bluuebunny/crossref_metadata_2025 huggingface dataset:
Different effects of melatonin pretreatment on cAMP and LH responses of the neonatal rat pituitary cells
Authors: Pelíšek Václav , Vaněček Jiří
Published: November 2003

The rhythm of the pineal hormone melatonin transduces the effect of photoperiod on seasonal functions. Duration of the melatonin pulse provides information about season and the long melatonin pulse induces reproductive involution in the long day breeders such as photoperiodic rodents. The length of melatonin pulse thus carries photoperiodic information, which regulates the function of target cells. Therefore, we have studied the effects of melatonin pretreatment of various lengths on responsiveness of the neonatal rat pituitary cells cultured in vitro to GnRH or forskolin. In these cells, melatonin treatment inhibits the GnRH‐induced LH release as well as the forskolin‐induced cAMP accumulation. However, long preincubation with melatonin has a paradoxical stimulatory effect on the cellular responsiveness. When the cells are pretreated with melatonin for 16 hr or more, then rinsed thoroughly and treated with forskolin for 30 min, the increase of cAMP is potentiated. Moreover, in the melatonin‐pretreated cells, the subsequent melatonin treatment inhibits the forskolin‐induced cAMP accumulation relatively more than in the non‐pretreated cells. Although melatonin pretreatment does not potentiate the GnRH‐induced LH release, it protects the gonadotrophs against the GnRH‐induced desensitization: pretreatment with GnRH for 12 hr or more renders the cells insensitive to subsequent GnRH stimulation, while after pretreatment with GnRH and melatonin, the subsequent GnRH treatment induces significant increase of LH release. These observations indicate that long pretreatment with melatonin improves responsiveness of the pituitary cells to the subsequent stimulation, but its effects on cAMP accumulation and LH release are different.
Long‐term daily melatonin infusion induces a large increase in N‐acetyltransferase activity, hydroxyindole‐O‐methyltransferase activity, and melatonin content in the Harderian gland and eye of pinealectomized male Siberian hamsters (Phodopus sungorus)
Authors: Djeridane Yasmina , Pitrosky Bruno , Vivien‐Roels Berthe , Simonneaux Valérie , Kirsch Raymond , Pévet Paul
Published: November 2003

The effects of long‐term daily melatonin infusions on the melatonin synthetic pathway in the Harderian glands and eyes of male Siberian hamsters were studied. Hamsters were pinealectomized (PX) and infused daily for 8 hr with either melatonin (6 μg/hr) or vehicle for 7 days in short photoperiod (SP, 10L:14D), followed by 14 wk in either SP (SP group) or in constant darkness (DD group). After the infusion period (15 wk), the infusion was stopped and animals were transferred into SP for 3 wk. The hamsters were then killed at midday or midnight. Exogenous melatonin infusion caused an increase in the Harderian gland weight, which was still evident 3 wk after the end of the treatment. In addition, exogenous melatonin increased endogenous melatonin concentrations (4‐fold) and hydroxyindole‐O‐methyltransferase (HIOMT) activity
(2‐fold). N‐acetyltransferase (NAT) activity, however, was not increased, and no day/night difference in melatonin content and HIOMT activity was observed in the Harderian glands. In the eye, melatonin infusions significantly increased day and night‐time melatonin levels (up to 3‐fold) and both NAT and HIOMT activities (up to 3.5‐fold). This effect of melatonin treatment was observed in both SP and DD groups. These observations demonstrate that exogenously‐infused melatonin at relatively high doses activates the synthesis of endogenous melatonin in the Harderian gland and eye of the Siberian hamster. Circulating levels of melatonin were also markedly increased, indicating that in these conditions melatonin may be released from extra‐pineal sites.
Melatonin inhibits vasospastic action of oxidized low‐density lipoprotein in human umbilical arteries
Authors: Okatani Yuji , Wakatsuki Akihiko , Watanabe Kazushi , Ikenoue Nobuo , Fukaya Takao
Published: November 2003

We evaluated the antioxidant property of melatonin in countering the vasospastic effect of oxidized low‐density lipoprotein (ox‐LDL), which has been reported to be the most important risk factor for atherosclerosis and also may be linked to preeclampsia. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean deliveries between 37 and 39 weeks of gestation. Changes in maximal tension induced by potassium chloride were measured in arterial sections with intact endothelium. ox‐LDL (200 or 300 μg protein/mL) increased vascular tension by 15.6±2.3 or 31.9±4.0%, respectively. In contrast, native LDL only slightly increased vascular tension (2.7±1.0% for 200 μg protein/mL and 6.0±1.7% for 300 μg protein/mL). Pretreatment with L‐NG‐monomethyl‐arginine (2×10−4 M) significantly reduced the vasospastic effect of ox‐LDL, as did pretreatment with mannitol (30 mM). Melatonin (10 μM) significantly reduced the vasospastic effect of ox‐LDL. These findings suggest that ox‐LDL potentiates vascular tension in the human umbilical artery, possibly by suppressing endothelial synthesis of nitric oxide. Melatonin significantly suppressed the vasospastic effect of ox‐LDL, probably because it scavenges hydroxyl radical arising from ox‐LDL.
Chronic exposure to 25–80‐μT, 200‐Hz magnetic field does not influence serum melatonin concentrations in patients with low back pain
Authors: Karasek Michal , Czernicki Jan , Woldanska‐Okonska Marta , Zylinska Krystyna , Swietoslawski Jacek
Published: November 2003

There is substantial evidence that magnetic field (MF) exposure influences melatonin secretion in animals. However, data on its influence on human melatonin levels are scarce, and seemingly contradictory. Because of its many beneficial effects, very low‐frequency MF exposure is used in physiotherapy of some neurological diseases and overloading syndromes of the locomotor system. In previous studies, we observed a decrease in human serum melatonin nocturnal concentrations after exposure to MF (2.9 mT, 40 Hz), and we suggested that differences among various studies may depend on different characteristics of the applied MF. Therefore, in the present study, we examined whether or not MF of different parameters exerts the same effect. The study was performed in seven men (mean age: 36.7±3.8 years; range: 32–42) suffering from low back pain. Patients were exposed to a pulsating MF (induction: 25–80 μT; frequency: 200 Hz, modulated, automatically programmed; complex saw‐like impulse shape; bipolar) generated by a Quatronic MRS 2000 apparatus (“magnetic bed”) for 3 wk (5 days/wk, twice a day at 08:00 and 13:00 hr for 8 min each), applied to the whole body in patients laying in a horizontal position. The study was performed in spring. Diurnal serum melatonin profiles were estimated 1 day before exposure to MF (baseline), and 1 day and 1 month after the last exposure. No changes in melatonin concentrations were observed either after 1 day or after 1 month following the exposure in comparison to baseline.
Melatonin inhibits apoptosis during early B‐cell development in mouse bone marrow
Authors: Yu Qingnan , Miller Sandra C. , Osmond Dennis G.
Published: November 2003

The pineal secretory product, melatonin, exerts a variety of effects on the immune system. Administration of melatonin stimulates cell‐mediated immunity, particularly by inhibiting apoptosis among T lymphocytes in the thymus and inducing production of T‐cell‐derived cytokines. However, its possible effects on the humoral immune system are unclear. In the present study, we have examined whether melatonin may influence the in vivo development of B lymphocytes in mouse bone marrow, a process in which apoptosis is normally a prominent feature. Double immunofluorescence labeling and flow cytometry were used to quantitate phenotypically defined precursor B‐cell and mature B‐cell populations and their apoptotic rates in bone marrow of mice fed either melatonin‐containing or control diet for 16 days from 9 wk of age. In short‐term bone marrow cultures, the incidence of apoptosis among large pre‐B cells, including cells expressing the Λ5 component of pre‐B‐cell receptor, was markedly reduced in melatonin‐treated mice, associated with an increase in the absolute number of large pre‐B cells in bone marrow. In contrast, apoptosis of earlier precursor B cells and mature B lymphocytes did not differ from control values. The results indicate that orally administered melatonin can substantially promote the survival of precursor B cells in mouse bone marrow. Melatonin treatment may thus boost the survival of newly formed B cells mediating humoral immunity.
Comparative effects of melatonin, l‐deprenyl, Trolox and ascorbate in the suppression of hydroxyl radical formation during dopamine autoxidation in vitro
Authors: Khaldy H. , Escames G. , León J. , Vives F. , Luna J.D. , Acuña‐Castroviejo D.
Published: November 2003

Degeneration of nigrostriatal dopaminergic neurons is the major pathogenic substrate of Parkinson's disease (PD). Inhibitors of monoamine oxidase B (MAO‐B) have been used in the treatment of PD and at least one of them, i.e., deprenyl, also displays antioxidant activity. Dopamine (DA) autoxidation produces reactive oxygen species implicated in the loss of dopaminergic neurons in the nigrostriatal pathway. In this study we compared the effects of melatonin with those of deprenyl and vitamins E and C in preventing the hydroxyl radical (•OH) generation during DA oxidation. The rate of production of 2,3‐dihydroxybenzoate (2,3‐DHBA) in the presence of salicylate, an •OH scavenger, was used to detect the in vitro generation of •OH during iron‐catalyzed oxidation of DA. The results showed a dose‐dependent effect of melatonin, deprenyl and vitamin E in counteracting DA autoxidation, whereas vitamin C had no effect. Comparative analyses between the effect of these antioxidants showed that the protective effect of melatonin against DA autoxidation was significantly higher than that of the other compounds tested. Also, when melatonin plus deprenyl were added to the incubation medium, a potentiation of the antioxidant effect was found. These findings suggest that antioxidants may be useful in brain protection against toxicity of reactive oxygen species produced during DA oxidation, and melatonin, alone or in combination with deprenyl, may be an important component of the brain's antioxidant defenses to protect it from dopaminergic neurodegeneration.
Different circulatory response to melatonin in postmenopausal women without and with hormone replacement therapy
Authors: Cagnacci Angelo , Arangino Serenella , Angiolucci Marco , Melis Gian Bendetto , Tarquini Roberto , Renzi Antonella , Volpe Annibale
Published: November 2003

In young men and women, melatonin influences vascular reactivity and reduces blood pressure and norepinephrine levels. Herein, we investigated whether these effects are conserved in postmenopausal women without and with hormone replacement therapy (HRT). Oral melatonin (1 mg) or placebo was randomly and in double blind fashion administered to 18 untreated and 13 postmenopausal women who were treated continuously with transdermal estradiol (50 μg/day) plus cyclic medroxyprogesterone acetate (5 mg/day×12 days every 28 days). Internal carotid artery pulsatility index (PI), an index of downstream resistance to blood flow, blood pressure and catecholamine levels were evaluated. In untreated postmenopausal women, melatonin was ineffective, while in HRT‐treated women, studied during the only estrogenic phase, melatonin reduced, within 90 min, systolic (−8.1±9.9 mmHg; P=0.054),
diastolic (−5.0±7.0 mmHg; P=0.049) and mean
(−6.0±6.6 mmHg; P=0.037) blood pressure.
Norepinephrine (−50.1±66.7 pg/mL; P=0.019), but not
epinephrine levels, were also significantly reduced. Similarly,
resistance to blood flow in the internal carotid artery, as evaluated by
the PI, decreased (−0.190±0.15; P=0.0006) in a way
that was linearly related to pre‐existing PI values (r2=0.5; P=0.0059). These data show that the circulatory response to melatonin is conserved in postmenopausal women on HRT but not in untreated postmenopausal women. Possible physiological and pharmacological implications of these data on the cardiovascular risk of postmenopausal women can be envisioned.
Melatonin effects on intercellular junctional communication in MCF‐7 human breast cancer cells
Authors: Cos Samuel , Fernández Rosario
Published: November 2003

Melatonin exerts a direct antiproliferative effect on estrogen‐responsive MCF‐7 cells in culture. Recently, the importance of the anti‐invasive actions of melatonin as a part of the oncostatic action of this indolamine has been reported. Gap junctional intercellular communication is known to be involved in controlling cell proliferation and differentiation, and a decrease in intercellular junctional communication has been described in highly invasive mammary cancer cells. Because melatonin at physiological doses (1 nM) shifts MCF‐7 cells to a lower invasive status, we postulate that melatonin could modulate the levels of gap junctional intercellular communication in these tumor cells. To test our hypothesis, we studied gap junctional intercellular communication in MCF‐7 human breast cancer cells previously (7–8 days) treated, or not, with melatonin (10 μM or 1 nM). Using the scrape‐loading assay dye‐transfer technique to introduce 0.05% Lucifer yellow into cells, we measured the ability of the tumor cells to transfer dye to adjacent cells. Rhodamine dextran (0.05%) was used as a control dye to verify that dye‐transfer occurs through intercellular junctions. The presence of melatonin (10 μM or 1 nM) in the culture medium significantly increased (P<0.01) the transfer of the dye to
adjacent cells through gap junctions. This increase was greater at 10
μM melatonin, and averaged scan profiles of cells treated with
melatonin 10 μM showed a statistically significant increase
(P<0.01) in the integrated optical density values, and a broadening of the densitometric scan. These findings suggest that melatonin could exert its antitumor action, at least in part, by increasing regulatory signals that are passed between adjacent epithelial cells through intercellular junctions.
Nitrosation of melatonin by nitric oxide and peroxynitrite
Authors: Blanchard Béatrice , Pompon Denis , Ducrocq Claire
Published: November 2003

Peroxynitrite (ONOO−) is an endogenous molecule,
formed by rapid coupling between NO and
O2−. ONOO− is known
to be a strong oxidant of thiols and metalloorganic compounds and also a
nitrating agent of aromatic compounds such as tyrosine. However, its
chemistry is not yet well elucidated under physiological conditions.
Melatonin, which is an indole‐amine produced by the pineal gland and
other organs, has antioxidant properties. We show that melatonin reacts
with ONOO− in phosphate‐buffered solutions. We provide
evidence of nitrosation and oxidation at the pyrrole nitrogen leading to
1‐nitrosomelatonin and 1‐hydroxymelatonin, these being the major
reactions in aqueous phosphate‐buffered solutions besides other aromatic
hydroxylations and nitration. 4‐Nitromelatonin is formed, but in small
amounts. The kinetics of all transformations were strictly dependent on
ONOO− decay, whereas yields varied with pH and the
presence of CO2. The N‐oxidation became competitive with
nitrosation at pH 7.4, in medium containing a sufficient amount of CO
2. A proposed mechanism involves the transient formation of
melatonyl radical and ONOO radical derived from
ONOO− decay.
Analyzing Rural Local Governments' Financial Condition: An Exploratory Application of Three Tools
Authors: Honadle Beth Walter , Lloyd‐Jones Mary
Published: November 2003

Rural local governments frequently lack the capacity to analyze and monitor their financial condition. This article presents three tools that were used in a pilot project to analyze the fiscal health of a rural Minnesota county. The article compares and contrasts these methodologies by pointing out the strengths and weaknesses, the usefulness of the results, and the ease or difficulty of use of the tools.
Federal Budget Concepts—Bright Lines or Black Holes?
Authors: Cuny Thomas J.
Published: November 2003

This article reviews a range of issues that are central to the organizing principles of the federal budget—the guidelines that determine whether a transaction belongs in or outside of the budget; and, if it belongs in the budget, how it should be recorded. The article starts by discussing the nature of the federal budget, the powers and responsibilities of the federal government, and related issues, and then discusses four broad sets of budget concepts issues: (I) Budgeting for Earmarked Taxes and Spending; (II) Budgeting for Capital Investment; (III) Classification Categories Within the Budget; and (IV) Evasions of Budgetary Coverage.
New Financing Instruments for State and Local Capital Facilities
Authors: Steiss Alan Walter
Published: November 2003

Municipal bonds traditionally have been classified into two general types: term bonds, paid off in a lump sum at the end of the term of the loan, and serial bonds, retired in annual installments. Beginning in the late 1970s, however, a number of new fiscal instruments have been devised to meet the changing needs of the municipal bond market. While these new financing techniques are not a panacea, their careful application may uncover some real opportunities for meeting the needs of local government for expanded capital facilities.
Budget Deficits, Hyperinflation, and Stabilization in Ukraine, 1991–96
Authors: Kravchuk Robert S.
Published: November 2003

Since gaining independence in 1991, the former Soviet republic of Ukraine has been plagued by persistent fiscal deficits and punctuated periods of rampant inflation. Having few options to cover the fiscal deficit, Ukraine in 1992–94 largely resorted to money creation. The result was that hyperinflation broke out in late 1993, its burden falling mainly on households, but also eroding the capital of state enterprises. Falling revenues and robust expenditures—even in the face of the continuing output collapse—were exacerbated by a policy of lavishing large amounts of cheap credits on state enterprises. This article reviews and analyzes the causes of Ukraine's inflationary impulse, the descent into hyperinflation in 1993–94, its effects, and the subsequent drive to stabilization by 1996. It concludes that a substantial erosion of the inflation tax base by late 1995 propelled the government to pursue stabilization through an IMF‐sponsored program of fiscal restraint. A two‐year drive to fiscal and monetary stabilization ensued. Stabilization was largely achieved by mid‐1996, permitting a currency reform in September.
Service Efforts and Accomplishments Reporting: Has Its Time Really Come?
Authors: Brown Richard E. , Pyers James B.
Published: November 2003

In April 1994 GASB released Concepts Statement No. 2, Service Efforts and Accomplishments Reporting, bringing required SEA external financial reporting a very large step closer to reality. Before long, public financial officials may be required to annually report measures of performance. We are now about halfway through the experimentation phase established in Statement 2. This article summarizes the status of GASB's SEA experimentation process. It then suggests important behavioral, auditing, and other issues which GASB ought to address before proceeding with any formal pronouncements regarding SEA reporting requirements.
Federal Agency Budget Officers: Who Needs Them?
Authors: Persil Herbert G.
Published: November 2003

This article examines the role of federal agency budget officers and their responsibilities from the author's own perspective and experience. The article suggests that it is inadequate to standardize the role of an agency budget oficer other than that used by the agency head to determine if he or she is satisfied with the budget processes in the agency.
Serological Status and Abortion Rate in Progeny Obtained by Natural Service or Embryo Transfer fromNeospora caninum‐Seropositive Cows
Authors: Campero C. M. , Moore D. P. , Lagomarsino H. , Odeón A. C. , Castro M. , Visca H.
Published: November 2003

Bovine neosporosis is an important disease in dairy herds in Argentina. Embryo transfer (ET) technology offers the opportunity to minimize vertical transmission of neosporosis. The objective of this work was to compare the serological status and the incidence of abortion between heifers obtained via natural service and heifers obtained by ET fromNeospora‐infected cows. Progeny from eightNeospora‐infected cows belonging to a commercial dairy farm where ET was routinely performed were studied. Between 1996 and 2001, 16 and 15 heifers were obtained by natural service and ET, respectively. Serostatus and reproductive performance were recorded in both progeny. Serostatus was determined by indirect fluorescent antibody test (IFAT). All heifers obtained by natural service were seropositive and six of 16 pregnancies ended in abortion. All heifers obtained by ET were seronegative and only two abortions of 15 pregnancies were recorded.
Decay of Acquired Colostral Antibodies to Actinobacillus pleuropneumoniae in Pigs
Authors: Vigre H. , Ersbøll A. K. , Sørensen V.
Published: November 2003

The main objective of this study was to estimate the decay of acquired colostral antibodies to Actinobacillus pleuropneumoniae serotype 2 in pigs. Data were obtained from pigs in an isolated cohort of 47 pigs born to five sows seropositive to A. pleuropneumoniae serotype 2. The pigs were examined serologically at 18 different times from birth until an age of about 22 weeks, using an A. pleuropneumoniae serotype 2‐specific blocking enzyme‐linked immunosorbent assay. Antibody concentration was expressed as an OD% derived from the optical density of the sample and the median from eight wells without serum on the same plate. A non‐linear mixed model assuming a constant rate of decay (half‐life) was specified and fitted to the serological data. To estimate the between‐pig variability of different components, between‐pig random effects of each component of the model were estimated. The estimated average half‐life of acquired colostral antibodies was approximately 2 weeks, but there was a considerable variation between pigs (half‐life ranged from 1–3 weeks). The duration until acquired colostral antibodies were no longer detectable ranged from 2 weeks to 2 months postpartum among the pigs in the study, mainly depending on the initial level of acquired colostral antibodies to A. pleuropneumoniae serotype 2.
Prader–Willi syndrome: clinical picture, psychosocial support and current management
Authors: Wigren M. , Hansen S.
Published: November 2003

Aim  Prader–Willi syndrome (PWS) is a rare, genetically based disorder that occurs in about 1 of 15 000 live‐born children. To raise a child with PWS is challenging for parents and requires support from multiprofessional habilitation services. This paper maps the need for psychosocial support and current management of children and adolescents with PWS.

Method  Parents to 58 children with PWS (aged 5–18 years) completed questionnaires covering clinical, diagnostic and psychosocial issues.

Results  The children received their diagnosis at a mean age of 2.5 year. Growth hormone treatment was given to 72%. Sixty‐three per cent of the sample was not overweight. Neuropsychiatric symptoms were common from early age and some were related to obesity. Most parents wanted information as to availability of external resources and future child needs. Few parents needed family‐directed support.

Conclusion  The overall impression is that the eating disorder is managed relatively well. Even so PWS symptoms typically exacerbate over time and consequently parents need continuous support throughout childhood and adolescence. Greater attention should be paid to idiosyncrasies in cognitive functioning and to clinical markers of neuropsychiatric problems.
The therapeutic power of play: examining the play of young children with leukaemia
Authors: Gariépy N. , Howe N.
Published: November 2003

Background  The therapeutic function of play has been investigated in relation to recognized stressors such as hospitalization, illness and medical treatments for ill children. While medical treatments in the past 30 years have improved survival rates, children's psychological experiences and quality of life during and after their illness have received limited attention.

Objective  The present study investigated the therapeutic effects of play on 3‐ to 5‐year‐old children with leukaemia compared with a control group of healthy children.

Method  The participants with leukaemia (n = 11) were from the external oncology clinic of an urban children's hospital; control children (n = 11) attended a day care centre. Measures included children's experience of stress, social and cognitive play behaviours, and daily mood.

Results  A series of manova revealed that the children with leukaemia, compared with the control children, engaged in (a) significantly fewer total play behaviours, and in particular less (b) parallel, (c) group and (d) dramatic play. Pearson correlations revealed significant relationships between reports of ‘being happy’ and play only for children with leukaemia. Quantitative and qualitative analyses revealed a pattern of repetitive play activities week after week for children with leukaemia, but not controls.

Discussion  Findings are discussed in light of the theoretical and practical implications for children undergoing treatment for leukaemia.
Static balance in children with hand–eye co‐ordination problems
Authors: Forseth A. K. , Sigmundsson H.
Published: November 2003

Objective The aim of the present study was to examine static balance on one leg in 10‐year‐old children with and without hand–eye co‐ordination problems (HECP) in an attempt to come closer to an understanding of developmental co‐ordination disorder in children.

Method The children were compared on three different balance tasks with the right and/or left leg together with a systematic manipulation of vision.

Results The results showed that when the scores for both legs were combined, the control group, in general, had superior performance in all conditions. Separate preferred and non‐preferred leg analyses demonstrated that the differences between the HECP group and control group could be accounted for by lowered performances when the non‐preferred leg was used in only one static balance task, stork stand with vision. In the two other balance tasks, balance on beam and one‐board balance, the HECP group displayed significantly worse performance than the control group irrespective of the use of the preferred or non‐preferred leg.

Conclusions Explanation related to the development of the hemispheres controlling the preferred and non‐preferred leg is invoked to account for the poor performance in the HECP group.
The infection of nymphal Baetisbicaudatus by the mermithid nematode Gasteromermis sp.
Authors: VANCE SARAH , PECKARSKY BARBARA
Published: November 2003

1. This study reports the infection in nymphs of a bivoltine mayfly host (Baetisbicaudatus) in a high‐elevation watershed by the mermithid nematode Gasteromermis sp. Infection by Gasteromermis causes mortality in two ways. Fifty per cent of the infections do not successfully develop beyond the initial stage of penetration and result in the early death of both host and parasite.

2. Infected hosts that survive this initial stage are rendered completely sterile by the infection (reproductively dead). In addition to complete sterility, the emergence size of parasitized nymphs is reduced and development time lengthened compared with unparasitized nymphs.

3. Parasite infection levels are stable from year to year at one site, but with a higher incidence of infection in the mayfly summer generation. Size differences between the generations at the time of infection may account for their different susceptibilities.

4. Within a year infection levels vary seasonally and spatially from 1 to 71%. Seasonally, there is a condensation of parasitized hosts towards the end of development as unparasitized nymphs emerge earlier. Spatially, infection levels show a downstream decline that may result from upstream dispersal by infected hosts or differential parasite survivorship at different elevations.
Combined effects of allelochemical‐fed and scarce prey on the generalist insect predator Podisusmaculiventris
Authors: BOZER STEPHEN , TRAUGOTT MATTHEW , STAMP NANCY
Published: November 2003

1. The simultaneous effects of allelochemicals ingested by herbivorous insect prey and prey scarcity on the performance of a generalist insect predator were examined.

2. Fifth‐instar predatory stinkbugs (Podisusmaculiventris: Pentatomidae) were fed caterpillars (Manducasexta: Sphingidae) in three prey scarcity treatments: every day (unlimited amount), one caterpillar every third day, one caterpillar every fifth day. The caterpillars were fed either a plain diet or a diet containing rutin, chlorogenic acid and tomatine, which are three of the major allelochemicals in tomato leaves (Lycopersiconesculentum: Solanaceae), the preferred food of these caterpillars.

3. Food consumed, efficiency of conversion of ingested food to biomass (ECI), biomass gained, stadium duration and relative growth rate (RGR) of predators were negatively affected by prey scarcity. The allelochemicals negatively affected food consumed and ECI.

4. There were prey scarcity by allelochemical interactions for ECI, biomass gained and RGR. For ECI, the allelochemicals had a greater negative impact on the predatory stinkbugs when prey were scarce. When prey diet contained allelochemicals, biomass gained and RGR declined more steeply with increased prey scarcity. There was an allelochemical by predator gender interaction for biomass gained. Allelochemicals had no effect on biomass gained by female stinkbugs, whereas biomass gained declined more steeply with increased prey scarcity for male stinkbugs fed caterpillars containing allelochemicals than for males fed control caterpillars.
Synchronization of larval emergence in winter moth (Operophtera brumata L.) and budburst in pedunculate oak (Quercus robur L.) under simulated climate change
Authors: BUSE ALAN , GOOD JOHN
Published: November 2003

1. The hypothesis that a 3 °C elevation in temperature and doubled CO2 concentration would have no effect on the synchronization of winter moth egg hatch with budburst in oak was tested by comparing the separate and interactive effects of ambient and elevated (+ 3 °C) temperature and ambient and elevated (doubled to 340 p.p.m.) CO2 in eight experimental Solardomes. In addition, an outdoor control was compared with the ambient temperature/CO2 treatment combination.

2. Elevated temperature accelerated darkening (preceding egg hatch by about 5–10 days) and hatching of eggs developing off the trees; elevated CO2 had no effect. The same effects were observed in eggs developing on the trees.

3. Within treatments, date of egg hatch was the same on trees with early or late budburst.

4. Egg darkening and budburst were closely synchronized at both ambient and elevated temperatures.

5. Both eggs and trees required fewer cumulative heat units (day degrees > 4 °C), for hatching and budburst, respectively, at ambient than elevated temperatures. The requirements in the outdoor control treatment were similar to those in the ambient Solardome treatment.

6. Egg hatch between 10 and 25 °C, on a temperature gradient in the laboratory, required a constant number of heat units; fewer were required below 10 °C.

7. Elevated temperatures, in the Solardomes and the field, delayed adult emergence from the pupae.

8. The results suggest that a general increase in temperature with climatic change would not affect the closeness of the synchronization between egg hatch of winter moth and budburst of oak.
Plant effects on prey choice by a vespid wasp, Polistes arizonensis
Authors: GEITZENAUER HEATHER L. , BERNAYS ELIZABETH A.
Published: November 2003

Abstract.

The effects of sunflower, Helianthus annuus, and groundcherry, Physalis pubescens, eaten by the tobacco budworm (Heliothis virescens), on predation by paper wasps (Polistes arizonensis) were examined.

Polistes arizonensis foragers took more caterpillars from H. annuus plants than P. pubescens in paired‐choice tests.

They took longer to locate prey and apparently gave up searching faster on artificial plants mimicking P. pubescens than on artificial plants mimicking H. annuus.

In paired‐choice tests for chemical effects, wasps chose more caterpillars within H. annuus odour than in P. pubescens odour.

They also chose more H. annuus‐reared larvae than P. pubescens‐reared larvae when they were presented without plants. Handling time was not affected.
Oviposition of the dung beetle Aphodius ater in relation to the abundance of yellow dungfly larvae (Scatophaga stercoraria)
Authors: HIRSCHBERGER PETRA , DEGRO HELGA NAVINA
Published: November 2003

1. The dung beetle Aphodius ater and the yellow dungfly Scatophaga stercoraria are temporally co‐occurring species in sheep dung, which they use for reproduction and nutrition (A. ater) or for reproduction only (S. stercoraria) during the spring in northern Germany. Scatophaga stercoraria uses fresh sheep dung pellets a few hours old for oviposition, whereas A. ater lays eggs into 2–10‐day‐old pellets. In the present study, the egg laying behaviour of A. ater in sheep dung in relation to the presence of larvae of S. stercoraria was investigated experimentally.

2. Choice experiments, based on examining the egg laying behaviour of beetles in 2‐ and 4‐day‐old pellets with and without high and low densities of fly larvae, showed the following. In 2‐day‐old pellets, the beetles did not distinguish between pellets without fly larvae or with fly larvae at low larval density but avoided laying eggs into pellets with a high larval density. In 4‐day‐old pellets, the beetles always preferred to lay their eggs into pellets without fly larvae, regardless of larval density.

3. The influence of different densities of larvae of S. stercoraria on dung depletion was examined by measuring the dry weight, organic matter content and organic nitrogen content of the remaining dung after larval development. The presence of the larvae led to a reduction in all three parameters.

4. The beetles’ behaviour of laying eggs into older pellets, and their awareness of the presence of high densities of fly larvae, enables them to avoid egg laying into pellets that will have been depleted by fly larvae before the beetle larvae have finished their development.
The relationships between host selection and subsequent larval performance in three free‐living graminivorous sawflies
Authors: BARKER A. M. , MACZKA C. J. M.
Published: November 2003

1. Selection of host plants for oviposition by females of three graminivorous sawfly species, Doleruspuncticollis C. G. Thomson, Doleruspicipes Klug. and Pachynematusclitellatus Lepeletier, was investigated experimentally using three grass species, Loliumperenne L., Festucarubra L. and wheat, Triticum aestivum L. cv. Hunter.

2. Both species of Dolerus showed significant preferences for one grass over the other two, D. puncticollis preferring L. perenne and D. picipes selecting F. rubra. P. clitellatus females used L. perenne and F. rubra equally for oviposition, but avoided wheat.

3. The results correlated closely with larval performance trials, with D. puncticollis larvae having maximal survival and growth rates on L. perenne, and D. picipes larval performance being maximized on F. rubra. P. clitellatus larvae survived well on both grasses, but had a high level of mortality on wheat.

4. P. clitellatus larval growth rates were significantly higher on L. perenne than on F. rubra. Individual P. clitellatus adult females developing from larvae reared on L. perenne reached a significantly greater dry weight than those reared on F. rubra, but there was no significant difference in weight between males reared on the two hosts. There was some evidence that this disproportionate effect of host plant quality on the weight gain of the two sexes was translated into a bias in sex ratio of the eggs laid towards a greater proportion of females on L. perenne than on F. rubra. This manipulation of sex ratio would have a potential benefit for ovipositing females through disproportionate fecundity gains for female offspring.
Factors determining the distribution of the green spruce aphid, Elatobium abietinum, on young and mature needles of spruce
Authors: JACKSON DEBORAH , DIXON ANTHONY
Published: November 2003

1. The green spruce aphid Elatobium abietinum, was less active and more likely to feed when on mature rather than young needles of Sitka spruce.

2. Compared with survival on mature needles, survival of aphids on young needles was significantly reduced, especially on newly flushed needles, but became less so as the needles matured. The survival of aphids kept close to, but not in contact with, young needles was similarly reduced.

3. On young needles stripped of epicuticular wax, aphids were less active and fed and survived for longer than aphids on untreated young needles. In contrast, the supply of additional amino acids to shoots bearing young needles did not significantly improve the survival of aphids on these needles.

4. In a choice test, aphids were able to discriminate between epicuticular wax from young and mature needles. The reciprocal transfer of wax between young and mature needles reversed the aphids’ marked preference for mature needles.

5. These results indicate that the aphid is deterred from settling and feeding on young needles by a volatile substance present in the epicuticular wax.
Variations in sperm number in relation to larval crowding and spermatophore size in the armyworm, Pseudaletia separata
Authors: HE YIBIN , MIYATA TADASHI
Published: November 2003

1. Number of sperm and its relationship with larval rearing density were investigated in the armyworm Pseudaletia separata. Males that emerged from crowded larvae produced significantly more apyrene sperm than those from solitary larvae (375 700 ± 116 600 and 290 300 ± 99 600 at a mating with a 3‐day old virgin, respectively), with no significant difference in number of eupyrene sperm between the two types being observed.

2. For both solitary‐ and crowded‐type, the amount of fertile sperm the males produced at a mating exceeded the number needed to fertilize all of a female’s eggs, suggesting that sperm competition may be a major selective force for keeping sperm numerous. The production of more apyrene sperm by crowded‐type males may be an adaptation to cope with the increased sperm competition from rival males at high density.

3. The relationship between number of sperm and spermatophore size was also studied using solitary‐type moths. Large spermatophores were found to have more eupyrene and apyrene sperm than small ones.
The significance of prey in the diet of the phytophagous thrips, Frankliniella schultzei
Authors: M. MILNE  , G. H. WALTER
Published: November 2003

1. Patterns of mite egg consumption by the phytophagous thrips Frankliniella schultzei Trybom were investigated. Although F. schultzei predation is somewhat similar to that of F. occidentalis (Pergande), the understanding of predation by these two phytophagous thrips was extended, allowing the functional significance of flower thrips’ predatory behaviour to be reinterpreted.

2. Second‐instar larvae consumed significantly more eggs than any other life‐stage, and the daily intake of eggs by second‐instar larvae declined significantly with each successive day of the 4‐day duration of instar two.

3. Mite eggs that had had their silken webbing removed were consumed at a significantly greater rate than those with their webbing intact.

4. Frankliniella schultzei immatures developed successfully both on diets containing cotton (Gossypium hirsutum L.) leaf tissue plus mite eggs and on cotton leaf tissue alone. Supplementing a leaf tissue larval diet with mite eggs lowered the developmental time from egg to adult significantly, as well as lowering the percentage mortality. Continuation of the mite egg supplement beyond adult eclosion increased fecundity significantly and extended life span over that achieved on a leaf diet alone.

5. In laboratory choice tests, mite eggs and pollen of Wax Mallow (Malvaviscus arboreus Cav.), the usual host of F. schultzei in Brisbane, were encountered with similar frequencies. Furthermore, the mean proportion of encounters with pollen grains that resulted in consumption of pollen did not differ significantly from the encounter : consumption rate for mite eggs.

6. Frankliniella schultzei, like F. occidentalis, does not seem to be specifically adapted for preying on mite eggs, even though such predation enhances performance and reproductive output of F. schultzei when constrained on cotton leaves. Comparison of performance results with those published for F. schultzei when reared on the floral parts of one of its primary hosts (M. arboreus) (Milne et al., 1996), indicates that mite egg predation does not make up completely for a deficient adult or larval diet.
Sexual size dimorphism and sex‐specific survival in adults of the damselfly Lestes disjunctus
Authors: ANHOLT BRADLEY
Published: November 2003

1. A population of adult Lestes disjunctus (Odonata: Lestidae) was studied in eastern Ontario, Canada. Mass at sexual maturity and activity rates of individuals were measured. Population density was estimated on transects, while survival rates and population size were estimated using mark−recapture methods.

2. There was no difference in mass of mated and unmated males. Females were more than 50% heavier than males, and were also more active than males.

3. Males were almost eight times more abundant on transects than females, but Manly−Parr estimates of male population size were only a maximum of 2.5 times larger than estimates for females.

4. Males were 2.5 times more likely to be resighted after marking than were females. This accounts for much of the discrepancy between transect estimates and mark−recapture estimates of relative population size.

5. Daily survival rates of sexually mature females were not significantly less than those of males, and therefore cannot account for a change in sex‐ratio from 1 : 1 at emergence to more males than females in sexually mature adults.

6. Differences in mortality must occur prior to sexual maturity, coincident with the time during which differences in mass gain are also taking place.
Rainfall, nitrogen and host plant condition: consequences for the processionary caterpillar, Ochrogaster lunifer
Authors: FLOATER GRAHAM
Published: November 2003

1. At the end of November in subtropical areas of Australia, second‐instar larvae of the processionary caterpillar Ochrogaster lunifer (Lepidoptera: Thaumetopoeidae) initiate feeding on the peripheral shoots of acacias (first‐instar larvae do not feed). Field surveys at ten localities in south‐east Queensland showed that larval survival was highly variable both among and within localities. Within‐locality variation in larval growth was low compared with variation among localities. Larval growth and survival rates were higher at coastal and island localities, where November rainfall was high, than at drier inland localities.

2. Potted Acacia concurrens were grown in the greenhouse under high and low watering regimes, with and without nitrogen‐rich fertilizer. Plant vigour (height, foliar water content and quantity of flush growth) was significantly greater in high‐water treatments than in low‐water treatments. Watering also affected foliar nitrogen, with plants in the high‐water/no fertilizer treatment having similar nitrogen levels to those in fertilized treatments. Fertilizer increased foliar nitrogen levels of plants in low‐water treatments and increased the number of shoots in high‐water treatments. Different treatments had no effect on leaf toughness. After the first 3 weeks of feeding, size and survival of larvae were significantly reduced on the small, less vigorous plants in low water treatments. These results do not support the plant stress hypothesis.

3. Early‐instar larvae (instar II–IV) developed more quickly and grew larger when reared on flush leaves than when reared on senescent leaves of A. concurrens. As water uptake affects the quantity of flush growth available to early stage larvae as well as foliar quality, rainfall and water availability may have important consequences for the distribution and population dynamics of the moth at local and regional scales.
Female size and fitness in the leaf‐cutter bee Megachile apicalis
Authors: KIM JONG‐YOON
Published: November 2003

1. The effects of female size on fitness of the leaf‐cutter bee Megachile apicalis Spinola (Hymenoptera: Megachilidae) were examined using artificial nesting sites in the field.

2. Although female size had no significant effect on female longevity or sex ratio of progeny, it did have a significant effect on fecundity; larger females attained greater realized fecundity than did smaller females.

3. This significant effect of female size on fecundity occurred because larger females produced cells faster than did smaller females.

4. Female size also had a significant effect on egg size; larger females laid larger eggs than did smaller females.

5. Female size had a significant effect on the size of investment in each progeny. The size of investment estimated by brood cell weight was greater for larger females than for smaller females. This pattern was largely absent, however, when the size of investment was estimated by adult progeny weight.

6. Female size had a significant effect on nest usurpation behaviour; larger females had a higher capacity to usurp nests than did smaller females.
Effects of density on the reproductive success of pine engravers: is aggregation in dead trees beneficial?
Authors: ROBINS GENEVA , REID MARY
Published: November 2003

1. The pine engraver bark beetle Ips pini (Say) (Coleoptera: Scolytidae), aggregates primarily on dead or dying pine trees. In this study pine engravers were laboratory‐reared on logs at a range of low densities to determine whether there was a fecundity advantage of breeding aggregations.

2. Mean reproductive success for both males and females declined exponentially with increasing density.

3. Female pine engravers had shorter egg galleries at higher densities, suggesting that they left high‐density breeding sites earlier. This would reduce the number of eggs that failed to survive due to larval competition.

4. Some pine engravers colonized the logs voluntarily during the experiment. These volunteers settled independently of the original density.

5. The fungus Ophiostoma sp. was present on the logs and may be competing with the pine engravers for limited bark area.

6. Aggregation resulted in a considerable cost to pine engraver reproductive success even at low densities. Thus, it remains perplexing why pine engravers aggregate actively in nature.