Abundance Of Culicoides (Diptera, Ceratopogonidae) Species .

3y ago
39 Views
2 Downloads
735.48 KB
13 Pages
Last View : 1m ago
Last Download : 2m ago
Upload by : Maxine Vice
Transcription

Abundance of Culicoides (Diptera, Ceratopogonidae) species in saltmarshes of the Patos Lagoon estuary, Rio Grande do Sul, Brazil:influence of climatic variablesDAIANE CARRASCO1, MARIA LUIZA FELIPPE-BAUER2, LUÍS FELIPE DUMONT3& FERNANDO D’INCAO31Universidade Federal do Rio Grande, FURG, Institute of Oceanography, Graduate Program in BiologicalOceanograph. Av. Itália, Km 8, s/n. Bairro Carreiros CEP.: 96203-900, Rio Grande, RS, Brazil. E-mail:daiane carrasco@hotmail.com2FIOCRUZ, Oswaldo Cruz Institute, Diptera Laboratory, Ceratopogonidae Collection, Rio de Janeiro, Brazil.3Universidade Federal do Rio Grande, FURG, Oceanography Institute, Laboratory of Decapod Crustaceans, RioGrande, BrazilAbstract. Salt marshes are intertidal areas with vegetation dominated by grasses, rushes and sedges,where many Diptera occur due to the abundance of substrates available for their development. Culicoidesare common in such habitats and are known for being a nuisance to man and domestic animals. This studyaimed to investigate the relationships between temporal variability in Culicoides species in salt marshesand climate variables. Samples were collected on Torotama Island (31 53’33”S; 052 14’33”W), PólvoraIsland (32 02’01’’S; 052 10’45”W) and the West Breakwater of the Rio Grande (32 10’65”S;052 08’52”W) from September 2008 to September 2010. Two malaise traps were set in each area.Interactions between the temporal fluctuations in Culicoides species populations and environmentalvariables were assessed using Spearman correlation and canonical correlation analysis. The three speciessampled in this study were Culicoides insignis Lutz, Culicoides venezuelensis Ortis and Misa, andCulicoides caridei Brethes. C. insignis was found throughout the sampling period; C. venezuelensis wasassociated with El Niño periods, and C. caridei was associated with La Niña periods. The variableshumidity, temperature, precipitation and wind speed influenced the species’ temporal variations.Key words: biting midges, El Niño, La Niña, precipitation, seasonality, temperatureResumo. Abundância das espécies de Culicoides (Diptera: Ceratopogonidae) nas marismas doestuário da Lagoa dos Patos: influência das variáveis climáticas. Marismas são áreas intermareaiscom vegetação dominada por gramíneas, juncos e ciperáceas, onde vários dípteros ocorrem devido àabundância de substratos para o seu desenvolvimento. Culicoides são comuns nesse tipo de habitat e sãoconhecidos pelo incômodo que causam ao homem e aos animais domésticos. O objetivo do trabalho foiinvestigar as relações existentes entre a variabilidade temporal das espécies de Culicoides nas marismas eas variáveis climáticas. As coletas foram efetuadas na Ilha da Torotama (31 53’33”S; 052 14’33”W), naIlha da Pólvora (32 02’01’’S; 052 10’45”W) e no Molhe Oeste da Barra de Rio Grande (32 10’65”S;052 08’52”W), de setembro de 2008 a setembro de 2010. Foram utilizadas duas armadilhas malaisesinstaladas em cada área. As interações entre a flutuação populacional das espécies de Culicoides e asvariáveis ambientais foram investigadas através da correlação de Spearman e pela análise de correlaçãocanônica. As três espécies coletadas no estudo foram Culicoides insignis Lutz, Culicoides venezuelensisOrtis e Misa e Culicoides caridei Brethes. C. insignis foi coletada durante todo o período amostral; C.venezuelensis esteve associada a períodos de El Niño e C. caridei de La Niña. As variáveiscondicionantes na variabilidade temporal das espécies foram umidade e temperatura ambiente,precipitação e velocidade do vento.Palavras chave: maruins, El Niño, La Niña, precipitação, sazonalidade, temperaturaPan-American Journal of Aquatic Sciences (2014), 9(1):8-20

Climate impact on Culicoides abundanceIntroductionSalt marshes are intertidal areas that areusually located in coastal lagoons and estuaries intemperate and subtropical regions, are periodicallyflooded by salt water and have vegetation dominatedby grasses, rushes and sedges (Costa et al. 1997).Salt stress exerts a strong selective pressure on thespecies present. Species of the same genera ofgrasses and rushes and animals such as crabs arefrequently found in widely separated geographicalregions (Chapman 1960, Cooper 1974). Likewise,biting midge species of the genus CulicoidesLatreille are found in this habitat type in manyregions of the world (Kettle & Lawson 1952,Forattini et al. 1958, Becker 1961, Kline & Axtell1977).Some Culicoides species are known to bevectors of protozoa and nematodes for birds andmammals and to be vectors of viruses for humansand wild and domestic ruminants. Thus, thesespecies are engaged in disease transmission tohumans and animals (Linley et al. 1983). TheBluetongue and Oropouche (OROV) viruses are themain midge-transmitted diseases of veterinary andmedical significance (Wirth & Dyce 1985, Pinheiroet al. 1998, Mellor et al. 2000, Ronderos et al.2003a). The presence of these insects may be a riskfactor for cattle ranching in this region.Many authors have investigated therelationships between Culicoides species and theenvironmental variables responsible for the species’seasonal fluctuations. Maia-Herzog et al. (1988), instudies conducted in the state of Rio de Janeiro,observed an inverse relationship between Culicoidesabundance and rainfall. The authors observed nocorrelation between temperature and humidity inspecies emergence. Silva et al. (2001) report higherCulicoides abundance during low precipitationperiods preceded by heavy rains. In contrast,Sherlock & Guitton (1965), in Bahia state, and DeBarros et al. (2007), in Maranhão state, reportedhigher abundance during the colder and rainiermonths. Breidenbaugh et al. (2009), studyingCeratopogonidae assemblies in salt marshes fromSouth Carolina, USA, observed a higher correlationbetween the presence of some species and highrainfall, while other species were present during dryperiods. These studies demonstrate that Culicoidesspecies are sensitive to fluctuations in rateprecipitation, generally coordinating the emergencyperiod with high rainfall.El Niño events are associated with excessiverainfall in southern Brazil, Uruguay and northeasternArgentina (Garcia et al. 2003, 2004). The El NiñoSouthern Oscillation (ENSO) is the clearest signal of9interannual climate variability. Its warm (El Niño)and cold phases (La Niña) lead to worldwide climateanomalies (Trenberth 1997). The abundance ofterrestrial insect population can double in responseto El Niño and reduce drastically in the subsequentdry period (Holmgren et al. 2001). According toPeck (1994), El Niño periods favor flying insectactivity due to humid conditions and strong winds,which are typical of this event. There is evidencethat climate variability influences the life cycle ofmany mosquito species, as well as pathogentransmission (Kovats 2000).Despite the health significance of Culicoidesspecies, there are currently no relevant publicationson the bionomics of these vectors in Brazilian saltmarshes. Considering the above information, thisstudy aimed to evaluate the potential temporalvariations in Culicoides species abundance in thearea that are possibly caused by the ENSOphenomenon, considering the environmentalvariables of temperature, relative humidity andrainfall, under the hypothesis that higher abundancesof Culicoides are positively related to El Niñoperiods.Materials and methodsStudy areaThe coastal region of Rio Grande do Sulstate has a subtropical maritime climate.Temperatures range from 17 to 32 C (mean of24.5 C) in summer and from 6 to 17 C (mean of11.5 C) in winter, and the rainfall is 1,317 mm/year.According to the Köppen classification, the climatein the region is type Cfa, i.e., a temperate climatewith well-distributed rainfall throughout the yearand harsh summers (Vieira 1983).In Rio Grande do Sul, 95% of the saltmarshes are found in the Patos Lagoon estuary(Costa & Davy 1992). According to Costa (1998),the degree of flooding in the salt marshes of thePatos Lagoon estuary determines the differencesamong the communities that use the marshes. Thelow-salt marshes are flooded more than 40% of thetime and are dominated by Spartina alternifloraLoisel, Scirpus maritimus Kük and Scirpus olneyi A.Gray. Medium-salt marshes are subject to flooding10-25% of the time and have characteristic Spartinadensiflora Brongn and S. olneyi coverage. High-saltmarshes remain flooded less than 10% of the yearand are dominated by a dense Juncus kraussiiHochst and Myrsine parvifolia A. DC cover.Sampling was carried out in three saltmarshes of the Patos Lagoon estuary, Rio Grande,RS (Fig. 1): Torotama Island (31 53’33”S;052 14’33”W), Pólvora Island (32 02’01’’S;Pan-American Journal of Aquatic Sciences (2014), 9(1):8-20

10052 10’45”W) and the West Breakwater of RioGrande (32 10’65”S; 052 08’52”W).SamplingSamples were collected from September2008 to September 2010 for a total of 25 months.Two malaise traps were set in each area; one in thehigh-salt marsh stratum and the other on the low-saltmarsh stratum. Collector cup removal was carriedD. CARRASCO ET AL.out every 15 days for a total of 12 samples permonth. Specimens were preserved in 70% alcohol,taken to the laboratory, sorted and identified basedon the Culicoides Atlas of Wirth et al. (1988). Thebiological material was stored in the FIOCRUZCollection of Ceratopogonidae (Coleção deCeratopogonidae da FIOCRUZ – CCER), Rio deJaneiro (RJ), Brazil.Figure 1. Patos Lagoon estuary, Rio Grande, RS. Sampling sites: A) Torotama Island; B) Pólvora Island; C) WestBreakwater. Source: Decapod Crustaceans Laboratory, Institute of Oceanography, FURG.Environmental dataThe environmental variables of temperature,relative humidity, rainfall and wind speed wereobtained from the INMET (National Institute ofMeteorology – Instituto Nacional de Meteorologia)database, station A802 (32 04’43”S; 052 10’03”W)at an average distance of 15 km from the sampledsites. Salinity values of the Patos Lagoon estuary,Rio Grande, RS, were supplied by the Program forLong-Term Ecological Studies (Programa deEstudos Ecológicos de Longa Duração – PELD).Daily measurements were transformed into monthlyaverages, except for precipitation, for which theaccumulated value for the month was used.To test the influence of the El Niño/La NiñaSouthern Oscillation (ENSO) phenomenon, thePan-American Journal of Aquatic Sciences (2014), 9(1):8-20Multivariate ENSO Index (M.E.I.) was used. Thisindex is based on the six main variables observedover the tropical Pacific: sea-level pressure; zonaland meridional components of the surface wind; seasurface temperature; surface air temperature; and thetotal cloudiness fraction of the sky (Wolter 2012).On a scale from -6 to 6, negative indices indicate LaNiña influence, and positive values indicate El Niñoinfluence. Values between -0.5 and 0.5 areconsidered neutral periods.Data analysisSpearman correlation analysis was used tomeasure the strength of the relationship betweenenvironmental variables and the abundance ofCulicoides species due to the lack of a normaldistribution in the data. The significance level was

Climate impact on Culicoides abundanceset at 5%.A canonical correspondence analysis (CCA)was performed to assess the influence of the ENSOon the species’ temporal variability. The CCAenables a direct gradient analysis, explaining thespecies’ distribution in relation to the environmentalvariables (Ter Braak 1986, 1987). Two matriceswere developed: a matrix for the mean abundancevalues of each species per month sampled and anenvironmental matrix including mean temperature,relative humidity, wind speed, salinity andaccumulated rainfall for each month. The variableswere tested considering a 5% significance levelbefore being included in the analysis. The analysiswas performed using the CANOCO software forWindows 4.5 (Ter Braak & Smilauer 2002).For both the Spearman correlation and CCA,the mean species abundance was square roottransformed to stabilize the data variance (Zar1999). Because the environmental variables haddifferent units, they were standardized by the Z [(x–μ) /σ] score, where x was the sample mean, μwas the population mean and σ was the standarddeviation of the population. This procedure wascarried out to avoid distortions due to the range ofmagnitude of the variables (Ter Braak 1986).ResultsEnvironmental parametersSeptember 2008 to February 2009 was a LaNiña period as indicated by M.E.I., and thefollowing months (March and April) were neutral.From May 2009 to March 2010, an El Niño periodwas detected. The subsequent months (April andMay 2010) were neutral (Figs. 2A-2E).The monitoring of monthly data showed alow precipitation period, below 100 mm, fromOctober 2008 to January 2009, during a La Niñaperiod. However, in February 2009 and July 2010,there were rainfall anomalies for La Niña periods,with rainfall rates of 220 and 230 mm, respectively(Fig. 2A). From October 2008 to February 2009, theair humidity values were low for the region (meanbelow 75%) (Fig. 2B).A clear seasonal variation was observed forthe temperature for both sampled years. The averagetemperature was between 16 and 20 C in September,October and November and between 22 and 26 C inDecember, January and February. The averagetemperature gradually decreased from March(approximately 20 C) to July/August, when thelowest temperatures for the period (approximately12 C) were detected. However, in the winter of2009, under an El Niño influence, the lowest11temperatures were observed, with minimum valuesreaching 6 C in July. The El Niño summer was alsowarmer compared with the previous summer, whichwas under the effect of La Niña. January andFebruary 2010 had the highest temperatures (meansabove 25 C) (Fig. 2C).During the fall-winter transitions, from Aprilto July 2009 and April to June 2010, a wind intensitydecrease occurred, with average values ofapproximately 2 m/s for El Niño and La Niñaperiods (Fig. 2D). High estuary salinity occurredfrom December 2008 until August 2009. FromSeptember 2009 to February 2010, the lowestsalinity levels reported for the studied period weredetected, reaching zero in January 2010. FromMarch to July 2010, during a second La Niña period,the estuary returned to a brackish state, with averagesalinity values near 10% (Fig. 2E). The salinityvariability matched the rainfall pattern: lowprecipitation periods had higher salinity values, anda precipitation increase led to a reduction in thesalinity values in the estuary (Figs. 2A and 2E).Temporal species variabilityThe three species sampled in this study wereC. caridei Brèthes, Culicoides insignis Lutz and C.venezuelensis Ortis & Misa, with 1,129, 906 and 703specimens, respectively.Culicoides insignis was present in all of thesamples. However, the highest abundances wererecorded in January and February 2010 with meansof 25 10 and 35 18 specimens, respectively, andthe lowest abundance was recorded from April toJuly 2009 and June to August 2010, with averageabundances near zero. The Spearman correlationcoefficient (ρ) showed no significant influence of theENSO on the temporal variability of this species,although there was a tendency for higher abundanceduring El Niño periods (Fig. 3A).Culicoides venezuelensis was more abundantfrom August 2009 to March 2010 (period affectedby El Niño), especially in September and October2009 (means of 33 7 and 45 5 specimens,respectively). The lowest abundances were near zeroand were recorded from September 2008 to February2009 and from April to August 2010, periodsinfluenced by La Niña. Yet, C. venezuelensis alsohad low abundances in June and July 2009, the mostrigorous winter of the sampling period, which wasinfluenced by El Niño. The Spearman correlationcoefficient for this species (ρ 0.71) showed thattemporal variability was positively correlated withthe M.E.I. In other words, the highest abundanceswere related to El Niño periods (Fig. 3B).Pan-American Journal of Aquatic Sciences (2014), 9(1):8-20

12D. CARRASCO ET AL.Figure 2. Monthly variation of the environmental variables in the Patos Lagoon estuary from September 2008 toSeptember 2010 and the Multivariate ENSO Index (M.E.I). A) Accumulated precipitation (mm); B) mean temperature( C); C) average humidity (%); D) average wind speed (m/s); E) average salinity (%). The vertical lines indicate themaximum and minimum values of the means. The horizontal lines indicate the neutral M.E.I. intervals. Blue barsindicate La Niña influence, green bars indicate El Niño influence, and white bars indicate neutral periods.Pan-American Journal of Aquatic Sciences (2014), 9(1):8-20

Climate impact on Culicoides abundanceCulicoides caridei had a more irregular temporaldistribution, even though it was the most abundantof the three sampled species. This species was notsampled in July and November 2009 nor in Januaryand February 2010. The lowest abundances wererecorded from May 2009 to March 2010, an El Niñoperiod. The highest abundances were recorded fromABC13September 2008 to February 2009, with meansreaching over 50 specimens for this period, whichwas influenced by La Niña. A less significant peakin abundance was recorded from July to September2010. The Spearman correlation coefficient for thisspecies (ρ -0.79) indicated the occurrence ofhigher abundances during La Niña periods (Fig. 3C).ρ 0.25ρ 0.71ρ -0.79Figure 3. Monthly abundance variability of the species Culicoides insignis (A), Culicoides venezuelensis (B) andCulicoides caridei (C) sampled on the salt marshes of the Patos Lagoon estuary from September 2008 to September2010, and the Multivariate ENSO Index (M.E.I). The vertical lines indicate the maximum and minimum values of themeans. The horizontal lines indicate the neutral M.E.I. intervals. Blue bars indicate La Niña influence, green barsindicate El Niño influence, and white bars indicate neutral periods. The Spearman correlation coefficient is representedby ρ.Pan-American Journal of Aquatic Sciences (2014), 9(1):8-20

14D. CARRASCO ET AL.Conditioning variablesCulicoides insignis significantly correlatedwith the following variables: precipitation (ρ 0.40), temperature (ρ 0.67) and wind speed (ρ 0.52). The species had a wide distribution within therainfall range of 30 to 250 mm. However, abundancepeaks were recorded near 200 mm of rain. Thehighest abundances were recorded for temperaturesranging from 20 to 25 C. C. insignis was mostabundant when the wind speed was approximately 3m/s. Correlations with the relative humidity andsalinity were not significant, despite being negative(Figs. ted with temperature (ρ 0.39), and hadhigher abundances in the temperature range of 15 to20 C. Precipitation and salinity were negativelycorrelated with species abundance, and relativehumidity and wind speed were positively correlatedwith species abundance. However, in both cases, thecorrelations were not significant (Figs. 4A-4E).Culicoides caridei had a significant negativecorrelation with relative humidity (ρ -051); whenthe humidity was over 80%, the species abundancewas close to zero. The correlations with temperature,wind speed and salinity, although positive, were notsignificant (Figs. 4A-4E).Aρ 0.40ρ -0.07ρ -0.10ρ 0.67ρ 0.39ρ 0.05ρ -0.10ρ 0.05ρ -0.51ρ 0.52ρ 0.33ρ 0.33ρ -0.38ρ 0.28BCDEρ -0.38Figure 4. Scatter plot of the environmental variables precipitation (A), temperature (B), relative humidity (C), windspeed (D) and salinity (E), and the abundance of the species Culicoides insignis, Culicoides venezuelensis andCulicoides caridei in salt marshes of the Patos Lagoon estuary from September 2008 to September 2010. The Spearmancorrelation coefficient is represented by ρ.Pan-American Journal of Aquatic Sciences (2014), 9(1):8-20

Climate impact on Culicoides abundance15The canonical correlation analysis (CCA)indicated that 90.3% of the variation in theabundance of studied Culicoides species could beexpl

daiane_carrasco@hotmail.com 2FIOCRUZ, Oswaldo Cruz Institute, Diptera Laboratory, Ceratopogonidae Collection, Rio de Janeiro, Brazil. 3Universidade Federal do Rio Grande, FURG, Oceanography Institute, Laboratory of Decapod Crustaceans, Rio Grande, Brazil Abstract.

Related Documents:

IV International Conference on Bluetongue and Related Orbiviruses. November 5‑7, 2014 ‑ Rome, Italy ‑ Selected papers Parole chiave Culicoides spp., Moscerino, Sudafrica, Svernamento, Virus della Bluetongue, Virus della Peste equina africana. Riassunto I Culicoides sono noti vettori del virus della Bluetongue (BTV) e del virus della Peste equina africana (AHSV). Il lavoro riporta i .

IV International Conference on Bluetongue and Related Orbiviruses. November 5‑7, 2014 ‑ Rome, Italy ‑ Selected papers Keywords Avaritia, Culicoides chiopterus, Culicoides dewulfi, Obsoletus complex, Vector competence. Veterinaria Italiana 2016, 52 (3-4), 235-241. doi: 10.12834/VetIt.35.100.1 Accepted: 03.06.2016 Available on line: 30.09.2016 Parole chiave Avaritia, Competenza .

1977] Jackson DictynaandMallos 271 Species Type ofPrey NumberofPrey Smaller Same Larger than Size as than Spider Spider Spider Total Mallos dugesi Becker Mallos niveus O. P. Cambridge Mallos trivittatus Banks Diptera 3 2 6 Diptera 57 38 18 113 Coleoptera 0 3 2 5 Homoptera 0 0 Hymenoptera 0 2 3 Orthoptera 0 0 Thysanoptera 2 0 0 2 Salticid spider 0 0 Diptera 163 20 38 221 Coleoptera 0 0 .

Order Diptera: House fly, Musca domestica, L. Clunie, Manaaki Whenua Landcare Research Order Diptera: Green bottle fly (blow fly), Phaenicia sericata, Joseph Berger, www.insectimages.org Order Diptera: Blue bottle fly (blow fly), Calliphora vomitoria, Stratford Landing Elementary School Sponging mouthparts are used to sponge and suck liquids.

Assessing new lures for Bactrocera latifrons 69 Detection/Monitoring of Bactrocera latifrons (Diptera: Tephritidae): Assessing the Potential of Prospective New Lures Grant T. McQuate 1, Eric B. Jang, and Matthew Siderhurst2 1USDA-ARS, U.S. Pacific Basin Agricultur

IDENTIFICATION MANUAL FOR THE LARVAL CHIRONOMIDAE (DIPTERA) OF NORTH AND SOUTH CAROLINA John H. Epler, Ph.D. INTRODUCTION version 1.0 . INTRODUCTION Key to Paracladopelma larvae of the southeastern U.S.ae of the southeastern U.S. . 8.113 Paralauterborniella .

Rueda, Leopoldo M. Pictorial keys for the identification of mosquitoes ( Diptera: Culicidae) associated with dengue virus transmission. WALTER REED ARMY INST OF RESEARCH WASHINGTON DC DEPARTMENT OF ENTOMOLOGY, 2004. Gjullin, C. M. "A key to the Aedes females of America north of Mexico ( Diptera, Culicidae)." Proc. Ent. Sot. Washington. Vol. 48 .

course. The course was advertised as a training for social and philanthropic work. Birmingham was the first UK University to give aspiring social workers full status as students. From its founding in 1900 University staff had been actively involved in social welfare and philanthropic work in the City of Birmingham. Through research into the employment and housing conditions of poor people in .