Larval descriptions and biology ofTephritis dilacerata [Dip.: Tephritidae], a candidate for the biocontrol ofSonchus arvensis in Canada

Annals of the Entomological Society of America

1990

Descriptions are provided of the egg, larvae, and puparium of Paracantha gentilis Hering, a native, stenophagous tephritid which infests the capitula of thistles. Detailed examination of larvae led to the discovery of a median oral lobe between the mouth hooks. This is the first structure of this kind described for Tephritidae. Two sensory structures on the anterior lobes of P. gentilis also were discovered, the lateral sensory organ and the pit sensory organ. In comparing the anterior sensory apparatus of P. gentilis larvae with those in Anthomyiidae, Calliphoridae, Drosophilidae, Muscidae, and Syrphidae, striking similarities were apparent. Photographs that illustrate the development of the spiracular system of the puparial stage are the first offered for a nonfrugivorous tephritid.KEY WORDS Insecta, mouth hooks, sensory organs, Cirsium THIS STUDY is an outgrowth of faunistic surveys (Goeden & Ricker 1986) of the thistles Cirsium californicum Gray and C. proteanum J. T. Howell. In this report, we describe the morphology of the heretofore undescribed immature stages of Paracantha gentilis Hering; subsequent papers will treat its biology and ecology. Materials and MethodsAll immature stages were dissected from capitula of C. californicum collected at Mill Creek, San Bernardino National Forest, San Bernardino Co., Calif, from 25 April to 5 June 1987, and C. proteanum capitula collected from Sawmill Mt, Angeles National Forest, Los Angeles Co., Calif., on 29 July 1987. Eggs used to study eclosion were placed on filter paper soaked with Ringer's solution in covered glass Petri dishes and held in darkened growth chambers at 27°C. Other eggs and larvae were preserved in 70% EtOH for later examination. Puparia were dissected from heads, air-dried, then stored in capped, 6-ml glass shell vials.In preparation for scanning electron microscopy, all soft-bodied specimens were sonicated 20 min. Eggs were dehydrated to 95% EtOH overnight, placed in 100% EtOH for 5 min, and fixed in hexamethyldisilizane (Nation 1983). Larvae were placed in 2.5% glycerol and serially saturated to 100% glycerol (Sher & Bell 1975) or rehydrated through graded alcohols to distilled water, and fixed in osmium tetroxide for 24 h (Sabatini et al. 1963). All specimens were mounted on stubs and coated with a gold-platinum alloy. The scanning electron microscope used was a JEOL-JSM-35C3 in the Department of Nematology, University of California, Riverside. Specimens were examined and micrographs were prepared at 15 kV accelerating voltage, except for specimens in glycerol which were studied at 10 kV. Micrographs were prepared with Polaroid 55 P/N film.Third instars were dissected in 70% EtOH with 0.1% acid fuchsin for viewing the median oral lobe.Voucher specimens of P. gentilis are stored in the tephritid collection of the second author. This collection will eventually be offered for incorporation into the insect collection of the Department of Entomology, University of California, Riverside. ResultsEgg. The body of the newly laid egg is smoot...

Section: Resultsmentioning

confidence: 99%

Description of the Immature Stages of Paracantha gentilis (Diptera: Tephritidae)

Annals of the Entomological Society of America

1990

“…They never challenge ants feeding on capitula but, rather, continue their search for an unoccupied capitulum. Agonistic behavior of adult tephritids toward other insects in defense of territory or oviposition sites but not in defense of a food source has been reported by other workers; e.g., Tauber & Toschi (1965a,b), Prokopy & Bush (1973), Webb et al (1976), Berube (1978), and Batra (1979).…”

Section: Resultsmentioning

confidence: 61%

“…The wings occasionally were vibrated rapidly as they were brought forward. Wing extension also has been described in several other Tephritidae; e.g., Tauber & Toschi (1965a,b), Pritchard (1967), Prokopy & Bush (1973), Piper (1976), Berube (1978), Batra (1979), Prokopy & Hendrichs (1979), Cavender & Goeden (1983, 1984, and Goeden et al (1987). The rapidity of wing extension was variable and corresponded to the associated behavior; i.e., fast extension during apparently agonistic behavior.…”

Section: Resultsmentioning

confidence: 77%

Life History of Paracantha gentilis (Diptera: Tephritidae)

Annals of the Entomological Society of America

1990

The life history of Paracantha gentilis Hering in southern California is described. This stenophagous tephritid reproduces in the capitula of native Cirsium thistles. Courtship and mating behavior are described from field and laboratory observations. Territorial and courtship behavior of males and the morphological characters involved in possible male pheromone emission are described and illustrated, as are the oviposition behavior and reproductive morphology of females. Egg clutch sizes ranged from one to 13 eggs, with a maximum of six clutches per capitulum. Larvae fed gregariously within stage-specific niches. Pupariation occurred in the capitula, from which adults emerged in mid-June through early July. After emergence, most adults probably disperse to higher elevations to feed until autumn, then return to lower elevations and reproduce the following year. Limited reproduction also occurs in late-formed capitula or in capitula of alternate Cirsium hosts.

“…The aculeus may pierce plant tissues to gain access to a particular area for egg deposition; however, little necrosis of plant tissues usually results from such oviposition [see Goeden et al (39) for an exception]. Avoidance of physical damage to the host plant during oviposition is sometimes a factor if the host plant secretes resins or latex that might entrap the female, egg, or newly hatched larvae or might compromise egg respiration (6,88). These physical limits on egg laying also factor into the timing of oviposition (see below).…”

Section: Eggmentioning

confidence: 99%

The Biology of Nonfrugivorous Tephritid Fruit Flies

1998

Annu. Rev. Entomol.

This review is the first comprehensive treatment of the biology of nonfrugivorous fruit flies of the family Tephritidae. Feeding habits of destructive and useful species, morphology of immature stages, and hypotheses regarding structural homology and the evolutionary biology of nonfrugivorous tephritids are reviewed, including zoogeography and theories involving resource heterogeneity, guild structure, resource partitioning, resource utilization, facultative niche exploitation, extrinsic and intrinsic factors, host associations, seasonal distribution and phenology, aggregative and circumnatal life history strategies, voltinism, diapause, aestivation, oviposition site, clutch size, and supernumerary oviposition. PERSPECTIVES AND OVERVIEWThere is no comprehensive family-wide review of the biology of tephritid fruit flies. Reviews exist that focus on economically important taxa within the family (2,8,105,127), discuss regional faunas (9,14,20, 64,86,100,126), or treat one related subject such as gall formation by tephritids (18) or tephritids used in biological control of weeds (67,85,118,121). These reviews are extremely useful and taken together provide good coverage of the Tephritidae, except for a comprehensive picture of the biology and ecology of nonfrugivorous species.Our goal is to review important aspects of nonfrugivorous tephritid biology and ecology, to highlight relevant hypotheses that have been developed, and to suggest where future research may lead. Accordingly, we do not re-review the