Sticky Panels Research Articles

The evolution of striped coat patterns in African mammals-what function do the stripes have?

<p class="jbls"><span lang="EN-GB">Several families of mammals have stripes and many hypotheses have been proposed to explain the evolution of the striped coat patterns. However, there is very limited experimental evidence to support which hypotheses are the most likely to explain the evolution of the striped patterns. Therefore, what adaptive function the stripes serve in all these species is still largely unknown. In this study I investigated the characteristics of stripes such as stripe width for both white and black stripes on 36 striped African mammals’ coats collected in four museums and three countries. My study further revealed that the appearance of stripes on mammalian coats is most likely not involved in sexual selection. There were close similarities in stripes number or stripes width between sexes for <em>Equus grevyi</em> and <em>Tragelaphus</em> <em>imberbis</em>. In order to evaluate the effects of stripes on tabanids attractiveness, two experiments designed to test tabanids attraction were performed. Data on tabanids daily activity revealed that the flies were more active on partly cloudy and sunny weather. Especially, <em>Haematopota pluvialis</em> is known to have a high flight intensity in cloudy weather before an anticipated rain. Using sticky panels and models, tabanids were more attracted to sunny sides in the both experiments. Moreover, the findings revealed that the stripes in all striped patterns were extremely important in stimulating tabanid flies’ repellency. My results suggest that the appearance of stripes on different mammalian coats could be an evolutionary force reducing the attraction of tabanids to many striped animals, consequently, reducing disease transmission risk.</span></p>

Comparative field studies of Bactrocera oleae baits in olive orchards in Crete

Protein-based food attractants are used in Bactrocera oleae (Gmelin) (Diptera: Tephritidae) management for monitoring populations, estimating the time of bait sprays and for Mass Trapping. McPhail traps loaded with two trophical attractant solutions (two formulations of hydrolysed proteins equal to 55% and 75% w/w) at 0.5, 1, 2, 4 and 8% concentrations were tested for their attractiveness, which was indicated by the captures of flies in McPhail traps during two periods in successive summers. The results indicated that lower concentrations than the 2% concentration recommended for both tested proteins (highest captures of 31.4 olive fruit flies/trap/week were recorded at 1% for protein equal to 55% and 28.5 at 0.5% for protein equal to 75%) were also attractive to olive fruit flies, whereas 8% was the least attractive concentration for both attractants (18.7 and 9.9 olive fruit fly/trap/week respectively). In addition, the 2% attractant concentration for both proteins was evaluated for attractiveness over time compared with ammonium sulphate; three-day-old solution of the protein equal to 75% was significantly more attractive to flies (at least twice) than 7-, 10-, 14-, 17-, 20- or 24-day-old solutions while the 7-day-old solution of the protein equal to 55% did not display differences compared with other solution ages. The attractiveness of ammonium sulphate weakened as time passed (below 5 olive fruit flies/trap/week). On the other hand, olive stems sprayed with the tested proteins under field conditions attracted approximately 0.6–1.0 adults per day, as indicated by captures in yellow sticky panels, with the highest number of flies recorded on the first day (0.9–1.4 adults). Finally, changes of pH values of these trophical attractants after dilution to the water are also reported.

Monitoring European Cherry Fruit Fly (Rhagoletis Cerasi L.) Through Vizual Traps

Rhageletis cerasi (L.) is the most important pest in cherry orchards and it’s attak can affect the quality of fruit on a large percentage (45-100%). The European cherry fruit fly is prezent in all cherry and sweet cherry orchards, therefore monitoring this population is required as an element of integrated protection. The aim of this study is to establish population dynamics in Cluj area. Adult flight was monitored twice a week on yellow sticky panels. Traps were placed in different parts of the orchard. The first captures were recorded in May 29, with a number of 4 adults/orchard and in 24 June we recorded the maximum number, 89 adults/orchard. By monitoring population dynamics we can determine the correct time for application of chemical treatments.

The Monarthopalpus Buxi Species Population Dynamics in Cluj County (Romania)

Monarthropalpus buxi (  Diptera: Cecidomyiidae) has been described for the first time by Rubsaamen in 1982 (Perju et al., 2001). It is a monophagus species developing on Buxus sempenvirens as its dendrological species, which plays host to Monarthropalpus buxi, and is attacked by its larva. The attack is observed on the leaves of Buxus sempenvirens : the larva feeds on the cellular juice of the leaves, which have a goffering aspect, yellow-rusty in color. The objectives of the research regarded establishing the dynamics of flight curve, circadian rhythm, the effectiveness and efficacy of colored panels. The experiment developed along 24 days, starting with April 30, 2012 until May 24, 2012. Sticky panels have been used, in four different colors, placed above Buxus sempenvirens bushes, in one single row, at three different height levels. The first captures have been observed on May 3, 2012. The maximum of flight curve has been registered on May 11, 2012. The last captures have been registered on May 22, 2012. This year, there have been captured as many as 21,984 adults; the greatest number of individuals have been captured on yellow panels, which means 34.74% of the whole Monarthropalpus buxi  population captured in 2012.

Estimation of fly population density of Bactrocera oleae in olive groves of Crete

Population density of adults of Bactrocera oleae (Gmelin) (Diptera: Tephritidae) was obtained from olive trees during a two-year study by means of two different methods, namely, knock down by an insecticide applied as a fog (‘sondage’) and trap captures (of yellow sticky panels and McPhail traps baited with ammonium). First it was concluded that yellow sticky panel traps give a poor representation of the olive fruit fly population density of the olive grove. Yellow panel trap captures were significantly lower than McPhail’s (September) and than the actual population of B. oleae as recorded in olive tree canopy (August of 2008).

Temporal Analysis of Sesquiterpene Emissions From Manuka and Phoebe Oil Lures and Efficacy for Attraction of Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-borer that vectors the fungal agent (Raffaelea lauricola) responsible for laurel wilt. Laurel wilt has had severe impact on forest ecosystems in the southeastern United States, killing a large proportion of native Persea trees, particularly redbay (P. borbonia) and swampbay (P. palustris), and currently poses an economic threat to avocado (P. americana) in Florida. To control the spread of this lethal disease, effective attractants are needed for early detection of the vector. Two 12-wk field tests were conducted in Florida to evaluate efficacy and longevity of manuka and phoebe oil lures, and to relate captures of X. glabratus to release rates of putative sesquiterpene attractants. Two trap types were also evaluated, Lindgren funnel traps and sticky panel traps. To document lure emissions over time, a separate set of lures was aged outdoors for 12 wk and sampled periodically to quantify volatile sesquiterpenes using super-Q adsorbant and gas chromatography-mass spectroscopy analysis. Phoebe lures captured significantly more X. glabratus than manuka lures, and sticky traps captured more beetles than funnel traps. Phoebe lures captured X. glabratus for 10-12 wk, but field life of manuka lures was 2-3 wk. Emissions of alpha-copaene, alpha-humulene, and cadinene were consistently higher from phoebe lures, particularly during the 2-3 wk window when manuka lures lost efficacy, suggesting that these sesquiterpenes are primary kairomones used by host-seeking females. Results indicate that the current monitoring system is suboptimal for early detection of X. glabratus because of rapid depletion of sesquiterpenes from manuka lures.

Simplified and improved monitoring traps for sampling sand flies

Simplified and improved monitoring traps for sampling sand flies Gunter C. Muller1, Edita, E. Revay2, and John C. Beier3 1Department of Microbiology and Molecular Genetics , IMRIC, Kuvin Centre for the Study of Infectious and Tropical Diseases, Faculty of Medicine, Hebrew University, Jerusalem 91120, Israel, guntercmuller@hotmail.com 2Department of Anatomy and Cell Biology, Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel 3Department of Epidemiology and Public Health, University of Miami Miller School of Medicine, Miami, FL 33136, U.S.A.

Multiple Trypanosoma infections are common amongst Glossina species in the new farming areas of Rufiji district, Tanzania

BackgroundTsetse flies and trypanosomiasis are among several factors that constrain livestock development in Tanzania. Over the years Rufiji District was excluded from livestock production owing to tsetse fly infestation, however, a few years ago there was an influx of livestock following evictions aimed at conserving the Usangu wetlands.MethodsA study was conducted to determine the efficiency of available traps for catching tsetse flies, Glossina species infesting the area, their infection rates and Trypanosoma species circulating in the area. Trapping was conducted during the semi dry season for a total of 30 days (ten days each month) during the onset of the dry season of May - July 2009. Harvested flies after every 24 hours were dissected and examined under a light microscope for trypanosome infections and whole fly DNA was extracted from 82 flies and analyzed for trypanosomes by polymerase chain reaction (PCR) using different sets of primers.ResultsThe proportions of total tsetse catches per trap were in the following decreasing order S3 (33%), H-Trap (27%), Pyramidal (19%), sticky panel (11%) and biconical trap (10%). Of the 1200 trapped flies, 75.6% were identified as Glossina pallidipes, 11.7% as G. brevipalpis, 9.6% as G. austeni and 3.0% G. morsitans morsitans. Dissections revealed the overall infection rate of 6.6% (13/197). Whole DNA was extracted from 82 tsetse flies and the prevalence of trypanosomes circulating in the area in descending order was 92.7% (76/82) for T. simiae; 70.7% (58/82) for T. brucei types; 48.8% (40/82) for the T. vivax types and 32.9% (27/82) for the T. congolense types as determined by PCR. All trypanosome types were found in all tsetse species analysed except for the T. congolense types, which were absent in G. m. morsitans. None of the T. brucei positive samples contained human infective trypanosomes by SRA - PCR testConclusionAll tsetse species found in Rufiji are biologically important in the transmission of animal trypanosomiasis and the absence of T. congolense in G. m. morsitans could be a matter of chance only. Therefore, plans for control should consider all tsetse species.

Parasitism of Bactrocera oleae (Diptera; Tephritidae) by Psyttalia concolor (Hymenoptera; Braconidae) in the Balearic Islands (Spain)

Abstract Psyttalia concolor (Hymenoptera; Braconidae) was introduced to Spain in the early 1970s to control the olive fruit fly Bactrocera oleae. Previous studies showed that P. concolor was poorly adapted to temperate zones, such as the Balearics. In this study, we demonstrate a high rate of natural parasitism of B. oleae by P. concolor in Majorca (Balearic Islands). Surveys were carried out from August to September 2007 in two organically‐farmed olive orchards and two insecticide‐managed orchards. A total of 250 olive fruits were examined weekly from each of the orchards. Olives were kept under laboratory conditions until the emergence of B. oleae pupae, which were collected and placed in Petri dishes until the emergence of B. oleae and/or P. concolor adults. In addition, red sticky spheres and yellow sticky panel traps were placed in every orchard for monitoring adults of P. concolor. Red spheres captured more individuals of the parasitoid when compared with the yellow panels. Seasonal average parasitism levels of B. oleae pupae by P. concolor were high (22.4% and 23.4%) in the two organically‐farmed orchards and 0% in the insecticide treated orchards. The high rates of parasitism by P. concolor found in the organically‐farmed olive orchards supports the use of this parasitoid for the biological control of B. oleae in the Balearic Islands.

Comparison of olive fruit fly (Bactrocera oleae (Gmelin)) (Diptera: Tephritidae) captures in several commercial traps in California

The trapping efficiency of three commercially available traps for monitoring the olive fruit fly (Bactrocera oleae (Gmelin)) was tested in California. ChamP yellow sticky traps and IMPT plastic McPhail-type traps were tested in three locations during 2 years. The McPhail traps captured significantly more flies than other trap types. In the second year, three variants of AM yellow sticky traps were included in testing. The AM yellow sticky panel was more efficient than the ChamP panel. The ChamP and AM traps were baited with an ammonium bicarbonate food lure and Spiroketal pheromone lure, and the McPhail traps were baited with a torula yeast food lure. Under the conditions of this study, it appears that the aqueous food lure used in the McPhail traps was more attractive to olive fruit flies than ammonia lures. Traps were also deployed in irrigated and unirrigated olive blocks at one location for 1 year, and more olive fruit flies were caught in the irrigated trees than in the unirrigated. The ChamP traps were initially used for olive fruit fly monitoring at the onset of their invasion into California, but the use of McPhail traps is now recommended.

Attraction, Feeding, and Control of Rhagoletis pomonella (Diptera: Tephritidae) with Gf-120 and Added Ammonia in Washington State

Experiments were conducted in 2005 and 2006 in western Washington state to determine effects of adding ammonium carbonate (AC) and ammonium acetate (AA) to GF-120 NF Naturalyte® Fruit Fly Bait (Dow AgroSciences, Indianapolis, IN) on attraction, feeding, and control of the apple maggot fly, Rhagoletis pomonella (Walsh). In the field, sticky yellow panel traps baited with GF-120 10% AC attracted more flies than those baited with GF-120 10% AA or GF-120 alone. In the laboratory, female flies responded more frequently to sucrose and 20% GF-120 than to water and 40% GF-120 10% AA on apples, perhaps because of the confined conditions during testing. In the field, fly attraction and feeding were greater for GF-120 10% or 2.5% AC or AA than GF-120 alone on apple leaves. In 2 spray tests with 100 mL of GF-120 alone and GF-120 2.5% AC or AA applied on single apple trees, larval infestations in fruit were reduced up to 99% compared with controls, but there were no differences among treatments, and none was different from spinosad alone. Results indicate the attractiveness of GF-120 to R. pomonella can be increased with added ammonia, but that this does not necessarily result in greater control, perhaps because the added ammonia volatilizes too quickly. Results suggest that at the spray volumes used, GF-120 alone or even spinosad alone can greatly reduce local R. pomonella populations in Washington.

Field Comparison of Chemical Attractants and Traps for Caribbean Fruit Fly (Diptera: Tephritidae) in Florida Citrus

Field studies in citrus were conducted to compare the following as attractants for the Caribbean fruit fly, Anastrepha suspensa (Loew): torula yeast-borax; propylene glycol (10%); a two-component lure consisting of ammonium acetate and putrescine; a two-component lure consisting of ammonium bicarbonate and putrescine; and a three-component lure consisting of ammonium bicarbonate, methylamine hydrochloride, and putrescine. Various combinations of these attractants in glass McPhail, plastic McPhail-type (Multi-Lure), and sticky panel traps were investigated in two replicated studies. In one study on wild flies, the most effective and least complex trap-lure combination tested was the Multi-Lure with propylene glycol baited with ammonium acetate and putrescine. This trap-lure combination captured significantly more female and male flies than the standard glass McPhail baited with torula yeast-borax in water. All of the trap-lure combinations were female biased, with an overall average of 80.8% (SEM 1.4) flies captured being female. A second study on laboratory-reared, irradiated flies indicated no significant differences among these trap-lure combinations with respect to number of flies recaptured, although rankings based on mean number of flies recovered per trap per day supported results of the first study. The percentage of flies recaptured that were female (83.0%, SEM 0.9) was statistically the same as in the first study. Weekly percentage recovery of flies during the second study was low, possibly due to our fly release strategy. Future release/recovery studies with laboratory-reared flies would benefit from some basic research on release strategies by using different trap densities and on relating recapture rates of laboratory-reared flies (nonsterile and sterile) to capture rates of wild flies.

A Simple and Effective Method for Capturing Viable Adult Blueberry Maggot Flies, Rhagoletis mendax (Diptera: Tephritidae)

The blueberry maggot fly, Rhagoletis mendax Curran, (Diptera: Tephritidae) is a widely distributed pest of lowand highbush blueberries (Vaccinium angustifolium Aiton and Vaccinium corymbosum L., respectively) (Vacciniaceae) within the northeastern and midwestern United States, as well as Canada. Given its economic importance, the fly has been the target of considerable research with respect to the development of monitoring and control strategies within the context of integrated pest management (Prokopy and Coli, 1978; Liburd et al., 1998a, b, 2000). Several attempts have been made to develop and refine blueberry maggot fly monitoring programs in order to forecast the presence of infestations in commercial blueberry plantings (Liburd et al., 1998a, 2000). The current monitoring practices employed by commercial growers of lowand highbush blueberries involve the deployment of ammonium-baited Pherocon AM yellow sticky panels or green and red sticky spheres (Prokopy and Coli, 1978; Liburd et al., 1998a). Such practices allow growers to detect fly emergence for more accurate timing of sprays. The blueberry maggot is also a member of the R. pomonella (Walsh) sibling species complex and has been used as part of a long-running study system by evolutionary biologists for investigating the mechanisms of speciation in sympatry (Feder and Bush, 1989). The blueberry maggot fly completes larval development inside blueberry fruit and undergoes an obligate annual diapause, making laboratory-rearing difficult. To our knowledge, a continuously-reared laboratory colony of blueberry maggot does not exist. The blueberry maggot has been the subject of many laboratory studies investigating toxicity of potential insecticides (Ayyappath et al, 2000; Stelinski et al, 2001; Liburd et al, 2003). Other laboratory investigations have focused on the antennal sensitivity and oviposition preference of blueberry maggot flies with reference to host-plant related chemical cues (Frey and Bush, 1996). In these laboratory studies, the investigators have relied on the use of adult flies reared from larvae collected the previous year from infested fruit. We describe here a simple and effective method for capturing viable male and female blueberry maggot fly adults in both abandoned and commercial highbush blueberry Vaccinium spp. plantations. Such field-captured, live blueberry maggot flies could be used in the laboratory for toxicological studies, electrophysiological investigations, behavioral assays or in genetic analyses of specific populations. Potentially, this technique could also be adopted for other tephritid species of broad interest.

Field evaluation of plant odor and pheromonal combinations for attracting plum curculios.

The attractiveness of different synthetic host odors and a synthetic aggregation pheromone (grandisoic acid [GA]) to overwintered adult plum curculios (PCs), Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), was examined using two types of traps (sticky panels and black pyramids) placed in border areas surrounding an unsprayed section of an apple orchard in Massachusetts. In 2001, we evaluated the response of PCs to three synthetic fruit volatiles (benzaldehyde [BEN], ethyl isovalerate [EIV], and limonene [LIM]) assessed alone and in combination with GA, as well as the response to GA alone and a no-odor (control) treatment. BEN was the only host volatile that synergized the response of PCs to GA for both trap types. For both trap types, GA was as attractive to PCs as a single component as when in combination with either EIV or LIM. In 2002, four release rates of BEN (0, 2.5, 10, and 40 mg/day) and two release rates of GA (1 and 2 mg/day) were evaluated for attractiveness to PCs using panel and pyramid traps. For panel traps, an increase in amount of GA released (from 1 to 2 mg/day) was associated with a 35% increase in captures. However, PC captures by pyramid traps were similar regardless of the amount of GA released. For panel traps, 10 and 40 mg/day of BEN were the most attractive release rates regardless of the amount of GA released. For pyramid traps baited with GA. PC captures were enhanced by the presence of BEN, regardless of release rate. In 2003, GA at 1 mg/day + BEN at 80 mg/day of release did not enhance PC captures by panel traps relative to lower release rates of BEN. Pyramid traps releasing GA at 1 mg/day performed best when baited with BEN at 10 mg/day of release; a release rate of 80 mg/day of BEN decreased the attractiveness of the binary combination of BEN + GA. Combined results suggest that BEN at 10 mg/day + GA at 1 mg/day of release constitutes an attractive lure that may improve the effectiveness of monitoring traps for PCs.

Odor-Baited Trap Trees: A New Approach to Monitoring Plum Curculio (Coleoptera: Curculionidae)

We compared a trap approach with a trap-tree approach to determine the need and timing of insecticide applications against overwintered adult plum curculios, Conotrachelus nenuphar (Herbst.), in commercial apple orchards in Massachusetts in 2002. All traps and trap trees were baited with benzaldehyde (attractive fruit odor) plus grandisoic acid (attractive pheromone). Sticky clear Plexiglas panel traps placed at orchard borders, designed to intercept adults immigrating from border areas by flight, captured significantly more adults than similarly placed black pyramid traps, which are designed to capture adults immigrating primarily by crawling, or Circle traps wrapped around trunks of perimeter-row trees, which are designed to intercept adults crawling up tree trunks. None of these trap types, however, exhibited amounts of captures that correlated significantly with either weekly or season-long amounts of fresh ovipositional injury to fruit by adults. Hence, none appears to offer high promise as a tool for effectively monitoring the seasonal course of plum curculio injury to apples in commercial orchards in Massachusetts. In contrast, baiting branches of selected perimeter-row trees with benzaldehyde plus grandisoic acid led to significant aggregation (14-15-fold) of ovipositional injury, markedly facilitating monitoring of the seasonal course of injury to apples. A concurrent experiment revealed that addition of other synthetic fruit odor attractants to apple trees baited with benzaldehyde plus grandisoic acid did not enhance aggregation of ovipositional injury above that of this dual combination. We conclude that monitoring apples on odor-baited trap trees for fresh ovipositional injury could be a useful new approach for determining need and timing of insecticide application against plum curculio in commercial orchards.

Response of plum curculio (Coleoptera: Curculionidae) to odor-baited traps near woods.

Response of overwintered plum curculios, Conotrachelus nenuphar (Herbst), to odor-baited traps was evaluated from the beginning until nearly the end of emigration from overwintering sites in woods. We evaluated clear sticky Plexiglas panels and black pyramid traps placed close to woods adjacent to apple trees in an unsprayed section of an orchard. Traps were baited with aggregation pheromone (grandisoic acid) alone or in combination with one of six synthetic fruit volatiles (benzaldehvde, decyl aldehyde, E-2-hexenal, ethyl isovalerate, hexyl acetate, or limonene). Unbaited traps served as a control treatment. Plum curculio emigration from woods was divided into early-, mid-, and late-season periods based primarily on phenological stage of apple bud and fruit development (tight cluster to bloom, petal fall, and fruit set, respectively). During both early- and late season, panel and pyramid traps baited with benzaldehyde plus pheromone were significantly more attractive than any other traps (baited or unbaited), except panel traps baited with ethyl isovalerate plus pheromone in early season, which likewise captured significantly more adults than unbaited panel traps. During midseason, no lures were significantly attractive, possibly due to prevailing cool weather, unfavorable for adult activity. Over the entire season, panel or pyramid traps baited with benzaldehyde plus pheromone captured nearly six times as many plum curculios as unbaited traps of each type, whereas traps baited with pheromone alone captured about twice as many as unbaited traps of each type. We provide information on sex ratio, female maturity stage, and mating status, and several weather parameters associated with trap captures. We conclude that panel or pyramid traps, or a combination, baited with benzaldehyde plus pheromone placed at borders of plum curculio overwintering sites can be a valuable tool for monitoring the beginning, peak, and end of adult immigration into apple orchards.

Long-term sampling of gamma sterilised male Glossina austeni (Diptera: Glossinidae) with sticky panels on Unguja Island (Zanzibar)

Daily catches of gamma sterilised male Glossina austeni Newstead with experimental sticky panels were analysed from March 1996 to July 1997. The flies were released weekly by light aircraft over primary and secondary forest ecosystems of Unguja Island, Zanzibar. In the primary forest, the cross-shaped royal blue XT panel (two interlocking panels of each 70×60 cm) trapped significantly more flies than the royal blue-white leg panel (panel with a body of 65×30 cm and two legs of each 15×15 cm) in all months, except in July 1996 and July 1997. In the same habitat, the cross-shaped royal blue-white leg panel (two interlocking leg panels) trapped from 1.7 (not significant) to 3.0 times (highly significant) as many flies as the standard leg panel depending on the season. Significantly more flies were trapped with the cross-shaped XT panel than with the leg panel in the secondary forest compared to the primary forest. Catches of the cross-shaped XT panel on each of a series of days, correlated well with those of the leg panel on the same day, except for panels deployed in the primary forest during the hot-dry and the beginning of the cold-dry season. Catches of the cross-shaped leg panel correlated less well with the catches of the standard leg panel in the primary forest. The data presented indicate that the behavioural responses in time and space of sterile male G. austeni are influenced by the type of trapping device used.

Responses of Glossina austeni to sticky panels and odours.

The responses of male tsetse Glossina austeni Newstead (Diptera: Glossinidae) towards blue and white sticky legged panels, baited with odour attractants, and towards modified panels were studied in the Jozani forest of Unguja Island, Zanzibar. Increasing the height of the body of a standard panel from 30 to 60 or 90 cm, increased the catch two-fold. Increasing the height of the legs (from 15 to 60 or 120 cm) or raising the device more than 5 cm above the ground reduced the catch significantly. The legs of the panels were the preferred landing sites of the flies, irrespective of the height of the body of the panel. Acetone (300 mg/h) combined with cow urine (60-130 mg/h) significantly increased the catches two- to threefold during the rainy season, but not during the dry season. Acetone had no effect during the dry season and its effect during the rainy season was less consistent. There was no effect of octenol (2.5-12.5 mg/h), used alone or in combination with acetone. Likewise, the catch did not increase through the addition of cow sebum, pig urine (60-860 mg/h), pig urine combined with acetone and octenol. The observed seasonal differences in the response of G. austeni towards odours are discussed in relation to host location strategies.

Notes on the Ecology of a Natural Glossina austeni (Diptera: Glossinidae) Population in the Jozani Forest, Unguja Island of Zanzibar

Studies were made of Glossina austeni captured with sticky panels during the dry and wet season in the northern and central part of the Jozani forest on the island of Unguja, Zanzibar. The density of the fly population was significantly higher in the northern part of the forest than in the central. Female and male daily catches remained stable in time in the northern part of the forest but the density of the male fly population declined significantly in the central part of the forest at the end of the dry season. The magnitude of the catch and the sex ratio of the samples was highly affected by the trap site in both locations. Only samples in the central part of the forest were biased towards one of the sexes depending on the seasons. The age composition of the male flies was independent of locality and season but the one of female flies was influenced by the seasons in the central part of the forest. The breeding and abortion rate of flies were similar in the two locations both during the wet and dry seasons. The stability of the fly population in terms of density and composition is probably a reflection of the optimal environmental conditions in this primary forest habitat.

VISUAL AND SEMIOCHEMICAL DISRUPTION OF HOST FINDING IN THE SOUTHERN PINE BEETLE

The importance of visual silhouettes for host finding by the southern pine beetle (SPB), Dendroctonus frontalis (Coleoptera: Scolytidae), and the potential for disruption of this process using visual deterrents were evaluated with multiple-funnel traps, painted white or black, and with clear, white, or black Plexiglas sticky panels. All traps and panels were baited with the SPB attractant frontalure. The effect of combined semiochemical and visual disruption was evaluated in funnel traps by including the antiaggregation pheromone verbenone, or the repellent/inhibitory host compound 4-allylanisole, in addition to the attractant. Visual treatments had a highly significant effect on catch of SPB and the predatory clerid beetle Thanasimus dubius. In attractant-baited traps, white paint alone reduced the average number of SPB caught by 72% in Florida and 68% in Louisiana. The repellent 4-allylanisole reduced catch of SPB by 56% in Florida and 45% in Louisiana. Verbenone was eluted at 25% of the targeted rate a...