SHORT COMMUNICATION
Ammonia as an Attractant for Adult Hybomitra lasiophthalma (Diptera: Tabanidae) LAWRENCE J. HRIBAR, DANIEL J. LEPRINCE, AND LANE D. FOIL Department of Entomology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803
J. Med. Entomol. 29(2): 346-348 (1992)
ABSTRACT Ammonia and carbon dioxide were evaluated as attractants in canopy traps for Hybomitra lasiophthalma (Macquart). Ammonia-baited traps collected 2.5 times as many flies as did unbaited traps (33.27 versus 12.93 per trap per day). Over 45 times as many flies were captured in carbon dioxide-baited traps as in unbaited traps (1,630.64 versus 35.82 per trap per day). Both ammonia and carbon dioxide are effective attractants for H. lasiophthalma. KEY WORDS Insecta, Hybomitra lasiophthalma, attractants, trapping
ATTRACTANTS INCREASE THE EFFECTIVENESS of
Catts' (1970) canopy trap for collecting tabanids. Carbon dioxide was found to be an attractant for horse flies by Wilson et al. (1966), and CO 2 is the bait of choice when sources are readily available. However, alternate attractants are often desirable. Recently, studies have been conducted on the efficacy of octenol as a bait (French & Kline 1989). Ammonia is known to be attractive to some arthropods (Dethier 1947). It is attractive to house flies (Richardson 1914, 1916), and it instigates host seeking behavior by ticks (El-Ziady 1958, Haggart & Davis 1980), and macrochelid mites (Wallwork & Rodriguez 1963, Jalil & Rodriguez 1970). In southern Louisiana, Hybomitra lasiophthalma (Macquart) is an early-season species with a flight activity period from early March to mid-April (Leprince et al. 1991). An objective of this study was to determine whether ammonia was attractive to H. lasiophthalma. A separate experiment to compare the response of this species with canopy traps with and without carbon dioxide bait also is reported.
Materials and Methods All experiments were conducted at the Thistlethwaite Wildlife Management Area (WMA) [30°39'N, 9 2 W W ] , =10 km north of the town of Washington, St. Landry Parish, La. Most of the WMA grounds are forested; however, a natural gas pipeline runs through the WMA with 50-mwide rights-of-way mowed throughout the year. This provides a forest—meadow interface along which host-seeking tabanids are often abundant (Sheppard & Wilson 1977, Goodwin et al. 1985).
All flies were collected with canopy traps modified from Catts (1970). Ammonia. Ten canopy traps were placed at the WMA in pairs in the open area of the pipeline right-of-way. Traps within pairs were at least 30 m apart and were located along two transects 10 m from the forest-meadow interface on each side of the pipeline right-of-way. Each pair of traps was located at least 60 m from the previous pair and across the right-of-way such that each pair of traps along transects on the same side of the pipeline was about 120 m apart. Traps were operated for 6 consecutive d from 3 to 8 April 1991. Ammonium hydroxide solution (NH 4 OH, 15M, 29.7% NH3), was used as bait. The ammonia bait was delivered in a manner similar to that used by French & Kline (1989) for dispensing l-octen-3-ol. A 20-ml patent-lip vial was filled with 18 ml of ammonium hydroxide solution. A wick was made from two pipe cleaners. The ends of the pipe cleaners were twisted together to form an oval, and the oval was flattened so that the pipe cleaners formed one long, double wick. The vials were sealed with parafilm; ~2 cm of wick were allowed to penetrate the seal. The vials were suspended about 36 cm from the apex of the trap by a wire. Vials were alternated between traps in each pair daily. The mean discharge rate of this release system was calculated to be 201 ± 2 mg/h (n = 8). Flies were collected and wicks and ammonium hydroxide solution were changed daily. Preliminary analysis revealed that these data were not normally distributed, so a Wilcoxon paired-sample signed rank test was used (PROC UNIVARIATE, SAS Institute 1985). Results are reported as the mean number of flies ± SE per trap per day.
0022-2585/92/0346-0348$02.00/0 © 1992 Entomological Society of America
March 1992
HRIBAR ET AL: AMMONIA AS ATTRACTANT FOR
Carbon Dioxide. Canopy traps were operated from 0930 to 1800 h (CST) on 9 d from 20 March to 27 May during 1987. Six traps were used each day, except on 20 May 1987 when seven traps were run. The traps were 0.78-1.5 km apart and were baited with «=5 kg of dry ice suspended from the center pole in a black muslin drawstring bag. The discharge rate of this system was not determined. Three traps per day were baited at random, except on 20 May when four traps were baited. Preliminary analysis revealed that the data were not normally distributed; therefore, a nonparametric analysis of variance procedure was used (PROC NPAR1WAY, SAS Institute 1985). Results are reported as mean number of flies ± SE per trap per day. Results and Discussion Ammonia. A total of 1,356 flies belonging to six species was collected, all of which were females except for one male Tabanus wilsoni Pechuman. Hybomitra lasiophthalma accounted for 98.6% (1,337) of the flies collected. Other species collected were Chrysops pudicus Osten Sacken, C. univittatus Macquart, Leucotabanus annulatus (Say), and T. lineola F. Significantly more flies were captured in ammonia-baited traps than in unbaited traps (mean = 32.27 ± 1.08 (x ± SE) versus 12.93 ± 0.72 flies per trap per day; T = 826.5, n = 60, P < 0.0001). Richardson (1916) reported a 17-fold increase in capture of Musca domestica L. in ammoniabaited traps versus unbaited controls. The present study documents a 2.5-fold increase in numbers of horse flies caught in ammonia-baited traps. Ammonia apparently is not the attractive element in host urine, because Hassanali et al. (1986) identified the tsetse attractant in buffalo urine to be phenolic compounds. Urine and phenols have two modes of action as baits for tsetse, attracting flies from a distance and increasing trap-entering activity of flies (Vale et al. 1988). Low levels of NH 3 are found in sweat (a 7-mM solution of NH 4 OH is about the concentration of ammonia in human sweat), whereas higher NH 3 levels are found in urine or feces (Haggart & Davis 1980). Cattle excrete 1-17 mg NH3/kg body weight per day in their urine (Dittmer 1961). By using the larger of the two values for bovine excretion, and assuming a weight of 500 kg for an average cow, up to 8.5 g of NH 3 could be excreted by one animal in a single day. This is equivalent to a release rate of 0.5 moles of NH3/d. The vial-wick system delivered 0.09 moles of NH3/d at the point source, or almost one-fifth the amount in urine. The amount of ammonia released from the vials was small but was apparently attractive to H. lasiophthalma. In this study, no attempt was made to compare ammonia with other, more commonly used attractants such as CO 2 and octenol. Future research
H. lasiophthalma
347
should study interactions among ammonia and other attractants. Carbon Dioxide. A total of 46,661 H. lasiophthalma was collected, along with small numbers of Chrysops spp., Chlorotabanus crepuscularis (Bequaert), Tabanus americanus Forster, T. atratus F., T. trimaculatus Palisot de Beauvois, and Whitneyomyia beatifica atricorpus Philip. About 46 times as many flies were captured in CO2-baited traps than in unbaited traps (1,630.6 ± 9.23 versus 35.8 ± 1.51 flies per trap per day), and these means were significantly different (F = 12.039, df = 1, P < 0.001). Other studies have shown that CO 2 bait increases collections of H. lasiophthalma (Carts 1970, Roberts 1971, McElligott & Mclver 1987), but the magnitude of the difference observed in this study is unprecedented. Roberts (1971) reported an 8-fold increase in the number of H. lasiophthalma captured in CO2-baited versus unbaited Malaise traps. Leprince & Bigras-Poulin (1990) reported only a 4-fold difference in capture of this species between baited and unbaited canopy traps in Quebec, and no difference in parity rates between H. lasiophthalma collected in traps with and without CO 2 bait was found. The traps were almost 1 km apart at their closest position, so interference between treatments was unlikely (Roberts 1971). Several factors may have influenced the numbers of flies collected by baited traps. The first factor is temporal. It is not uncommon to collect 1,500-7,500 specimens of H. lasiophthalma per CO2-baited trap per day at this study site during March and April (Leprince et al. 1991). The fact that this study was conducted during the peak flight period of H. lasiophthalma accounts, in part, for the large number of flies collected. The other factor is spatial (i.e., trap location). There is the possibility that one or more of the traps were located near a larval habitat or in an area where larger numbers of host-seeking females occur. Host-seeking tabanids are more common in open areas near the woods' edge than in the woods or far from the woods' edge (Sheppard & Wilson 1977), so trap location may be an important consideration in an experiment such as this. A comparison of the mean numbers of flies collected at each site for which data from both baited and unbaited traps were collected reveals that, at all trap sites, baited traps collected more flies than did unbaited traps (site 1: 1,690.0 versus 48.8; site 2, 4,249.3 versus 32.8; site 3, 669.2 versus 35.7; site 4, 391.4 versus 7.7; site 5, 2,393.3 versus 66.8; site 6, 2,117.6 versus 13.5). It is likely that the CO 2 bait rather than the location of the traps accounted for the differences between baited and unbaited traps. Ammonia is attractive to H. lasiophthalma females. Although CO 2 is used commonly to attract tabanids, it must be transported to study sites in pressurized cylinders or as dry ice, both of which
348
JOURNAL OF MEDICAL ENTOMOLOGY
are heavy and difficult to transport to remote areas. The identification of attractants other than CO 2 will facilitate trapping in areas where CO 2 is not readily available. Acknowledgment We thank the staff of Louisiana Department of Wildlife and Fisheries District 6 and the Thistlethwaite heirs for allowing us to work at the Thistlethwaite Wildlife Management Area. J. Harris, R. James, and E. Moran provided technical assistance. This study was supported in part by USDA grants 86-CRSR-2-2906 and 89-34103-4251 and has been approved for publication by the director of the Louisiana Agricultural Experiment Station as manuscript number 91-17-5266.
References Cited Catts, E. P. 1970. A canopy trap for collecting Tabanidae. Mosq. News 23: 472-474. Dethier, V. G. 1947. Chemical insect attractants and repellents. Blakiston, Philadelphia. Dittmer, D. S. [ed]. 1961. Biological handbooks: blood and other body fluids. Federation of American Societies for Experimental Biology, Washington, D.C. El-Ziady, S. 1958. The behavior of Ornithodoros erraticus (Lucas, 1849), small form (Ixodoidea, Argasidae), towards certain environmental factors. Ann. Entomol. Soc. Am. 51: 317-336. French, F. E. & D. L. Kline. 1989. l-octen-3-ol, an effective attractant for Tabanidae (Diptera). J. Med. Entomol. 26: 459-461. Goodwin, J. T., B. A. Mullens & R. R. Gerhardt. 1985. The Tabanidae of Tennessee. Tenn. Agric. Exp. Stn. Bull. 642. Haggart, D. A. & E. E. Davis. 1979. Electrophysiological responses of two types of ammonia sensitive receptors on the first tarsi of ticks, pp. 421-426. In J. G. Rodriguez [ed.], Recent advances in acarology, vol. 1. Academic, New York. 1980. Ammonia-sensitive neurons on the first tarsi of the tick, Rhipicephalus sanguineus. J. Insect. Physiol. 26: 517-523. Hassanali, A., P. G. McDowell, M.L.A. Owaga & R. K. Saini. 1986. Identification of tsetse attractants from excretory products of a wild host animal, Syncerus caffer. Insect Sci. Appl. 7: 5-9. Jalil, M. & J. G. Rodriguez. 1970. Studies on the
Vol. 29, no. 2
behavior of Macrocheles muscaedomesticae (Acarina: Macrochelidae) with emphasis on its attraction to the house fly. Ann. Entomol. Soc. Am. 63: 738— 744. Leprince, D. J. & M. Bigras-Poulin. 1990. Gonotrophic status, follicular development, sperm presence, and sugar feeding patterns in Hybomitra lasiophthalma (Macquart) populations (Diptera: Tabanidae). J. Med. Entomol. 27: 31-35. Leprince, D. J., L. J. Hribar, R. T. Bessin & L. D. Foil. 1991. Seasonal patterns of abundance of horse flies (Diptera: Tabanidae) from two locations in southern Louisiana. Proc. La. Acad. Sci. 54: 10-18. McElligott, P. E. & S. B. Mclver. 1987. Range of attractiveness of carbon dioxide to Hybomitra spp. (Diptera: Tabanidae). J. Am. Mosq. Control Assoc. 3: 655-656. Richardson, C. H. 1914. Fly control on the college farm, pp. 396-399. In 35th Annu. Rep. N.J. State Agric. Exp. Stn. & 27th Ann. Rep. N.J. College Agric. Exp. Stn. 1916. The response of the house-fly (Musca domestica L.) to ammonia and other substances. N.J. Agric. Exp. Stn. Bull. 292. Roberts, R. H. 1971. Effect of amount of CO 2 on collection of Tabanidae in Malaise traps. Mosq. News 31: 551-558. SAS Institute. 1985. SAS user's guide: statistics, version 5 ed. SAS Institute, Cary, N.C. Sheppard, C. & B. H. Wilson. 1977. Relationship of horse fly host seeking activity to the edge of wooded areas in southern Louisiana. Environ. Entomol. 6: 781-782. Vale, G. A., D. R. Hall & AJ.E. Gough. 1988. The olfactory responses of tsetse flies, Glossina spp. (Diptera: Glossinidae), to phenols and urine in the field. Bull. Entomol. Res. 78: 293-300. Wallwork, J. H. & J. G. Rodriguez. 1963. The effect of ammonia on the predation rate of Macrocheles muscaedomesticae (Acarina: Macrochelidae) on house fly eggs, pp. 60-69. In J. A. Naegle [ed.], Advances in acarology, vol. 1. Comstock, Ithaca, N.Y. Wilson, B. H., N. P. Tugwell & E. C. Burns. 1966. Attraction of tabanids to traps baited with dry-ice under field conditions in Louisiana. J. Med. Entomol. 3: 148-149. Received for publication 10 May 1991; accepted 27 August 1991.
Ammonia as an Attractant for Adult Hybomitra lasiophthalma (Diptera: Tabanidae) LAWRENCE J. HRIBAR, DANIEL J. LEPRINCE, AND LANE D. FOIL Department of Entomology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803
J. Med. Entomol. 29(2): 346-348 (1992)
ABSTRACT Ammonia and carbon dioxide were evaluated as attractants in canopy traps for Hybomitra lasiophthalma (Macquart). Ammonia-baited traps collected 2.5 times as many flies as did unbaited traps (33.27 versus 12.93 per trap per day). Over 45 times as many flies were captured in carbon dioxide-baited traps as in unbaited traps (1,630.64 versus 35.82 per trap per day). Both ammonia and carbon dioxide are effective attractants for H. lasiophthalma. KEY WORDS Insecta, Hybomitra lasiophthalma, attractants, trapping
ATTRACTANTS INCREASE THE EFFECTIVENESS of
Catts' (1970) canopy trap for collecting tabanids. Carbon dioxide was found to be an attractant for horse flies by Wilson et al. (1966), and CO 2 is the bait of choice when sources are readily available. However, alternate attractants are often desirable. Recently, studies have been conducted on the efficacy of octenol as a bait (French & Kline 1989). Ammonia is known to be attractive to some arthropods (Dethier 1947). It is attractive to house flies (Richardson 1914, 1916), and it instigates host seeking behavior by ticks (El-Ziady 1958, Haggart & Davis 1980), and macrochelid mites (Wallwork & Rodriguez 1963, Jalil & Rodriguez 1970). In southern Louisiana, Hybomitra lasiophthalma (Macquart) is an early-season species with a flight activity period from early March to mid-April (Leprince et al. 1991). An objective of this study was to determine whether ammonia was attractive to H. lasiophthalma. A separate experiment to compare the response of this species with canopy traps with and without carbon dioxide bait also is reported.
Materials and Methods All experiments were conducted at the Thistlethwaite Wildlife Management Area (WMA) [30°39'N, 9 2 W W ] , =10 km north of the town of Washington, St. Landry Parish, La. Most of the WMA grounds are forested; however, a natural gas pipeline runs through the WMA with 50-mwide rights-of-way mowed throughout the year. This provides a forest—meadow interface along which host-seeking tabanids are often abundant (Sheppard & Wilson 1977, Goodwin et al. 1985).
All flies were collected with canopy traps modified from Catts (1970). Ammonia. Ten canopy traps were placed at the WMA in pairs in the open area of the pipeline right-of-way. Traps within pairs were at least 30 m apart and were located along two transects 10 m from the forest-meadow interface on each side of the pipeline right-of-way. Each pair of traps was located at least 60 m from the previous pair and across the right-of-way such that each pair of traps along transects on the same side of the pipeline was about 120 m apart. Traps were operated for 6 consecutive d from 3 to 8 April 1991. Ammonium hydroxide solution (NH 4 OH, 15M, 29.7% NH3), was used as bait. The ammonia bait was delivered in a manner similar to that used by French & Kline (1989) for dispensing l-octen-3-ol. A 20-ml patent-lip vial was filled with 18 ml of ammonium hydroxide solution. A wick was made from two pipe cleaners. The ends of the pipe cleaners were twisted together to form an oval, and the oval was flattened so that the pipe cleaners formed one long, double wick. The vials were sealed with parafilm; ~2 cm of wick were allowed to penetrate the seal. The vials were suspended about 36 cm from the apex of the trap by a wire. Vials were alternated between traps in each pair daily. The mean discharge rate of this release system was calculated to be 201 ± 2 mg/h (n = 8). Flies were collected and wicks and ammonium hydroxide solution were changed daily. Preliminary analysis revealed that these data were not normally distributed, so a Wilcoxon paired-sample signed rank test was used (PROC UNIVARIATE, SAS Institute 1985). Results are reported as the mean number of flies ± SE per trap per day.
0022-2585/92/0346-0348$02.00/0 © 1992 Entomological Society of America
March 1992
HRIBAR ET AL: AMMONIA AS ATTRACTANT FOR
Carbon Dioxide. Canopy traps were operated from 0930 to 1800 h (CST) on 9 d from 20 March to 27 May during 1987. Six traps were used each day, except on 20 May 1987 when seven traps were run. The traps were 0.78-1.5 km apart and were baited with «=5 kg of dry ice suspended from the center pole in a black muslin drawstring bag. The discharge rate of this system was not determined. Three traps per day were baited at random, except on 20 May when four traps were baited. Preliminary analysis revealed that the data were not normally distributed; therefore, a nonparametric analysis of variance procedure was used (PROC NPAR1WAY, SAS Institute 1985). Results are reported as mean number of flies ± SE per trap per day. Results and Discussion Ammonia. A total of 1,356 flies belonging to six species was collected, all of which were females except for one male Tabanus wilsoni Pechuman. Hybomitra lasiophthalma accounted for 98.6% (1,337) of the flies collected. Other species collected were Chrysops pudicus Osten Sacken, C. univittatus Macquart, Leucotabanus annulatus (Say), and T. lineola F. Significantly more flies were captured in ammonia-baited traps than in unbaited traps (mean = 32.27 ± 1.08 (x ± SE) versus 12.93 ± 0.72 flies per trap per day; T = 826.5, n = 60, P < 0.0001). Richardson (1916) reported a 17-fold increase in capture of Musca domestica L. in ammoniabaited traps versus unbaited controls. The present study documents a 2.5-fold increase in numbers of horse flies caught in ammonia-baited traps. Ammonia apparently is not the attractive element in host urine, because Hassanali et al. (1986) identified the tsetse attractant in buffalo urine to be phenolic compounds. Urine and phenols have two modes of action as baits for tsetse, attracting flies from a distance and increasing trap-entering activity of flies (Vale et al. 1988). Low levels of NH 3 are found in sweat (a 7-mM solution of NH 4 OH is about the concentration of ammonia in human sweat), whereas higher NH 3 levels are found in urine or feces (Haggart & Davis 1980). Cattle excrete 1-17 mg NH3/kg body weight per day in their urine (Dittmer 1961). By using the larger of the two values for bovine excretion, and assuming a weight of 500 kg for an average cow, up to 8.5 g of NH 3 could be excreted by one animal in a single day. This is equivalent to a release rate of 0.5 moles of NH3/d. The vial-wick system delivered 0.09 moles of NH3/d at the point source, or almost one-fifth the amount in urine. The amount of ammonia released from the vials was small but was apparently attractive to H. lasiophthalma. In this study, no attempt was made to compare ammonia with other, more commonly used attractants such as CO 2 and octenol. Future research
H. lasiophthalma
347
should study interactions among ammonia and other attractants. Carbon Dioxide. A total of 46,661 H. lasiophthalma was collected, along with small numbers of Chrysops spp., Chlorotabanus crepuscularis (Bequaert), Tabanus americanus Forster, T. atratus F., T. trimaculatus Palisot de Beauvois, and Whitneyomyia beatifica atricorpus Philip. About 46 times as many flies were captured in CO2-baited traps than in unbaited traps (1,630.6 ± 9.23 versus 35.8 ± 1.51 flies per trap per day), and these means were significantly different (F = 12.039, df = 1, P < 0.001). Other studies have shown that CO 2 bait increases collections of H. lasiophthalma (Carts 1970, Roberts 1971, McElligott & Mclver 1987), but the magnitude of the difference observed in this study is unprecedented. Roberts (1971) reported an 8-fold increase in the number of H. lasiophthalma captured in CO2-baited versus unbaited Malaise traps. Leprince & Bigras-Poulin (1990) reported only a 4-fold difference in capture of this species between baited and unbaited canopy traps in Quebec, and no difference in parity rates between H. lasiophthalma collected in traps with and without CO 2 bait was found. The traps were almost 1 km apart at their closest position, so interference between treatments was unlikely (Roberts 1971). Several factors may have influenced the numbers of flies collected by baited traps. The first factor is temporal. It is not uncommon to collect 1,500-7,500 specimens of H. lasiophthalma per CO2-baited trap per day at this study site during March and April (Leprince et al. 1991). The fact that this study was conducted during the peak flight period of H. lasiophthalma accounts, in part, for the large number of flies collected. The other factor is spatial (i.e., trap location). There is the possibility that one or more of the traps were located near a larval habitat or in an area where larger numbers of host-seeking females occur. Host-seeking tabanids are more common in open areas near the woods' edge than in the woods or far from the woods' edge (Sheppard & Wilson 1977), so trap location may be an important consideration in an experiment such as this. A comparison of the mean numbers of flies collected at each site for which data from both baited and unbaited traps were collected reveals that, at all trap sites, baited traps collected more flies than did unbaited traps (site 1: 1,690.0 versus 48.8; site 2, 4,249.3 versus 32.8; site 3, 669.2 versus 35.7; site 4, 391.4 versus 7.7; site 5, 2,393.3 versus 66.8; site 6, 2,117.6 versus 13.5). It is likely that the CO 2 bait rather than the location of the traps accounted for the differences between baited and unbaited traps. Ammonia is attractive to H. lasiophthalma females. Although CO 2 is used commonly to attract tabanids, it must be transported to study sites in pressurized cylinders or as dry ice, both of which
348
JOURNAL OF MEDICAL ENTOMOLOGY
are heavy and difficult to transport to remote areas. The identification of attractants other than CO 2 will facilitate trapping in areas where CO 2 is not readily available. Acknowledgment We thank the staff of Louisiana Department of Wildlife and Fisheries District 6 and the Thistlethwaite heirs for allowing us to work at the Thistlethwaite Wildlife Management Area. J. Harris, R. James, and E. Moran provided technical assistance. This study was supported in part by USDA grants 86-CRSR-2-2906 and 89-34103-4251 and has been approved for publication by the director of the Louisiana Agricultural Experiment Station as manuscript number 91-17-5266.
References Cited Catts, E. P. 1970. A canopy trap for collecting Tabanidae. Mosq. News 23: 472-474. Dethier, V. G. 1947. Chemical insect attractants and repellents. Blakiston, Philadelphia. Dittmer, D. S. [ed]. 1961. Biological handbooks: blood and other body fluids. Federation of American Societies for Experimental Biology, Washington, D.C. El-Ziady, S. 1958. The behavior of Ornithodoros erraticus (Lucas, 1849), small form (Ixodoidea, Argasidae), towards certain environmental factors. Ann. Entomol. Soc. Am. 51: 317-336. French, F. E. & D. L. Kline. 1989. l-octen-3-ol, an effective attractant for Tabanidae (Diptera). J. Med. Entomol. 26: 459-461. Goodwin, J. T., B. A. Mullens & R. R. Gerhardt. 1985. The Tabanidae of Tennessee. Tenn. Agric. Exp. Stn. Bull. 642. Haggart, D. A. & E. E. Davis. 1979. Electrophysiological responses of two types of ammonia sensitive receptors on the first tarsi of ticks, pp. 421-426. In J. G. Rodriguez [ed.], Recent advances in acarology, vol. 1. Academic, New York. 1980. Ammonia-sensitive neurons on the first tarsi of the tick, Rhipicephalus sanguineus. J. Insect. Physiol. 26: 517-523. Hassanali, A., P. G. McDowell, M.L.A. Owaga & R. K. Saini. 1986. Identification of tsetse attractants from excretory products of a wild host animal, Syncerus caffer. Insect Sci. Appl. 7: 5-9. Jalil, M. & J. G. Rodriguez. 1970. Studies on the
Vol. 29, no. 2
behavior of Macrocheles muscaedomesticae (Acarina: Macrochelidae) with emphasis on its attraction to the house fly. Ann. Entomol. Soc. Am. 63: 738— 744. Leprince, D. J. & M. Bigras-Poulin. 1990. Gonotrophic status, follicular development, sperm presence, and sugar feeding patterns in Hybomitra lasiophthalma (Macquart) populations (Diptera: Tabanidae). J. Med. Entomol. 27: 31-35. Leprince, D. J., L. J. Hribar, R. T. Bessin & L. D. Foil. 1991. Seasonal patterns of abundance of horse flies (Diptera: Tabanidae) from two locations in southern Louisiana. Proc. La. Acad. Sci. 54: 10-18. McElligott, P. E. & S. B. Mclver. 1987. Range of attractiveness of carbon dioxide to Hybomitra spp. (Diptera: Tabanidae). J. Am. Mosq. Control Assoc. 3: 655-656. Richardson, C. H. 1914. Fly control on the college farm, pp. 396-399. In 35th Annu. Rep. N.J. State Agric. Exp. Stn. & 27th Ann. Rep. N.J. College Agric. Exp. Stn. 1916. The response of the house-fly (Musca domestica L.) to ammonia and other substances. N.J. Agric. Exp. Stn. Bull. 292. Roberts, R. H. 1971. Effect of amount of CO 2 on collection of Tabanidae in Malaise traps. Mosq. News 31: 551-558. SAS Institute. 1985. SAS user's guide: statistics, version 5 ed. SAS Institute, Cary, N.C. Sheppard, C. & B. H. Wilson. 1977. Relationship of horse fly host seeking activity to the edge of wooded areas in southern Louisiana. Environ. Entomol. 6: 781-782. Vale, G. A., D. R. Hall & AJ.E. Gough. 1988. The olfactory responses of tsetse flies, Glossina spp. (Diptera: Glossinidae), to phenols and urine in the field. Bull. Entomol. Res. 78: 293-300. Wallwork, J. H. & J. G. Rodriguez. 1963. The effect of ammonia on the predation rate of Macrocheles muscaedomesticae (Acarina: Macrochelidae) on house fly eggs, pp. 60-69. In J. A. Naegle [ed.], Advances in acarology, vol. 1. Comstock, Ithaca, N.Y. Wilson, B. H., N. P. Tugwell & E. C. Burns. 1966. Attraction of tabanids to traps baited with dry-ice under field conditions in Louisiana. J. Med. Entomol. 3: 148-149. Received for publication 10 May 1991; accepted 27 August 1991.
