Comparative Scanning Electron Microscopic Study of Antennae and Hearing Organ of Two Indian Mantids Mantis Religiosa and Gongylus Gongylodes
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International Journal of Zoological Investigations Vol. 4, No. 1, 73-80 (2018) _______________________________________________________________________________________ International Journal of Zoological Investigations Contents available at Journals Home Page: www.ijzi.net ISSN: 2454-3055 Comparative Scanning Electron Microscopic Study of Antennae and Hearing Organ of Two Indian Mantids Mantis religiosa and Gongylus gongylodes Kavya M. K., Raghunandan K. S., Padmanabha B. and Channaveerappa H.* P.G. Department of Applied Zoology, Maharani Science College for Women, University of Mysore, Mysuru – 570 005, India *Corresponding Author Received: 30th April 2018 Accepted: 29th May 2018 ______________________________________________________________________________________________________________ Abstract: Antennae of Mantis religiosa and Gongylus gongylodes exhibit sexual dimorphism. In G. gongylodes the male has pectinate antennae with terminal filiform structure but female has filiform antennae.The antennae of male M. religiosa are longer than the female and filiform in both. Antennae of these two species posed for SEM studies showed differences in the distribution of sensillae at basal, middle and terminal flagellomeres in both tsexes of these species. In G. gongylodes the terminal segments had more number of sensilla chaetica and sensilla trichodea than sensilla basiconica and coeloconica. In M. religiosa sensilla coeloconica were more in terminal segments of both the sexes.Tip of antennae was flat, depressed and enclosed sensilla coeloconica in both the sexes. Single hearing organ found in meso-metathoracic region on ventral side. In both species the structure of hearing organ was of DK type in both sexes. Keywords: Sexual dimorphism, Flagellomeres, Sensillae, Terminal segments, Hearing organ , DK type ______________________________________________________________________________________________________________ Introduction Mantids have evolved sensory structures to scanning electron microscopic studies have locate different signals which are adapted been carried out by several workers (Fauchex, specifically to perform certain functions. Two 2006; Holwell et al., 2007; Fauchex, 2009; such structures are antennae and hearing Greven and Brenner, 2009) but such an organs. So far, the antennae have been utilized analysis in Indian mantids is wanting. as tool to describe or discriminate species of Mantids have single ventral hearing organ mantids at taxonomic level and to assess commonly referred to Mantid ear. The sexual dimorphism (Mukherjee et al., 1995; auditory system is unique (Yager, 1999). Vyjayandi, 2005; Sureshan, 2009). The first These organs can trace ultrasonic sounds morphological description of antenna was generated by flying bats (Triblehorn and done by Slifer (1968). Recent works on Yoger, 2005). Few workers have utilized the 73 auditory systems of mantids to trace pressed EVAC button. The sound of rotatory phylogeny (Yager and Svenson, 2008) and pump is heard and then wait for more than 20 described six different kinds of hearing minutes to achieve high vacuum. organs, of these four are found to be most commonly distributed among mantid fauna. Then the SEM is turned on by pressing ‘on’ The present study performed the scanning button. Then select magnification on the electron microscopic structures of antennae of screen obtaining from 10X made to high two Indian mantids, M. religiosa and G. desired magnification. For this the key of Z gongylodes to observe whether there is axis were used and adjusted the images using geographical variation existing in the antennal key on the SEM table board. structures already described in other species Results from different parts of the world. Also, SEM analysis of antenna Gongylus gongylodes description of hearing organs of two mantids G. gongylodes and M. religiosa are presented. The antenna (Figs. 1-4) of both the sexes scanned for the detailed study revealed Materials and Methods similar types of sensilla with difference in Hearing organs of both the species are located distribution on the antennal segments. The on the ventral meso-metathoracic region pectinate section of male antenna had more viewed by lateral stretching of the meso- members of sensilla basiconica, sensilla metathoracic segments. Hearing organs were coeloconica, as well sensilla trichodeum photographed using NIKON D7000 DSLR (Table 1). The sensillae were found to be camera. located in a round depression irrespective of the type, sensilla coeloconica and trichodeum Scanning Electron Microscopy had straight stem and surrounded by cuticular The procedure by Doug Kim and Chunmin wall. The terminal part of the antenna of male Fung (2005) was followed for SEM imaging. and female had more number of sensilla Scanning electron microscope studies were trichodea, sensilla basiconica and sensilla done using Carl Zeiss Electron Microscope at coeloconica. In the non-pectinate region of the IOE University of Mysore, Mysore. The parts male antenna large sized trichodium was to be imaged were obtained from the freshly recorded. In female the long trichodial sensilla prepared specimens of mantids of both sexes. and large trichodial sensilla were present in The samples of antennae or parts of leg were all the segments but the number was more separated and critically dried and mounted on compared to the male terminal structures. to carbon sticky tapes, the position of each Their number in the flagellar segments was sample noted. The values of the nitrogen gas more than 25 in each terminal as well mid tank (less than 100 psi) kept open, vent segments of female. Even the small button on the microscope table pressed. After coeloconica and basiconica sensilla were the click sound the chamber door is opened by found scattered in each antennal segment and pulling the lever up. The sample mounting their number was equally high compared to stage moved down by operating the Z axis key. male antennal terminal segment. All types of The sample holder stubs are placed into the sensilla were present in circular cuticular mounting holes. Closed the door and then depression in female antennal segment like 74 that of male antennae. The length of antenna Hearing organ in male was 18.05 mm and of female was 6.86 Hearing organ (Figs. 8a, b) is located in mm. between meta and mesothoracic legs on the SEM analysis of antenna of Mantis religiosa ventral surface in Gongylus gongylodes and Mantis religiosa and were of DK form (deep Antennae of both the sexes in Mantis religiosa groove and prominent knobs). The ultrasound (Figs. 5-7) are filiform and exhibited variation sensitive chambers were separated at its in between male and female. The antennal anterior end by two well defined thick length of male was 24.51 mm and had 99 cuticular lobes. At right angle to the long axis of the thorax, the rostral border of the knob segments whereas in females the length was was present. The two lateral walls of the 10.61 mm and had 62 antennomeres. Each chamber almost touch the rostral region at antenna irrespective of the sex is formed of a 1/3 of the length and progressively the wall scape, a pedicel and flagellomeres. The scape are widely separated in the posterior region. is long compared to other segments of the Two furcal pits lie deep in the chamber near antenna and cylindrical in shape. The pedicel the caudal end which were not visible from is bulbus and articulates with flagellum. The outside. The lateral wall of the auditory chamber faces medially and include three first flagellomere is twice longer than the distinctive structure—(i) cuticle ridge (ii) other mid anteomeric segments. 2-5 basal tympanal depression and (iii) the bifid flagellomeres are referred to and could be sensillum. The cuticle ridge or ventral rod recognized easily by their short length and runs from rostral to caudal direction in the carry few sensilla. After 10th/11th segment middle of the wall. Dorsal to this wall is a tear only the flagellomere acquire regular size, drop shape tympanal depression, it is the real whereas the distal flagellomere is three times tympanum. At the extreme point to the ends of the ventral rod and the tympanum is longer than normal segments. The SEM present a conical sensory structure -- the bifid studies have revealed that the flagellum bears sensillum which is encircled by a thin cuticle. different types of sensilla coeloconica and In Gongylus gongylodes, a dark brown sensilla basiconica (Table 1) which are expanded structure (Fig. 8 b) was present on present in both sexes of this species. The basal abdomen in between the 6th--8th abdominal segments showed a plain structure without segments which was strongly represented in any sensilla whereas the last few segments males whereas in female it was present had different type of sensilla-- sensilla between 6th-7th segments and feebly basiconica, sensilla coeloconica, sensilla represented. This patch has velvet like trichodium (a long hair-like structure covering and its significance is not scattered in each of the terminal segments, understood. The butterfly like brown 50-60 flagellomres) and sensilla chactica (5-6 structure expanded in the corner angles scattered in each of the terminal segments). appeared as bright dark brown marks. In On the basal flagellomere and on scape Mantis religiosa this marking was totally bohm’s sensilla and sensilla chaetica were absent in both sexes. found. 75 Table 1: Measurements of different types of sensilla present in antenna Types of sensilla M. religiosa G. gongylodes Sensilla basiconica 4.5 ± 0.4µm 4.01 0.4µm Sensilla coeloconica 1. 1.2 ± 0.2µm 1. 3.04 0.4µm 2. 3.01 ± 0.2µm 2. 6.6 ± 0.01µm 3. 6.2± 0.1µm Sensilla trichodia 21.01 to 35.6 ± o.2µm 20.09 to 37.56 o.1µm Sensilla chaetica 1. 33.1 ± 3.0µm 1. 30.2 8.0µm 2. 109 9.5µm 2. 110.1 8.5µm Fig. 1: Gongylus gongylodes male antenna: A = Fig. 2: Gongylus gongylodes male antenna: Enlarged Pectinate and B = Terminal part portion of Pectinate region showing sensillae B- Basiconica C- Coeloconica Fig. 3: Gongylus gongylodes Female antenna Fig. 4: Gongylus gongylodes Female antenna Terminal part : C = Chaetica; T = Trichodia 76 Fig.