Reduced oviposition by ladybirds in the presence of tracks of fourth instar larvae owing to the presence of oviposition deterring pheromones is well established across many genera. However, deterrence, if any, by other life stages has not been well investigated, in particular the effect of conspecific presence. The present study investigates the effects of conspecific presence and semiochemicals of conspecific life stages (eggs, fourth instar larvae, pupae, adult males and females) on oviposition by five ladybird (Coleoptera: Coccinellidae) species, viz. Coccinella septempunctata, Coccinella transversalis, Cheilomenes sexmaculata, Propylea dissecta and Anegleis cardoni. Results reveal that the presence of life stages inhibits oviposition and the inhibition is density-dependent, although the degree of inhibition is species-specific. Surface semiochemicals of eggs and larval and adult tracks also show density-dependent inhibitory effects. Moreover, the semiochemicals in tracks (oviposition deterring pheromones) and egg surface semiochemicals are not similar, indicating semiochemical parsimony. Of all species tested, C. transversalis and C. septempunctata were the most and the least responsive to both conspecific presence and semiochemicals, respectively., Geetanjali Mishra ... [et al.]., and Obsahuje seznam literatury
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.
Ionizing radiation and somatostatin analogues are used for acromegaly treatment to achieve normalization or reduction of growth hormone hypersecretion and tumor shrinkage. In this study, we investigated a combination of somatostatin (SS14) with ionizing radiation of 60Co and its effect on reparation of radiation-induced damage and cell death of somatomammotroph pituitary cells GH3. Doses of γ-radiation 20-50 Gy were shown to inhibit proliferation and induce apoptosis in GH3 cells regardless of somatostatin presence. It has been found that the D0 value for GH3 cells was 2.5 Gy. Somatostatin treatment increased radiosensitivity of GH3 cells, so that D0 value decreased to 2.2 Gy. We detected quick phosphorylation of histone H2A.X upon irradiation by the dose 20 Gy and its colocalization with phosphorylated protein Nbs-1 in the site of double strand break of DNA (DSB). Number of DSB decreased significantly 24 h after irradiation, however, clearly distinguished foci persisted, indicating non repaired DSB, after irradiation alone or after combined treatment by irradiation and SS14. We found that SS14 alone triggers phosphorylation of Nbs1 (p-Nbs1), which correlates with antiproliferative effect of SS14. Irradiation also increased the presence of p-Nbs1. Most intensive phosphorylation of Nbs1 was detected after combined treatment of irradiation and SS14. The decrease of the number of the DSB foci 24 h after treatment shows a significant capacity of repair systems of GH3 cells. In spite of this, large number of unrepaired DSB persists for 24 h after the treatment. We conclude that SS14 does not have a radioprotective effect on somatomammotroph GH3 cells., M. Řezáčová, J. Čáp, D. Vokurková, E. Lukášová, J. Vávrová, J. Cerman, V. Mašín, N. Mazánková., and Obsahuje bibliografii a bibliografické odkazy
In the Mediterranean area the orthopterans Calliptamus barbarus barbarus, Dociostaurus maroccanus and Tettigonia viridissima are considered to be pests of major economic importance crop plants. The aim of the present study was to evaluate the area of leaf of vine, cotton and potato plants consumed by these Orthoptera at two temperatures. Leaf area was determined for each plant species before the leaves were provided to the insects. Virgin male and female adults were allowed to feed on a leaf of each plant species and the area of leaf consumed was determined after 24h at 25 and 30°C. Results showed that temperature had a significant affect on consumption by both males and females of all the species examined, and it was higher at 30°C. The influence of plant species was not significant for C. barbarus barbarus. D. maroccanus and T. viridissima, however, consumed a greater area of potato leaves than of the other species of plants. Females consumed more food than males in all the species tested. The results of the present study provide a first approximation of the area of leaf consumed and the potential loss of foliage these plants might suffer if attacked by the three species of Orthoptera tested., Spyridon A. Antonatos, Nikolaos G. Emmanuel, Argyro A. Fantinou., and Obsahuje seznam literatury
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
In order to enhance the mass production of the house fly, Musca domestica, five aspects of its oviposition biology were analyzed. Oviposition substrate and the manner of its presentation, the composition of the diet of the adults, size of the pupae and numbers of flies in a cage were identified as critical. Females preferred to lay eggs on a substrate which was presented within a shelter and with increased linear edges against which the flies could oviposit. Different types of oviposition substrate resulted in comparable yields of eggs. The presence of an oviposition attractant (ammonia) in the manure was found to have a potentially positive effect on female fecundity. Egg yield increased when two protein sources (yeast and milk) were included in the adult diet. However, flies fed a mixture of sugar and yeast laid over 50% fewer eggs than those fed the same proportion of sugar and milk. The fecundity of flies decreased with increase in the number of flies per cage, but the highest total number of eggs per cage was obtained when the flies were most crowded (14.2 cm3 per fly). The size of the pupae did not significantly affect egg production. and Berta Pastor, Helena Čičková, Milan Kozánek, Anabel Martínez-Sánchez, Peter Takáč, Santos Rojo.
The Asian long-horned beetle, Anoplophora glabripennis, is a serious destructive pest of forests throughout China as it attacks a wide range of host plants. The effect of host trees on the cold hardiness of A. glabripennis larvae could be the basis for predicting the performance of this forest pest on different common hosts.To evaluate the effect of different species of host plant on the cold hardiness of overwintering larvae of A. glabripennis, we measured the supercooling point (SCP), fresh mass, protein content and concentrations of low molecular weight substances in overwintering larvae collected from three different host species (i.e., Populus opera, Populus tomentosa and Salix matsudana). Mean SCPs and protein contents of larvae from these three hosts differed significantly. The SCPs and protein contents of the larvae collected from P. opera and P. tomentosa were significantly higher than those collected from S. matsudana. The concentrations of glycerol, glucose and trehalose in overwintering larvae collected from these host species also differed significantly, but there were no significant differences in the concentrations of sorbitol and inositol. The larvae that were collected from S. matsudana had the highest concentrations of glycerol and trehalose and those from P. opera the lowest contents of glycerol, whereas those from P. tomentosa had the lowest concentrations of trehalose but the highest concentrations of glucose. Because of the significant differences in the quantities of these biochemical substances in their bodies, the cold hardiness of overwintering larvae of A. glabripennis was significantly dependent on the tree they fed on. These effects on the cold hardiness of the overwintering larvae might affect the selection of a host tree and therefore the spread of this beetle. and Yuqian Feng, Reaxit Tursun, Zhichun Xu, Fang Ouyang, Shixiang Zong.
The red flour beetle, Tribolium castaneum, is a pest of stored products. It is also regarded as a model species for studying development, genetics, biology, physiology and biochemistry. Recently, it has become a model for use in RNA interference experiments. 20-hydroxyecdysone (20E) is involved in insect metamorphosis and its role in organ development in T. castaneum are based on hormonal treatment in conjunction with RNAi. However, information on the biological, morphological and physiological effects of 20E on T. castaneum is still limited. This study reveals the responses of T. castaneum larvae to injections with various doses of 20E (100, 200, 300, 400 and 500 ng / insect). The results show that larvae injected with 20E reached the prepupal, pupal and adult stages earlier than the control group. Different degrees of morphological change were observed in nine traits, including the appearance of pupal prothetelic organs in the larvae. Moreover, an injection of a high dose of 20E reduced the body weights of the resulting insects at each stage, as well as the length and width of elytra. The enzymatic activity of α-amylase in the resulting adults also decreased significantly. This indicates that injection of 20E caused precocious metamorphosis in T. castaneum by inducing changes in morphology and α-amylase activity, and the optimal concentrations that induce such phenomena were in the range of 100-200 ng / insect. Further investigations are needed to examine the roles of 20E in the regulation of α-amylase in T. castaneum., Nujira Tatun, Phiraya Kumdi, Jatuporn Tungjitwitayakul, Sho Sakurai., and Obsahuje bibliografii
The effects of serosally added 5-hydroxytryptamine (5-HT, 100 μM) on the short circuit-current (Isc) across jejunum and ileum taken from fed, starved and undernourished (Gerbillus cheesmani) were investigated. The effects of the neurotoxin, tetrodotoxin (TTX, 10 μM) on the basal Isc as well as on the maximum increase in Isc induced by 5-HT were also studied. There were regional variations in the basal Isc as well as in the way by which the small intestine responds to 5-HT. The basal Isc was greater in jejunum than in ileum and such differences were TTX-sensitive. The maximum increase in Isc, which results from addition of 5-HT, was higher in jejunum than in ileum under all three feeding conditions. TTX reduced the maximum increase in Isc induced by 5-HT across stripped and intact intestine of the two regions in the three nutritional states. The 5-HT-induced Isc in the jejunum of both starved and undernourished gerbils and in the ileum of starved animals was the function of both submucosal and myenteric plexus. In jejunum and ileum taken from starved and undernourished gerbils the 5-HT-induced Isc was both chloride- and bicarbonate-dependent. Thus the results indicated that both starvation and undernourishment increase that response and such increases were TTX-sensitive and both chloride- and bicarbonate-dependent., F. Y. Al-Balool., and Obsahuje bibliografii a bibliografické odkazy
Adenosine is secreted from adipocytes, binds to adenosine A1 receptor and modulates various functions of these cells. In the present study, the effects of an adenosine A1 receptor antagonist (DPCPX; 0.01, 0.1 and 1 μM) on lipogenesis, glucose transport, lipolysis and the antilipolytic action of insulin were tested in rat adipocytes. DPCPX had a very weak effect on lipogenesis and did not significantly affect glucose uptake. In adipocytes incubated with 1 μM DPCPX, lipolysis increased. This effect was blunted by insulin and by a direct inhibitor of protein kinase A. Moreover, 0.1 μM DPCPX substantially enhanced the lipolytic response to epinephrine and increased cAMP in adipocytes. However, DPCPX was ineffective when lipolysis was stimulated by direct activation of protein kinase A. Adipocyte exposure to epinephrine and insulin with or without 0.1 μM DPCPX demonstrated that this antagonist increased the release of glycerol. However, despite the presence of DPCPX, insulin was able to reduce lipolysis. It is concluded that DPCPX had a weak effect on lipogenesis, whereas lipolysis was significantly affected. The partial antagonism of adenosine A1 receptor increased lipolysis in cells incubated with epinephrine alone and epinephrine with insulin due to the synergistic action of 0.1 μM DPCPX and epinephrine., T. Szkudelski, K. Szkudelska, L. Nogowski., and Obsahuje seznam literatury