Morphological characteristics of Triatoma rubrofasciata at different developmental stages

Abstract

Abstract:

Objective To describe and compare the morphological characteristics of Triatoma rubrofasciata at different developmental stages. Methods Adult T. rubrofasciata were captured and fed to obtain eggs and nymphs, which were then observed under a dissecting microscope to measure egg length, egg middle width, egg lid width, and egg lid middle height. For nymph and adult T. rubrofasciata, the following were measured: body length, head length, head width, length of anteocular part, length of postocular part, distance between ommateums, distance between ocelli, length of antennal joints, length of rostral segments, length of pronotum, length of anterior lobe of pronotum, length of posterior lobe of pronotum, maximum width of throax, maximum width of abdomen and length of forewing bud/hemelytron. Morphological comparisons were made between the adult T. rubrofasciata observed in this study and those of Panstrongylus, Rhodnius, and Triatoma sinica recorded in Medical Entomology and Chinese Bug Identification Manual. Results The life history of T. rubrofasciata includes egg, nymphⅠ-Ⅴ and adult stages. The eggs had a long oval shape, sized 1.838 mm × 0.976 mm on average, with an egg lid. The eyespot emerged in the late development stage. The body length increased from nymph to adult stage, being 2.546 mm, 4.834 mm, 7.127 mm, 10.258 mm, 17.062 mm and 21.787 mm at nymphⅠ-Ⅴ and adult stages, respectively. The wing buds grew out at nymph Ⅲ and then elongated gradually, which finally developed into wings at the adult stage. The average lengths of forewing bud/hemelytron from nymphⅢ to adult were 0.584 mm, 1.261 mm, 3.832 mm and 13.359 mm, respectively. The ocelli did not develop from nymphⅠ to nymphⅣ, showed a trace at nymphⅤ and finally developed into ocellus pair at adult. T. rubrofasciata could be differentiated from the genera of Panstrongylus and Rhodnius based on the shape of the head and the location of the antennae. The T. rubrofasciata had a moderate head length, and antennas between eyes and the clypeus. In contrast, the Panstrongylus had a thick and short head, and antennas located rightly ahead of the eyes. The Rhodnius had a narrow and long head and antennas located at the anterior region of the head, close to the clypeus. T. rubrofasciata could be differentiated from T. sinica based on the presence of particles on the head and the pronotum, and the morphological characteristics of the front angles of the pronotum and the angulus parielis of the scutel. For T. rubrofasciata, there were many particles on the head and the pronotum. The front angles of the pronotum were long and the angulus parielis of the scutel was needle-like. For T. sinica, there were no particles but wrinkles on the head and the pronotum. The front angles of the pronotum were short and the angulus parielis of the scutel did not appear needle-like. Conclusion The T. rubrofasciata had distinct morphological characteristics at different developmental stages. The morphological characteristics of adult T. rubrofasciata can be differentiated from those of Panstrongylus and Rhodnius genera as well as T. sinica.

Key words: Triatoma rubrofasciata, Nymph, Morphological characteristic

CLC Number:

R384.9

Li-zhen XIAO, Zhu-yun CHEN, Rong OUYANG, Xian-liang XIE, Han-guo XIE. Morphological characteristics of Triatoma rubrofasciata at different developmental stages[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2018, 36(6): 605-610.

Figures/Tables 4

Fig. 1

Fig. 2

Fig. 3

Table 1

Morphological measurements of T. rubrofasciata nymphs and adults (n = 10)

形态特征测量/mm Morphological measure- ment/mm	Ⅰ龄若虫 Nymph Ⅰ	Ⅱ龄若虫 Nymph Ⅱ	Ⅲ龄若虫 Nymph Ⅲ	Ⅳ龄若虫 Nymph Ⅳ	Ⅴ龄若虫 Nymph Ⅴ	成虫 Adult
体长 Body length	2.546 (2.389, 2.670)	4.834 (4.335, 5.275)	7.127 (6.582, 7.568)	10.258 (7.828, 11.578)	17.062 (15.848, 18.577)	21.787 (18.986, 23.933)
头长 Head length	0.856 (0.791, 0.902)	1.136 (1.034, 1.271)	1.575 (1.477, 1.679)	2.068 (1.739, 2.280)	2.843 (2.664, 3.001)	3.248 (2.603, 3.810)
头宽 Head width	0.475 (0.454, 0.503)	0.626 (0.590, 0.673)	0.885 (0.861, 0.930)	1.172 (0.925, 1.308)	1.572 (1.381, 1.693)	1.980 (1.185, 2.232)
眼前部分长 Length of anteocular part	0.526 (0.469, 0.586)	0.692 (0.630, 0.740)	0.977 (0.871, 1.105)	1.284 (1.116, 1.471)	1.739 (1.595, 1.859)	1.781 (1.400, 1.993)
眼后部分长 Length of postocular part	0.162 (0.134, 0.181)	0.219 (0.172, 0.286)	0.269 (0.237, 0.308)	0.346 (0.247, 0.465)	0.529 (0.443, 0.656)	0.545 (0.354, 0.726)
复眼间距Distance between ommateum	0.349 (0.304, 0.388)	0.491 (0.457, 0.517)	0.647 (0.596, 0.682)	0.813 (0.676, 0.962)	1.178 (1.045, 1.257)	0.914 (0.779, 1.045)
单眼间距 Distance between ocelli	-	-	-	-	-	0.809 (0.691, 0.940)
触角长Ⅰ Length of antennal joints Ⅰ	0.179 (0.156, 0.202)	0.227 (0.186, 0.277)	0.295 (0.263, 0.322)	0.390 (0.325, 0.467)	0.660 (0.560, 0.759)	0.889 (0.790, 1.117)
触角长Ⅱ Length of antennal joints Ⅱ	0.413 (0.385, 0.434)	0.606 (0.563, 0.656)	0.919 (0.852, 1.081)	1.246 (1.047, 1.409)	2.401 (2.013, 2.585)	3.651 (2.835, 4.064)
触角长Ⅲ Length of antennal joints Ⅲ	0.570 (0.484, 0.643)	0.751 (0.714, 0.807)	0.990 (0.929, 1.092)	1.254 (1.066, 1.364)	1.897 (1.754, 2.062)	2.438 (2.335, 2.580)
触角长Ⅳ Length of antennal joints Ⅳ	0.630 (0.405, 0.725)	0.849 (0.810, 0.899)	1.023 (0.872, 1.103)	1.132 (1.004, 1.221)	1.585 (1.501, 1.621)	1.695 (1.623, 1.798)
喙长Ⅰ Length of rostral segments Ⅰ	0.245 (0.227, 0.263)	0.339 (0.301, 0.389)	0.557 (0.514, 0.591)	0.671 (0.509, 0.757)	1.005 (0.884, 1.141)	1.234 (0.903, 1.470)
喙长Ⅱ Length of rostral segments Ⅱ	0.425 (0.384, 0.462)	0.611 (0.562, 0.701)	0.920 (0.857, 0.974)	1.165 (0.824, 1.394)	1.584 (1.441, 1.755)	1.974 (1.681, 2.214)
喙长Ⅲ Length of rostral segments Ⅲ	0.223 (0.196, 0.254)	0.263 (0.236, 0.309)	0.386 (0.358, 0.427)	0.450 (0.391,0.522)	0.609 (0.556, 0.674)	0.638 (0.532, 0.784)
前胸背板长 Length of Pronotum	0.282 (0.255, 0.298)	0.462 (0.424, 0.485)	0.792 (0.744, 0.842)	1.139 (0.866, 1.308)	1.910 (1.683, 2.055)	3.530 (2.241, 4.020)
前胸背板前叶长 Length of anterior lobe of pronotum	0.463 (0.430, 0.482)	0.668 (0.632, 0.699)	0.984 (0.937, 1.039)	1.253 (1.044, 1.380)	1.895 (1.799, 1.997)	2.102 (1.931, 2.320)
前胸背板后叶长 Length of posterior lobe of pronotum	0.645 (0.622, 0.668)	0.942 (0.893, 0.975)	1.462 (1.370, 1.521)	2.082 (1.672, 2.416)	3.446 (3.042, 3.590)	5.333 (4.728, 5.936)
胸部最大宽度 Maximum width of throax	0.683 (0.647, 0.731)	1.074 (0.053, 1.116)	1.717 (1.636, 1.777)	2.631 (1.878, 3.469)	4.376 (4.032, 4.826)	5.333 (4.728, 5.936)
腹部最大宽度 Maximum width of abdomen	0.980 (0.921, 1.056)	2.052 (1.885, 2.175)	2.943 (2.582, 3.237)	4.251 (2.979, 5.176)	7.074 (6.392, 7.638)	8.104 (6.499, 9.045)
前翅翅芽/前翅长 Length of forewing bud/ hemelytron	-	-	0.584 (0.551, 0.609)	1.261 (0.617, 1.612)	3.832 (3.423, 4.122)	13.359 (11.752, 14.553)

Table 1

References 20

[1]	萧采瑜. 中国蝽类昆虫鉴定手册[M]. 北京: 科学出版社, 1981: 390-538.
[2]	柳支英, 陆宝麟. 医学昆虫学[M]. 北京: 科学出版社, 1990: 297-302.
[3]	Carod-Artal FJ.American trypanosomiasis[J]. Handb Clin Neurol, 2013, 114: 103-123.
[4]	Coura JR.The main sceneries of Chagas disease transmission. The vectors, blood and oral transmissions: a comprehensive review[J]. Mem Inst Oswaldo Cruz, 2015, 110(3): 277-282.
[5]	Pérez-Molina JA, Perez AM, Norman FF, et al. Old and new challenges in Chagas disease[J]. Lancet Infect Dis, 2015, 15(11): 1347-1356.
[6]	World Health Organization.Informal consultation on Chagas disease in the Western Pacific[R]. Geneva: WHO, 2011.
[7]	World Health Organization. Chagas disease (American trypano-somiasis) [EB/OL]. (2018-02-01)[2018-09-28]. .
[8]	Schmunis GA, Yadon ZE.Chagas disease: a Latin American health problem becoming a world health problem[J]. Acta Trop, 2010, 115(1): 14-21.
[9]	Jackson Y, Pinto A, Pett S.Chagas disease in Australia and New Zealand: risks and needs for public health interventions[J]. Trop Med Int Health, 2014, 19(2): 212-218.
[10]	Roure S, Valerio L, Vallès X, et al. Oesophageal motility disorders in infected immigrants with Chagas disease in a non-endemic European area[J]. United European Gastroenterol J, 2016, 4(4): 614-620.
[11]	Tarleton RL, Curran JW.Is Chagas disease really the “new HIV/AIDS of the Americas”[J]. PLoS Negl Trop Dis, 2012, 6(10): e1861.
[12]	孙懿, 黄韦华, 牛紫光, 等. 1例输入性非洲锥虫病的病原学鉴定[J]. 中国寄生虫学与寄生虫病杂志, 2016, 34(4): 350-354.
[13]	陈朱云, 谢汉国, 林耀莹, 等. 首例输入性布氏罗得西亚锥虫病病例分析[J]. 中国人兽共患病学报, 2018, 34(4): 388-390.
[14]	Liu Q, Chen XL, Chen MX, et al. Trypanosoma brucei rhodesiense infection in a Chinese traveler returning from the Serengeti National Park in Tanzania[J]. Infect Dis Poverty, 2018, 7: 50.
[15]	林耀莹, 张山鹰, 谢汉国, 等. 一例输入性非洲锥虫病的实验室诊断[J]. 中国寄生虫学与寄生虫病杂志, 2018, 36(4): 366-369.
[16]	钱颖骏, 李石柱, 王强, 等. 中国输入性美洲锥虫病疫情的快速风险评估[J]. 中国寄生虫学与寄生虫病杂志, 2013, 31(1): 57-59.
[17]	Liu Q, Zhou XN.Preventing the transmission of American trypanosomiasis and its spread into non-endemic countries[J]. Infect Dis Poverty, 2015, 4: 60.
[18]	萧采瑜. 锥蝽——新种记述(半翅目, 猎蝽科)[J]. 动物分类学报, 1965, 2(3): 197-199.
[19]	Liu Q, Guo YH, Zhang Y, et al. First records of Triatoma rubrofasciata (De Geer, 1773) (Hemiptera, Reduviidae) in Foshan, Guangdong Province, Southern China[J]. Infect Dis Poverty, 2017, 6: 129.
[20]	任树芝. 蝽类昆虫卵形态细微结构扫描电镜观察(半翅目 : 蝽科)[J]. 南开大学学报(自然科学版), 2001, 34(2): 109-113.