Vero Beach Research Articles

Evidence for Allee effects in an over-harvested marine gastropod: density-dependent mating and egg production

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 202:297-302 (2000) - doi:10.3354/meps202297 Evidence for Allee effects in an over-harvested marine gastropod: density-dependent mating and egg production Allan W. Stoner*, Melody Ray-Culp** Caribbean Marine Research Center, Lee Stocking Island Field Station, Exuma Cays, Bahamas Present addresses: *Fisheries Behavioral Ecology Program, Alaska Fisheries Science Center, NOAA, National Marine Fisheries Service, 2030 S. Marine Science Dr, Newport, Oregon 97365, USA. E-mail: al.stoner@hmsc.orst.edu **The Environmental Learning Center, 255 Live Oak Dr, Vero Beach, Florida 32963, USA ABSTRACT: Conservation programs often focus on studying extinction risks encountered by small populations and determining minimum population sizes below which they cannot recover. In certain cases, per capita rates of population growth become negative at low population density. This ŒAllee effect¹ (or Œdepensation¹) is rarely considered in marine systems. We conducted surveys of adult density, reproductive behavior, and spawning in natural populations of Caribbean queen conch Strombus gigas at 2 locations in the Exuma Cays, Bahamas, to test for Allee effects. Mating never occurred when density was <56 conch ha-1, and spawning never occurred at <48 conch ha-1, clearly demonstrating the operation of depensatory mechanisms. Reproductive behavior then increased rapidly to asymptotes at densities near 200 conch ha-1. Heavily exploited populations of queen conch in the Caribbean have been slow to recover despite fishery closures. Failure to recover could result from spawning stock densities that are reduced to the point at which Allee effects begin to operate on reproductive behavior. KEY WORDS: Conservation · Depensation · Fisheries management · Reproduction · Spawning · Strombus gigas Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 202. Online publication date: August 28, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.

Costs of reproduction and geographic variation in the reproductive tactics of the mosquito Aedes triseriatus.

The eastern treehole mosquito, Aedes triseriatus (Say), was used in two experiments testing assumptions and predictions of life history theory. Experiment 1 employed direct, phenotypic manipulations of reproductive investment (blood meal mass) to test for a physiological cost of reproduction expressed as reduced longevity with increasing reproductive investment. As predicted, A. triseriatus from Vero Beach, Fla., showed costs increasing with investment in reproduction, but mosquitoes from Ashland, Va., showed the opposite response. This difference in apparent costs of reproduction may influence patterns of reproductive investment documented in the second experiment. To test the hypothesis that different predator-induced expected mortality rates among juveniles result in different patterns of reproductive allocation, we compared the allocation tactics of A. triseriatus from eight geographic populations, four sympatric with and four allopatric to the predatory mosquito, Toxorhynchites rutilus (Coq). Path analysis identified a phenotypic trade-off between offspring size and number, supporting this fundamental assumption of life history theory. Analysis of covariance revealed significant variation among populations in replete blood meal mass, reproductive output per unit blood meal mass (both measures of reproductive investment), mean egg mass, and egg number, although intrapopulation variation greatly exceeded interpopulation variation for all traits. Despite this variation among populations, there were no consistent or significant differences between populations sympatric vs. allopatric to the predator T. rutilus. This experiment therefore fails to support the hypothesis that greater mortality of juveniles should be associated with greater offspring size, lower offspring number, and lower reproductive investment. Our results are interesting, however, because they suggest that reproductive investment, reproductive output, and the trade-off between offspring size and number may evolve independently in this system.

A dilemma on Orchid Island.

“Ah, Indian River country,” remarked Theodore Conrad as he drove the car rental southward to Vero Beach. “Our favorite vacation spot,” affirmed Elizabeth. “I was just thinking about a potential public health conundrum that might take place in this part of the world,” added Theodore. “Tell us about it,” pleaded Thaddeus and Alexandra from the back seat. “With pleasure….” At the wheel of his new silver Volvo sat Seymour Lavin. Sy and his new bride, Joyce, were headed south on US 1 to their new home in Orchid Island. They had just left the Blue Gull Marina in Sebastian, where they had enjoyed a lunch of charbroiled shrimp over endive with balsamic-based vinaigrette and a bottle of their favorite California Chardonnay. With the solitude provided by closed windows and the stereo featuring a Mozart concerto, Sy and Joyce each quietly contemplated the future. Sy had a new lease on life, a new bride and a new home. He had finally come to grips with the loss of Ruth, his first wife, and her painful battle with the ravages of metastatic breast carcinoma. For more than a year after Ruth’s passing in 1994, Sy had been severely depressed, seemingly lost without his soulmate and partner. He had been unable to concentrate on his successful real estate business in Chicago. He barely coped with life. However, his grief had been assuaged 18 months later when he met 31-year-old Joyce through a mutual friend. A physical therapist, Joyce was bright, vivacious and sensitive. Her attentiveness, engaging personality and feminine charms had restored Sy’s peace of mind, and he felt like a young man again. Sy and Joyce were married on December 15, 1996, and chose to spend their winter months at their new home on the shores of Orchid Island in central Florida. …

Observations on the Oviposition Process of Diaprepes abbreviatus (Coleoptera: Curculionidae)

A single adult Diaprepes abbreviatus L. was discovered in a citrus nursery in Orange County Florida (Woodruff 1964). D. abbreviatus was not collected again until 1968, when larvae were collected at the same nursery and several hundred adults and larvae were subsequently collected in and around Apopka, FL (Woodruff 1968). Since its introduction in 1964, D. abbreviatus has spread to 20 counties in Florida, where it currently infests approximately 164,000 acres (66,420 ha) (Anonymous 1997). This area contains approximately 30,000 acres (12,150 ha) of infested commercial citrus and has a limited and localized geographical distribution. D. abbreviatus is an insidious pest; tree symptoms may not appear until the larvae are well established on the tree roots (Wolcott, 1936). Adults feed on young foliage, females lay egg clusters between leaves, and the larvae feed on the roots of a host (Fennah 1942, Jones 1915, Wolcott 1936, Woodruff 1968). Oviposition by D. abbreviatus appears to be restricted to nighttime hours (Jones 1915, Schroeder 1981, Wolcott 1936). Females oviposit approximately 60 egg masses during their lifetime which may contain from 30 to 260 eggs each and an average of about 5,000 eggs over their life span (Wolcott 1936). Wolcott (1933) observed that female D. abbreviatus preferred to oviposit between paper strips compared to leaves. Neonate larvae failed to emerge from these strips (Wolcott 1933). Fennah (1942) found that D. abbreviatus preferred paper strips over tin foil strips and mature leaves which were both favored over immature leaves for oviposition. Immature leaves are preferred feeding sites (Jones 1915, Wolcott 1936). Adair et al. (1998) reported that freezer paper strips might serve as a potential oviposition trap in citrus. Adult D. abbreviatus were field collected in Vero Beach, Florida and maintained as previously described (Adair et al. 1998). Thirty females and 30 males per cage were held in 30 x 30 x 60 cm aluminum rearing cages (Bioquip Products, Gardena, CA 90248-3602) at 27 ? 2?C, 30% RH and photoperiod of 11:13 (L:D). Five 2.54 cm x 15.24 cm doubled strips of transparency film (polyester, Labelon, Canadaigua, NY 14424) were provided for oviposition sites. At 10:00 PM, transparency film strips containing an ovipositing female were removed to a microscope stage for observation and photographing. Microscopic observations were conducted with an Olympus S2-6045 zoom stereo microscope with a 100AL 0.5x objective lens, lOx eyepiece and a NFK 2.5 x LD 125 lens and Olympus S2-PT (with L-adapter) adapter for a SLR camera. An Olympus OM 2S camera with automatic shutter speed and f-stop was used with Kodak Kodacolor 400 Gold? film. The transparency film strip with an ovipositing female was placed across an open Petri dish and illuminated above and below with a tungsten halogen lamp (Olympus Highlight 3000) equipped with bifurcating cold fiber optic goose neck

Progress in Controlled Maturation and Spawning of Summer Flounder Paralichthys dentatus Broodstock

Abstract— Wild‐caught, adult summer flounder Paralichthys dentatus (avg. wt. = 740 g; range = 264–1,540 g; N= 60), collected in northeastern US coastal waters during October 1994, were transported to Vero Beach, Florida in March 1995 and held in 2.6‐m3 indoor tanks through November 1995 under two artificial photothermal regimes: (1) natural regime, simulating natural habitat conditions; and (2) accelerated thermal regime, with seasonal temperature changes advanced by one month. A third group of fish was held in outdoor tanks under ambient photothermal conditions. Under all photothermal conditions, onset of vitellogenesis was associated with declining daylength and temperature, beginning in the accelerated group, then progressing to the natural and the ambient groups. From 20 September to 28 November 1995, 23 vitellogenic stage females from the accelerated and natural regimes were implanted with a cholesterol‐cellulose pellet containing LHRH‐a (100 μg/kg body wt). Females with initial mean oocyte diameters ranging from 258–456 μm spawned voluntarily 2.5–5.5 d postimplantation, while no maturational response was obtained from females with mean diameters ranging from 165–231 μm. Two females were spawned twice during the study period by LHRH‐a pellet implantation. Infrequent, natural spawning without hormone intervention was also obtained. Females released from 22.7–396.9 × 103 eggs on the first day of spawning, with fertilization and hatching rates of 0–93.470 and 0–81.1%, respectively.

Interrupted blood feeding by Culex (Diptera:Culicidae) in relation to individual host tolerance to mosquito attack.

Field studies at Delta Marsh (1991) and Winnipeg (1993), MB, and Vero Beach (1992), FL, examined variation among individual quail hosts in terms of the blood-feeding success by mosquitoes that fed on them. Culex tarsalis Coquillett was the predominant species collected in box traps baited with 2 quail at Delta Marsh in 1991, Culex nigripalpus Theobald was the predominant species collected at Vero Beach in 1992, and both Cx. tarsalis and culex restuans Theobald were collected in approximately equal numbers at Winnipeg in 1993. In 48 of 70 samples, blood feeding was skewed significantly from an even distribution between the 2 quail in each trap. In 5 of 13 samples of Cx. tarsalis collected in 1991, incomplete feeding (proportion of blood meals < or = 1/2 full) was from 2 to 8 times more likely on one bird relative to the other. In 7 of 13 samples of Cx. nigripalpus collected in 1992, incomplete feeding was from 2 to > 10 times more likely on one bird relative to the other. Incomplete feeding was from 2 to > 10 times more likely on one bird relative to the other is 7 of 11 mixed Cx. restuans/Cx. tarsalis samples collected in 1993. The probability that a given quail would interrupt a feeding mosquito was correlated negatively with the probability of the same quail being fed on. The proportion of detectable multiple meals in a given trap night was correlated negatively with the degree to which the distribution of blood meals in each trap night was skewed away from 0.5 on each bird. Individual quail varied significantly in terms of the blood feeding success of mosquitoes that fed on them.

Rate of Removal of Fenoxycarb (Logic®) Fire Ant Bait by Red Imported Fire Ants (Hymenoptera: Formicidae) from Treated Pastures

Field studies were conducted in Vero Beach, FL, in November 1993 and 1994 to determine the rate of removal of Logic® fire ant bait by red imported fire ants, Solenopsis invicta Buren, from treated improved pastures of bahiagrass, Paspalum notatum Fluegge. Logic® fire ant bait was applied at the maximum label rate of 1.68 kg/ha (16.8 g ai/ha). In 1993, fire ants had removed approximately 35% of the granules by 4 h after application and about 67% by 12 h. By 24 h, 82% had been removed. By the last count (48 h after application) about 95% had been removed. In 1994, the granules were removed slightly faster, with about 60% removed by 4 h and 92% by 24 h after application. Nearly 97% of the granules had been removed by the last count (30 h after application). In 1993, several mounds of the ant, Dorymyrmex bureni Trager, were found in the test area while in 1994 only red imported fire ant mounds were present. The results indicate that Logic® fire ant bait is found and harvested very rapidly by fire ant workers under favorable foraging conditions and that a dose which will provide effective population reduction can be obtained in 12 to 24 h after application at 1.68 kg/ha. Additionally, with its low use rate, specificity to certain insects and rapid removal by fire ants, Logic® fire ant bait when used according to label poses minimal risk to non-target organisms.

5439821 DNA encoding peptide hormone that inhibits digestion in insects : Borovsky Dov; Carlson David A Vero Beach, FL, United States assigned to University of Florida Research Foundation; The United States of America as represented by the United States Department of Agriculture

5439821 DNA encoding peptide hormone that inhibits digestion in insects : Borovsky Dov; Carlson David A Vero Beach, FL, United States assigned to University of Florida Research Foundation; The United States of America as represented by the United States Department of Agriculture

Recent developments in membrane water reuse projects

There is increasing interest in the use of membrane processing of wastewater for reuse as industrial process water, groundwater recharge, and irrigation. Status reports are presented on six current projects. The 1 mgd San Pasqual, California facility processes municipal effluent for irrigation. The 0.2 mgd Vero Beach, Florida facility processes secondary municipal effluent for reuse as boiler makeup for a power plant. The 0.13 mgd Mexico City, Mexico facility will process secondary municipal effluent for reuse by a tree farm that will raise 30 million pine seedlings per year to reforest the region. The 0.75 mgd Livermore, California demonstration project will process municipal effluent for groundwater recharge and irrigation with proposed eventual expansion to about 6 mgd. The 0.05 mgd Scottsdale, Arizona pilot facility will process secondary municipal effluent for ground water recharge and irrigation with proposed full-scale expansion in stages to about 40 mgd. The 1.1 mgd Chandler, Arizona facility will process industrial effluent from a semiconductor chipmaking facility for reuse.

Reclaimed Wastewater Irrigation and Fertilization of Mature `Redblush' Grapefruit Trees on Spodosols in Florida

An experiment was designed to determine the effects of canal water and reclaimed wastewater on growth, yield, and fruit quality of mature (25-year-old) `Redblush' grapefruit (Citrus paradisi Macf.) trees on sour orange (C. aurantium L.) rootstock. The study was conducted from 1 Oct. 1990 to 18 Apr. 1994 at a site adjacent to the Indian River County municipal wastewater treatment facility located near Vero Beach, Fla. Treatments included canal water applied based on one-third or two-thirds soil water depletion and reclaimed wastewater applied using microsprinklers at 23.1 mm/week (low), 30.7 mm/week (moderate) and 38.6 mm/week (high). Trees receiving low and moderate levels of reclaimed wastewater had the largest canopies and trunk diameters and highest yields, even though the amount of fertilizer applied was less than that of canal water plots. Leaf nutrient levels were generally within acceptable ranges for N, P, K, Ca, Mg, and Na except in 1991 when levels were deficient due to excessive rainfall and leaching. Leaf B levels were similar for all reclaimed wastewater treatments but were lower for the canal water treatment in 1992 and 1993. Fruit growth rate, fruit and juice weight, total soluble solids (TSS), titratable acidity (TA), and TSS: TA ratio were similar for all treatments in 2 of 3 years. Peel thickness was similar for all treatments. Heavy metal concentration in the reclaimed wastewater was at low or nondetectable levels. Similarly, enteric viruses in the effluent were always &lt;0.003 plaque forming units/liter. Reclaimed wastewater irrigation significantly increased weed growth compared to the canal water treatment.

Proposals for a new classification of iridescent viruses

The need for comparative studies of iridoviruses to elucidate the relationships between them has been well appreciated. Sixteen iridoviruses, including type species from each of the four recognized genera of the Iridoviridae, were compared by restriction endonuclease characterization, hybridization to the major structural protein (MSP) gene of an invertebrate iridescent virus (IV) isolate at various stringencies, PCR amplification of the MSP gene region and by dot-blot hybridization studies. The results broadly supported previous serological studies. The vertebrate iridoviruses, frog virus 3 (genus Ranavirus) and flounder lymphocystivirus (genus Lymphocystivirus), appeared distinct from one another and from the invertebrate isolates. Naming and numbering invertebrate IV isolates according to history and host is no longer useful since IVs infect a number of species. A revised system, involving names based on the geographical origin of the isolate is proposed, in line with other virus families. The large IVs of invertebrates represented by Vero Beach IV (previously IV3 or mosquito IV; genus Chloriridovirus) showed little similarity to any other IVs. Members of the genus Iridovirus, the small invertebrate IVs, fell into three distinct groups of interrelated isolates. The largest group, containing the Plowden (IV1), Tia (IV2), Nelson (IV9, IV10 and IV18), Aberystwyth (IV22), Srinagar (IV24), Fort Collins (IV29) and Stoneville (IV30) iridoviruses, is named the Polyiridovirus complex. The Plowden iridovirus (IV1) is suggested as type species for this complex given the data available on its molecular biology. Based on previously published data, Timaru (IV16 and IV19) and Uitenhage (IV23) iridoviruses are also assigned to this complex. The second but smaller group is named the Oligoiridovirus complex, which includes Dazaifu (IV6) as the type species and contains Ntondwe (IV21 and IV28) on a tentative basis. Riverside IV (IV31) was distinct from both of the other groups, and is proposed as a third complex, Crustaceoiridovirus.

267 RECLAIMED WATER EFFECTS ON LEAF, SOIL AND SOIL SOLUTION NUTRIENT LEVELS OF GRAPEFRUIT

A field study was conducted on mature `Redblush' grapefruit trees (Citrus paradisi Macf.) on sour orange (Citrus aurantium L.) rootstock from 1991 to 1993 near Vero Beach, Fla. on poorly drained (flatwoods) soil to determine the effects of reclaimed water on leaf, soil and shallow well-water nutrients. Treatments consisted of a canal water applied based on soil moisture depletion, and reclaimed water applied at 23.1, 30.7 and 36.6 mm/wk. Reclaimed water treatments received supplemental fertilization in addition to the N present in the water. All treatments received about 130 kg/ha/yr N. Leaf tissue N, P, K, Ca, Mg and Na concentrations were similar for all treatments, but B concentrations were significantly higher for the reclaimed water treatments in 1991 and 1993. Soil P and Na concentrations also increased in the reclaimed water treatments. Water samples taken from shallow depth wells showed that reclaimed water treatments had lower levels of NO, compared to the control possibly due to leaching. Reclaimed water contained only trace or undetectable levels of heavy metals.

Microsprinkler Irrigation of Young `Redblush' Grapefruit Trees Using Reclaimed Water

Two field studies conducted from 1990 to 1991 evaluated the effects of reclaimed water on growth and development of 1- and 2-year-old `Redblush' grapefruit (Citrus paradisi Macf.) trees on Swingle citrumelo [Citrus paradisi (L.) Osb. ×Poncirus trifoliata (L.) Raf.] rootstock. Treatments were arranged as a3 (water sources) x 3 (irrigation levels) factorial at two locations on an Arredondo (well drained) and Kanapaha (poorly drained) fine sand near Gainesville, Fla. Irrigation treatments included 1) reclaimed water, 2) reclaimed water plus fertigation, and 3) well water plus fertigation. The reclaimed water was formulated to simulate that of a sewage treatment plant at Vero Beach, Fla. Irrigation was applied at 20% soil moisture depletion, or at 19 or 25 mm·week regardless of rainfall. In both experiments, visual ratings of tree vigor, and measured tree height and trunk diameter, were significantly lower for trees watered with reclaimed water without fertilizer than for the others in both years. Moreover, there was no fourth leaf flush in 1991 with reclaimed water. There was a significant increase in leaf Na, Cl, and B concentrations for the reclaimed water and reclaimed water plus fertigation treatments in 1990; however, in 1991 only leaf B concentrations showed a similar trend. In 1991, there were no significant differences in leaf Cl concentrations. Visual symptoms of N deficiency were observed by the end of the first season in trees grown with reclaimed water. Irrigation levels generallv did not affect tree growth.

Seasonal Abundance, Age Composition, and Body Size of Salt- Marsh Anopheles (Diptera: Culicidae) in South Florida

Five CO2-baited light traps operated fortnightly between November 1989 and May 1991 near a salt marsh in Vero Beach, FL, caught 1,961 Anopheles crucians Wiedemann (s.l.) and 691 An. atropos Dyar & Knab. Both species were most abundant in winter and least abundant in summer; their numbers correlated inversely with lagged mean ambient temperatures. Annual parous rates were 55% for An. crucians and 58% for An. atropos and varied little seasonally. Wing lengths of female An. crucians measured for eight consecutive months were negatively correlated with ambient temperatures, and parous females of this species had significantly longer wings than nullipars. Parous rates and wing length classes were positively correlated among An. crucians, confirming that larger mosquitoes are longer-lived.

RECLAIMED WATER AND IRRIGATION OF MATURE `REDBLUSH' GRAPEFRUIT TREES.

A field study was conducted near Vero Beach, Fla. on poorly drained (flatwoods) soil to determine the effects of reclaimed water on the growth and development of mature `Redblush' grapefruit trees (Citrus paradisi Macf.) on sour orange (Citrus aurantium L.) rootstock. Treatments consisted of a control (canal water), and reclaimed water applied at 2.31, 3.07 and 3.86 cm/wk. For the first two years after treatments were implemented there were no significant differences among treatments in yields, trunk diameter, fruit growth rates or fruit quality (fruit and juice weight, total soluble solids, acids or solids:acid ratio), and leaf nutrient levels. Moreover, although reclaimed water increased leaf B, Na and Cl levels over control values, no toxicity symptoms were observed. Soil moisture content was always well above field capacity for the reclaimed water treatments; however, soil redox potentials rarely were in the anaerobic range. The reclaimed water treatment receiving 3.86 cm/wk also provided about 80 kg/ha of N which is ⅔ of the yearly N requirement. All reclaimed water treatments caused significantly greater weed growth than control treatments.

Antitranspirant and Cryoprotectant Do Not Prevent Peach Freezing Injury

Two chemicals-FrostFree [50% propylene block copolymer of polyoxyethylene, 50% propylene glycol (Plant Products, Vero Beach, Fla.)] and Vapor Gard [96% di-lpmenthene (pinolene, a terpenic polymer), 4% inert (Miller Chemical & Fertilizer, Hanover, Pa.)] have been promoted as low-temperature protectants. Vapor Gard did not prevent freezing damage to several tropical foliage plants (Fitzpatrick et al., 1986), several varieties of immature peaches [Prunus persica (L.) Batsch] in the field at rates double and equal to the manufacturer’s recommended rate at -5.0C (Matta and Mullenax, 1986), or several peach varieties in the field at postbloom or small fruit stages at -4.5C (Matta et al., 1987). FrostFree did not protect peaches in the orchard (Matta et al., 1987) study, at full bloom at a controlled -2.7C, or in the field at -2.5 to -4.5C (Rieger and Krewer, 1988), nor did it increase freezing resistance in developing grape (Vitis labruscana Bailey) shoots (Himelrick et al., 1991). In addition, tomato (Lycopersicon esculentum Mill.) or pepper (Capsicum annuum L.) transplants were not protected at 0 to -3.5C (field test) (Perry et al., 1992). We determined 1) if FrostFree and Vapor Gard protect peaches at postbloom (petal fall) and small fruit stages at -1.0 to -4.5C, 2) the lowest temperature at which these products provide protection, and 3) the duration of the putative effectiveness of these products. Six-year-old ‘Legend’ peach trees near Clayton, N.C. (lat. 35o40’N, long. 78o30’, elevation 106 m), were used. The controlledenvironment experiment was conducted in Spring 1990 and 1991 in the phytotron, North Carolina State Univ. The field test was conducted only in Spring 1990. A randomized complete-block design was used for both stud-

Factors Influencing the Distribution of Blackchin Tilapia Sarotherodon melanotherodon (Osteichthyes: Cichlidae) in the Indian River System, Florida

The blackchin tilapia, Sarotherodon melanotheron, was first collected from the Indian River system, in Brevard County, Florida, in 1980. Since its introduction, this species has expanded its range northward along the coast approximately 37 km, to just north of Whites Point, Brevard County, and southward about 68 km to Vero Beach, Indian River County. Laboratory studies on salinity tolerance indicate an ability of this species to tolerate hypersaline concentrations of at least 100 ppt, and to reproduce in salinities of up to 35 ppt. The northern distribution of blackchin tilapia is almost certainly limited by cold temperature; however, the potential exists for extensive coastal, and possibly inland, invasion south of Its present limits.

Progressive coastal community implements both desalination and reuse in a comprehensive water resource program

This paper discusses the actions taken by the City of Vero Beach to secure a reliable source of potable water and to reduce the demand on the potable system caused by irrigation. This discussion includes evaluation of a new raw water source, treatment process evaluation, and the interaction with the existing treatment plant. It also discusses the process the City followed in identifying the demand that a reuse system would generate, the development of the reuse master plan, and the procedure followed in determining an equitable price for the reclaimed water.

THEOLOGICAL EDUCATION FOR THE TWENTY‐FIRST CENTURY

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsRichard SpeckRichard Speck is parish minister of the Unitarian Universalist Fellowship in Vero Beach, Florida.

Effect of Sterile Boll Weevils (Coleoptera: Curculionidae) and Insecticide in Isolated Small Plots in Florida

In the spring and summer of 1989, insecticide and sterile boll weevils, Anthonomus grandis Boheman, were applied to plots of cotton on two private research farms at Vero Beach, Florida to suppress the native boll weevil population. Plots were treated weekly with azinphosmethyl followed by the release of about 500 sterile boll weevils per acre two days later. Egg hatch was 5% on the Mobay farm where serially planted plots of cotton were destroyed soon after blooming. On the Ciba-Geigy farm egg hatch averaged 32% prior to the formation of bolls 2.5 cm (1 in.) or larger in diameter and 77% when bolls were larger than 2.5 cm in diameter. Normally, egg hatch in fields with no sterile weevils is about 94% so their effect in preventing or significantly lowering the reproductive activity of native females entering the cotton fields was demonstrated. After natives began emerging from the clumped areas where oviposition had taken place, the effectiveness of the sterile weevils was significantly diminished. The Ciba-Geigy research farm had received more than 30 applications of azinphosmethyl during the 1988 growing season, and the Mobay farm had received 6 applications of methomyl. In 1989, 16 pheromone baited traps placed around the perimeter of each farm in 1989 captured an average of 12 (Mobay) and 37 (Ciba-Geigy native weevils per week before and during the treatment period. At Ciba-Geigy 41% of the trapped weevils were sterile compared to 34% at Mobay. In 1990, 16 pheromone traps placed around the Mobay and Ciba-Geigy farms averaged 0 and 4 weevils per week, respectively, during the growing season.