Traditional Trap Research Articles

Derivation of an empirical frequency-dependent friction factor for transient response analysis of water trap seals in building drainage systems

Flows in building drainage systems (BDS) are inherently unsteady. The changing nature of these flows produce pressure transients that can be harmful to water trap seals, the last line of defence against sewer gas ingress into habitable spaces. Air pressure transients propagate throughout BDS until they are diminished by either a relief valve, an open termination or, under certain circumstances, produce their own ‘relief valve’ through a compromised water trap seal. The spread of the SARS virus through empty water traps in Hong Kong in 2003 highlighted the worst possible consequences of water trap seal compromise. These air pressure transients can be simulated and their effects predicted. Only one numerical model exists for modelling airflow and the associated air pressure regime in BDS—the method of characteristics-based AIRNET. The current water trap boundary condition within the AIRNET model consists of a steady laminar frictional flow relationship, which does not replicate the unsteady pressure regime in the building drainage system. An improvement on this frictional representation is due to Carsten—Zilke, a methodology that allows a moving frictional term for water to trap surface interaction. This research proposes an alternative, empirically derived friction factor, and represents a significant simplification of the calculation process, leading to a robust, dynamic prediction methodology for water trap seal response to applied air pressure waves. Practical application: The development of new empirically derived frictional expressions to predict the effects of air pressure transients on appliance trap seals within a method of characteristics model provides far superior prediction results to those currently available. These new expressions enhance the modelling capabilities of AIRNET and prove that high frequency air pressure waves do not contribute to water trap seal depletion. The non-destructive nature of short duration or high frequency air pressure wave oscillations has contributed to the development of a non-invasive methodology for detecting water trap seal defects in building drainage systems, and this research serves to prove conclusively that using low amplitude, short duration pulses or sinusoidal pressure waves with a frequency above 3 Hz is non-destructive to traditional water trap seals in building drainage systems.

PENGARUH MINYAK CUMI PADA UMPAN BUBU DASAR TERHADAP HASIL TANGKAPAN IKAN-IKAN KARANG

Bottom trap have been used widely by coastal communities in North Sulawesi to catch coral fishes, since it simple in design, cheaper and easy to manage with a small boat. Unfortunately, the fishing practice of the traditional trap is usually conducted in destructive way, where fishermen cover the gear with live coral to attract fishing target. Although the gear’s design has evolved over centuries, there is still potential for improving its catching efficiency and selectivity. An attempt to understand the fishing process of bottom trap should therefore be focused on bait and how its chemical composition, visual and physical properties may stimulate target species to attack the bait and captured. Addition of squid liver oil to the bait could increase the fishing power of bottom trap gear. But scientific information’s about its applications are not available yet. Therefore, the objective of this research was to study the effect of squid liver oil on bait of bottom trap toward the capture of coral fishes. This research was done in Bangka Strait North of Minahasa, based on experimental method. Six units of bottom trap (bamboo) were operated ten nights in collecting data; where tree units of them used scad mackerel bait that injected by squid liver oil, and tree other units just used scad mackerel bait without squid liver oil; and the capture data were analyzed by ttest. The catch was 117 fish in total consist of 2 genera; 74 fish was caught by scad mackerel bait with squid liver oil, and 43 fish was caught by bait without squid liver oil. Analysis of ttest show that t0= 8.908>t0.05; 5= 3.250; which means that the addition of squid liver oil on bait could increase the catch of bottom trap.

Monitoramento de Ecdytolopha aurantiana (Lima) em Laranjeira Valência com Feromônio Sexual

The citrus borer, Ecdytolopha aurantiana (Lima), is one of the most important citrus pests, because of damage and increase of citrus production cost. The purpose of this experiment was to evaluate the possibility of using the sexual pheromone ((E)-8-dodecenyl acetate and (E)-8-dodecenol) for monitoring E. aurantina, influence of the climate and the trap colour in the capture of E. aurantiana, in compare with the standard procedures, and to determine the losses caused by the pest. The experiment was carried out in a 12-year old Valencia citrus groves located in Araraquara County, SP. In this grove, four blocks were chosen and delimited for placing the yellow, red and white traps in compare to the traditional white trap (Ferocitrus Furao®) kit. The evaluation consisted of counting the number E. aurantiana adults captured per trap and the number of attacked fruits per 10 plants randomly chosen in each block. No statistical difference was observed between trap colors to capture E. aurantiana. In all blocks, the population of the pest remained above threshold level (six males/trap/week) in most of the sampling dates during the experiment. However, no damage was observed because of low humidity that causes decreasing of female longevity and fecundity. The correlation analysis between capture and climatic parameters was significant only with the average temperature.

Optical trapping and manipulation of live T cells with a low numerical aperture lens

An optical manipulation system that employs both optical and temperature gradients to simultaneously enable trapping, manipulating and imaging of live cells with a low magnification, low numerical aperture objective lens (10x/0.4 N.A.) is reported. This approach negates the requirement for a high N.A. lens used in traditional optical trapping. Our system comprised a dual scanning system and two independent lasers which provided the ability to move the trapping spot independently of the confocal imaging process in close to real-time and without pre-programming. To demonstrate the efficacy of this innovative method, trapping and manipulation of live T cells was simultaneously performed over a field of view exceeding 1 mm(2) for extended periods without compromising cell viability.

Farmer survey in the hinterland of Kisangani (Democratic Republic of Congo) on rodent crop damage and rodent control techniques used

We conducted a survey on rodent crop damage among farmers in the hinterland of Kisangani (Democratic Republic of Congo). We studied the amount of crop damage, the rodent groups causing crop damage, the growth stages affected and the control techniques used. We conducted this survey in three municipalities using a standard questionnaire form translated into local languages, between November 2005 and June 2006 and during July 2007. We used the Quotas method and interviewed 70 households per municipality. Farmers indicated rodent groups implicated in crop damage on color photographs. Two types of survey techniques were used: individual and focus-group surveys. The sugar cane rat, Thryonomys sp. and Lemniscomys striatus caused most damage to crops, but inside granaries, Rattus rattus was the primary pest species eating stored food supplies and causing damage to stored goods. Cassava and maize were the most cultivated crops, followed by rice. Maize and rice are the most vulnerable during the heading stage. The most usable part of cassava (tubers) was attacked less often. Farmers mostly applied traditional trapping techniques, using local snap traps to decrease rodent abundance and sometimes used a labor-intensive trap-barrier system to trap Thryonomys . Inside buildings (granaries), farmers used chemical control methods.

An all-optical ion-loading technique for scalable microtrap architectures

An experimental demonstration of a novel all-optical technique for loading ion traps, that has particular application to microtrap architectures, is presented. The technique is based on photo-ionisation of an atomic beam created by pulsed laser ablation of a calcium target, and provides improved temporal control compared to traditional trap loading methods. Ion loading rates as high as 125 ions per second have so far been observed. Also described are observations of trap loading where Rydberg state atoms are photo-ionised by the ion Doppler cooling laser.

URBAN HABITAT EVALUATION FOR WEST NILE VIRUS SURVEILLANCE IN MOSQUITOES IN ALBUQUERQUE, NEW MEXICO

As part of an ongoing mosquito surveillance program, 27 sites in the greater metropolitan Albuquerque area (Bernalillo County, New Mexico) were trapped from May through September 2004. Each site was sampled for 1 night weekly, using a standard CO2-baited Centers for Disease Control and Prevention light trap and a gravid trap. Captured mosquitoes were catalogued by location, species, and date, and selected pools were tested for West Nile virus (WNV) by reverse transcription-polymerase chain reaction. Based on previous surveillance, WNV was already established in the state of New Mexico. Surveillance during 2003, the 1st year of WNV detection in New Mexico mosquitoes, was focused on the bosque forest of the Rio Grande river valley. Surveillance during summer of 2004 was extended to additional areas around the city of Albuquerque, the state's largest population center. In addition to the standard surveillance objectives, a secondary goal was to determine whether foci of WNV activity were detectable in other habitats besides the riparian ecosystem of the Rio Grande, and in other species not previously identified as vectors. There was no demonstrable advantage to extending the traditional trapping area outside of the Rio Grande valley. Sites in the valley area had WNV-positive mosquitoes earlier in the season, and for a longer period than the added sites. In addition, riparian sites had the highest diversity of species, the largest numbers of Culex spp. captured, and the largest proportion of the WNV-positive mosquito pools from the study. Species found in other areas of the metropolitan area were also represented in the valley. Although WNV activity was detected in other areas of the city, its activity began later and ended earlier than in the river valley. We surmise that the greatest benefit to mosquito surveillance could be achieved by focusing on the river valley area.

Sporulation and diversity of arbuscular mycorrhizal fungi in Brazil Pine in the field and in the greenhouse

The aim of this work was to assess the sporulation and diversity of arbuscular mycorrhizal fungi (AMF) at different forest sites with Araucaria angustifolia (Bert.) O. Ktze. (Brazil Pine). In addition, a greenhouse experiment was carried out to test the use of traditional trap plants (maize + peanut) or A. angustifolia to estimate the diversity of AMF at each site. Soil samples were taken in two State Parks at southwestern Brazil: Campos do Jordão (Parque Estadual de Campos do Jordão [PECJ]) and Apiaí (Parque Estadual Turístico do Alto Ribeira [PETAR]), São Paulo State, in sites of either native or replanted forest. In PECJ, an extra site of replanted forest that was impacted by accidental fire and is now in a state of recuperation was also sampled. The spore densities and their morphological identification were compiled at each site. In the greenhouse, soil samples from each site were used as inoculum to promote spore multiplication on maize + peanut or A. angustifolia grown on a sandy, low-fertility substrate. Plants were harvested, respectively, after 4 months or 1 year of growth and assessed for mycorrhizal root colonization. Spore counts and identification were also performed in the substrate, after the harvest of plants. Twenty-five taxa were identified considering all sites. Species richness and diversity were greater in native forest areas, being Acaulospora, the genus with the most species. Differences in number of spores, diversity, and richness were found at the different sites of each State Park. Differences were also found when maize + peanut or A. angustifolia were used as trap plants. The traditional methodology using trap plants seems to underestimate the diversity of the AMF. The use of A. angustifolia as trap plant showed similar species richness to the field in PECJ, but the identified species were not necessarily the same. Nevertheless, for PETAR, both A. angustifolia and maize + peanut underestimated the species richness. Because the AMF sporulation can be affected by many conditions, it is impossible to draw detailed conclusions from this kind of survey. More precise experiments have to be set up to isolate the different factors that modulate the ecophysiological interactions between host plant and endophyte.

Comparison of a gas detection tubes test with the traditional alkaline trap method to evaluate compost stability

Compost stability is an important parameter of compost quality. Among tests proposed to evaluate compost stability, microbial respiration is one of the better accepted tests. Variations in rates of CO2 evolution during composting were studied in two pilot pruning waste piles using a windrow composting system. To measure the CO2 production rate, two methods were compared: the alkaline trap test and gas detection tubes. Both respiration tests indicated increasing compost stability with processing time, but CO2 evolution rates from the alkaline trap method were higher than values from the gas detection tube method. A first-order kinetic equation was used to describe CO2 evolution over time. A linear relationship (r=0.81, p<0.01) was found between the two methods. Although both methods could distinguish unstable compost from stable compost, CO2 detection tubes were easier to use and gave results in a shorter period of time.

Philosophical and paradoxical issues in corporate governance

The current debate on corporate governance has been polarised between, on the one hand, the shareholding paradigm and, on the other hand, the stakeholding paradigm. However, underpinning the main theories are hidden paradoxical assumptions that lead to concerns over the credibility and validity of this dichotomised approach. Both camps of the debate rely on a homeostatic and entitative conception of the corporation and its governance structures. Both camps suffer from an inadequate attention to the underlying philosophical presuppositions in which the static approach is rooted. To avoid the traditional trap in theorising, an alternative processual approach is proposed for a better understanding of the inherent overflow and heterogeneity of corporate governance practice.

The Role of Estuaries in South African Fisheries: Economic Importance and Management Implications

Existing catch data for 129 of 255 functional estuaries on the South African coastline were reviewed and the relationships between fish catch and estuary size, type and biogeographical region analysed using simple and multivariate models. The best predictive models were obtained by analysing data separately for each biogeographical region. Estuary size alone explained >80% of the variation in catch in the warm temperate region and >90% of the variation in catch in the cool temperate and subtropical region. Further analysis of the two main estuary types, i.e.permanently open and temporarily open/closed estuaries revealed a steeper regression slope and therefore greater productivity for the permanently open systems. Estuary size (ha) and type (five) were used to explain catches within the warm temperate and subtropical regions using general linear models. The models were able to explain 82 and 98% of the variance in catches for the two regions respectively, and both were significant (p < 0.001). These models were applied to estuary type and size data for all 246 estuaries in the two regions and a total catch of 1 840 tons per year was estimated. Including the cool temperate region the total estuarine catch in South Africa was estimated at 2 480 tons per year. In all, 50% of the estuarine catch was attributed to commercial seine and gillnet fisheries, 46% to recreational angling and 4% to traditional trap and spear fisheries. Total catch value was R433 million per year, of which 99% could be attributed to recreational angling. Estuarine contribution to the inshore marine fisheries was estimated at approximately R490 million per year, estuarydependent species constituting 83% of the catch of the recreational shore and commercial seine and gillnet fisheries and only 7% of the catch of the recreational spearfishery and commercial and recreational boat fisheries. In 2002, the total value of estuarine and estuary-dependent fisheries was estimated to be R1.251 billion.

Measurement of plasma corticosterone and fecal glucocorticoid metabolites in the chicken ( Gallus domesticus), the great cormorant ( Phalacrocorax carbo), and the goshawk ( Accipiter gentilis)

A method for the non-invasive measurement of glucocorticoid metabolites in feces of chickens was established and validated. After high-performance liquid chromatography (HPLC) the presence of at least two fecal immunoreactives was demonstrated, one co-eluting with authentic corticosterone, whereas the second substance migrates close to corticosterone sulphate. We investigated the relationship between corticosterone in blood plasma obtained by a vena brachialis catheter and fecal samples in groups of five chickens after an ACTH and a dexamethasone injection to stimulate and to suppress adrenal activity. A control group received a saline injection. After ACTH plasma cortisol concentrations increased 16-fold after 1.5 h to levels between 19 and 38 ng/ml and dropped to pre-treatment levels (1.1–2.5 ng/ml) 4 h after stimulation. Dexamethasone did not result in a distinct suppression of adrenocortical activity and plasma corticosterone dropped only slightly below pre-treatment levels. The concentrations in fecal metabolites corresponded to the changes in the levels of biological active hormone in plasma. Fecal peak excretion (105–295 ng/g) was obtained with a delay of approximately 4 h compared to plasma. The profile obtained after ACTH challenge reflected a broader and dampened pattern of glucocorticoid secretion and provided a more integrated measure of adrenal activity. Dexamethasone treatment did not induce a measurable decrease in fecal metabolites and concentrations fluctuated around a mean of 30.0±9.9 ng/g, almost identical to those obtained from the saline treatment group (29.4±13.9 ng/g). In a separate experiment the effect of an alternative capture method (remote-controlled injection system) was investigated in cormorants. Plasma corticosterone measurements revealed a significantly diminished stress reaction compared to traditional trapping (1.24±0.78 vs. 10.9±12.1 ng/ml). Investigations whether goshawk nestlings infected with Trichomas gallinae differ in fecal corticosterone metabolite concentrations compared to healthy subjects revealed no significant changes. However, a significant correlation was found between the glucocorticoid metabolite concentrations and the number of nestlings per nest. The demonstration that adrenal activity can be detected by the assay is a prerequisite that ecologically meaningful levels of imposed stress can be validated. Therefore, non-invasive measurements of fecal metabolites are a promising perspective to monitor stress in birds.

A large-mesh salmon trap: a way of mitigating seal impact on a coastal fishery

Abstract A new design for a salmon trap aimed at minimizing damage to catch and gear caused by grey seals was tested. The traditional trap design used in the northern Baltic permits an efficient hunting strategy by seals, whereby chased fish entangle themselves in the side panels and can then easily be taken, with associated damage to the net. The side panels of the test trap (excluding the fish chamber) are made of large-mesh (400 mm) netting compared to ≤200 mm in traditional traps. This should allow seal-chased and panicking salmon to pass through, while less stressed individuals should still be guided efficiently towards the fish chamber. Trials with the two trap types were performed at the mouth of the river Indal (northern Sweden) in a comparative test programme. Catches of salmon and trout in the test trap were larger than in the standard trap. We estimated that 65% of the potential catch was lost in the standard trap owing to seal predation, while escape rate through the large meshes in the test trap was 52%. The standard trap had a total of 269 holes owing to seal damage, while only six holes were found in the test trap. Seal activity in and around the standard trap was up to 16 times higher compared with the test trap and decreased considerably during the following year when only large-meshed traps were used in the area. We suggest that seals are difficult to deter from fishing gear as long as they get a reward in terms of food and propose that a strategy that deprives seals of a reward will make the gear uninteresting to them and may have long-term mitigation effects.

Experimental Consideration of an Optical Fiber Trapping Method by Measuring the Reflected Beam from an Optically Trapped Microsphere.

Optical fiber trapping method was experimentally investigated by measuring the reflected beam from an optically trapped microsphere. From these results, we verified that our proposed fiber optic trapping system captured a microsphere by a mechanism different from traditional trapping systems using a high-numerical-aperture objective.

Corporate governance : paradigms, dilemmas and beyond

The current debate on corporate governance has been &amp;apos;polarised&amp;apos; between, on the one hand, the shareholding paradigm and, on the other hand, the stakeholding paradigm. However, underpinning the main theories are hidden paradox assumptions which leads to concerns over the credibility and validity of this dichotomised approach. Both camps of the debate rely on a homeostatic and entitative conception of the corporation and its governance structures, they suffer from inadequate attention to the underlying philosophical presuppositions in which the static approach is rooted. To avoid the traditional trap in theorising, an alternative processual approach is proposed for a better understanding of the inherent overflow and heterogeneity of corporate governance practices. (original abstract)

Managing wildlife ethics issues ethically

Wildlifers seldom write about ethics, yet ethical issues are among the most intractable of wildlife management issues. Society's value orientations about wildlife have been changing slowly over the last several decades. An increasingly urbanized and educated population no longer unequivocally supports wildlife management programs that tend to regard wildlife as utilitarian objects. State wildlife agencies and their employees have been slow to acknowledge and respond to social changes and accommodate them into wildlife management programs. As a result, traditional wildlife management hunting and trapping practices increasingly have become subjects of ballot initiatives. Younger, more idealistic employees often embrace and reflect wildlife protection philosophies, bringing them into conflict with agency administrators and traditional clients. Forced to choose between loyalty to ideals and loyalty to authority, many exit. Resolving ethical issues requires ethics rooted in fundamental democratic values. Wildlife agencies will learn to manage issues of wildlife ethics when they rediscover democracy.

Torch-light transect surveys for moths

The use of light traps in sampling moth populations is an established technique used by entomologists and ecologists. However, trap data partly reflect the variable attractiveness of UV light to different species of moth. There are also potential problems of the practicality and expense of running traps in certain locations. An alternative method of recording moth populations is developed, using a modification of the transect count technique used for butterflies (Pollard and Yates, 1993) and recently applied to moths (Spalding, 1997). During transects, moths were observed by torch-light in a 5 by 5 m box, before the recorder walked on for 10 paces, and recorded moths in the next 5 m box. The transect approach was tested in the field, alongside traditional light trap and sugar methods. Transects recorded moth species for relatively little effort, produced repeatable measures of relative density, and provided habitat-specific data. This approach is likely to provide a valuable addition to light trapping in biodiversity inventories, species surveys, and in monitoring the effects of habitat management for conservation.

Dear Sister: Medieval Women and the Epistolary Genre ed. by Karen Cherewatuk, Ulrike Wiethaus

REVIEWS KAREN CHEREWATUK and ULRIKE WIETHAUS, eds. Dear Sister: Medieval Women and the Epistolary Genre. Middle Ages Series. Philadelphia: Uni­ versity of Pennsylvania Press, 1993. Pp. viii, 218. $32.95 cloth, $14.95 paper. Feminist investigations of medieval documents have demonstrated that women successfully participated in the public culture of their time but resorted to differing forms and modes ofexpression. Yet to grasp the extent to which women were able to utilize the written word, we must turn to the mostly marginalized yet powerful genre of letters. In the present volume the contributors analyze the oeuvres ofsome ofthe most important women letter writers from the early to the late Middle Ages and thus are shedding new light on the broad spectrum of literary expressions, political interests, and religious inspirations medieval women were capable of. As the editors rightly point out, medieval letters transcended gender and educational bar­ riers (p. 3) and facilitated the transition from oral to written culture (see A. N. Doane and C. Braun Pasternack, eds., Vox intexta, 1991). As the present volume makes abundantly clear, the examination of women's letters opens our eyes to the hitherto not fully understood world ofwomen's intellectual life in the Middle Ages. This anthology aims, how­ ever, primarily at women's self-consciousness surfacing in letters, not at their role in medieval literature; their epistles are "the primary vehicle for {their} own voice" (p. 15). Beginning with St. Radegund's (ca. 520-87) Latin epistles, Karen Cherewatuk highlights the options which the writer had at her hands to influence public opinion through her texts and to maintain an authoritative position in society. Radegund heavily utilized contemporary and classical literature to formulate her personal concerns about political developments. Unquestionably she fell back to some Anglo-Saxon lament songs (p. 35), but Cherewatuk's claim that a similar tradition of literary laments by women extended into the Middle High German Minnesang (p. 37) cannot be confirmed. Gillian T. W Ahlgreen reaches similar conclusions regarding Hildegard von Bingen's letters through which she established her authority as vision­ ary. This in turn allowed her to intervene in disputes over administrative and theological questions in the church. A statistical analysis reveals that the writer claimed morevigorously her function as a vessel ofdivine inspi­ ration in letters to men of authority than in those to women, thus instru­ mentalizing her mystical experiences for political purposes. A similar phe­ nomenon can be observed in Catherine of Siena's letters, here analyzed by 169 STUDIES IN THE AGE OF CHAUCER Karen Scott, who demonstrates that the mystic explicitly derived from God her authority to speak up in political debates about the schism and other affairs in the church. In addition Scott notices the considerable self­ awareness and casualness with which Catherine composed her letters. In part they reflect oral culture, in part they derive their material from written culture, but the writer wanted them both to be preserved and to be distrib­ uted among her readers. Scott seems to fall into the traditional trap, how­ ever, of assuming that the author's straightforward writing style indicates "simply a form of speaking" (p. 109). Moreover, it amounts to a conven­ tional fallacy to claim that the rusticality of her letters helped her protect herself from misogynistic attacks (p. 113), because it ignores the stylistic strategies underlying the simplicity of her style. Finally, it negates the important factor of Catherine's reputation as a saint. Glenda McLeod offers a close reading of Heloise's letters to Abelard in which she naively builds on the assumption that the heated debate over the authenticity of the correspondence can be solved if we accept that Heloise fought for the establishment of her own self through these texts. I also believe that we can trust the letters as Heloise's personal statements, but no firm proofcan be adduced for this hypothesis. McLeod perceives a struggle in these epistles addressed to Abelard to maintain a personal integrity and to reach a level ofself-realization denied by her husband. It does not come as a surprise that the writer thematizes the conflict between public and private in her correspondence with the famous philosopher, but McLeod...

Comparison of Glass and Plastic McPhail Traps in the Capture of the South American Fruit Fly, Anastrepha fraterculus (Diptera: Tephritidae) in Brazil

McPhail traps have been used throughout the new world for many decades to detect and monitor for fruit flies of genus Anastrepha. Since no sexual lures or host attractant have been developed for Anastrepha spp., a food lure containing protein hydrolysate, torula yeast and carbohydrate has been used for bait in McPhail traps (Lopez & Hernandez Bacerril 1967, Lopez et al. 1971, Malavasi & Morgante 1981). Many modifications in the original design of McPhail have been proposed in recent years but none have substantially increased effectiveness. The traditional glass McPhail has two problems. First, it is expensive when compared with polyethylene made traps, and second, it is fragile, heavy and difficult to handle. Its lifetime is short compared with other models. Under extreme conditions, for example when the temperature reaches over 40?C inside the trap, spontaneous breakage is common. In regions where large Anastrepha spp. monitoring and detection programs have been conducted for certification of fruit fly-free areas, the large number of traps required is a major expense. In an attempt to replace the original glass McPhail trap with a more economical plastic model of identical shape and similar size, we tested the efficiency of both models in trapping the South American fruit fly, Anastrepha fraterculus (Wiedemann). The experiments were conducted in a non-commercial grove, where previous studies had determined large populations of A. fraterculus were found (Malavasi & Morgante 1980, Amaral 1987). The experiment was conducted in Itaquera, 30 Km east Sao Paulo city where there are more than 15 species of Anastrepha host trees. Traps were suspended in guava (Psidium guajava), Surinam cherry (Eugenia uniflora) and loquat (Eryobotrya japonica) during 8 consecutive weeks in March-May 1989. Two traps models were tested. The traditional McPhail glass trap was made in Mexico, and the plastic model made in Brazil. Both were similar in shape, the glass trap with 19 cm diameter and the plastic trap with 17 cm diameter. Both traps were the same height (14 cm) and had a similar entrance hole (glass 4.5 cm, plastic 4.0 cm diameter). All traps were baited with 250 ml of 3% protein hydrolysate solution with borax added to prevent decomposition. Two traps (one of each model) were placed in opposite quadrants of each tree. Traps were hung at 1.7 to 2.0 m high, in the peripheral canopy with a minimum of 2.0 m between each trap. Trap positions were alternated, the bait was changed and the adults were collected and counted weekly. Ten sets of the two traps were hung up in 5 loquat, 3 guava, 1 grumixama and 1 Surinam cherry trees. Statistical comparisons of means were made with t tests, and by analysis of variance (ANOVA) (SAS Institute 1987). A total of 7,148 A. fraterculus flies were caught in the grove. No statistical difference between glass and plastic traps was observed using t test analysis (F = 1.18; df = 15; p > 0.7450) (Table 1). There were no significant differences in the sex ratios of the trap catches between trap models. More females were captured than males. Females may require more frequent feeding than males and so may be captured in greater numbers in food-baited traps (Davis et al. 1984).

Comparison of an Aerial Water-pan Pheromone Trap with Traditional Trapping Techniques for the European Corn Borer (Lepidoptera: Pyralidae)

An aerial water-pan pheromone trap (AWPT) was compared with 15-W blacklight (BLT) and Pherocon 1-C sticky traps (ST), for trapping the European corn borer (ECB), Ostrinia nubilalis (Hubner). At low ECB population densities, the catches in AWPT and BLT were not significantly different, whereas at higher ECB densities, catches in BLT were greater. The AWPT caught significantly more ECB, at all densities, than did the ST. Night observations revealed the AWPT to be 400% more efficient at trapping ECB than the ST. Competition by virgin females, and the sedentary tendency of males, could explain why catches were similar at low densities and dissimilar at higher densities.