple linear regression model explained more than 41 % of the emigration, and most other models explained considerably less. Results of this study suggest that emigrations of both brown and rainbow trout as part of their fluvial life histories are potentially influenced by a variety of environmental factors, and can be expected to show considerable variation yearly based on the complex, poorly defined genetic origins of the fish and the highly variable climatic conditions associated with the Missouri River Basin.