Oviposition Devices Research Articles

Evaluation of synthetic oviposition stimulants to enhance egg collection of the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

Tephritid flies are pests of horticultural importance throughout the globe. The oriental fruit fly, Bactrocera dorsalis (Hendel), is particularly feared because it attacks many commercial fruits and vegetables causing huge economic losses. The sterile insect technique (SIT) can be an effective, target-specific and economically feasible control method. However, implementation of SIT depends on mass production of high-quality insects. Production of superior quality eggs is of foremost importance in insect mass production. However, present protocols make use of fruit juices or fruit domes that attract saprophytic insects or microorganisms, reducing the quality of eggs. Furthermore, fermentation of juices is known to decrease oviposition efficiency, and daily sanitation of oviposition devices is required. Here, in a laboratory-scale study, we evaluate the effectiveness of four synthetic oviposition stimulants (OS) of B. dorsalis for egg production in dual choice tests, using oviposition devices similar to those used in mass rearing. Results indicated that γ-octalactone, benzothiazole, octen-3-ol and ethyl tiglate significantly increased egg laying compared to controls (water). Of these, γ-octalactone was particularly effective and elicited a 263-fold increase in oviposition on treated oviposition devices compared to control. Our findings demonstrate the potential of using OSs to improve the efficiency and cost effectiveness of mass production of B. dorsalis.

Collection of host-marking pheromone from Rhagoletis mendax (Diptera: Tephritidae)

AbstractBlueberry fruit fly, Rhagoletis mendax Curran (Diptera: Tephritidae), females deposit a host-marking pheromone (HMP) on the surface of fruit immediately after oviposition that deters oviposition by female conspecifics. We collected this HMP from artificial oviposition devices and faeces. In subsequent two-choice bioassays, gravid females showed a strong preference for untreated oviposition devices as compared to those treated with extracts from either of these two sources. The methods described for collecting HMP of R. mendax will be useful for its eventual identification and synthesis, with potential applications in R. mendax management.

Effectiveness of Metarhizium anisopliae formulations against dengue vectors under laboratory and field conditions

ABSTRACTThe oviposition behaviour of Aedes aegypti and the effectiveness of Metarhizium anisopliae conidia formulated in water or oil-in-water against A. aegypti adults and eggs were tested in multi-choice and no-choice tests in oviposition devices under laboratory conditions. Both females and males rested in the devices, regardless of the formulation, and were not repelled by the presence of conidia (up to 106 conidia/cm2) without oil or formulated with oil on treated filter paper arranged in the device. However, at higher oil concentrations (≥0.1 μl/cm2), regardless of the presence of conidia, the number of eggs laid by gravid females on the filter paper dropped. The susceptibility of adults, especially of males, to fungal infection increased up to a 15-day incubation. An elevated number of larvae (≥41%) eclosed from eggs laid on the moistened filter paper in the device even without submersion of eggs in water, and these larvae subsequently died. In the laboratory, 1 μl/cm2 oil combined with 106 conidia/cm2 clearly reduced eclosion to 1.8% after submersion of eggs in water compared to ≥13% eclosion in the control. In field tests in Goiânia, Brazil, eclosion of aedine larvae from eggs laid on filter paper previously treated with oil-in-water formulated conidia dropped to between 0% and 36% compared to 22–50% in the control. Promising results of laboratory and field tests with M. anisopliae formulated in water or oil-in-water and tested in a device emphasised the effectiveness of a fungus-based formulation for aedine mosquitoes in peridomestic areas.

Mass Production Cage forAedes albopictus(Diptera: Culicidae)

Mass production is an important co mponent of any pest or vector control program that requires the release of large number of insects. As part of efforts to develop an area-wide program involving the sterile insect technique (SIT) for the control of mosquitoes, the Insect Pest Control Laboratory of the Food and Agriculture Organization-International Atomic Energy Agency (FAO-IAEA Joint Division) has developed a mass production cage (Aedes MPC) for brood stock colonies in a mass production system for Aedes albopictus (Skuse, 1895). A preliminary experiment using Plexiglas cages was carried out to estimate the impact of cage volume on egg productivity. Transparent Plexiglas cages of different dimensions but loaded with the same adult density were tested. Egg productivity (number of eggs laid per adult female) and adult survival were recorded and analyzed. According to the results, the optimal volume of 100 liters has been chosen to develop the Aedes MPC. The numbers of adults introduced into the Aedes MPC did not affect the egg production and adult survival in comparison with the Plexiglas cage experiment data, confirming the possible use of Aedes MPC for mass-rearing procedures. Finally, the modification of Aedes MPC and creation of a new prototype model of MPC (Anopheles MPC) to effectively contain Anopheles arabiensis (Patton, 1905) adults is discussed with major changes pioneered to oviposition devices and systems for automatic collection of the eggs.

Are citrus species favorable hosts for the Mediterranean fruit fly? A demographic perspective

AbstractWe studied, under laboratory conditions, demographic parameters of adult Mediterranean fruit flies,Ceratitis capitata(Wiedemann) (Diptera: Tephritidae) (medfly), obtained from three sweet orange varieties, lemon, and bitter oranges. These data were combined with immature developmental rates and survival on the same hosts to estimate host‐specific population parameters. Pairs of newly emerged adults from each citrus variety were held individually in transparent plastic cages, and females were allowed to oviposit in either red domes (artificial, pre‐punctured plastic oviposition devices), or intact, whole citrus fruits. We found strong effects of larval host (citrus fruits) on adult longevity and fecundity. In all five citrus varieties, females did not manage to deposit eggs into fruit pulp. The proportion of eggs laid in either the flavedo or albedo area of the fruit peel differed depending on the citrus variety. In all cases except bitter oranges, females oviposited fewer eggs in citrus fruits than in the artificial oviposition substrates, suggesting that most citrus fruits cause a significant reduction in the reproductive potential of medflies. Negative correlations were found between fecundity and (a) the density of oil glands, and (b) the amount of essential oils in the flavedo area of citrus fruits. There was no correlation between fecundity and other fruit physical characteristics, such as resistance of fruit peel to pressure and thickness of the flavedo. Apparently, resistance of citrus fruits to medfly infestation is directly related to citrus essential oils. The intrinsic rate of increase (r) was higher in bitter oranges than in the three sweet orange varieties tested. A negative r was estimated for flies that developed and oviposited in lemons, indicating a tendency for population decrease in this host. The suitability of citrus fruits for medfly development and the practical implications of our findings for management of medflies in citrus orchards are discussed.

Mass Rearing of Anastrepha fraterculus (Diptera: Tephritidae): A Preliminary Strategy

The South American fruit fly, Anastrepha fraterculus (Wiedemann), occurs from Mexico to Argentina and attacks some 80 species of host plants, including mango, citrus, guava, apple and coffee (Da Silva et al. 1996). In extensive fruit producing regions of Uruguay, Argentina and Peru, the only two fruit fly species of economic and quarantine importance areA. fraterculus and the introduced Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Manso & Lifchitz 1992). Unfortunately, there is as yet no environmentally friendly and effective strategy as Sterile Insect Technique (SIT) to use against A. fraterculus. If no reliable and economic methods were found, any possible benefits from C. capitata control in areas where it is sympatric with A. fraterculus, would be greatly reduced. The ability to massrear A. fraterculus is the key to development of SIT. At the A. fraterculus mass rearing Workshop held in 1996 at Vinia del Mar, Chile, various participants from Argentina, Brazil, Colombia and Peru reported on their efforts to rear this fruit fly under laboratory conditions (Ortiz 1999). It was agreed that the main limiting factor to successful mass rearing was the need to develop a technique that would promote effective oviposition, facilitate collection of the eggs, and assure maximum fertility of the eggs (Salles 1992, 1999) Here we describe a new method to potentially mass-rear A. fraterculus that produces high egg fertility and allows eggs to be collected easily with a minimum handling. REARING ROOM: Rearing conditions were 23 ? 2?C and 60-80% R.H., light intensity ranged from 4,000 to 5,000 lx, with a photoperiod of 12:12 (L:D). CAGES: The colony was kept in iron-framed cages (0.96 x 0.60 x 0.30 m), with a front and rear panel. The rear panel was covered with a fabric (voile) with 25 holes per linear centimeter. The front panel was made of the same fabric coated with a thin layer of transparent silicon rubber (0.5 mm thickness). This panel is very similar to that used for A. obliqua in Mexico (Dominguez, 1998). One or 2 days before emergence, 8,500 pupae were placed in each cage. After 10-14 days adults mated and begun oviposition. Adults were kept in the cages for 40 days. EGG COLLECTION: Females laid their eggs through the oviposition panels onto foam rubber sheets (0.01 x 0.90 x 0.60 m), which were moistened with a mixture of water and peach juice (3:1) to avoid the dehydration and to attract females to oviposit. After 24 h the foam rubber sheets were taken out and washed in water to collect the eggs. The eggs were placed in a wet chamber (petri dishes with wet filter paper in the bottom) and kept at a temperature of 23-260C until hatching. After 48 h the eggs began to hatch. LARVAL DEVELOPMENT: The diet described by Salles (1992) was used with the addition of streptomycin sulfate at rates of 1 g per thousand to avoid bacterial contamination. Two hundred grams of diet was poured over the trays (18 x 12 cm) 2 cm deep. After 48 h the eggs were placed on the larval diet at a density of 8 to 10 eggs per gram of diet. The trays were placed in racks and covered with a fine voile mesh to prevent contamination by Drosophila spp. Wet sand was incorporated in the bottom of the racks. The larvae developed in the diet and, 16 days later, they crawled out of the trays and buried in the sand to pupate. PUPATION: The pupae were collected and maintained, in a small container with sterilized wet sand. Fifteen days later they were introduced in cages to begin a new cycle. ADULTS: Adults were maintained on a mixture of yeast hydrolyzed enzymatic 10 g; corn protein 10 g; sugar 40 g; water 50 ml; vitamins (Dayamineral, Abbott) 500 mg; aminoacids (Aminocefa 5%, Roux Ocefa) 1 ml. Water was also supplied to the adults. This rearing has been carried out over 18 generation (F18) without problems. QUALITY CONTROL: The quality of insects was assessed using some of standard quality control based in IAEA, USDA, FAO Quality Control publication (IAEA, USDA, FAO. 1998) and Orozco et al. (1983). REARING PARAMETERS: Results of tests mentioned above are shown in Table 1.The main differences between our rearing technique and 3 previously published methods are shown in Table 2. The four rearing techniques used different oviposition devices. Nuniez & Guzman (1999) and Salles (1992, 1999) used colored hemispheres or domes to attract the female fruit flies and to stimulate oviposition, but they had to be placed inside the cage, which made handling difficult. Using

Artificial Oviposition Sphere for Mediterranean Fruit Flies (Diptera: Tephritidae) in Field Cages

Colored, polyethylene plastic balls were modified to serve as oviposition devices for a laboratory strain of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), in the laboratory and the field. In outdoor field cages, large balls (100 mm diameter) yielded significantly more eggs than small balls (25 mm diameter) for all four colors tested (black, red, yellow, and blue). Blue and yellow balls yielded fewer eggs than black or red balls for small and medium (50 mm diameter) sizes, whereas numbers oviposited in black, red, and yellow spheres were not significantly different for numbers laid in the large size. Twice as many eggs were laid into large balls when guava juice was used as an attractant as compared with water. Large black or red balls with guava juice gave roughly as many eggs as did ‘Golden Delicious’ apples, and three times as many eggs as did ‘Red Delicious’ apples. Laboratory flies oviposited three times as many eggs into large yellow balls with guava juice as did wild flies reared in fruit.

γ線照射されたウリミバエＤａｃｕｓ ｃｕｃｕｒｂｉｔａｅの産卵行動

Oviposition behavior in non-irradiated and irradiated melon fly, Dacus cucurbitae COQUILLETT, was studiedunder laboratory conditions. A few irradiated female melon flies inserted their ovipositors into slices of host fruits (melon and watermelon) and artificial oviposition devices. The quantity and frequency of ovipositional “acts” for irradiated flies was much lower than that of the non-irradiated ones. “Number” indicates the quantity of females which engaged in oviposition behavior per 1, 000 females per 15min. “Frequency” indicates the total number of acts in varying behavioral modes per 1, 000 females per 15min.

Oviposition-deterring, Male-arresting, Fruit-marking Pheromone in Rhagoletis cerasi13

Females of the European cherry fruit fly, Rhagoletis cerasi L., deposit a pheromone (or a complex of pheromones) immediately after oviposition by dragging their extended ovpositor over the surface of cherries or artificial oviposition devices. The function of this pheromone is the prevention of repeated oviposition in already infested oviposition sites, thus assuring a uniform egg dispersion among available fruits. Apparently it also plays a role in sexual behavior by functioning as a male arrestant. The pheromone is soluble in water and methanol, persisting at least 12 days on the fruit surface under laboratory conditions. Chemotactile but no long-range olfactory mechanisms appear to be involved in its perception by the flies. A simple bioassay and a method to collect pheromone solutions by using artificial oviposition devices is described.

Artificial Egging System for the European Cherry Fruit Fly2

A simple technique is described for mass production and employment of plates of large numbers of ceresin wax domes as oviposition devices for Rhagoletis cemsi (L.). During their lifetime, 50 females deposited 12,903 eggs into these domes (an average of 258 eggs per female, yielding 234 larvae per female). This production proved 3-4 times greater than that from 2 other egging systems in current use and 1.6 times greater than the highest reported in the literature using fresh cherries as the oviposition medium. Individual ceresin domes had a remarkable longevity and retained 100% of their maximum potential effectiveness after receiving 50 eggs each and 68% of their potential even after 200 eggs each.

Factors Influencing Effectiveness of Artificial Oviposition Devices for Apple Maggot1

Paraffin-petrolatum domes or Parafilmed® wire hemispheres developed as oviposition devices for the apple maggot, Rhagoletis pomonella (Walsh), were more effective (l) when used in cages shaded from direct light than when in unshaded cages; (2) when positioned on the cage floor and upright than when 13 cm above the floor or inverted; and (3) when baited with pre-ripe, crisp chunks of apple than when baited with fresh juice from such apples, apple cider, apple essence, or unbaited, Adults in unshaded cages appeared more excited and died earlier than adults in shaded cages. Paraffin-petrolatum domes were more effective (1) when formed with a smooth, rather than an irregular outer surface; (2) when colored with the largest amount of blue dye tested (short of that affecting the consistency of the paraffin-petrolatum mixture); and (3) when formed with the largest mesh size of cheesecloth tested. Wire hemispheres surfaced with 5 layers of Parafilm were more effective than those with 1 or 10 layers. When the most favorable levels of each of these factors were incorporated into a single experiment, a mean of 217.1 eggs per female (yielding 181.5 larvae) was obtained using paraffin-petrolatum domes and 133.9 eggs per female (yielding 117.8 larvae) using Para filmed wire hemispheres. Oviposition was at its peak when the adults were 4-6 weeks old; some continued to lay viable eggs even when 20 weeks old. Under the most favorable conditions, females lived an average of 69 days and males 60 days. An inadvertent increase in the relative humidity in some cages from the normal level of circa 51% to that of 85% or more resulted in earlier death of many adults. When moisture began to condense on the outer surface of the oviposition devices, females did not oviposit.

Artificial Oviposition Devices for Apple Maggot

An oviposition medium other than apple could facilitate both the mass rearing of the apple maggot, Rhagoletis pomonella (Walsh), and investigations of its fecundity. This paper deals with the development of 2 types of quite satisfactory artificial oviposition devices for this insect.