Bonn zoological Bulletin Volume 57 Issue 1 pp. 91-98 Bonn, April 2010 Antennal sensilla of the rice hispa Dicladispa armigera (Olivier, 1808) (Coleoptera: Chrysomelidae) Munna Rani Saikia1 Lakshmi Kanta Hazarika1 2 Surajit Kalita1 & Ramen Lai Baishya1 ; ; •Assam Agricultural University, Department ofEntomology, Jorhat-785 013, Assam, India; 2E-mail: lkhazarika(®aau.ac.in Abstract.Numberandtypesofsensillaoneachantennal segmentofmaleandfemaleadultricehispaDicladispaarmigera (Olivier) (Coleoptera: Chrysomelidae) were determined based on light and scanning electron microscopic observations. The males had a significantly greater total number (0 1828.11) ofsensilla than females (0 1764.43). Five types ofsen- silla, namely, sensilla chaetica, sensilla trichodea I, sensilla trichodea II, sensillabasiconica andpitorcoeloconic sensil- la were distinguished in both sexes. Sensilla trichodea I and II were distributed over the entire length ofthe antenna, whereas sensilla chaeticawere observed only on the apical five flagellomeres. Methoprene affected antennal morpholo- gybyproducing two-clubbedantenna (additional one atthe 3rd flagellomere) andalteration inthe sensillaofthe last fla- gellomere. Key words. Rice hispa, sensilla chaetica, sensilla trichodea I, sensilla trichodea II, sensilla basiconica, methoprene. INTRODUCTION The rice hispa Dicladispa armigera (Olivier, 1808) smdies has been conducted on the sensilla of other (Coleoptera: Chrysomelidae) occurs in South East Asia coleopteran insects like fleabeetles,Phyllotetra crucifer- andAfrica, and is one ofthe major pests ofrice in many ae (Goeze, Mil), Psylliodes punctulata Melsheimer, & rice growing states of India (Deka Hazarika 1996; 1847, P. affinis (Paykull, 1799) and Epitrix cucumeris & Palaszek et al. 2002; Islam et al. 2004; Hazarika et al. (Harris, 1851) (Ritcey Mclver 1990); however, current- 2005). It causes considerable damage to vegetative ly there is no information available describing the sensil- stages ofrice resulting inyield loss of28% in India (Nath laofthe ricehispa. Accordingly, thepresent sUtdywasun- & Dutta 1997), between 20-30% in Nepal (Dhaliwal et dertaken in order to determine the number and types of al. 1998) and up to 52% in deepwater rice in Bangladesh sensilla on each antennal segment of male and female (Islam 1989); however, it may be as high as 100% in the adults ofD. armigera. rice transplantedpost flood inAssam (Hazarika 2005). In order to manage this pest, attempts were made to identi- fypheromones in this insect, with mixed results (Deka & MATERIALS AND METHODS Hazarika 1997). Pheromones are not only usedforsurvey and surveillance of insect pest but also used to manage Fordetermination ofnumberofsensilla, male and female them. antennae offield collected adults were fixed separately in carnoy-lebrun fixative for30 min andwashed for 10 min- During the last three decades, insect communication utes in each ofthe 30%, 50% and 70% alcohol. The an- through antennal sensilla has received substantial inter- tennae were then allowed to remain for twenty minutes est (Rao et al. 1990; Kumaret al. 1995;Axtell 1999). Gen- in each ofthe 90% and absolute alcohol, afterwhich they erally, antennae are covered with huge numbers of sen- were again passedthrough xylene and cleared in clove oil. silla, relevant as sensory organs (Chapman 1982).Anten- Thesewere thenmountedin DPX. Sensillawere observed nal sensilla are involved in host recognition and mate or under the compound microscope at 100X, 400X and microhabitat choice by pheromone- thenno- andhygrore- 1000Xmagnification in oil andwere counted on each seg- ception (Hazarika & Bardoloi 1998; Chen et al. 2003; ment following the method of Ramaswamy & Gupta Ploomi et al. 2003; Marttje et al. 2004). A number of (1981). 92 Munna Rani Saikia et al. Table 1. Estimated number (Mean±S.E.) ofsensilla on each antennal segment ofadult male and female D. armigera. Segment Male Female t-value Scape 25.25±0.29' 21.23i0.37i 8.95** Pedicel 28.45±0.32h 24.99±0.28h 8.77** Flagellum (Fl) Fl l I9.28±0.25k 18.02±0.29J 2.95** Fl 2 22.48±0.30J 2l.48±0.30' 2.48* Fl 3 33.66±0.32s 26.69±0.30g 15.15** Fl 4 6l.67±0.65f 56.77±0.38f 6.82** Fl 5 220.43±0.34e 223.25±0.35e -6.53** Fl 6 265.20±0.4ld 258.36±0.49d 9.79** Fl 7 302.26±0.33< 295.73±0.40<-' 11.99** Fl 8 336.ll±0.28b 332.84±0.39b 8.15** Fl 9 490.84±0.53^ 485.07±0.46a 7.47** S.Ed. (±) 0.05 0.52 C-D- O.ll 1.04 o.05 SE = standard error, sample size = 50. Means within columns are separated by Duncan's Multiple Range Test (DMRT) at p < 0.05. Means followed by the same letter shown in superscript(s) are not significantly different; means within the rows followed by * and ** are significantly different at p < 0.01 and p < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f = 49). RESULTS For determination oftypes ofsensilla, the antennae were The clubbed antennae of adult specimens consisted of fixed for six hours in carnoy-lebrun fixative and mount- scape, pedicel and nine sub-segmented flagellum, each ed in DPX (Schafer & Sanchez 1976). Based on the mor- sub-segment is called flagellomere, the first flagellomere phology ofthe sensilla, sensillawere classified into types. being the longest (0.30±0.02 mm) while eighth is the Sizes ofthese sensilla were measured with the ocularmi- shortest (0.15±0.02 mm). A spine is present on the ven- crometer and readings were converted into urn. We also tral surface ofthe scape though the rest ofthe antenna is bleached the antennae in 2% hydrogenperoxide for24 hr. free from such spines. Scanning electronmicroscopic stud- Permeable areas ofantennae were examined underbright ies revealed the presence ofscales on the scape, pedicel fieldilluminationusing crystal violetmethod (Slifer 1960). and first to sixth flagellomere. The numbers ofsensilla in One hundred 6-12 h old pupae were treated with 5 ppm male and female adults ofD. armigera are shown in Tab. methoprene (Altosid SE, 62.5% RS methoprene, Zoecon, 1. In male and female antennae, the distal segments are Palo Alto, CA). Twenty adultoids were randomly select- densely covered with sensilla. There is a distinct differ- ed for this study. ence in shape ofthe 9th flagellomerebetween themale and female. In each segmentas well as sub-segments, themale Scanning electron microscopy studies ofthe antennae of adults had a significantly greater number ofsensilla than the adults and adultoids were undertaken by followingthe its female counterpart (Tab. 1) except on the fifth flagel- method described in Hazarika & Bardoloi (1998). Anten- lomere, where it was reverse. nae were dissectedout ofthe head and cleaned in distilled water, which were then fixed in buffered glutaraldehyde. The mean numberofsensillaperunit area is shown inTab. They were dehydratedbypassingthrough a series oface- 2. Both in male and female, the maximumpopulationwas tone starting from 30% to 100%. On drying, antennaewere observed on the eighth and ninth flagellomere (7.11±0.03 mm mm placed on stubs using double sided, scotch tapes and coat- 2 and 8.89±0.03 2 respectively) andthe lowestwas , mm ed with gold-palladium in a sputterer (JEOL, JFC 1100, observed on the scape (0.37±0.01 2 and 0.29±0.01 mm Japan) for 5-10 min. The specimens were scanned in a 2 respectively). Though density of sensilla on each , scanning electron microscope (JEOL, 35-CF, Japan) at 15 segment was significantly higher in the male, but on the KV andphotographs were taken foreach ofthe specimens. fifth to ninth flagellomere, it was reverse (Tab. 2). Bonn zoological Bulletin 57 (1): 91-98 ©ZFMK 5 Antennal sensilla ofthe rice hispa Dicladispa armigera (Olivier, 1808) 93 Table 2. Mean±S.E. density ofsensilla (number/mm2 on each antennal segment ofadult male and female D. armigera. ) Segment Male Female t-value Scape 0.37±0.01' 0.29±0.0U 10.28** ST Pedicel 0.60±0.01h 9.45** Flagellum (Fl) Fl 1 0.42±0.01' 0.35±0.0U 4.35** F12 0.63±0.02h 0.57±0.01h 2.80* Fl 3 0.96±0.01§ 0.81±0.01g 7.77** F14 2.03±0.02f 2.09±0.03f -I.94NS Fl 5 4.49±0.02f 5.26±0.02^ -26.47** Fl 6 5.98±0.16d 6.30±0.04d -1.89NS Fl 7 6.15±0.02c 7.65±0.03c -48.52** Fl 8 6.95±0.03t> 7.75±0.03b -17.18** F19 7.11±0.03a 8.89±0.03a -42.61** S.Ed. (±) 0.07 0.03 C-D. 0.14 0.07 o.o5 SE = standard error, sample size= 50. Means within columns are separatedbyDuncan's Multiple Range Test(DMRT) at P< 0.05. Means followed by the same letter shown in superscript(s) are not significantly different. Means within the rows are followed by * and ** are significantly different at p < 0.01 and p < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). Table 3. Size (Mean±S.E., length x width in urn) ofsensilla trichodea I on each antennal segment ofadult male and female D. armigera. Segment Male Female t-value Length Width Scape 41.46±0.03a x 1.86±0.02=d 39.52±0.04a x 1.83±0.02"i 41.07** -2.27* Pedicel 39.23±0.08bx 1.80±0.01d 38.50±0.07c xl.74±0.02e 13.70** 2.46* Flagellum (Fl) Fl 1 36.50±0.09h x 1.74 ±0.02^ 36.56±0.05fx 1.74±0.02e -0.53NS 0.01Ns F12 37.18±0.07gx 1.81±0.01«i 35.21i0.051 x 1.81±0.01d 32.91** 0.42Ns Fl 3 37.46±0.07fx 1.84±0.02«i 35.80±0.03h x 1.83±0.02^ 23.55** 0.1 NS Fl 4 37.84±0.12^x 1.81±0.01<* 36.37±0.16gx 1.84^:0.02^ 9.53** -1.08NS Fl 5 37.87±0.18e x 1.85±0.01c 38.00±0.05*x 1.86±0.02bc -0.70Ns -0.55NS Fl 6 38.00±0.07de x 1.89±0.01b 38.10±0.04d^x 1.90±0.02ab 1.91NS 0.31Ns Fl 7 38.22±0.06de x 1.90±0.02b 38.22±0.04^d x 1.89±0.01ab 0.01NS 0.41Ns Fl 8 38.51±0.06c x 1.92±0.02b 38.52±0.04bx 1.99±0.01ab 26.17Ns 0.82Ns F19 38.54±0.07c x 1.96±0.01a 38.63±0.03b x 1.92±0.01a 24.52ns 6.56** S.Ed. (±) 0.13 0.02 0.09 0.02 0.25 0.04 0.18 0.05 SE= standard error, sample size = 50. Means within columns are separatedby Duncan's Multiple RangeTest (DMRT) at p < 0.05. Means followed by the same letter shown in superscript(s) are not significantly different. Means within the rows are followed by * and ** are significantly different at p < 0.01 andp < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). ©ZFMK Bonn zoological Bulletin 57 (1): 91-98 31 94 Munna Rani Saikia et al. Table 4. Estimated number (Mean±S.E.) ofsensilla trichodea I on each antennal segment ofadult male and femaleD. armigera. Segment Male Female t-value Scape 2.51±0.37J 1.88±0.42J 1.29NS Pedicel 5.81±0.52hi 5.50±0.50h 0.46NS Flagellum (Fl) Fl 1 3.93±0.50u 3.45±0.21'J 0.83NS Fl 2 6.44±0.48h 5.02±0.47hi 2.02NS n PI Tj. 19 79-1-0 A9i> /.Dy^KJ.JOo */1.fO\l1 ** Fl 4 21.82±0.66f 11.46±0.52f 12.11** Fl 5 141.77±0.66e 137.22±0.82e 3.96** Fl 6 155.43±0.66d 176.46±0.84d -16.56** Fl 7 181.34±0.79c 182.43±0.82^ -1.13NS 209.44±1.97b 204.10±0.64b 2.74NS Fl 8 Fl 9 235.03±0.69a 198.29±0.76a 31.57** S.Ed. (±) 1.17 0.89 CD. 2.32 1.76 o.o5 SE= standard error, sample size = 50. Means within columns are separatedby Duncan's Multiple Range Test (DMRT) atp < 0.05. Means followed by the same letter shown in superscript(s) are not significantly different. Means within the rows are followed by * and ** are significantlydifferentatp < 0.01 andp <0.05 probability level, respectively (Studentt-test; t-values are shown against each pair; d.f. < 49). Table 5. Size (Mean±S.E., length x width in um) ofsensilla trichodea II on each antennal segment ofadult male and female D. armigera.. Segment Male Female t-value Length Width Scape 38.11±0.23a x 1.73±0.01cd 36.52±0.05*x 1.70±0.03def 6.77** 0.87NS Pedicel 36.52±0.09b x 1.71±0.01de 34.75±0.04b xl.68±0.02ef 20.00** 1.33NS Flagellum (Fl) Fl 1 30.03±0.05e x 1.69 ±0.01e 29.12±0.04fx 1.67±0.01f 11.60** LIONS Fl 2 31.45±0.01d x 1.73±0.01cd 31.04±0.06d x 1.73±0.01de 5.93** 0.3 NS Fl 3 32.06±0.09c x 1.72±0.01cd 31.73±0.04^x 1.74±0.01cd 2.83* -1.59Ns Fl 4 32.15±0.10c x 1.73±0.02cd 30.04±0.04e X 1.74±0.02^d 22.25** -0.46NS Fl 5 25.05±0.12' x 1.73±0.01cd 26.51±0.06h x 1.78±0.02abc -8.97** -1.64Ns Fl 6 27.73±0.12gx 1.75±0.0L 26.83±0.07gx 1.74±0.02bcd 7 44** -0.1 Ns Fl 7 28.24±0.05fx 1.78±0.01b 25.01±0.04i x 1.78±0.01abc 40.29** -0.43NS Fl 8 26.17±0.07h x 1.80±0.01b 24.30±0.04J x 1.79±0.01ab 26.57** 1.75NS Fl 9 24.52±0.06J x 1.87±0.01a 24.04±0.03k x 1.80±0.01a 6.77** 8.11** S.Ed. (±) 0.15 0.01 0.07 0.02 0.29 0.02 0.13 0.04 SE= standard error, sample size= 50. Means within columns are separated by Duncan's Multiple RangeTest (DMRT) atp < 0.05. Means followedby the same lettershown in superscript(s) are not significantly different; means withinthe rows followedby * and ** are significantly different at p < 0.01 and p < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). Bonn zoological Bulletin 57 (1): 91-98 ©ZFMK Antcnnal sensilla ofthe rice hispa Dicladispa armigera (Olivier, 1808) 95 Table 6. Estimated number (Mean±S.E.) ofsensilla trichodea II on each antennal segment ofadult male and female D. armige- ra Segment Male Female t-value scape 22.61±0.49t 19.31±0.69« 4A.11A0,**, Pedicel 22.92±0.56' 19.63±0.59s 4.2/** Flagellum (Fl) rT7l1 11 15.61±L).67n 114A.7//6±i0A.4A6n A 1OKI's Fl ? 1lfO\.0U1lx+U0.JSSJh" 1O.JJXU.jj" O 44NS Fl 3 20.10±0.53e 20.10±0.62g -0.01NS Fl 4 39.88±0.61e 45.37±0.74f -5.55** Fl 5 63.90±0.61d 64.68±0.66e -0.84NS F16 73.66±0.61c 70.81±0.62d -2.52* Fl 7 83.21±0.62b 79.10±0.70c 3.28** Fl 8 83.37±0.84b 90.75±0.82b 7.19** F19 136.75±0.77a 156.84±0.73a -19.07** S.Ed. (±) 0.89 0.93 C.D. 1.76 1.84 o.05 SE=standard error, sample size= 50. Means within columns are separatedby Duncan's Multiple RangeTest (DMRT) at p < 0.05. Means followedbythe same letter shown in superscript(s) are not significantly different; means within the rows followedby * and ** are significantly different at p < 0.01 andp < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). Table 7. Size (Mean±S.E., length x width in urn) ofsensilla chaetica on each antennal segment ofadult male and femaleD. ar- migera. Segment Male Female t-value Length Width Scape Pedicel Flagellum (Fl) Fl 1 Fl 2 Fl 3 Fl 4 Fl 5 30.15±0.19e x2.70±0.02d 32.24±0.05c x2.74±0.01d -22.17** -2.15* F16 33.41±0.06dx2.86±0.02c 32.99±0.05d x 2.89±0.05c 7.26** -0.64NS Fl 7 34.11±0.06cx2.94±0.02b 33.50±0.04^ x 2.85±0.02c 11.79** 3.83 ** Fl 8 37.57±0.06b x 3.00±0.03b 38.40±0.04b x 2.99±0.03b -11.92 ** 0.28NS Fl 9 38.15±0.06a x 3.12±0.02a 38.70±0.03a x 3.10±0.03a -6.67 ** 0.67ns S.Ed. (±) 0.09 0.03 0.06 0.04 0.18 0.06 0.12 0.08 SE= standard error, sample size= 50. Means within columns are separatedby Duncan's Multiple RangeTest (DMRT) atp < 0.05. Means followed by the same lettershown in superscript(s) arenot significantly different; means within the rows followedby *and ** are significantly different atp < 0.01 and p < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). ©ZFMK Bonn zoological Bulletin 57 (1): 91-98 1 96 Munna Rani Saikia et al. Table 8. Estimated number (Mean±S.E.) ofsensilla chaetica on each antennal segment ofadult male and female D. armigera. iScgmenr A/I.tlii rciiiaie t-vaiue Scape rCCllCcl ridgeiium yri) Frl1 11 Fl 9 JT Fl 3 Fl 4 Fl 5 14.76±0.60d 21.35±0.63d -6.33** F16 36.58±0.61^ 10.83±0.62e 29.58** Fl 7 37.84±0.58c 32.34±0.61c 6.05** Fl 8 42.55±0.66b 37.99±0.68b 5.45** Fl 9 119.01±0.79a 130.15±0.70a -12.06** S.Ed. (±) 0.92 0.91 C-D. 1.84 1.82 o.o5 SE= standard error, sample size= 50. Means within columns are separatedby Duncan's Multiple RangeTest (DMRT) atp < 0.05. Means followedby the same letter shown in superscript(s) arenot significantly different; means within the rows followedby * and ** are significantly different at p < 0.01 and p < 0.05, respectively (Student t-test; t-values are shown against each pair; d.f. = 49). Based on morphology, sensillatrichodea (ST) I, STII, sen- widths varied from 1.69±0.01 to 1.87 ± 0.01 um. In fe- silla chaetica (SC), sensilla basiconica (SB) I and coelo- males, their lengths varied from 24.04 ± 0.03 to 36.52 ± conic sensilla were identified in both sexes ofthe insect. 0.05 urn and their widths varied from 1.67±0.01 to The ST I and II werenumerous andobserved overthe en- 1.80±0.01 um. tire length ofthe antennae whereas SC were observed on- ly on the apical five flagellomeres. In addition, some sen- The highest number of ST II was observed on the ninth silla suspected to be thermoreceptors (Tr) were also ob- flagellomere (136.75 ± 0.77) and lowest on the first fla- served on scape, pedicel and some flagellomeres. gellomere (15.6±0.67) in males. Likewise, in females al- so the highest number ofST II was observed on the ninth The ST I pointed distally and curved towards the anten- flagellomere (156.84± 0.73) andthe lowestwas observed nal shaft. It is a slender structure, which tapers gradually on the first flagellomere (14.76 ± 0.46) (Tab. 6). into a very sharp point at the distal end. In males, the lengths of ST I varied from 36.50 ± 0.09 urn to 41.46± The SC werepointed distally andprojected outward from 0.03urn. Likewise, theirwidths varied from 1.74±0.02 um a socket at an approximate angle of50°, thick-walledand to 1.96± 0.01 um. In female, the lengths varied from longitudinally grooved. Theywere restricted to the termi- 35.21± 0.05 urn 39.52± 0.04 um and their widths varied nal five flagellomeres and were unaffected when a solu- from 1.74± 0.02 urn to 1.99± 0.01 um (Tab. 3). The high- tion ofcrystal violet was applied. In males, their lengths est population of ST I was observed on the ninth flagel- variedfrom 30.15±0.09 to 38.17±0.06 um (Tab. 7), where- lomere (235± 0.03± 0.69) and the lowest was observed as in femalestheyvaried from 32.24±0.05 to 38.70±0.03 on the scape (2.51± 0.37) in males, whereas in females, um. In male and female, the highest number of SC was the highest population was observed on the eighth flagel- observedon the ninth flagellomere and the lowestwas ob- lomere (204.10± 0.64), and the lowest was observed on served on the fifth flagellomere (Tab. 8). the scape (1.88 ± 0.42) (Tab. 4). A few sensilla basiconica (SB) were present in different The ST II were also similar to ST I except that they were flagellomere of D. armigera. SB are smaller than ST unaffected when a solution ofcrystal violet was applied. measuring 5-6 um, wall being porous. Pit or coeloconic It might be due to non- permeability of the senisilla to sensilla are also present on the antennae, however, details crystal violet. In males, the lengths of ST II varied from oftheir structure were not studied. 24.52±0.06 to 38.11±0.23 um (Tab. 5). Likewise their Bonn zoological Bulletin 57 (1): 91-98 ©ZFMK Antenna] sensilla ofthe rice hispa Dicladispa armigera (Olivier, 1808) 97 After application ofgrowth regulator, methoprene, some Paragnetina media (Walker, 1852) andby Ritcey & Mclv- deformities not only on the antennal structure but also on er(1990) in flea beetles. SC is a common type usually en- the sensillarmorphology were observed; the4th flagellom- countered in many insects (Ilango 2000). The presence of ere got deformed. This is very prominent on the tip ofthe SC on antennae was also reported by Ritcey & Mclver ninth flagellomere where SC were observed to be disori- (1990) in the flea beetles, P. cruciferae, P. punctulata, P. ented (Baishya 1992). affinis and E. cucitmeris. As Hazarika & Baishya (1996) showed, application of DISCUSSION methoprene inducedmorphogenesis inD. armigera; how- ever, onlythe fourth andthe last flagellomere were affect- Densely covered distal segments ofthe antennae as ob- ed. The cause ofthe selectivity ofthis effect is unclearup served here are also present in many other insects like to now. Hormonal regulation ofantennal sensillais report- Blatella germanica (Linnaeus, 1767) (Ramaswamy & ed for many insects (Wheeler & Gupta, 1986; Yamamo- & Gupta 1981, Wheeler Gupta 1986), Croesia curvala to-Kihara et al. 2004). Injection of a neurohormone, (Kearfott, 1907) (Langmaid & Seabrook 1985), Bootet- [His7]-corazonin, reduced the number ofcoeloconic sen- tix argentatus Bruner, 1890 (Chapman & Fraser 1989), silla inLocusta migratoria. Asimilarstudy onD. armigera Geotrupes awatus Motschulsky, 1858 (Inouchi et al. is alsorequired since it couldhelpto clarifythe causal net- 1987) and Homoeosoma electellum (Hulst, 1887) work in the development ofthe antennal sensilla pattern. (Faucheux 1995), and fourhemipteran species (Usha Rani & Madhavendra 2005). Palpation conducted with the dis- Acknowledgements. This work was partly funded by the Na- tal segments ofantenna may provide an explanation for tionalAgricultural Technology Project, Indian Council ofAgri- this pattern. cultural Research, New Delhi. We are also grateful to Dr. G. B. Staal, Zoecon, Palo Alto, CA for providing the methoprene as On the scape, pedicel and three flagellomeres (first to agift forexperimental purpose. Scanning electronmicrographs were taken at the Regional Sophisticated Instrumentation Cen- third), males had significantly greater number ofsensilla tre, North Eastern Hill University, Shillong, Meghalaya. per unit area than females. However, from the fourth to ninth flagellomere, females had a greater number ofsen- REFERENCES sillaperunit area than males; a similarpattern was report- & edby Ritcey Mclver(1990) in case ofPsylloidespunc- Axtell RC (1999) Poultry integrated pest management: Status tulata and P. affinis. A study by Usha Rani & Madhaven- and future. Integrated Pest Management Revue 4: 53-73 dra (2005) suggested that sensillae in scape and pedicel BaishyaRL(1992) Effectofinsectgrowthregulatorsonthepost may not be used in sensory perception, which remains embryonic development and reproduction ofrice hispa, Di- however to be tested critically. cladispa armigera (Olivier) (Coleoptera: Chrysomelidae). M.Sc. (Agri.) Thesis, Assam Agricultural University, Jorhat, Assam SimilartoDicladispa armigera, terminal segments ofan- Bland RG (1981) Antennal sensilla ofthe adult alfalfa weevil, tennae covered with ST I and ST II were also reported Hyperapostica (Gyllenhal) (Coleoptera: Curculionidae). In- in Homoeosoma electellum (Faucheux 1995), Phothori- ternational Journal ofInsect Morphology & Embryology 10: maea operculella (Zeller, 1873) (Sharaby etal. 2002),He- 265-274 M licoverpa armigera (Hiibner, 1808) (Wang et al. 2002). BromelyAK, DunnJA,Anderson (1980)Ultrastructureofan- Bromely et al. (1980) stated that the ST at the antennal tennal sensilla ofaphids. II. Trichoid, chordotonal and cam- paniform sensilla. Cell and Tissue Research 205: 493-511 tips ofaphids have a contact chemosensory function, and Chapman RE (1982) Chemoreception: The significance ofre- may be involved in gustation ofthe plant surface, which ceptor populations. Advances in Insect Physiology 16: might be the case in the insect studied here as well. 247-356 Chapman RF, FraserJ (1989) The chemosensory system ofthe The population of ST I was highest on the ninth flagel- monophagous grasshopper, Bootettixargentatus Bruner(Or- flloamgeerleloimnermea.leTsh,iswhkeirnedaosfivnartihaetfieonmailneSiTtwIapsopounlatthieoenimghatyh ChotehgnoyptH&eHra,E:mAZbchrrayiodoildYoaXge,y).1KI8na:tne1gr1n1aLt-iE1o1n8(a2l0J0o3u)r.naAlntoefnInnaslectseMnosrilplhaolo-f be associatedwith specific functionperformedby the sen- grasshoppers(Orthoptera:Acrididae) inrelationto foodpref- silla. Similar cases were also recorded in Trichoplusia ni erences and habits. Journal ofBiosciences 28: 743-752 (Hiibner, 1803) (Mayer et al. 1981), Grapholitha moles- Deka M, Hazarika LK (1996) Mating behavior ofDicladispa ta (Busck, 1916) (George & Nagy 1984), Hyperaposti- armigera (Coleoptera: Chrysomelidae). Annals ofthe Ento- ca (Gyllenhal, 1813) (Bland 1981). However, in case of mological Society ofAmerica 89: 137-141 Deka M, Hazarika LK (1997) Investigation of male sex both males and females, the ST II population was high- pheromone in rice hispa, Dicladispa armigera (Oliv.) est on the ninth flagellomere, which was also reported by (Coleoptera: Chrysomelidae). Pestology 21: 24-25 Bland (1981) in Hypera postica, by Kapoor (1985) in ©ZFMK Bonn zoological Bulletin 57 (1): 91-98 98 Munna Rani Saikia et al. Dhaliwal GS,Arora R, RandhwaNS, DhawanAK (1998) Eco- tuidae). International Journal ofInsectMorphology& Embry- logicalAgricultureand sustainable development. In: Proceed- ology 10: 185-201 ingsofan International ConferenceonEcologicalAgriculture: Nath R, Dutta B (1997) Economic injurylevel ofricehispa,Di- Towards Sustainable Development,Vol 1, Chandigarh, India, cladispaarmigera (Oliv.). 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The micromorphology Yamamoto-Kihara M, Hata T, Breuer M, Tanaka S (2004) Ef- ofthe antennae ofthe blueberry leaftier moth, Croesia cur- fectof[His7]-corazoninonthe numberofantennal sensillain valana (Kft.) (Lepidoptera: Tortricidae). Canadian Journal of Locusta migratoria. Physiological Entomology 29: 73 Zoology 63: 1189-1193 M MaartjeAK, BleekerHans Smid,Adriaan C VanAelst, Joop JAVan Loon, Luise EMVet (2004). Antennal sensilla oftwo parasitoid wasps: A comparative scanning electron mi- croscopy study. Microscopy Research and Technique 63: 266-273 Received: 03.07.2008 MayerMS, Mankin RW, Carlysle TC (1981) External antennal Accepted: 08.07.2009 morphometryofTrichoplusiani(Hubner) (Lepidoptera: Noc- Corresponding editor: M. Schmitt Bonn zoological Bulletin 57 (1): 91-98 ©ZFMK