See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/229014126 Cuticular structures on antennae of the bot fly, Portschinskia magnifica (Diptera: Oestridae) ARTICLE in PARASITOLOGY RESEARCH · JULY 2012 Impact Factor: 2.1 · DOI: 10.1007/s00436-012-3004-9 · Source: PubMed CITATIONS READS 11 58 4 AUTHORS, INCLUDING: Dong Zhang Beijing Forestry University 49 PUBLICATIONS 109 CITATIONS SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Dong Zhang letting you access and read them immediately. Retrieved on: 25 November 2015 Parasitol Res (2012) 111:1651–1659 DOI 10.1007/s00436-012-3004-9 ORIGINAL PAPER Cuticular structures on antennae of the bot fly, Portschinskia magnifica (Diptera: Oestridae) Dong Zhang & Qi-Ke Wang & De-Fu Hu & Kai Li Received: 9 April 2012 /Accepted: 8 June 2012 /Published online: 10 July 2012 # Springer-Verlag 2012 Abstract Portschinskia magnifica Pleske, 1926, is an en- described in the oestrid funiculus. Interestingly, these dangered subcutaneous parasitic fly of voles that mimics bristles can appear as multi-tipped short structures in bumblebees in appearance. Although the importance of some individuals. P. magnifica lacks sensory pits that antennae in Diptera has been repeatedly stressed, there is are usually abundant in other oestrid flies. The size, still a lack of morphology information of this group, let number, and distribution of sensilla on the male and alone this species. Antennae of adult P. magnifica were female antennal funiculus are provided here, armed with studied with a stereoscopic microscope and scanning elec- a discussion of their presumable sensilla functions and tron microscope. Six subtypes of antennal sensilla were evolutionary trends. observed on the funiculus and arista (one subtype of trichoid sensilla, one subtype of basiconic sensilla, and four subtypes of coeloconic sensilla). Sensilla on the antennal funiculus Introduction from one sample of both male and female flies were also mapped. Female P. magnifica bear a larger number of sen- Portschinskia magnifica Pleske, 1926, is one of the largest silla than males, and more sensilla were discovered on the parasitic flies that belong to the subfamily Hypodermatinae, posterior surface than on the anterior surface. However, Oestridae. Adult Portschinskia flies strikingly resemble bum- what make this species special are the distinct structures blebees in size and shape (Fig. 1b), which suggests mimicry. and new morphological characteristics discovered in the The larvae of this genus are subcutaneous parasites which antenna. The antennal funiculus of P. magnifica is complete- typically spend their larval stages in the skin or soft tissues ly enveloped by an antennal pedicel. A large number of of rodents and lagomorphs. P. magnifica mainly infests the branched or unbranched trichoid and basiconic sensilla are field vole, Apodemus speciosus (Rodentia: Muridae). Gener- identified on the antennal funiculus. These two make the ally, only one larva can be found on the ventral surface near most numerous types of sensilla distributed all over the the tail of voles (Colwell et al. 2006). Larval development funicular surface. P. magnifica has the most coeloconic requires approximately 2 months, and there is a distinct pupal sensilla subtypes in previously studied oestrid flies. A total diapause for overwintering. Zumpt (1965) indicated that of four subtypes of coeloconic sensilla are found, with infested mice are sluggish and easily approached, thus making subtype I and subtype II on the proximal and middle part them susceptible to predation; he also pointed out that “large” of the antennal funiculus and subtype III and subtype IV on numbers of larvae often cause death among mice. the antennal arista. Two large bristles that resemble mecha- P. magnifica that has been studied in this paper was listed noreceptors on the proximal two antennal segments located by Colwell et al. (2009) as a rare and endangered bot close to the arista are a unique feature. This has never been species. It is endemic to Asia and recorded for the first time in Beijing. Currently, there is a paucity of information on : : : oestrid fly sensory organs (Hunter and Adserballe 1996; D. Zhang Q.-K. Wang D.-F. Hu K. Li (*) Fernandes et al. 2002; Ngern-klun et al. 2007; Poddighe et Department of Zoology, College of Biological Sciences al. 2010). This situation prevents a deeper understanding of and Biotechnology, Beijing Forestry University, – Qinghua East Road No. 35, Mailbox 162, Beijing 100083, China the biology, host parasite interactions, and morphology of e-mail: [email protected] this group. Since the antennal sensory organs are one of the 1652 Parasitol Res (2012) 111:1651–1659 Fig. 1 Light micrographs of the body, heads, and antennae of adult P. magnifica. a Head of male P. magnifica. b Lateral view of male adult P. magnifica. c Head of female P. magnifica. d Magnification of the male antenna. e Magnification of the female antenna. f Magnification of the female antenna, showing the position of the funiculus inside the scape. g The opening of the female scape, showing the position of the arista. Ar arista, Fn funiculus, Pd pedicel, Sc scape. Scale bar02mmina and c, 5 mm in b, 0.5 mm in d, f, and g, and 1 mm in e main sources for Diptera to pick up outside information (Canon, Inc., Tokyo, Japan) coupled with the stereoscopic (Boo 1980; Amer and Mehlhorn 2006; Guha et al. 2012; microscope for further analysis. Wang et al. 2012), this study looks at the fine antennal To prepare for observation with the scanning electron structure of adult P. magnifica. Descriptions of cuticular microscope (SEM), the heads of ten pinned flies (males05, structures and, in particular, sensilla with presumed olfacto- females05) were first cut off and rinsed in phosphate-buffered ry function, are reported herein. saline (PBS) buffer (pH 7.4) to remove surface debris. There- after, for further cleaning, the funiculus was dissected from the head and cleaned with detergent. Specimens were then Materials and methods rinsed with PBS and dehydrated in a graded ethanol series (30, 50, 70, 80, 90, 95, and 100 %, in each case for 2 h), Both male and female adult bot flies (P. magnifica) were mounted on stubs with double-sided adhesive tape, left in captured during June of 2006, 2009, and 2011 in Songshan a desiccator overnight to dry thoroughly, and then coated Mountain or Xiaolongmen, Beijing, China. The specimens with gold (Ngern-klun et al. 2007). Samples were ob- were pinned as museum samples and air-dried on site. served using a HITACHI S34Q scanning electron micro- The morphology of the antenna was studied by using an scope (Hitachi Corp., Tokyo, Japan) at the Microscopy Core Olympus SZX16 stereoscopic microscope (Olympus Corp., Facility, Biological Technology Center, Beijing Forestry Uni- Tokyo, Japan). A series of photographs of continuous versity (Beijing, China). Micrographs of antennae were taken; sequences was taken by a Cannon 500D digital camera the dimensions of the sensilla were measured. Abundant Parasitol Res (2012) 111:1651–1659 1653 distribution and measurements of the antennal sensilla types structures (Fig. 5a), a characteristic to distinguish microtri- were compared between males and females. chiae from basiconic sensilla and trichoid sensilla. Different All the micrographs and ultra-micrograph files were an- from any sensilla, the microtrichiae gradually tapers into a alyzed on a standard Windows XP platform by Adobe sharply pointed tip. An observation of the antennal funiculus Photoshop CS2 (Adobe Systems, Inc., San Jose, CA, reveals that a total of four morphological types of sensilla are USA) and Helicon Focus (Helicon Soft Ltd., Kharkov, scattered on the entire funicular surface, including trichoid Ukraine) for Windows. The sequence series of light photo- sensilla, basiconic sensilla, and two kinds of coeloconic graphs was fed to Helicon Focus to compose images with sensilla. more field depth. The types, original distribution, and num- The arista (Ar) consists of two short basal segments and ber of sensilla from a single specimen of both sexes were one long distal segment that twisted towards the tip marked and presented in Fig. 6. (Fig. 2d). The surface of the aristal segment is also covered The terminology and nomenclatures used to describe with microtrichiae. Two subtypes of cone-shaped coelo- antennal morphology and classification of sensilla types in conic sensilla are found at the base. this study follow the ones used by Hunter and Adserballe Trichoid sensilla and basiconic sensilla are located random- (1996), Shanbhag et al. (1999), and Setzu et al. (2011). ly all over the funicular surface (Fig. 6), while the two types of coeloconic sensilla are only distributed on the proximal and middle part. The ventral surface in both sexes has more Results sensilla than the dorsal surface. The number of sensilla on the funicular surface of P. magnifica shows sexual dimor- General description of the antenna of P. magnifica phism. All four types of funicular sensilla were found on both sexes, but females have a significantly larger number than One of the largest species in Calyptratae, P. magnifica,is males. However, Fig. 6 was made according to antennal SEM equipped with a pair of antennae located on the frontal images of two individuals, the images could not cover the region of the head between the compound eyes (Fig. 1a, c, whole surface area, and inaccuracy could not be avoided. d, and e). Each antenna consists of three well-developed Two bristles are found on the antennal funiculus near the segments, a proximal scape (Sc), a pedicel (Pd), and a arista in some specimens. The larger one is about 152.4± flagellum; the latter is further divided into a funiculus (Fn) 11.2 μm in length and 9.4±3.2 μm in width, and the smaller and an arista (Ar) (Fig.