Sensory Trichites Associated With the Food Canal of Chrysops callidus (Diptera: Tabanidae)

Sensilla, beginning at the distal-most tip of the labrum and extending proximally through the cibarium to the stomodaeum, were examined in females of Chrysops exitans Walker. Totals of 328 setiform sensilla (range, 14 to 21; mean = 18.2; ±1 SD = 1.67), and 36 basiconic sensilla (mean = 2.0; ±1 SD = 0) were observed in the food canal of n = 18 sample individuals. Both types of sensilla were aggregated distally in the canal. Additionally, a group of five to 10 sensilla was observed in each lateral wall of the epipharynx, with a single median group, consisting of both setiform and basiconic sensilla, positioned immediately distal to the mouth opening into the cibarium. Two pairs of basiconic sensilla were consistently observed in the stomodaeum of every fly.

Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Distribution of sensory sensilla in the labral food canal and cibarium of Chrysops exitans (Diptera: Tabanidae).

Ranavaya

Joy

2017

“…The "spacing" of sensilla noted by Buerger (1967) suggests that aggregation of food canal sensilla in H. rupestris is similar to that found in H. difficilis (Table 1). Increased spacing of sensilla in the food canal, from distal to proximal, has also been reported in the deer fly, Chrysops callidus (Joy and Stephens 2016). Mean numbers of food canal sensilla provided by Scudder (1953) and Buerger (1967) appear somewhat greater than the mean ± 1SD (50.15 ± 10.02) observed for H. difficilis, but without measures of variability in the T. quinquevittatus or H. rupestris data, statistical comparisons between numbers of labral sensilla in those species with the H. difficilis sample population cannot be made.…”

Section: Sensilla Of the Food Canalmentioning

confidence: 66%

Putative Sensory Structures Associated with the Food Canal of Hybomitra difficilis (Diptera: Tabanidae).

Setser

Joy

2017

The feeding tube of Hybomitra difficilis is made up of a short distal vestibule followed by a food canal that leads to the cibarium; the two regions demarcated by the vestibule/food canal junction. Two pairs of sensilla were consistently observed in the vestibular walls, the first pair of basiconic design in the mid-vestibular region, and the latter pair of setiform design at the base of the vestibule. Numbers of setiform sensilla in the food canal varied from 31 to 69 (mean = 48.15; ± 1 SD = 10.02), and were aggregated in the distal and distal median regions of the food canal. This aggregation was significant (X 2 = 241.49; P < 0.0001), leading to rejection of the null hypothesis that setiform sensilla were evenly distributed throughout the length of the food canal.Two basiconic sensilla were observed in the food canal of every fly examined. While basiconic sensilla varied in position (i.e., distance) from the vestibule/food canal junction, they were significantly aggregated (X 2 = 14.42; P < 0.0024) in the two median sections of the distal canal region, thus leading to the rejection of Ho that basiconic sensilla were evenly distributed in subdivisions (i.e., sections) of the distal canal region.

“…Curiously, aggregation patterns of sensory sensillae in the food canal/cibarium complex of tsetse flies are quite different from those found in bloodfeeding tabanids despite both groups of flies being PWVAS housed in the Brachycera clade and sharing similar diets. For example, sensory sensillae are aggregated in the distal regions of the food canals of tabanid flies (Buerger 1967, Joy and Stephens 2016, Joy 2017, Ranavaya and Joy, 2017, Setser and Joy 2017, whereas these sensillae are aggregated in the proximal-most canal region of tsetse flies (Stephens et al 1906, Buerger 1967, Rice, et al 1973. Why aggregations of sensory sensillae in deer flies and horse flies is so different from that of tsetse flies is uncertain, but a plausible explanation may lie in the structure of the distal labrum/food canal complex (Figs.…”

Section: Discussionmentioning

confidence: 99%

“…We sought to address this oversight by critically mapping positions of sensory sensillae in the food canal and cibarium of tsetse flies. This approach seems especially relevant, given that reports of aggregation patterns of sensory sensillae in the food canal of certain tabanid flies (Buerger 1967, Joy and Stephens 2016, Joy 2017, suggests that the monitoring of blood flow is more critical in certain regions of the tabanid feeding complex. Thus the focus of this study was to identify general sensilla types in the food canal and cibarium of Glossina m. morsitans, and determine if evidence of aggregation patterns of these sensory structures exists, and further, to determine if there are differences in any such patterns between female and male tsetse.…”

Section: Introductionmentioning

confidence: 99%

Aggregation Patterns of Sensory Sensillae in the Food Canal and Cibarium of Glossina morsitans morsitans (Diptera: Glossinidae)

Joy¹,

Rio

Setser³

et al. 2019

Mouthparts of hematophagous vectors serve as intermediaries, enabling the transfer of blood and pathogens from and to their hosts. We describe aggregation patterns of basiconic and setiform sensillae in the food canal and cibarium of the medically significant tsetse fly, Glossina morsitans morsitans Westwood. Mean body length of females was significantly greater than males (n = 20 for each sex). Mean lengths of food canal and cibarium were also significantly greater in females, even when correcting for the greater body lengths of females, but there was no significant difference in total number of sensillae in the food canal or cibarium between the sexes. A pair of basiconic (campaniform) sensillae was consistently present in the food canal of every individual, but numbers of setiform sensillae in the canal of both females and males varied from 53 to 74. No basiconic sensillae were observed in the cibarium proper of any individual, but four minute conical basicones embedded in a sclerotized plate at the posterior edge of the cibarial wall were observed. Number of setiform sensillae in the cibarium varied from 5 to 12 in females and 7 to 11 in males. Setiform and basiconic sensillae were significantly aggregated in the proximal-most (i.e., nearest the head) food canal region of both sexes, whereas setiforms were significantly aggregated in the mid regions of the cibarium. Sensilla aggregation patterns in tsetse flies are very different from those documented for tabanid flies indicating potential differences in monitoring blood flow between these two groups of hematophagous feeders.