Open Access is an initiative that aims to make scientific research freely available to all. To date our community has made over 100 million downloads. It’s based on principles of collaboration, unobstructed discovery, and, most importantly, scientific progression. As PhD students, we found it difficult to access the research we needed, so we decided to create a new Open Access publisher that levels the playing field for scientists across the world. How? By making research easy to access, and puts the academic needs of the researchers before the business interests of publishers.
We are a community of more than 103,000 authors and editors from 3,291 institutions spanning 160 countries, including Nobel Prize winners and some of the world’s most-cited researchers. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too.
To purchase hard copies of this book, please contact the representative in India:
CBS Publishers & Distributors Pvt. Ltd.
www.cbspd.com
|
customercare@cbspd.com
Culicoides biting midges are tiny blood-feeding insects of several diseases with veterinary and public health significance, including Bluetongue in ruminants, African horse sickness in equids and filarial diseases like Onchocercosis and Mansonellosis affecting various species such as humans. Their identification depends basically on the microscope examination of key morphological characters. Consequently, identification keys are important to any non experiment working with these biting midges. The Tunisian fauna of Culicoides biting midges consists of 35 species, whose morphological delineation may be troublesome for non-taxonomists. In response to this situation, and for the first time a key to the adult Culicoides species in Tunisia was prepared.
Laboratory of Medical and Molecular Parasitology-Mycology LP3M (code LR12ES08), Department of Clinical Biology B, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
Emna Chaker
Laboratory of Medical and Molecular Parasitology-Mycology LP3M (code LR12ES08), Department of Clinical Biology B, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
Hamouda Babba
Laboratory of Medical and Molecular Parasitology-Mycology LP3M (code LR12ES08), Department of Clinical Biology B, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
*Address all correspondence to: slama.darine@laposte.net
1. Introduction
Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) is a genus of biting midges, containing 1368 species divided into numerous subgenera [1]. Indeed, they are vectors of a variety of pathogens, including protozoans [2], filarial parasites [3] such as avian haemosporidians [4] and Tetrapetalonema spp. [5, 6, 7]. More than 50 viruses have been isolated from Culicoides spp. worldwide [8], such as African horse sicknes virus (AHSV), Bluetongue virus (BTV), Epizootic hemorrhagic virus (EHDV), Schmallenberg virus (SBV), or Oropouche virus (OROV) [9]. These viruses are responsible for outbreaks of non-contagious disease in ruminants, causing severe economic loses [10]. In the Mediterranean basin as well as sub-saharan Africa, the main vector of BTV and AHSV is Culicoides imicola [11]. Moroever, other Paleartic Culicoides species, within the subgenera Avaritia, such as C. obsoletus, C. scoticus, C. dewulfi and C. pulicaris are also known or potential BTV vectors [12, 13]. The recent BTV outbreaks in Tunisia demonstrate how a relatively neglected arthropod vector group can rapidly augment in interest. Thus identification of the vector is an important step in the epidemiology of vector born diseases. For instance, Tunisian fauna of Culicoides includes 35 distinct species [14]. Indeed, at the regional level, there are no proper morphological keys to Tunisia Culicoides Species. This can cause a major confront in the control effort as the accurate identification of vectors is crucial for vector incrimination. In this context, a morphological identification key was prepared for the adult of the recorded Culicoides species in Tunisia as simply as possible, using the most important characters. Hopefully, this will aid public health workers, students and entomologists for rapid and accurate identification of Culicoides to the genus and species levels.
Culicoides specimens used herein were collected at different locations, in studies conducted in Tunisia. Collection sites were selected based on their characteristics, including presence of animals, type of vegetation, and degree of urbanization. Two models of light traps: home-made miniature using CDC (Centre of Disease Control, Atlanta, USA) and OVI (Onderstepoort Veterinary Institute) were used.
2.2 Samples processing
All insects were collected in a beaker filled with 70% ethanol. Sampled Culicoides were separated from other insects and identified according to wing characters using a stereomicroscope. Culicoides midges were separated according to sex. Specimens were dissected on a glass slide separating the terminal part of the abdomen, wings and the entire head with a fine needle and mounted in a mix of Balsam Alcohol-Phenol for later identification. Species identification was made according to different morphological keys [15, 16, 17].
2.3 Morphological characterization
The morphological characteristics used here were based on original observations and previous usage in the litterature [15, 17, 18] (Figure 1). Several morphological characters were examined during the preparation of this morphological identification keys. The following main features were considered: Head (Eyes; Antenna (short segments: shape; sensilla coeloconica (Presence); antennal ratio XI/X ratio, length of segment XI divided by length of segment X; sensilla coeloconica, segments III to VI (Presence); sensilla coeloconica, segments VII to X (Presence); sensilla coeloconica, segments XI to XV (Presence)); Palpus (3rd palpal segment (shape, number of sensory pits, single sensory pits (opening versus depth)); Abdomen: Spermathecae (spermathecal duct at the end of the sclerotized ring, number, size, shape, abdominal sclerites (presence or absence)); Wings pale or dark spots (presence/absence), distribution, size.
Figure 1.
Adult of Culicoides (Diptera: Ceratopogonidae).
Representative Culicoides specimens for each species available were selected and relevant characters were image captured with a digital camera through Leica microscopy. For some illustrations of Tunisian Culicoides species we used a drawn image used by (18).
The present works illustrated the identification keys to adults of 35 Culicoides species (Diptera: Ceratopogonidae) which have been recorded in Tunisia (Table 1). Indeed, comprehensive identification keys of genera and species of Culicoides were elaborated. The simplified keys allow distinguishing each genus, subgenus and species based on the most important morphological features. Nevertheless, identification keys are fundamental for anyone dealing with insects of medical and veterinary significance, such as Culicoides biting midges. They are aimed to provide a guide for those interested to identify field-collected specimens obtained for many purposes and different type of studies. Indeed, identification keys especially those accompagnied by digital photographs and line drawing illustarting taxonomically relevant characters, are useful for species identification of Culicoides midges [15]. In Tunisia, even though the first record of Culicoides was documented in 1981 [15], field identification of this medically important group of insects has been carried out referring to the basic features and published literature. Indeed, in the case of the Tunisian biting midge fauna, [15] (in French) contain only restricted geographical areas, do not contain the new species records [14, 16, 19]. In the morphological identification keys presented here are accompanied by digital photographs taken from original specimens, which make the keys more user-friendly and facilitating the accurate identification of species.
Table 1.
Key to Culicoides species in Tunisia based on female and male morphology.
: photo of different part (wing, head, 3rd palpal and spermatheca) of Culicoides species were taken from Mathieu et al 2012
: photo of genitalia taken from Turgut F, 2018
: photo of drawn part of Culicoides were taken from Delecolle JC, 1985
Other image illustarting the different parts of Culicoides body in this chapter were taken from the Laboratory of Medical and Molecular Parasitology-Mycology LP3M (code LR12ES08), Department of Clinical Biology B, University of Monastir, Tunisia
One of the main limitations of the keys is that the males are incomplete. Therefore, species characterizations were not illustrated in the identification key based on male morphology. Furthermore, some species were not of good quality to take a clear photograph. For this, keys were supplemented with illustrations adapted from published literature [17, 18].
To the author’s knowledge, these are the first keys prepared for Tunisian Culicoides fauna which are meant as an aid to the rapid identification.
Key for Culicoides (Diptera: Ceratopogonidae) females from Tunisia
1
1 functional spermathecae………………………………………..
2
2 functional spermathecae………………………………………..
5
3 functional spermathecae………………………………………..
C. saevus
2
Sensilla coeloconica: presence on segments III to XI, presence on segments XII to XIIII…………………………………………
Spermatheca narrow opening……………………………………..
3
Sensilla coeloconica: absence on segments XII to XV, presence on segments III, VIII and X……………………………………..
3rd palpal segment slender with slightly swollen, multiple irregular pits………………………………………………………
Spermatheca wide opening, oval, elongated, heavily curved in the middle…………………………………………………………
4
3
Pharynx posterieur armature: presence…………………………..
Sensilla coeloconica: absence on segment XV…………………..
Wing: r-m cross vein, presence on dark spot in the corner with M1 vein……………………………………………………………
C. circumscriptus
4
Pale wing with only 1 dark spot cover the second radial cell…….
Antennal XI/X ratio: inferior or equal to 2………………………
C. parroti
Wing with 1 ore more pale spots…………………………………
Antennal XI/X ratio: inferior or equal to 2………………………
The simplified keys, would contribute towards improving research capacity among researchers in Tunisia as the identification is a fundamental requirement for anyone dealing with medically important insects.
We thank the heads of Hygiene Services of Public Health, all of whom facilitated the field work together, and the health agents who contributed to the achievement of this survey. This study was carried out with the financial support of the Research Lab, Laboratory of Medical and Molecular Parasitology-Mycology LR12ES08, Department of Clinical Biology B, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia.
1.Art Borkent. Numbers of Extant and Fossil Species of Ceratopogonidae. 2016;9(2):118–31.
2.Tomazatos A, Jöst H, Schulze J, Spînu M, Chanasit JS, Cadar D. Blood - meal analysis of Culicoides ( Diptera: Ceratopogonidae ) reveals a broad host range and new species records for Romania. Parasit Vectors [Internet]. 2020;1–12. Available from: https://doi.org/10.1186/s13071-020-3938-1
3.Carpenter, S.; Groschup, M.H.; Garros, C.; Felippe-Bauer, M.L.; Purse BV. Culicoides biting midges, arboviruses and public health in Europe. Antivir Res. 2013;100:102–113.
4.Chagas, C.R.F.; Bukauskaite, D.; Ilgunas, M.; Iezhova, T.; Valkiunas G. A new blood parasite of leaf warblers: Molecular characterization, phylogenetic relationships, description and identification of vectors. . Parasit Vectors. 2018;11:538.
5.Yates, J.A.; Lowrie, R.C., Jr.; Eberhard M. Development of Tetrapetalonema llewellyni to the infective stage in Culicoides hollensis. J Parasitol. 1982;68:293–296.
6.Lowrie, R.C., Jr.; Eberhard, M.L.; Orihel TC. Development of Tetrapetalonema marmosetae to the infective stage in Culicoides hollensis and C. furens. J Parasitol. 1978;64:1003–1007.
7.Linley JR. Biting midges (Diptera: Ceratopogonidae) as vectors of nonviral animal pathogens. J MedEntomol. 1985;22:589–599.
8.Carpenter, S.; Veronesi, E.; Mullens, B.; Venter G. Vector competence of Culicoides for arboviruses: Three major periods of research, their influence on current studies and future directions. Rev Sci Tech. 2015;34:97–112.
9.Franziska Sick, Martin Beer HK and KW. Culicoides Biting Midges — Underestimated Vectors for Arboviruses of Public Health and Veterinary Importance. Viruses. 2019;11:376.
10.Pinior B, Firth CL, Loitsch A, Stockreiter S, Hutter S, Richter V et al. Cost distribution of bluetongue surveillance and vaccination programmes in Austria and Switzerland (2007–2016). Vet Rec. 2018;182:257.
11.Slama D, Haouas N, Mezhoud H, Babba H, Chaker E. Blood meal analysis of Culicoides (Diptera: Ceratopogonidae) in Central Tunisia. PLoS One. 2015;10(3).
12.De Liberato C, Scavia G, Lorenzetti R, Scaramozzino P, Amaddeo D, Cardeti G et al. Identification of Culicoides obsoletus (Diptera: Ceratopogonidae) as a vector of bluetongue virus in Central Italy. Vet Rec. 2005;156:301–304.
13.Dallas, J.F., Cruickshank, R.H., Linton, Y.M., Nolan, D.V., Patakakis, M., Braverman Y, Capela, M., Capela, R., Pena, I., Meiswinkel, R., Ortega, M.D., Baylis, M., Mellor P, Mordue AJ. Phylogenetic status and matrilineal structure of the biting midge, Culicoides imicola, in Portugal, Rhodes and Israel . Med Vet Entomol. 2003;17:379–387.
14.Slama D, Chaker E, Zrelli S, Mathieu B, Delecolle JC et al. Culicoides (Diptera: Ceratopogonidae) Fauna in Central Tunisia. Entomol Ornithol Herpetol. 2016;5:184.
15.Chaker E. Contribution l’étude des Culicoides (Diptera: Ceratopogonidae) de Tunisie: Systématique, chorologie et écologie. Université Louis Pasteur; 1981.
16.Chaker E, Sfari M, Rabhi M, Babba H AR. Note faunistique sur les Culicoides (Diptera: Ceratopogonidae) du gouvernoratt de Monastir (Tunisie). Parasite. 2005;12:359–61.
17.Mathieu B, Cêtre-Sossah C, Garros C, Chavernac D, Balenghien T, Carpenter S, et al. Development and validation of IIKC: An interactive identification key for Culicoides (Diptera: Ceratopogonidae) females from the Western Palaearctic region. Parasites and Vectors. 2012;5(1):1–11.
18.Delécolle J. Nouvelle contribution à l’étude systématique et iconographique des espèces du genre Culicoides (Diptera: Ceratopogonidae) du Nord-est de la France. Université Louis Pasteur.; 1985.
19.Sghaier S, Hammami S, Hammami H, Dkhil A DJ. Entomological surveillance of Culicoides (Diptera: Ceratopogonidae), vector of Bluetongue in Tunisia. Rev Elev Med Vet Pays Trop. 2009;62:2–4.
Written By
Darine Slama, Emna Chaker and Hamouda Babba
Submitted: 27 September 2020Reviewed: 16 February 2021Published: 08 September 2021
Open access peer-reviewed chapter
