Discrimination of cryptic species: Tabanus triangulum and Tabanus occidentalis (Diptera: Tabanidae) differ in size and shape

Distinção de espécies crípticas: Tabanus triangulum e Tabanus occidentalis (Diptera: Tabanidae) diferem em tamanho e forma

Abstract

Horse fly females (Diptera, Tabanidae) are hematophagous and can vector pathogens that affect livestock. Complexes of cryptic species are common in Tabanidae, as exemplified by some species of Tabanus, including Tabanus triangulum and Tabanus occidentalis, both prevalent in the Southern region of Brazil. In this study, geometric morphometrics were employed to ascertain the wing venation in species identification. It was demonstrated that this tool effectively differentiates T. triangulum from T. occidentalis in the coastal plain of Rio Grande do Sul state, situated within the Pampa biome. The results indicate that T. triangulum and T. occidentalis occupy distinct regions of the morphological space, allowing their precise identification through geometric morphometrics, which is fast, affordable, and easy to implement.

Keywords:
Horse flies; wing geometric morphometric; mechanical vector

Resumo

Fêmeas de mutucas (Diptera, Tabanidae) são hematófagas e podem ser vetores de patógenos que afetam animais de criação. Complexos de espécies crípticas são comuns em Tabanidae, como exemplificado por algumas espécies de Tabanus, incluindo Tabanus triangulum e Tabanus occidentalis, ambas prevalentes na região Sul do Brasil. Neste estudo foi utilizada morfometria geométrica para avaliar a venação das asas na identificação de espécies. Foi demonstrada que essa ferramenta diferencia, efetivamente, T. triangulum de T. occidentalis na Planície Costeira do Rio Grande do Sul, situada no bioma Pampa. Os resultados indicam que T. triangulum e T. occidentalis ocupam regiões distintas do espaço morfológico, permitindo sua identificação precisa por meio da morfometria geométrica, a qual é rápida, acessível e fácil de implementar.

Palavras-chave:
Mutucas; morfometria geométrica de asas; vetor mecânico

Introduction

Tabanidae (horse flies) comprise approximately 4,525 species (Pape & Thompson, 2023), of which 27% are found in the Neotropical region (Henriques et al., 2012). Several species are mechanical vectors of pathogens to humans and animals (Baldacchino et al., 2014; Taioe et al., 2017; Bilheiro et al., 2019; Rodrigues et al., 2021; 2022; Ramos et al., 2023). Tabanid studies have focused on females because, since they need a blood meal before ovipositing, they are the vectors of pathogens (Barros, 2001; Rafael & Charlwood, 1980).

In the Pampa biome, covering Argentina, Uruguay, and southern Brazil, there are records of 46 horse fly species from 16 genera (Coscarón & Papavero, 2009; Krüger & Krolow, 2015; Lucas et al., 2020). Tabanus, boasting 1,367 described species (Pape & Thompson, 2023), is the most diverse genus of the family in the world. Among the Pampa horse flies, two species, Tabanus occidentalis Linnaeus, 1758 and Tabanus triangulum Wiedemann, 1828, are often difficult to separate due to their morphological similarities.

The species T. occidentalis is widely distributed in the Neotropics and is common in various vegetation types from Mexico to Argentina (Coscarón & Papavero, 2009). This polymorphic species shows variations in color, size, and the shape of the frons, callus, and antennae. In a review of the group, Fairchild (1983) considered some morphological variants as valid species or varieties (Fairchild & Burger, 1994), but later the individual species were synonymized with T. occidentalis by Coscarón & Papavero (2009). In contrast, T. triangulum has a more restricted distribution, Brazil, Paraguay, Uruguay, Bolivia, and Argentina (Coscarón & Papavero 2009; Guimaraes et al., 2016). Although the species shares habitats with T. occidentalis in the Atlantic Forest and Pampa (Krüger & Krolow, 2015; Guimaraes et al., 2016), it is more prevalent in Pampa areas. Although no varieties have been proposed for T. triangulum, variations in color, shape, and structure size have been observed in this species.

Besides the polymorphism and overlap in the distribution of both species, they also share many similarities, leading to frequent misidentifications (Silva, 2016) by researchers who are not specialized in the group. These similarities include body size and general coloring, including the color pattern of the tibia (Figures 112, 1.5-1.6), the shape of the frontal callus (Figures 113, 1.7), the frontal indices (FI) and divergence (ID) (Figures 113, 1.7), and the shape of the antenna and palp (Figures 114, 1.8). Despite the overlaps, some characters, when examined by trained specialists, allow for the differentiation of taxa. The features assisting in differentiation include the shape of the basal callus, the distribution of palp pilosity, and the coloration of the middle tibiae.

Figure 1
Morphological aspects of Tabanus occidentalis (1-4) and T. triangulum (5-8) from the coastal plain of Rio Grande do Sul state. Yellow arrows indicate characters that differ between the two species.

Both T. occidentalis and T. triangulum can be relevant for pathogen transmission. Tabanus occidentalis carries Trypanosoma species, possibly Trypanosoma vivax (Parra-Henao et al., 2008) and bacteria that can cause opportunistic diseases (Luz-Alves et al., 2007), while T. triangulum is a potential mechanical vector of Trypanosoma kaiowa (Rodrigues et al., 2021). The distribution of both species overlaps in the Atlantic Forest and Pampa. Thus the correct differentiation T. occidentalis and T. triangulum through low-cost and user-friendly methods is crucial for developing public policies targeting the control of these species with zoonotic potential.

Geometric morphometrics has been used as an alternative technique to characterize and distinguish groups with morphological similarities using anatomical landmarks (Bookstein, 1991). The advantages of this method include: low cost, high precision (Dujardin, 2008). In the past decade, the application of this technique has expanded to horse flies from various regions, highlighting differences between species that are sometimes indistinguishable by morphological characteristics and barcoding alone (Torres & Miranda-Esquivel, 2016; Changbunjong et al., 2021; Chaiphongpachara et al., 2022; Mullens et al., 2022).

Considering the polymorphism and morphological similarity between T. occidentalis and T. triangulum, this study aims to differentiate both species, from the coastal plain of the state of Rio Grande do Sul, using geometric morphometrics.

Materials and Methods

Study area

Horse flies were collected using Malaise traps (Townes, 1972) from October 27, 2011, to February 12, 2012, in the coastal plain of Rio Grande do Sul state (CPRS) (see Kirst et al., 2015; Zafalon-Silva et al., 2018). Three collection areas were selected: Area 1: Arroio Pelotas, Arroio Corrientes, and Arroio Grande, characterized by restinga vegetation, wetlands, lowland grassy areas, and sandy regions, distinct from Arroio Pelotas and the Arroio Corrientes have similar vegetation, both conserving remnants of the Atlantic Forest, where pioneer vegetation persists. Collection Area 2: the Lami Biological Reserve, Vila Pacheca on the Rio Camaquã, and the Private Natural Heritage Reserve Barba Negra (RPPN). The Lami area features riparian forests and predominant vegetation composed of shrubby wetlands, herbaceous wetlands, sandy fields, wet grasslands, and forests. Vila Pacheca, on the other hand, hosts primary riparian forest vegetation. A significant part of the RPPN consists of forest vegetation and sandy plains. Collection Area 3: the TAIM Ecological Station (Figure 2, Supplementary Material). This location includes wetlands with palustrine vegetation, coastal fields with savannah-grassy-woody formations, and dune vegetation forming a long stretch of “restinga” (Zafalon-Silva et al., 2018).

Figure 2
Collection sites of Tabanus triangulum and T. occidentalis in the coastal plain of Rio Grande do Sul state.

Data collection

The collected horse flies were identified using the methodology described by Silva (2016) and compared to specimens housed in the Entomological Collection of the Federal University of Tocantins (CEUFT). For the identification of the two species, the following characteristics were used (Silva, 2016): the shape of the basal callus, distribution of palp pilosity, and the coloration of the middle tibiae. The coloration of the middle tibiae is darker in T. triangulum (Figure 112, 1.6). Additionally, in T. triangulum, the callus has a more rectangular shape compared to that of T. occidentalis (Figure 113, 1.7). Lastly, T. occidentalis exhibits more pilosity at the base of the palps compared to T. triangulum (Figure 114, 1.8)

This study used females, which were more frequently captured in Malaise traps (Townes, 1972). The right-wing of collected specimens was extracted and subsequently fixed onto a histological slide and immersed in Enthellan. Following fixation, the wings were photographed using stereoscopes with attached cameras in dorsal view.

To describe the shape and size of the wings of T. triangulum and T. occidentalis, 15 type I two-dimensional landmarks were used. For the definitions of the anatomical landmarks, the methodology employed by Torres & Miranda-Esquivel (2016) was followed (Figure 3, Table 1).

Figure 3
Anatomical landmarks, digitized by TPSDig software, of the right wing of Tabanus occidentalis (A) and T. triangulum (B) from the coastal plain of Rio Grande do Sul state.

Table 1
Wing landmarks used in morphometric identification of Tabanus triangulum and T. occidentalis from the coastal plain of Rio Grande do Sul state.

Landmarks	Position of Points
1	Intersection between veins Cu, M and AR
2	Intersection between veins PR and PR2
3	Intersection between ramifications of vein M
4	Intersection between veins C and PR1
5	Intersection between veins C and PR2A
6	Extremities of vein PR2A and PR2B
7	Extremity of vein PR2B
8	Extremity of vein AM1
9	Extremity of vein AM2
10	Intersection between ramifications of vein M and vein AM2
11	Extremity of vein PM
12	Extremities of vein ACu
13	Extremities of vein A2Cu + AA
14	Intersection between vein AA and A2Cu
15	Intersection between vein PCu and A2Cu

• Note: C (costal), Sc (subcostal), AR (anterior radial), PR (posterior radial), PR1 (posterior radial 1), PR1A (posterior radial 1A), PR1B (posterior radial 1B), PR2 (posterior radial 2), PR2A (posterior radial 2A), PR2B (posterior radial 2B), AM (anterior medial), AM1 (anterior medial 1), AM2 (anterior medial 2), PM (posterior, medial), PM1 (posterior medial 1), PM2 (posterior medial 2), A1Cu (anterior cubital 1), A2Cu (anterior cubital 2), PCu (posterior ulnar cubital), AA (anterior anal), PA (posterior anal).

To obtain the coordinates of the anatomical landmarks, the TpsDig software was utilized. To attain a sufficient sampling size to achieve reliable results, 30 individuals from each species were used, as described by Cardini et al. (2015).

Morphometric geometry

From the obtained anatomical landmarks, a Generalized Procrustes Analysis (GPA) was conducted to superimpose the reference points of all individuals onto a standard coordinate system, removing the effects of translation, rotation, and scaling using least squares (Gower, 1975; Adams et al., 2004).

Subsequently, the general patterns of wing shape variation were obtained, and an alignment of both species was performed to apply the T-test to compare the centroid sizes of the species. Next, a Principal Component Analysis (PCA) was conducted to reduce dimensionality among variables for comparing wing shape patterns and the covariation of T. occidentalis and T. triangulum (Zelditch et al., 2012).

Multivariate analysis of variance (MANOVA) and canonical variate analysis (CVA) were used to compare the patterns of variation and covariation of the wing shape. In MANOVA, two necessary premises are followed: considering the Euclidean measurement space and ensuring that the number of shape variables is greater than the number of obtained variable coordinates (2K – 4), where ‘K’ is the number of reference points (Dryden & Mardia, 1993; Zelditch et al., 2012). The primary objective of MANOVA is to ascertain shape differences between classes of independent variables. In this instance, the difference between the means of variables obtained through the principal components it assessed. With CVA, differences between T. triangulum and T. occidentalis from the CPRS were examined based on newly generated axes called canonical variables (CV) to maximize group differences (Cooke & Terhune, 2015). For this, a 1000-times bootstrap was utilized. All analyses were conducted using R Core Team 4.3.3 (R Core Team, 2023) software with the 'Geomorph' (Adams et al., 2024), 'Vegan' (Oksanen et al., 2022), and 'Tidyverse' (Wickham et al., 2019) packages.

Results

The average centroid size calculated for T. occidentalis was 8.700 mm ± 0.305, and for T. triangulum, it was 8.330 mm ± 0.515 (Figure 4). Therefore, based on the centroid sizes, there was a significant difference between the two species (P= 0.001).

Figure 4
Boxplot of centroid size of the wings of Tabanus occidentalis and T. triangulum from the coastal plain of the state of Rio Grande do Sul.

The morphospace is formed by PC1 (20% of the total variance) and PC2 (15% of the total variance) with a cumulative proportion of 35%. The MANOVA indicated that T. occidentalis and T. triangulum differ in wing shape (Table 2). Although the two species can also be distinguished based on centroid size (Table 2 and previous analysis), the interaction between centroid size and wing shape was not statistically significant. Thus, both species exhibited the same allometric trajectories with shape variation without size differences (P= 0.646).

Table 2
Multivariate analysis of variance for 15 wing landmarks used in morphometric identification of Tabanus triangulum and T. occidentalis from the coastal plain of Rio Grande do Sul state.

	Df	Wilks	F	Residuals	P
Species	1	0.246	8.597		<0.001
Centroid Size	1	0.576	2.065	56	0.033
Species x Centroid Size	1	0.773	0.825		0.646

• Df: degrees of freedom; Wilks: test applied. F: approximate F value, P: P value.

The canonical variance analysis (CVA) of wing shape produced distinct clusters for the species (Figure 5). The CVA results for Tabanidae demonstrated substantial segregation between T. triangulum, with an accuracy of 83,33% and, T. occidentalis with an accuracy of 76,67%) with an overall classification accuracy of 80% and a Mahalanobis distance of 4.02 (P = 0.001).

Figure 5
Canonical Variates Analysis (CVA) showing the difference between the wings of T. triangulum and T. occidentalis.

The CVA results showed that T. occidentalis has a more elongated wing, as evidenced by the shifts in landmarks 5, 6, and 7. At the same time, landmark 15 moved posteriorly towards the base of the wing, making it more tapered. Additionally, landmarks 7 and 9 movements brought the veins closer at the tip of veins MA1 and MA2. The opposite trend was observed for T. triangulum: this species has a sturdier wing with a slightly angled base. The distal portion of the wing is more angled, as suggested by a shift in landmark five posteriorly, and landmark six towards the apex of the wing, which reduces cell size at the intersection with veins C and RP2A and the intersection with veins RP2A and RP2B (Figure 6). The changes observed in anatomical landmarks 13, 14, and 15 make the wing bases of T. triangulum and T. occidentalis very distinct, making the wing base sturdier in T. triangulum than in T. occidentalis. These changes in the anatomical landmarks of the wing base alter the membranous areas of the anal lobe, anal and posterior regions.

Figure 6
Mean shape of the wings based on the 15 highlighted points on the wings of T. triangulum (magenta) and T. occidentalis (cyan).

Discussion

In this study, it was demonstrated that the GM approach based on landmarks efficiently distinguishes between T. occidentalis and T. triangulum in the Pampa. Additionally, adaptations to the environment and the relationship between the wing shape of each species with size and function in flight behavior can be explored.

Various authors have applied GM to discriminate horse fly species worldwide (Chaiphongpachara et al., 2022; Mullens et al., 2022). Their findings revealed that methods based on landmarks and contours can distinguish between Tabanidae species. In the present study, 15 anatomical landmark positions were selected according to the study of Torres & Miranda-Esquivel (2016). These positions distinguished between T. occidentalis and T. triangulum. They can also be used to investigate the phenotypic variation of the group (Torres & Miranda-Esquivel, 2016; Mullens et al., 2022; Changbunjong et al., 2021), further allowing inferences about the functional morphology of the wings of these two species.

The wing of T. triangulum appeared smaller and sturdier than that of T. occidentalis, which is slightly more tapered with more significant modifications in the relationship of the radial veins 4 and 5 at the posterior tip and the veins in the anal region. These changes might be associated with shifts in the aerodynamic properties of the wings, as Belyaev & Farisenkov (2019) argued for insects. Changes in the radial ribs, which terminate on the posterior margin of the wing, can cause an increase in wing length from the base to the tip, allowing the fly to achieve faster speeds (Nabawy & Crowther, 2015, 2016). This suggests that T. occidentalis can fly faster than T. triangulum, since there is less drag movement in the case of more tapered wings (Walker, 2002). It is advantageous for larger insects to have long and narrow wings due to the peculiarities of vortex formation attached to the leading edge (Harbig et al., 2013). However, long and narrow wings are not always correlated with body mass (Belyaev et al., 2012).

The sturdier wings of T. triangulum tend to favour more stable flight but with fewer possibilities for changes in direction (Bhat et al., 2019; Krishna et al., 2020). More robust and stable wings benefit take-off, landing, and flight, especially at lower altitudes where greater air densities (fluid) exert greater forces on the wing (Dudley, 2002). In the coastal plain of the low altitudes of Rio Grande do Sul there are strong south-north oceanic winds, and high humidity. In this region, sturdier wings will be less affected by wind gusts due to their larger surface, providing more stability (Dudley, 2002).

Wings that are large with respect to body dimensions, like those of T. triangulum and T. occidentalis, favor high speeds and high lift capacity in relation to drag forces. They also help the feeding behaviour of female horse flies on vertebrates. Female horse flies perform telmophagy (Mullens, 2019); that is, they induce blood leakage for feeding, causing discomfort to the host and swift reactions. Consequently, the flies must sustain their flight for long periods, and sustaining flight demands robust, large wings that achieve high speeds and acceleration rates. This allows the fly to locate and pursue its hosts or to quickly switch to a nearby host (Barros & Foil, 2007).

Moreover, the behavior of horse flies requires great flight control capacity, especially during high sun exposure, since they are diurnal insects (Kriska et al., 2009) that can dehydrate during peak temperature hours (Burnett & Hays, 1974; Schutz & Gaugler, 1992). Therefore, open, sunny areas with consistent winds throughout the year, like the livestock fields in the Pampa biome and coastal plains, may favour species that are adapted to cope with these conditions, as is the case of T. triangulum.

The differences in the shape and size of the wing of T. triangulum and T. occidentalis in southern Brazil might not be explained solely by the differences in one of their locomotive structures. Wing geometric variations alone cannot explain the high abundance of T. triangulum in the region (Silva, 2016). Other factors might be involved in the great numbers of T. triangulum on the coastal plains and in the Pampa of Rio Grande do Sul, such as thermal limits for the development of immatures (Mullens, 2019), availability food resources for males (Kniepert, 1980), historical factors (Cranston, 2005), or even the latitudinal gradient (Chown & Gaston, 2010).

Allen's rule dictates that wing size correlates with the size of a species (Frӧhlich et al., 2023). One of the conclusions of this study is that this rule applies to T. triangulum and T. occidentalis. Considering the latitudinal pattern, species that occur and are dominant in colder climates, like T. triangulum, tend to be more robust. This is confirmed by looking at the distribution of both species, which can occur concomitantly in the eastern part of the south (Bassi et al., 2000; Silva, 2016) and southeast (Guimaraes et al., 2016) of Brazil. In these locations, T. triangulum displays high relative abundance, representing more than 70% of all specimens collected from many localities of the coastal plains of Rio Grande do Sul (Krüger & Krolow, 2015; Silva, 2016). T. occidentalis, is limited to the south, in the same localities where T. triangulum occurs, but with a much lower relative abundance (Silva, 2016), becoming more frequent in warmer localities to the north of the southern region (Bassi et al., 2000) and on the coast of the southeastern region, where both species co-occur (Guimaraes et al., 2016). This presents an intriguing process for future studies on the functional morphology and geographic variation of horse fly wings in the Neotropics.

The GM approach based on landmarks showed 80% accuracy in distinguishing T. triangulum and T. occidentalis. Thus, the landmark coordinate data of this study can be used to perform the morphometric identification of these species. Furthermore, it is suggested that a landmark-based GM approach can complement traditional morphological identification, especially when specimens are difficult to identify. The GM approach is a reliable tool for identifying cryptic species of Tabanidae and can lead to more effective control measures for horse flies in livestock farms.

Supplementary Material

Supplementary material accompanies this paper.

Legend S1 Location of collection points

This material is available as part of the online article from https://doi.org/10.1590/S1984-29612024028

• How to cite: Rodrigues GD, Centeno Filho BL, Morales DF, Dimer RFRM, Cavalheiro CS, Krolow TK, et al. Discrimination of cryptic species: Tabanus triangulum and Tabanus occidentalis (Diptera: Tabanidae) differ in size and shape. Braz J Vet Parasitol 2024; 33(2): e020123. https://doi.org/10.1590/S1984-29612024028

• Ethics declaration

  This study did not require official or institutional ethical approval. The animals were handled according to high ethical standards and national legislation.

References

• Adams DC, Collyer M, Kaliontzopoulou A, Baken E. Geomorph: software for geometric morphometric analyses. R package version 4.0.7 [online]. 2024 [cited 2024 Apr 19]. Available from: https://cran.r-project.org/package=geomorph
  » https://cran.r-project.org/package=geomorph
• Adams DC, Rohlf FJ, Slice DE. Geometric morphometrics: ten years of progress following the revolution. Ital J Zool (Modena) 2004; 71(1): 5-16. http://doi.org/10.1080/11250000409356545
  » http://doi.org/10.1080/11250000409356545
• Baldacchino F, Desquesnes M, Mihok S, Foil LD, Duvallet G, Jittapalapong S. Tabanids: neglected subjects of research, but important vectors of disease agents! Infect Genet Evol 2014; 28: 596-615. http://doi.org/10.1016/j.meegid.2014.03.029 PMid:24727644.
  » http://doi.org/10.1016/j.meegid.2014.03.029
• Barros ATM, Foil LD. The influence of distance on movement of tabanids (Diptera: Tabanidae) between horses. Vet Parasitol 2007; 144(3-4): 380-384. http://doi.org/10.1016/j.vetpar.2006.09.041 PMid:17112669.
  » http://doi.org/10.1016/j.vetpar.2006.09.041
• Barros ATM. Seasonality and relative abundance of Tabanidae (Diptera) captured on horses in the Pantanal, Brazil. Mem Inst Oswaldo Cruz 2001; 96(7): 917-923. http://doi.org/10.1590/S0074-02762001000700006 PMid:11685255.
  » http://doi.org/10.1590/S0074-02762001000700006
• Bassi RMA, da Cunha MCI, Coscarón S. A study of behavior of tabanids (Diptera, Tabanidae) from Brazil. Acta Biol Parana 2000; 29(1/4): 101-115. http://doi.org/10.5380/abpr.v29i0.585
  » http://doi.org/10.5380/abpr.v29i0.585
• Belyaev OA, Chukanov VS, Farisenkov SE. Comparative description of the wing apparatus and flight of some flies (Diptera, Brachycera). Moscow Univ Biol Sci Bull 2012; 67(3-4): 117-120. http://doi.org/10.3103/S0096392512030029
  » http://doi.org/10.3103/S0096392512030029
• Belyaev OA, Farisenkov SE. A study on allometry of wing shape and venation in insects. Part 2. Diptera. Moscow Univ Biol Sci Bull 2019; 74(1): 7-14. http://doi.org/10.3103/S0096392519010024
  » http://doi.org/10.3103/S0096392519010024
• Bhat SS, Zhao J, Sheridan J, Hourigan K, Thompson MC. Aspect ratio studies on insect wings. Phys Fluids 2019; 31(12): 121301. http://doi.org/10.1063/1.5129191
  » http://doi.org/10.1063/1.5129191
• Bilheiro AB, Camargo JSAA, Zamarchi TBO, Tonholo C, Bassin HCM, Sussuarana ITA, et al. Survey of Trypanosoma (Kinetoplastida: Trypanosomatidae) Infection in Monte Negro municipality, state of Rondônia, Western Amazon, with First Record of T. evansi in the state. Rev Soc Bras Med Trop 2019;52:e20190270. https://doi.org/10.1590/0037-8682-0270-2019.
• Bookstein FL. Morphometric tools for landmark data geometric and biology New York: CUP; 1991.
• Burnett AM, Hays KL. Some influences of meteorological factors on flight activity of female horse flies (Diptera: tabanidae). Environ Entomol 1974; 3(3): 515-521. http://doi.org/10.1093/ee/3.3.515
  » http://doi.org/10.1093/ee/3.3.515
• Cardini A, Seetah K, Barker G. How many specimens do I need? Sampling error in geometric morphometrics: testing the sensitivity of means and variances in simple randomized selection experiments. Zoomorphology 2015; 134(2): 149-163. http://doi.org/10.1007/s00435-015-0253-z
  » http://doi.org/10.1007/s00435-015-0253-z
• Chaiphongpachara T, Weluwanarak T, Changbunjong T. Intraspecific variation in wing geometry among Tabanus rubidus (Diptera: Tabanidae) populations in Thailand. Front Vet Sci 2022; 9: 1-10. http://doi.org/10.3389/fvets.2022.920755 PMid:36118331.
  » http://doi.org/10.3389/fvets.2022.920755
• Changbunjong T, Prakaikowit N, Maneephan P, Kaewwiset T, Weluwanarak T, Chaiphongpachara T, et al. Landmark data to distinguish and identify morphologically close Tabanus spp. (Diptera: tabanidae). Insects 2021; 12(11): 974. http://doi.org/10.3390/insects12110974 PMid:34821775.
  » http://doi.org/10.3390/insects12110974
• Chown SL, Gaston KJ. Body size variation in insects: a macroecological perspective. Biol Rev Camb Philos Soc 2010; 85(1): 139-169. http://doi.org/10.1111/j.1469-185X.2009.00097.x PMid:20015316.
  » http://doi.org/10.1111/j.1469-185X.2009.00097.x
• Cooke SB, Terhune CE. Form, function, and geometric morphometrics. Anat Rec (Hoboken) 2015; 298(1): 5-28. http://doi.org/10.1002/ar.23065 PMid:25339616.
  » http://doi.org/10.1002/ar.23065
• Coscarón S, Papavero N. Manual of Neotropical Diptera Tabanidae. Neotrop Diptera 2009; 6: 1-137.
• Cranston P. Biogeographic patterns in the evolution of Diptera. In: Yeates DK, Wiegmann BM, editors. The evolutionary biology of flies New York: CUP; 2005. p. 274-311.
• Dryden IL, Mardia KV. Multivariate shape analysis. Sankhya 1993; 55(3): 460-480.
• Dudley R. The biomechanics of insect flight: form, function, evolution New Jersey: PUP; 2002.
• Dujardin JP. Morphometrics applied to medical entomology. Infect Genet Evol 2008; 8(6): 875-890. http://doi.org/10.1016/j.meegid.2008.07.011 PMid:18832048.
  » http://doi.org/10.1016/j.meegid.2008.07.011
• Fairchild GB, Burger JF. A catalog of the Tabanidae (Diptera) of the Americas South of the United States Durham: Mem. of the Amer. Entomol. Inst.; 1994.
• Fairchild GB. Notes on Neotropical Tabanidae (Diptera) XIX. The Tabanus lineola complex Gainesville: Entomol. Soc. of America; 1983.
• Frӧhlich A, Kotowska D, Martyka R, Symonds MR. Allometry reveals trade-offs between Bergmann’s and Allen’s rules, and different avian adaptive strategies for thermoregulation. Nature Communications 2023;14(1):1101. http://doi.org/10.1038/s41467-023-36676-w
  » http://doi.org/10.1038/s41467-023-36676-w
• Gower JC. Generalized procrustes analysis. Psychometrika 1975; 40(1): 33-51. http://doi.org/10.1007/BF02291478
  » http://doi.org/10.1007/BF02291478
• Guimarães RR, Guimarães RR Jr, Harlan-Rodrigues RS, Guimarães RR, Carvalho RW. Checklist and notes on behavior of horse flies (Diptera: Tabanidae) from Marambaia Island, Rio de Janeiro, Brazil, with new records for the State. EntomoBrasilis 2016; 9(2): 73-80. http://doi.org/10.12741/ebrasilis.v9i2.585
  » http://doi.org/10.12741/ebrasilis.v9i2.585
• Harbig RR, Sheridan J, Thompson MC. Relationship between aerodynamic forces, flow structures and wing camber for rotating insect wing planforms. J Fluid Mech 2013; 730: 52-75. http://doi.org/10.1017/jfm.2013.335
  » http://doi.org/10.1017/jfm.2013.335
• Henriques AL, Krolow TK, Rafael JA. Corrections and additions to Catalogue of Neotropical Diptera (Tabanidae) of Coscarón & Papavero (2009). Rev Bras Entomol 2012; 56(3): 277-280. http://doi.org/10.1590/S0085-56262012005000042
  » http://doi.org/10.1590/S0085-56262012005000042
• Kirst FD, Marinoni L, Krüger RF. New distribution records for Sciomyzidae species (Insecta, Diptera) from Rio Grande do Sul, Brazil. Check List 2015; 11(1): 1-5. http://doi.org/10.15560/11.1.1552
  » http://doi.org/10.15560/11.1.1552
• Kniepert FW. Blood-feeding and nectar-feeding in adult Tabanidae (Diptera). Oecologia 1980; 46(1): 125-129. http://doi.org/10.1007/BF00346976 PMid:28310636.
  » http://doi.org/10.1007/BF00346976
• Krishna S, Cho M, Wehmann HN, Engels T, Lehmann FO. Wing design in flies: properties and aerodynamic function. Insects 2020; 11(8): 466. http://doi.org/10.3390/insects11080466 PMid:32718051.
  » http://doi.org/10.3390/insects11080466
• Kriska G, Bernáth B, Farkas R, Horváth G. Degrees of polarization of reflected light eliciting polarotaxis in dragonflies (Odonata), mayflies (Ephemeroptera) and tabanid flies (Tabanidae). J Insect Physiol 2009; 55(12): 1167-1173. http://doi.org/10.1016/j.jinsphys.2009.08.013 PMid:19699746.
  » http://doi.org/10.1016/j.jinsphys.2009.08.013
• Krüger RF, Krolow TK. Seasonal patterns of horse fly richness and abundance in the Pampa biome of southern Brazil. J Vector Ecol 2015; 40(2): 364-372. http://doi.org/10.1111/jvec.12175 PMid:26611972.
  » http://doi.org/10.1111/jvec.12175
• Lucas M, Krolow TK, Riet-Correa F, Barros ATM, Krüger RF, Saraiva A, et al. Diversity and seasonality of horse flies (Diptera: Tabanidae) in Uruguay. Sci Rep 2020; 10(1): 401. http://doi.org/10.1038/s41598-019-57356-0 PMid:31942013.
  » http://doi.org/10.1038/s41598-019-57356-0
• Luz-Alves WC, Gorayeb IS, Silva JCL, Loureiro ECB. Bactérias transportadas em mutucas (Diptera: Tabanidae) no nordeste do estado do Pará, Brasil. Bol Mus Para Emílio Goeldi Ciênc Nat 2007; 2(3): 11-20. http://doi.org/10.46357/bcnaturais.v2i3.691
  » http://doi.org/10.46357/bcnaturais.v2i3.691
• Mullens BA, Fryxell RT, Masonick PK, Yanega DA, Davis TM. Hiding in plain sight: An abundant and widespread north american horse fly (Diptera: Tabanidae) in the Tabanus sulcifrons group, Tabanus variegatus Fabricius, redescribed. J Med Entomol 2022; 59(4): 1217-1235. http://doi.org/10.1093/jme/tjac057 PMid:35639998.
  » http://doi.org/10.1093/jme/tjac057
• Mullens BA. Horse flies and deer flies (Tabanidae). In: Mullens BA, editor. Medical and veterinary entomology 3rd ed. Riverside: Acad Press; 2019. p. 327-343. http://doi.org/10.1016/B978-0-12-814043-7.00016-9
  » http://doi.org/10.1016/B978-0-12-814043-7.00016-9
• Nabawy MRA, Crowther WJ. Aero-optimum hovering kinematics. Bioinspir Biomim 2015; 10(4): 044002. http://doi.org/10.1088/1748-3190/10/4/044002 PMid:26248884.
  » http://doi.org/10.1088/1748-3190/10/4/044002
• Nabawy MRA, Crowther WJ. Optimum hovering wing planform. J Theor Biol 2016; 406: 187-191. http://doi.org/10.1016/j.jtbi.2016.06.024 PMid:27329340.
  » http://doi.org/10.1016/j.jtbi.2016.06.024
• Oksanen J, Simpson G, Blanchet F, Kindt R, Legendre P, Minchin P, et al. vegan: Community Ecology Package. R package version 2.6-4 2022. [cited 2024 Apr 19]. Available from: https://CRAN.R-project.org/package=vegan
  » https://CRAN.R-project.org/package=vegan
• Pape T, Thompson FC. Systema Dipterorum [online]. 2023 [cited 2023 Apr 10]. Available from: https://www.catalogueoflife.org/
  » https://www.catalogueoflife.org/
• Parra-Henao G, Alarcón-Pineda EP, López-Valencia G. Ecology and parasitological analysis of horse flies (Diptera: Tabanidae) in Antioquia, Colombia. Caldasia 2008; 30(1): 179-188.
• R Core Team. R: A language and environment for statistical computing [online]. Vienna, Áustria: R Foundation for Statistical Computing; 2023 [cited 2023 Oct 20]. Available from: https://www.R-project.org/
  » https://www.R-project.org/
• Rafael JA, Charlwood JD. Idade fisiológica, variação sazonal e periodicidade diurna de quatro populações de Tabanidae (Diptera) no Campus Universitário, Manaus, Brasil. Acta Amaz 1980; 10(4): 907-927. http://doi.org/10.1590/1809-43921980104907
  » http://doi.org/10.1590/1809-43921980104907
• Ramos CJR, Franco CS, da Luz SP, Marques J, de Souza KM, do Nascimento LFN, et al. First record of Trypanosoma evansi DNA in Dichelacera alcicornis and Dichelacera januarii (Diptera: Tabanidae) flies in South America. Parasit Vectors 2023; 16(1): 4. http://doi.org/10.1186/s13071-022-05562-7 PMid:36604766.
  » http://doi.org/10.1186/s13071-022-05562-7
• Rodrigues GD, Blodorn E, Zafalon-Silva Â, Domingues W, Marques R, Krolow TK, et al. Molecular detection of Trypanosoma kaiowa in Tabanus triangulum (Diptera: Tabanidae) from the coastal plain of Rio Grande do Sul, southern Brazil. Acta Parasitol 2021; 67(1): 518-522. http://doi.org/10.1007/s11686-021-00440-1 PMid:34196921.
  » http://doi.org/10.1007/s11686-021-00440-1
• Rodrigues GD, Lucas M, Ortiz HG, dos Santos Gonçalves L, Blodorn E, Domingues WB, et al. Molecular of Anaplasma marginale Theiler (Rickettsiales: Anaplasmataceae) in horseflies (Diptera: Tabanidae) in Uruguay. Sci Rep 2022; 12(1): 22460. http://doi.org/10.1038/s41598-022-27067-0 PMid:36577829.
  » http://doi.org/10.1038/s41598-022-27067-0
• Schutz S, Gaugler R. Thermoregulation and hovering behavior of salt marsh horse flies (Diptera: tabanidae). Ann Entomol Soc Am 1992; 85(4): 431-436. http://doi.org/10.1093/aesa/85.4.431
  » http://doi.org/10.1093/aesa/85.4.431
• Silva HILL. Tabanidae (Diptera) da Planície Costeira do Rio Grande do Sul [dissertação]. Pelotas: Universidade Federal de Pelotas; 2016.
• Taioe MO, Motloang MY, Namangala B, Chota A, Molefe NI, Musinguzi SP, et al. Characterization of tabanid flies (Diptera: Tabanidae) in South Africa and Zambia and detection of protozoan parasites they are harbouring. Parasitology 2017; 144(9): 1162-1178. http://doi.org/10.1017/S0031182017000440 PMid:28502276.
  » http://doi.org/10.1017/S0031182017000440
• Torres A, Miranda-Esquivel DR. Wing shape variation in the taxonomic recognition of species of Diachlorus Osten-Sacken (Diptera: Tabanidae) from Colombia. Neotrop Entomol 2016; 45(2): 180-191. http://doi.org/10.1007/s13744-015-0350-1 PMid:26680467.
  » http://doi.org/10.1007/s13744-015-0350-1
• Townes H. A light-weight Malaise trap. Entomol News 1972; 83(9): 239-247.
• Walker JA. Functional morphology and virtual models: physical constraints on the design of oscillating wings, fins, legs, and feet at intermediate Reynolds numbers. Integr Comp Biol 2002; 42(2): 232-242. http://doi.org/10.1093/icb/42.2.232 PMid:21708715.
  » http://doi.org/10.1093/icb/42.2.232
• Wickham H, Averick M, Bryan J, Chang W, McGowan LD, François R, et al. Welcome to the Tidyverse. J Open Source Softw 2019; 4(43): 1686. http://doi.org/10.21105/joss.01686
  » http://doi.org/10.21105/joss.01686
• Zafalon-Silva Â, Kirst FD, Krüger RF. Houseflies speaking for the conservation of natural areas: a broad sampling of Muscidae (Diptera) on coastal plains of the Pampa biome, Southern Brazil. Rev Bras Entomol 2018; 62(4): 292-303. http://doi.org/10.1016/j.rbe.2018.09.002
  » http://doi.org/10.1016/j.rbe.2018.09.002
• Zelditch M, Swiderski D, Sheets HD. Geometric morphometrics for biologists: a primer 2nd ed. Massachusetts: Cambridge; 2012.

Publication Dates

• Publication in this collection
  17 June 2024
• Date of issue
  2024

History

• Received
  21 Dec 2023
• Accepted
  17 Apr 2024