The nymphs of spittlebugs (Hemiptera, Cercopidae) are xylem-feeders and live on herbs, grasses or woody plants within their self-produced spittle masses. Nymphs of the spittlebug Neophilaenus albipennis live aggregated in these spittle masses on their host plant Brachypodium pinnatum, a common grass in dry grassland. The objective of this study was to estimate nymphal mortality rates and to examine what role aggregation and vegetation structure play in the mortality of the nymphs. The aggregation and mortality were measured using two different methods, direct monitoring and caging of nymphs. The nymphs passively aggregated with up to 4 nymphs per spittle and aggregation decreased with instar. The aggregation of the nymphs resulted in a reduced mortality in all instars. Although it has already been argued that aggregation may be an advantage, this study is the first direct evidence (i.e. direct measurement of single individuals) for the benefit of aggregation to individual spittlebug nymphs. Despite a clumped distribution of N. albipennis nymphs in tall vegetation, nymphal mortality was not correlated with vegetation height.
The cold hardiness of individuals from overwintering populations of a freeze susceptible bug Pyrrhocoris apterus from central and southern Europe differed significantly. Supercooling point (SCP) correlated well with both lethal temperature (LT50) and lethal time (Lt50), and is agood index of cold hardiness of adults during and after diapause. In January, diapause terminated, but cold hardiness was similar to that recorded in November; cold hardiness decreased slightly in March and markedly in May. Short exposure (less than a week) to higher temperatures before termination of diapause did not reduce the cold hardiness. Cold hardiness did not closely follow air temperatures.The Bulgarian bugs retained lower cold hardiness regardless of acclimation to harsh field conditions in the Czech Republic. The interpopulation difference is therefore a heritable character representing an adjustment to local climates.
The suitability of Liriomyza sativae Blanchard, L. trifolii (Burgess) and L. bryoniae (Kaltenbach) as hosts of the solitary larval-pupal parasitoid Dacnusa sibirica Telenga was studied. This parasitoid is used as a biological control agent against L. trifolii and L. bryoniae. The parasitoid laid eggs in L. sativae, but no adult parasitoids emerged from the puparia. In contrast, D. sibirica adults emerged from the puparia of L. trifolii and L. bryoniae, and there was no significant difference in emergence rate, female developmental time, or sex ratio when parasitizing these two host species. The parasitoid adults that emerged from the L. bryoniae puparia were significantly larger than those from L. trifolii puparia. In conclusion, D. sibirica, a useful biological control agent of L. trifolii and L. bryoniae, cannot control L. sativae.
Sarcopenia is an independent risk factor for morbidity and mortality in patients suffering from small cell lung cancer (SCLC), however, a universal indicator of sarcopenia usable in clinical practice is still missing. A novel indicator for describing the severity of cancer could be helpful in tailoring the anti-tumor therapy. The aim of this study was to evaluate the computed tomography (CT) scans of total muscle area and radiation attenuation in patients suffering from small cell lung cancer. We used staging CT scans performed at the time of diagnosis to measure total muscle area (TMA) and average psoas density (PD) at level of the 3rd lumbar vertebra. TMA and PD were statistically evaluated in association with overall survival and disease staging. We used Mann-Whitney test and Spearman´s correlation coefficient for statistical testing and p-value under 0.05 was considered statistically significant. Retrospectively we examined 47 patients suffering from SCLC (mean age 65.05±7.3 years, BMI 23.97±4.4 kg/m2 , BSA 1.77±0.2 m2 , 30-day mortality was 4.3 % with 10 months median survival). As sarcopenia was pointed TMA under 55 and 39 cm2 /m2 for men and women respectively. The sarcopenic patients had significantly shorter median survival (7 vs. 11 months, p=0.05). We observed a significant relationship between survival and performance status (Spearman´s correlation, R=-0.39, p=0.05). The patients were divided into two groups according to the extensive (ED, n=34) or limited (LD, n=13) form of the disease. We observed significant difference in PD (42.49±6.1 vs. 47.67±4.5 HU, p=0.006) between ED vs. LD groups.
Diapausing larvae of Aphidoletes aphidimyza (Diptera: Cecidomyiidae) had relatively low supercooling points (SCP) ranging from -19.0 to -26.4°C. None of the specimens that froze at this temperature survived. A high survival rate (up to 87%) at -10°C for 10 days was observed in supercooled larvae. Such features are characteristic for insects that use a chill-tolerance strategy of cold hardiness. However, the cocoons formed by the diapausing larvae were penetrable by external ice crystals and the larvae showed a relatively high survival rate (23 - 34%) at -10°C for 10 days also in the frozen state caused by inoculation by external ice at high subzero temperatures. Such a duality with respect to cold hardiness strategies seems to be ecologically relevant to overwintering in soil habitats where there may be unpredictable contact with external ice.
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.
We report that decreased expression of miR-30c in tumor compared to adjacent tissue is sex-dependent in colorectal cancer (CRC) patients. High expression of miR-30c was associated with better survival in the whole cohort. When the cohort was split into male and female subcohorts, decreased miR-30c expression in tumor compared to adjacent tissue was observed only in males. Expression of miR-30c was decreased in CRC tumor tissue in male patients with nodes involvement compared to those without metastases in nodes and this difference was not observe in females. Next dependency of miR-30c expression on oestrogen receptor β (ERβ) mRNA levels in tumor was tested. In males with low expression of ERβ, we observed a significant decrease in miR-30c levels in patients with nodes involvement compared to those without nodes involvement. This difference was not observed in males with high ERβ mRNA levels and in females. Accordingly, males with low expression of ERβ and high expression of miR-30c showed a better survival that those with low expression ERβ and low expression of miR-30c. It is possible to conclude that whole cohort survival dependence on miR-30c is mostly generated by a subcohort of males with low expression of ERβ mRNA in tumor tissue.
Results of studies on prey suitability for generalist predators are important for efficient mass rearing and implementing Integrated Pest Management Programmes (IPM). The green lacewing, Chrysoperla sinica (Tjeder), is a polyphagous natural enemy attacking several pests on various crops in China. We investigated the effect of feeding it different species of prey on its pre-imaginal development, survival, adult longevity and fecundity under laboratory conditions. The prey species tested were nymphs of Aphis glycines Matsumura, cotton aphid Aphis gossypii Glover, peach aphid Myzus persicae Sulzer, corn aphid Rhopalosiphum maidis Fitch and cowpea aphid Aphis craccivora Koch, and eggs of the rice grain moth, Corcyra cephalonica Stainin. None of these species of prey affected the pre-imaginal survival or percentage survival of the eggs of the predator. However, eggs of C. cephalonica and nymphs of M. persicae and A. glycines were the best of the prey species tested, in that when fed on these species the pre-imaginal developmental period of C. sinica was shorter and its adult longevity, fecundity and percentage survival greater than when fed the other species of prey. In contrast, when fed nymphs of A. craccivora the pre-imaginal development period was longer, adult longevity shorter and fecundity lower. These findings could be helpful in defining more optimum conditions for the mass rearing of C. sinica for use in integrated pest management (IPM) programmes for various crops., Niaz Hussain Khuhro ... [et al.]., and Obsahuje seznam literatury
This study investigates the thermal requirements, nymphal development rates and the fecundity of both alate and apterous adults of the giant willow aphid, Tuberolachnus salignus (Gmelin) at several temperatures. Nymphal development rate increased linearly with temperature. It was estimated that 196 ± 4 degree-days above a threshold temperature of 5.5 ± 0.3°C were required for apterae to complete development from birth to final ecdysis. The alate morph was significantly less fecund than the apterous morph and its fecundity did not vary with temperature. The apterous morph displayed highest fecundity at 20°C. Survival to reproduction was lower in the alate morph, but temperature had no effect on the proportion reproducing in either morph.
The potato tuberworm, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), is a major pest of potato, Solanum tuberosum L. (Solanales: Solanaceae), both in the field and storehouses. The rate of development and survival of P. operculella, reared on potato tubers cv. Spunta at eight constant temperatures (17.5, 20, 22.5, 25, 27.5, 30, 32.5 and 35°C), were studied in the laboratory. The duration of development of the immature stages was recorded. Adult longevity was also recorded under the same conditions. Developmental time decreased significantly with increase in temperature within the range 17.5-32.5°C. No development occurred at 35°C. Survival (%) from egg to adult was higher at temperatures within the range 17.5-27.5°C than at either 30 or 32.5°C. Linear and a non-linear (Logan I) models were fitted to our data in order to describe the developmental rate of the immature stages of P. operculella as a function of temperature and estimate the thermal constant (K) and critical temperatures (i.e., lower developmental threshold, optimum temperature for development, upper developmental threshold). Lower developmental threshold and optimum temperature for development ranged between 12.5-16.2 and 31.7-33.8°C, respectively. The estimated upper developmental threshold for total immature development was 35.0°C. Thermal constant for total development was 294.0 degree-days. Adult longevity was significantly shorter at high (30 and 32.5°C) than at low temperatures (17.5-27.5°C). Our results not only provide a broader insight into the thermal biology of P. operculella, but also can be used as an important tool in planning an effective pest control program both in the field and storehouses., Stefanos S. Andreadis, Christos G. Spanoudis, Georgia Zakka, Barbara Aslanidou, Sofia NoukariI, Matilda Savopoulou-Soultani., and Obsahuje bibliografii