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PubMed1999

Slit is the midline repellent for the robo receptor in Drosophila.

Previous studies suggested that Roundabout (Robo) is a repulsive guidance receptor on growth cones that binds to an unknown midline ligand. Here we present genetic evidence that Slit is the midline Robo ligand; a companion paper presents biochemical evidence that Slit binds Robo. Slit is a large extracellular matrix protein expressed by midline glia. In slit mutants, growth cones enter the midline but never leave it; they abnormally continue to express high levels of Robo while at the midline. slit and robo display dosage-sensitive genetic interactions, indicating that they function in the same pathway. slit is also required for migration of muscle precursors away from the midline. Slit appears to function as a short-range repellent controlling axon crossing of the midline and as a long-range chemorepellent controlling mesoderm migration away from the midline.

Animals↗
PubMed2002

Influence of odor from wood-decaying fungi on host selection behavior of deathwatch beetle, Xestobium rufovillosum.

Adult females of Xestobium rufovillosum de Geer demonstrated anemotactic orientation when exposed to an odor plume containing volatiles generated by wood-decaying fungi (Coriolus versicolor, Donkioporia expansa) and decayed oak wood (Quercus petraea, Quercus robur). They did not orient towards undecayed oak wood, beech (Fagus sylvatica), or pine wood (Pinus sylvestris). Although all insects tested showed anemotactic orientation, responses were nonlinear with respect to insect age. Adult females more readily oriented upwind when they were between 10 and 16 days old. Oviposition choice bioassays showed that ovipositing females would preferentially oviposit on extract-treated cellulose paper discs that had been treated with various strains of the wood-decaying fungus, Donkioporia expansa. HPLC-fractionated mycelial extracts were attractive to ovipositing deathwatch beetles, whereas HPLC-fractionated fungal broth extracts were repellent to ovipositing females. The implications of these results are discussed in the context of timber pest management in historically important buildings.

Animals↗
PubMed2001

Behavioral and electrophysiological responses of Arhopalus tristis to burnt pine and other stimuli.

The exotic longhorn beetle Arhopalus tristis is a pest of pines, particularly those damaged by fire, and a major export quarantine issue in New Zealand. Actinograph recordings of caged individuals showed that males and females were most active from dusk to midnight. Olfactometer experiments indicated that females moved upwind toward odors from burnt pine (80%, N = 75), compared to unburnt pine (20%). Oviposition choice tests showed that eggs were predominantly laid on burnt logs (79%, N = 20), compared to unburnt logs. Beetles were trapped by funnel traps baited with burnt (mean catch per trap 7.8) and unburnt (mean catch 4.1 per trap) pine bark from inside a screen cage (4 x 3 m), while unbaited traps had a mean catch 0.1 beetles (N = 8 replicates). The treatment of burnt pine bark with a 1:1:2 mixture of green leaf volatiles (E)-2-hexen-1-ol and (E)-2-hexenal) in mineral oil as a repellent reduced trap catch by fivefold in a similar experiment (mean catches of 1.2 beetles per trap to burnt pine bark plus repellent treatment and 6.2 beetles per trap to burnt pine bark alone). The treatment of burnt pine bark with this solution also reduced oviposition by 98.5% (mean eggs per log of 11.1 on burnt pine and 0.3 on burnt pine plus repellent), indicating that oviposition cues have the potential to be significantly disrupted. The electrophysiological responses of adult beetles were recorded to a range of odorants. Normalized responses to monoterpenes known to occur in Pinus radiata ranged from about 20 to about 150, with alpha-terpineol giving the greatest responses in both sexes. Green leaf volatiles also gave high responses. The potential exists to improve the management of this insect using chemical cues in various ways.

Animals↗
PubMed1994

Evaluation of permethrin-treated military uniforms for personal protection against malaria in northeastern Thailand.

A trial to compare the effect of military clothing treated by high-pressure spray with permethrin or placebo on the incidence of malaria in Royal Thai Army troops was conducted in northeastern Thailand. Bioassays of treated clothing using laboratory-reared Anopheles dirus females showed permethrin remained in the treated fabric for up to 90 days. Both permethrin- and placebo-treated uniform shirts provided > 84% protection from biting An. dirus in laboratory bioassays for the duration of the study. In laboratory tests, knockdown of An. dirus exposed to permethrin-treated cloth fell to < 20% after 3 hand washes, despite the presence of 28.7-59.9% of the original dose of permethrin. The use of permethrin-treated uniforms without adjunct application of topical repellents did not reduce malaria in Thai troops in an operational setting where incidence during 6 months was as high as 412 cases/1,000 in spite of chemoprophylaxis and use of untreated bednets.

Adult↗
PubMed2002

Development of granular boric acid sugar baits for house flies (Diptera: Muscidae).

Freeze-dried, granular sugar baits containing boric acid as the toxicant were evaluated against house flies, Musca domestica L., in two bioassays with toxicant dose ranges of 3, 5, 7, 8, and 12%, and 3, 5, 9, 17, and 33% boric acid, respectively, calculated and expressed on a dry weight basis. Flies in bioassay 1 were mixed sex and unstarved and flies in bioassay 2 were females only and starved 4 h before testing began. LC50s were 8.97 and 14.33%, and LT50s were 59.75 and 53.34 h in bioassays 1 and 2, respectively. Baits were tested at concentrations as high as 33%, however there was no indication of repellency as seen previously with liquid baits. Reasons for lack of repellency and potential uses for baits are discussed. Development of efficacious granular baits would allow the presentation of higher levels of boric acid in volumes much smaller than required for liquid baits.

Animals↗
PubMed1996

Human host avidity in Aedes albopictus: influence of mosquito body size, age, parity, and time of day.

Diel patterns of human host attack by Aedes albopictus in the laboratory were studied in relation to mosquito body size, age, parity, and time of day. Analysis of responses in 10-, 15-, and 20-day-old females indicated a significant main effect due to time of observation in the diel period, as well as significant time x parity and time x age interactions. The distribution of mean host attack responses during the diel period was bimodal with approximately 70% of all activity during photophase (0800-2000 h); attack rates were highest in the morning (0800 h) and evening (1400-2000 h) and lowest between 0200 and 0600 h. The diel pattern of attack responses was bimodal for nulliparous and parous females, but parous females were more active than nulliparous females between 1400 and 2000 h. This pattern became increasingly bimodal during photophase, as mosquitoes aged, regardless of mosquito body size or parity. Variations in host avidity patterns between young and old females suggest that mosquito repellent bioassays initiated early in the day, that last > or = 6 h, or that use young females (approximately 5 days old) overestimate the protection period of deet against mosquitoes > 10 days old.

Aedes↗
PubMed2006

Experience-altered oviposition responses to a neem-based product, Neemix, by the diamondback moth, Plutella xylostella.

The oviposition responses of the diamondback moth, Plutella xylostella L., to Neemix 4.5, a neem-based oviposition repellent/deterrent, with or without previous experience were studied in the laboratory on plain aluminum foil sheets, on aluminum foil sheets coated with cabbage juice, and on cabbage plants. In the plain aluminum foil sheet experiment, the females without prior experience of Neemix (inexperienced females) deposited more eggs (66.2%) on sections with untreated sheets than on sections with Neemix-treated sheets (33.8%), indicating that the inexperienced females were significantly repelled and/or deterred by Neemix. In contrast, the Neemix-experienced females deposited more eggs (69.2-69.7%) on sections with Neemix-treated sheets than on sections with untreated sheets (30.3-30.8%), implying that the females were not repelled and/or deterred by Neemix following an experience. In the tests using egg-laying sheets coated with cabbage juice or with cabbage juice plus Neemix, the inexperienced females deposited more eggs (63.8%) on the sections with sheets treated with cabbage juice only than on the sections with sheets coated with cabbage juice and Neemix (36.2%), indicating that inexperienced females were repelled and/or deterred by Neemix. Similarly, Neemix-experienced females deposited more eggs (62.2-65.6%) on the sections with sheets treated with cabbage juice plus Neemix than on the sections with sheets treated with juice only (34.4-37.8%), suggesting that the females were not repelled and/or deterred by Neemix following an experience. On cabbage plants, inexperienced females oviposited similar numbers of eggs on both Neemix-treated (50.8%) and untreated plants (49.2%). However, the Neemix-experienced females oviposited more eggs on the plants treated with Neemix (56.3%) than on untreated plants (43.7%), indicating that the females were attracted by Neemix-treated plants following an experience. The significance of this study for applications of insect repellents/deterrents in pest management is discussed.

Animals↗
PubMed2003

Problems in prescribing malaria chemoprophylaxis for travelers.

To offer effective malaria chemoprophylaxis for travelers in a country, the physician must know the precise status of malaria there (frequency, resistance), determine the degree of exposure to mosquito bites, evaluate the precise clinical condition of the traveler, and improve the traveler's compliance with treatment by providing good information on potential side-effects. These side-effects, sometimes overemphasized in the media, lead to poor compliance, particularly after returning home, and, consequently, increase the risk of acquiring malaria. The recently approved Malarone could overcome these drawbacks. But its cost is high and its wide use could also lead to the emergence of resistant strains. Therefore, training professionals in travel medicine is important in malaria prevention and decrease the prescription of abusive or inaccurate prophylaxis (e.g., most tourists traveling in organized tours in Asia, with no stay in remote malaria endemic areas, do not need any prophylaxis). In addition, prevention of mosquito bites with repellents, impregnated bed nets, and indoor insecticide-dispensing devices is still an important tool for controlling malaria in travelers.

Animals↗
PubMed1991

Behavioral response of Anopheles darlingi to DDT-sprayed house walls in Amazonia.

The behavioral response of Anopheles darlingi females to spraying of house walls with DDT was studied along the Ituxi River in Amazonas, Brazil, using a house sprayed with 2 g DDT per square meter of wall surface and an untreated house serving as a control. It was found that hardly any An. darlingi females entered, exited, or took blood meals inside the treated house after it was sprayed with DDT, and that specimens marked and released inside the house tended to depart immediately. This behavior appears to constitute true repellency rather than contact irritability. Since the typical house in the vicinity of the study site had only two walls, the persistence of malaria in the local area was probably due to home construction practices.

Animals↗
PubMed2004

Chemical and physical signals mediating conspecific and heterospecific aggregation behavior of first instar stink bugs.

We investigated cues that mediate the aggregation behavior of immature pentatomid bugs by using nymphs of six different pentatomid bug species (Nezara viridula, Acrosternum hilare, Chlorochroa ligata, Chlorochroa sayi, Thyanta pallidovirens, and Euschistus conspersus). When first instars of any two species were put together in a Petri dish, they readily formed heterospecific aggregations similar to their natural conspecific aggregations. The chemical profiles of first and second instar nymphs of each species were determined by solvent extraction with pentane, followed by GC-MS analysis. Immature bugs of the different species had some compounds in common, and some that were more species specific. Within a species, there were distinct differences in the profiles of compounds extracted from first and second instars. Bugs did not aggregate around untreated polysulfone beads (1 mm diam) that were glued together in groups approximating bug egg masses, suggesting that tactile cues alone were insufficient to induce aggregation. Furthermore, when tested over a range of doses, groups of polysulfone beads treated with crude whole-body extracts of bugs did not induce or maintain aggregations. However, first instar N. viridula nymphs did respond to beads treated with two of the three major components of bug extracts. 4-Oxo-(E)-2-decenal induced significant aggregations at two doses, whereas tridecane, the major component in extracts from all six species, did not, and (E)-2-decenal was repellent. The repellence of (E)-2-decenal may explain why we and previous researchers were unable to induce aggregations of first instar N. viridula using whole-body extracts.

Animals↗
PubMed2005

Coordinated group response to nest intruders in social shrimp.

A key characteristic of highly social animals is collective group response to important stimuli such as invasion by enemies. The marine societies of social snapping shrimp share many convergences with terrestrial eusocial animals, including aggressive reaction to strangers, but no group actions have yet been observed in shrimp. Here we describe 'coordinated snapping', during which a sentinel shrimp reacts to danger by recruiting other colony members to snap in concert for several to tens of seconds. This distinctive behaviour is a specific response to intrusion by strange shrimp into the colony's sponge and is highly successful at repelling these intruders. Although coordinated snapping apparently functions analogously to alarm responses in other social animals, colony members in social shrimp do not rush to the site of the attack. Coordinated snapping appears instead to be a warning signal to would-be intruders that the sponge is occupied by a cooperative colony ready to defend it. This is the first evidence for coordinated communication in social shrimp and represents yet another remarkable convergence between social shrimp, insects and vertebrates.

Animal Communication↗
PubMedDate not supplied

Insecticide impregnation can restore the efficiency of torn bed nets and reduce man-vector contact in malaria endemic areas.

Three trials with torn bed nets impregnated with permethrin and deltamethrin were made under field conditions at the Soumousso Field Station and the Vallée du Kou rice-field area, both in Burkina Faso, and the Djoumouna fish pond area in the Congo Republic. Even a considerably torn correctly impregnated bed net could be an useful method for limiting human-anopheline contacts. But bed nets in poor condition, i.e. too little impregnated and too much torn, cannot protect the users against anopheline bites. Protection increases with insecticide concentration, but at a high dosage insecticide could have more a repellent than a killing effect. Therefore a balance has to be found for the optimum rate of insecticide treatment of bed nets to obtain a real reduction in malaria transmission and morbidity, in every epidemiological situation.

Animals↗
PubMed1990

Toxicity, sublethal effects, and performance of sulfluramid against the German cockroach (Dictyoptera: Blattellidae).

Topical and oral toxicity of sulfluramid (N-ethyl perfluorooctane sulfonamide) were determined for the German cockroach, Blattella germanica (L.). The topical LD50 of sulfluramid was 175.6 micrograms/g for adult males, 117.8 micrograms/g for adult females, and 122.3 micrograms/g for gravid adult females. Ingestion increased toxicity approximately 1.4 times for adult male B. germanica. Twenty-four hours after topical treatment with 20 micrograms/insect sulfluramid, the percentage of female cockroaches that dropped their oothecae increased approximately 50% compared with controls treated with acetone. Sulfluramid also decreased oothecal hatch of both dropped and retained oothecae. Approximately 90% of oothecae from untreated females hatches, whereas less than 20% hatched from females treated with 20 micrograms/insect. Mean time for oothecal hatch increased linearly with increasing sulfluramid concentration. In arena studies in Ebeling choice boxes, LT50's ranged between approximately 2.3 and 3.9 d for a 0.331 mg/cm2 deposit and a 1.5% bait, respectively. Higher concentrations of sulfluramid were more repellent in both bait and residual formulations. Performance index values indicated excellent potential field efficacy. Field trials with 1.0 and 1.5% (AI) baits showed up to a 71.3% reduction in cockroach numbers. Baits controlled cockroaches throughout the 12-wk test.

Animals↗
PubMed2003

House-scale evaluation of bifenthrin indoor residual spraying for malaria vector control in India.

In an area of India where the main rural malaria vector, Anopheles culicifacies Giles, has developed triple resistance to DDT, HCH, and malathion sprayed indoors in antimalaria program, bifenthrin (10% wettable powder) was evaluated in a randomized house-scale trial between July 1999 and March 2000. Entomological impact of four serial doses of bifenthrin (25, 50, 100, and 200 mg/m2) sprayed in rooms in five villages was compared with malathion (2 g/m2) and unsprayed control. An. culicifacies was 100% susceptible to bifenthrin (0.1%), but only 57% to malathion (5%) test papers. Contact bioassays were carried out on sprayed surfaces for 24 wk, and 24 h mortality in An. culicifacies was recorded. Bifenthrin 100- and 200-mg doses caused > or = 80% mortality until 24 wk. The 50-mg dose caused > or = 80% mortality on tin, wood, and mud surfaces for 24 wk, and on brick walls for 16 wk. Bifenthrin 25-mg dose produced > or = 80% mortality for 24 wk on tin, 20 wk on mud walls, 16 wk on brick walls, and 8 wk on wood surfaces. Persistence of > or = 80% mortality did not differ for 25- and 50-mg doses on any surface except on wood (P < 0.05). Malathion sprayed in three rounds of 6 wk apart caused > or = 80% mortality for 16 wk on the brick and mud walls, and for 20 wk on the tin and wood surfaces. Bifenthrin 25- and 50-mg doses produced a similar impact on the densities of An. culicifacies and other mosquitoes but a superior one to malathion or control. Bifenthrin 25-mg dose caused least excitorepellency. Overall, efficacy of bifenthrin was superior to malathion. Considering the duration of the persistence of significant insecticidal action of bifenthrin on the most common surfaces (mud and brick walls), least excito-repellency and a relative impact on the mosquito densities, the 25-mg dose was the most superior among all the four doses evaluated.

Air Pollution, Indoor↗
PubMed1979

[Economic significance of the prevention of losses caused by blood-sucking diptera in grazing dairy cows].

It was was demonstrated in an experiment that the blood-sucking dipterous insects adversely affected the efficiency of cows on pasture; these cows showed a significantly decreased milk yield and milk fat percentage. The experiment was conducted in South Bohemia at Chlum u Trebonĕ where seven species of gnats occurred in considerable abundancy, including the largest populations of Aedes sticticus (Meig.), Ae. cinereus Meig., Ae. vexans Meig. and Ae. punctor Kirby, which represented more than 80% of all gnats, and where gad-flies lived at the same time, represented by 18 species of five genera, chief among which were the species Tabanus bromius (L.) and T. maculicornis (Zett.), forming over 60% of all gad-flies. The experiment with 25 control dairy cows of the Bohemian Spotted breed lasted 62 days (July, August 1977). Diethyltoluamide in a 10% water emulsion was used as repellent with which cows were sprayed (with a special spraying apparatus) in 48h intervals. In the experimental (sprayed) cows, compared with the untreated control cows, milk yield per head per day increased by 6.23%, i. e. 43.56 kg milk, and butterfat percentage increased by 11,81%, representing 3.62 kg per head per day. In conversion to fat-corrected milk (milk with a constant 4% fat content), milk yield increased by 9.69%. In conversion to values per 1000 cows on pasture the net value of milk increased by 709.41 Kcs per day. The return rate of the money expended is 1.31 crowns. The results were statistically significant to highly significant.

Aedes↗
PubMed2001

Effects of nutritional and physiological status on behavioral avoidance of Anopheles minimus (Diptera: Culicidae) to DDT, deltamethrin and lambdacyhalothrin.

The monitoring of behavioral responses of mosquitoes to insecticides are critical to the understanding of how chemicals function in the control of disease transmission. The excito-repellency avoidance responses of laboratory-reared Anopheles minimus females exposed to diagnostic concentrations of DDT (2 g/m2), deltamethrin (0.0625 g/m2), and lambdacyhalothrin (0.0369 g/m2) were observed using an excito-repellency escape chamber. Insecticide contact (measuring irritancy) and non-contact (measuring repellency) behavioral assays were conducted on non-blood-fed (unfed), sugar-fed, early blood-fed (recently engorged) and late blood-fed mosquitoes. Rates of escape from the contact and non-contact chambers, regardless of chemical compounds, were most dramatic in unfed mosquitoes compared to other nutritional states (P < 0.05). In general, across all 3 chemicals, slower escape response was observed in sugar-fed and early blood-fed specimens, whereas late blood-fed showed an intermediate response. Relative suppression of escape flight response in comparison to matched non-insecticide treated controls and the unfed condition is likely the result of normal reduced flight activity among recent blood and sugar-engorged mosquitoes. We conclude that nutritional states and physiological conditions of mosquitoes as a result of blood feeding can dramatically influence excito-repellency test results. Therefore, for interpretive purposes, studies on chemical irritancy and repellency must account and control for the inherent variability of avoidance responses to insecticides influenced by nutritional and physiological conditions of the mosquitoes at the time of test.

Animals↗
PubMed2006

Effects of hydrophilic and hydrophobic kaolin-based particle films on pea aphid (Homoptera: Aphididae) and its entomopathogen Pandora neoaphidis (Entomophthorales: Entomophthoraceae).

Hydrophobic and hydrophilic kaolin-based particle films are effective for control of insect pests in certain agricultural crops. How these products interact with potential biological control agents is not well documented. This study was conducted to evaluate the effects of the hydrophobic (M96-018) and hydrophilic (Surround WP) kaolin-based particle films (Engelhard Corporation, Iselin, NJ) on pea aphid, Acyrthosiphon pisum (Harris), on peas (Pisum spp.), and on the fungal aphid pathogen Pandora neoaphidis (Remaudière and Hennebert) Humber. Over two field seasons (2001 and 2002) in northern Idaho, applications of M96-018 significantly reduced the rate of pea aphid increase on pea, but Surround WP, tested only in 2001, did not reduce aphid population growth rate. Neither particle film treatment was as effective as a standard application of esfenvalerate (DuPont Asana). In the laboratory, particle films suppressed pea aphid populations by up to 30%. M96-018 seemed to have some repellent activity based on aphid distributions after treating plants. When applied along with P. neoaphidis conidia, M96-018 but not Surround WP caused higher percentage of infection mortality of pea aphids by P. neoaphidis than occurred on controls treated only with P. neoaphidis conidia. P. neoaphidis conidia deposited on glass slides coated with M96-018, produced more germ tubes and secondary conidia than those deposited on untreated glass slides or slides treated with Surround WP. This result suggests that greater infection of pea aphids on plants treated with M96-018 is in part a result of a direct enhancement of fungal germination by the particle film.

Analysis of Variance↗
PubMed2006

The courtship-inhibiting pheromone is ignored by female-deprived gregarious desert locust males.

Gregarious mature males of the desert locust (Schistocerca gregaria) emit a courtship-inhibiting pheromone continuously to repel rivals. This signal evokes a strong response from males with recent experience of mature females. However, if males have been female deprived for some time, they start to ignore the pheromone and attempt to usurp females that are guarded by males. The probability and intensity with which males struggle for an occupied mate was found to depend on the time previously spent without a female. This adaptive behaviour is similar to the response to host-marking pheromones in phytophagous insects and parasitoids.

Analysis of Variance↗