Toxotrypana Curvicauda Research Articles

Natural Host Plant Survey of the Economically Important Fruit Flies (Diptera: Tephritidae) of Chiapas, Mexico

We provide a natural host-plant list of some of the fruit flies (Diptera: Tephritidae) reported for the State of Chiapas. Out of 92 plant species sampled, 39 species representing 12 plant families were identified as natural host of Anastrepha distincta, A. fraterculus, A. leptozona, A. ludens, A. obliqua, A. serpentina, A. striata and Toxotrypana curvicauda.

Host Plants of Fruit Flies (Diptera: Tephritidae) of Economic Importance in Guatemala

5,740 kg (1,897 samples) of fleshy fruits were harvested from 89 species of plants in 321 locations at various elevations in Guatemala, C.A., during 1979-84. Ceratitis capitata (Wied.) was recovered from 38, 5 species of Anastrepha from 37, Toxotrypana curvicauda from 1, and none from 46 plant species.

Oviposition of the Papaya Fruit Fly Toxotrypana curvicauda Gerstaecker as Affected by Fruit Maturity

A scale for assessing damage to papaya fruit by the papaya fruit fly Toxotrypana curvicauda Gerstaecker was used in the field to help detect egg and larval infestation. There were more eggs in green fruits than in ripe fruit, whereas more larvae were found in ripe fruit than in green fruit. Under laboratory conditions, papaya fruit fly preferred to oviposit in green papayas than in ripe fruit. In an experiment of the choice type, papaya fruit flies showed strong preference for oviposition in green wax domes than in yellow wax domes. The color preference of papaya fruit fly females was confirmed.

Feeding Behavior of Toxotrypana curvicauda (Diptera: Tephritidae) on Young Papaya Seeds

Toxotrypana curvicauda Gerstaecker (Diptera: Tephritidae), the papaya fruit fly, is a major pest of papaya fruits in tropical America and as such, attempts have been made to rear larvae of this fly on semiartificial media (R. M. Baranowski, personal communication). Such efforts have not met with success, partly because first instar larvae feed on young seeds in the fruit's cavity while later instars feed on fruit pulp (Knab and Yothers 1914). Since seeds may play an important role in larval nutrition and the subsequent development of rearing media, we studied the feeding preferences of first instar larvae for different papaya seed layers. The investigation utilized fruits and insects collected in Dade County, Florida, during May 1983. In a preliminary study, immature (10 cm diameter, green) papaya fruits were halved and newly hatched larvae (derived from eggs incubated at 260C+ 10C, 75% RH) were placed on the seeds. -The larvae were observed for one hour with particular attention paid to larval feeding behavior on the gelatinous endosperm, the testa (which surrounds the endosperm), and the exterior layer, the sarcotesta (Fisher 1980). Larvae penetrated the seeds in two ways: a) by excavating the micropylar region, or b) by cutting a 0.2-0.3 mm perforation in the sarcotesta. Thereafter, the sarcotesta was not eaten further but the testa and endosperm were consumed. Subsequent examination of infested fruit from the field confirmed that the bulk of sarcotesta is not consumed by larvae, whereas the testa and endosperm are. To test the preference of first instar larvae were placed on sarcotesta, testa and endosperm of bisected seeds. The seeds were taken from immature fruit and embedded cut side up in agar (3 g/200 ml) in covered petri dishes. Feeding activity was monitored at 0, 2, 8 and 24 hrs. Tests on each seed layer were replicated 12 times, with each replicate consisting of 1 individual/seed layer/petri dish. Twelve replicates were also run on whole seeds imbedded in agar. On intact seeds, only 8% of the larvae placed on intact seeds began feeding immediately (on the sarcotesta), but by 24 hrs 92% of the larvae had already penetrated the seed and were feeding on the endosperm. Larvae placed on the sarcotesta of cut seeds were seldom observed feeding on this tissue, with the most feeding activity at 8 hrs when 33% of the individuals were feeding: After'24 hrs, 50% of the larvae remained on the sarcotesta but were not feeding on it, 17% 'were on the sarcotesta and feeding on it and 33% had moved to agar for food. In contrast, the percentage of larvae feeding on the testa or endosperm ranged from 50-to 92% throughout the experiment. These results suggested that early first in'star larvae are discriminating feeders, preferring the testa and endosperm over'the sarcotesta. To test

The Form and Function of Acoustic Courtship Signals of the Papaya Fruit Fly, Toxotrypana curvicauda (Tephritidae)

The male papaya fruit fly, Toxotrypana curvicauda Gerstacker, makes two acoustic signals during courtship: (1) the approach consists of one to five pulse trains (sound bursts) and is directed at females prior to mounting; (2) the precopulatory consists of one to seven pulse trains produced immediately after mounting the female. Unlike the somewhat similar calling song of the Caribbean fruit fly, the papaya fruit fly's approach is monotonic, a character which may be due to an absence of selection for escaping vegetation-filtering. Virgin females, but not males, become less active in the presence of broadcast approach sounds, suggesting that the proximate effect of the is to depress locomotion in the female. Large males pair more often than small and the sound pressure level of large male approach songs is louder. Females may detect the size/vigour of a singer by his song, and such sounds may have evolved as sexually selected male advertisements rather than a means of species isolation.

Behavioral Responses of Female Papaya Fruit Flies, Toxotrypana curvicauda (Diptera: Tephritidae), to Male-produced Sex Pheromone1

Courtship interactions of the papaya fruit fly, Toxotrypana curvicauda Gerstaecker, were observed and described in the development of an arena sex pheromone bioassay. Females responded to male-produced volatile chemicals presented on filter paper in arena bioassays by walking, running, flying, bobbing the abdomen, and turning in circles. Significant responses were obtained at concentrations as low as 0.0004 male-h equivalents. In a wind-tunnel bioassay, females flew upwind to calling caged males, landed on the cages and bobbed their abdomens. Females responded to male odors piped into the upwind end of the tunnel from a glass chamber that contained calling males by flying upwind in the tunnel with a zigzagging flight pattern and hovering in the plume near the pipe vent.

Reproductive Maturation and Premating Period of the Papaya Fruit Fly, Toxotrypana curvicauda (Diptera: Tephritidae)

Female papaya fruit flies, Toxotrypana curvicauda Gerstaecker, obtained from field-infested papayas, Carica papaya L., required 5 to 6 days to develop mature ovaries comparable in size to those of ovipositing field-collected females. Younger females, with ovaries less than 0.25 cm long, were absent from papaya groves, suggesting that female papaya fruit flies do not search out host plants until mature. In mating tests females mated when 5 days old or older, while males mated at any age (one to 6 days after emergence) although mating rates were less with one-day-old males.

Reproductive Behavior of the Papaya Fruit Fly, Toxotrypana curvicauda Gerstaecker (Diptera: Tephritidae)

During field observations of papaya fruit flies, Toxotrypana curvicauda Gerstaecker, on papaya plants, most activity occurred in late afternoon and evening and was concentrated on or near fruit. Males mounted ovipositing or probing females in attempts to mate. Flies in a field cage generally mated when at least 6 days old. Oviposition occurred in all sizes of fruit available, as well as blossom buds, with multiple ovipositions in all fruit under both field and cage conditions. Males puffed the pleural areas of the abdomen during much of the day, possibly releasing pheromone.