COMMENTS ON THE PUPA OF Zavrelimyia sp. (INSECTA: DTPTERA, CHIRONOMIDAE) FROM MADERA SAMANTHA J. t-IUGHES & DECLAN A. MURRAY MURRAY.2001. Comments on the pupa of Zavreiimyia sp. (Insecta: Diptera. Chironomidae) from Made~ra.Arquipdago. Life and Marine Sciences. Supplement 2 (Part 23): 33-37. Ponta Delgda. ISSN 0873-4704. FIUGHEs, S.J. & D.A.
Zavwlimyia nubila (Meigen, 1830) is the only species of Znvr~limvia F r r r ~ ~(1962) u recorded previous1y horn Madeira based on coifections of adult spcci mens. However, pupal exuvlae recen~lyobtained in Madeira differ lrom thosc or Z. rlublh in their overall smaller size, presence of a corona on the thoracic horn and in the abdomnal pigmentation and shagreen pattern. An lllnstrated dew~ptiono f these features i s given here to distinguish this rnorphotype from related Palaearciic species.
Samanfha June H ~ ~ g h e(e-mail: s
[email protected]). Lnborardrio Regional de Engenharia Civil, Deparramenta de Recarsos Nu'arurars c de Hidradica, Caminho de Esrrlemldo, ,Eoh?arlirro, PT - 9000 F~rnchal,P o ~ f f g a l-. Driclan A, Mrrrrqv, Dcpartmemt of Zoology, Universify College Dvbliri, Be Efield, Da bIin 4, Irelund.
INTRODUCTION Qualitative coIlections made in 1995 and 1996 to investigate the distribution and occurrence of Chironomidae in selected freshwater habitats of
Madeira yielded 53 taxa at species level, of which 16 were new to the island's fauna (HUGHES & MURRAY 2000). Additional pupal ex uviae material has since been obtained during the 1997 biological monitoring survey of Lahratdrio Regional de Engenharia Civil, Departamento de Recursos Naturias e de Kidraiilicn (LRECmRNI) to assess the ecological quality of Madeira's surface waters. The majority of specimens collected were readily identifiable using existing taxormmic detemination keys but 13 exhibited morphologicaI dificrences in comparison with descriptions of currently known species and possibly represent variant forms or species endemic to Madeira. This paper presents some of the characteristics of the pupal exuviae of a s p i e s of tcavre/ittzyta, collected from several sites on Madeira, that differ from the exuviae of Z nubilo (Meigen, 1830) the only species of Zavrelimyin previously recorded (as an adult) from the island. Thc pupal exuviae. the cast "skin"of the pupa remaining on the w a r surface following eclosfon of the adult,
possesses a wealth of species-specific diagnostic features. Examination of collections of pupal exuviae rapidly provides reliable information of thc resident fauna, species composition and phenology at a given site f WRSOY 1996).
METHODS During field sampling carried in September 1995, April 1996 and throughout 1997, collections of Chironornidae were obtained from 57 sites covering severaI types of freshwater habitat. Exuviae were collected by drift net in selected flowing-water sites, augmented by skimming the water surface with a hand net (250 pm mesh) and picking up flo~samto which pupal exuviac may adhere. APthough adult Chironomidae were collected at many sites. adult male nr female specimens of Zclvrdimy icl were not ohtained. However pupal exuvjae of Zavrelimyin were obtained at the sites indicated (Fig. 1, Table 1 ) . Exuviae of Z nubila from Ireland were used for comparison with the Madeiran specimens. All exuviae for examination by light microscopy were processed and slide mounted according to methods outlined in WIEDERHOLM (1986). Scanning electron
microscopy
specimens.
was carried out on selected Identifications are based on key
narks of F I ~ K A( U 1962), F I ~ K A & U MURRAY (1986) end LANGTON(1 99 11.
SAo Wictnte Ponta da Parg
Fig. 1. Sites where specimens of Zavreiirrlyia sp have been collected Defails oreach site arc given in Table 1 Table I. Sites where samples during 1995 and 1996 on Madeira and Porto Sanro (S= Sweep netting. A= Aquatic co2lcctions). S ~ t eco-ord~nateswerc obta~ncdusing a GARMIN GPS 45 receivcr. Date 15-09.95 13.04.96
21.05.97
% Location Method Co-ardinates Alt (nl) 1 Faj5 de Kogucira hydro elrctrlc reservoir SlPl N32O44.909 1 W 16"55'411 530 2 Curral das F~.eiras(Terra ChB) - rescrvoir A N32"42'7 E4 1 W 16'58'335 450 3 Perenn~salstream in laurissilva copsc Arco da Calheta A N32"43"59T J W 17'07'5 1 t 780
Material examined: Zavrdirnyin sp. Madeira
Pe, 15/09/1995, hydroelectric slation reservoir, Faja de Nagueira. PC, 13/04/1946, artificial irrigation reservoir, Terra Ch3, Curral das Freiras. Pe, 21/05/1997, IS' order stream in small copse of laurel forest, Arco da Calheta. 7~vrelintyianubila. Pe, 201051 1886, water tank, Ardsallagh, Co. Meath,
Ireland.
Pe, 29/09/1997, artificial small garden pool, Meadesbrook, near Ashbourne, Co. Meath, Ireland. RESULTS
The pupal exuviae of Zavrelin~yia sp. from Madeira differ from Z n~rbiIain the overall size, pigmentation pattern of the abdominal tergites, structure of the abdominal armature (shagreen)
and in features of the respiratory thoracic horn. The overall length of the Madeiran specimens. 5.0 mm, is shorter than that of 2. riubila at 6.5 mm. The tcrgitcs of the Madeiran specimens have a distinctly hnrnogennus pimentation pattern with a rounded anterior median mark on tergites 11 to VI (Fig. 2a and b) whereas in Dvrelnnyia nabiln dark anterior and posterior bands on each tergite are joined by a single median band (Fig. 3a and b). The shagreen on tergite 2 of the Madeiran specimens is composed of individual sp~nules(Fig. 2c) while in Z,t i ~ b i l a the spinules are grouped and occasionally branched (Fig. 3c). The thoraclc horns of all specimens obtained in Madeira have a distinct zlrn or corona that appears. under light microscopy, as a translucent area surrounding the plastron plate. The corona, which i s absent in Z ttubila, is clearly visible in scanning electron micrographs of the Madeiran specimens (Fig. 4). Reaching 0.075~the length of the thoracic horn, the plastron plate is broader than the neck of the resp~ratory atrium, which fills ?/a of the horn respiratory chamber.
Fig. 2 . Pupnl Exrlv~nof 7Alrrr(inrvin sp. from hT.l;~dc~r;i. Ftg ( a ) pigmwn1atlon of the atidnlninal lcr~itcs(hl rlet:t!l rll' tcrptcs I and If (c) Cli@riiln thc Cplnrs un tcrgllc 11.
-7. Pupal Exuvia nf Zavr(~lirl?~ticl rrrtE~i1c1 ( a ) piytncn~auot~ ol' [he ahdomtnal iergites (h) detail of rcrgitcs 1 ;mi.!1I (c) Juagram nr ~ h sprncs c on tergtte 11.
Fig. 4. f-.lccti-or: ~~u~,~-cj;r:tpl~ 11: t l ~ c~ l i o r ; ~I~ i o~rc~,0l1 / I i ~ i ~ ~ ~ c ~ \p. / ~ r hlLtdc'~~-r~. ~ ! ~ r ~ r \[)I' [ilc,11111 platc. This chasactcristic 1 % ithscnt in %rrr.relirr~,~ra t~rrbil~ ( M c ~ g c n ,1 530). Scale bar Inn pm.
; L T O I I I I L ~liic
plnslron
DISCUSSION
ACKNOWLEDGEMENTS
The authors would like to thank all colleagues Observations on the Zavrelirnyia pupal exuviae who helped identify material, in particular John examined indicate that the specimens in question R. Blackburn and Dr. Peter Langton. Thanks also differ from Znvrelinayia nubila, the on1y species to the technicians Agostinho Gouveia, Josge of Zavrelimyia recorded from Madeira until now Martins and Pedro Carreira for assistance in the (as adult only) by STORB, (in FREY 1949), field. Thanks to Dr. Filomena Seabra of the FREEMAN(1959) and BAEZ& A R M ~ A G(1990). E Laborat6rio Regional de Sadde P6blica for 2 nubiln has also been recorded (likewise as carrying out physico-chemical analyses. adult only) from the h r e s (SMRA in FREY 1945) and the Canary Islands (GRANSTON & A R M ~ A G1988). E REFERENCES Pupal exuviae of all known Zavrelu~~yia species have a background goldenlyel low colour. BAU. M. & P.D ARMITAGE. 1990. Chironomidae However, pigmentation patterns are evident in (Diptera, Nematocera) from Madeira. Bol~rimdo different species (FWTKAU1962). Whereas the Mrrseu Municipal do Funchal, 135: 1-6. P.S.& P.D. ARMKAGE.1988. The Canary gross structure of the thoracic horn of sp. CRANSTON. lslands Chironomidae described by T. Becker and Madeira most closely resembles 2, melanura, the by Santos Abreu. Deutsch etltomologisch~ abdominal tergites of 2 melanura possess dark Zpirschrift. 335. 341-354. transverse anterior and posterior bands connected F I ~ A UE.J. , 1962. Die Tanypodinae. (Dlptera : by median and lateral longitudinal bands. In 2. Chironomidae) Die Tribus Tanypodiini. nubila, a median longitudinal band connects dark Macropelopiini, und Pentamurini. Ahhandlung rur anterior and posterior bands. The panern in Z sp. LarvaIsysreniatik der Insekren. 6, 1-453. Akademie Madeira resembles neither of these species and is Yerlag, Berlin. restricted to a distinct rounded, median anterior F~TKAU. E.J. & D.A. MURRAY. 1986. The pupae of mark adjacent to the apophyses. Such a pattern is Tanypodinae (Diptera: Chironomidae) of the Holarctic region -Keys and diagnoses. Pp 31-1 13 known in Z berberi Fittkau, 1962, from in: WLEDWHOLM. T. (Eds) Chironemidae of the Morocco, but in that species the horn atrium is Holarctic reglon - Keys and diagnosis. Part 2. about half the width of the horn in conmst with Pupae. Entomodogica Scandinavica, Supplement the Madeiran specimen where the atrium is at 28: 31-113. least % as wide as the thoracic horn. FREEMAN. P. 1959. Chironomidae (Diptera, The shagreen on abdominal tergite 2 of the Nematocera) from the Azores and Madeira Bole~irn pupa of Z sp. Madeira also differs from that of 2. do Mrtseu Municipal do Funchal, 12 (29) 5-1 5. nubila. In 2 nidbila the shagreen is composed of PREY.R. 1945. Chironomidae, Die Dipterenfauna der grouped and occasionally branched spinules, Insel Madeira Societas Scbitarirtm Fennica somewhat similar to 2. harbatipes (Kieffer), in Cemrnn~tationesBiologicae 8 (10)22-32 contrast to the individual or single spinules of the FREY. R. 1949. Chi~onomidae,Die Dipterenfauna der Jnsel Madeira Soci~ras Scierzrarriurn Fennicn Madeiran specimens. Comrnct~ia~iones Biologica~8 ( 1 6 ) 15- 16 It is clear from these observations that the HUGHES S,J, & D.A. MURRAY. 2000. New records of exuviae of 2 sp. Madeira do not belong to Z. Chirononudae for Madeira and comments on nubila. Without re-examination of previously possible new forms. 9.525-533 in: 0. collected specimens and until definitive, reared HOFFRICHTER.(Eds). h t e 2Orh C~nacryRexearch and associatd, pupal and adult material is on Ckimnornidae. An anthology of the 131h obtained i s not possible to confirm the status of Intemaiional Symposium on Chironomidae. previous records or to state whether one or two Freiburg im Breisgau, Germany. 5-9 September, 1997, Aachen: Shaker Yerlag. species of Zavrelimyia occur a n the island.
LANCETON, P.H. 1991. R Kev 10 the pitpal txuviae oj wcsr Pulaeamic Chironumidae. Published by the author. 3 S1 Felix Rd, Ramsey Forty Fool, Carnhridgshire. W~EDERHOLM, T (FAIS). 1986. Chironomidae of the Holarctic rcgion. Kcys and diagnoses. Part 2. Pupae. Enton~aIogica Scarldinavica. Supplement 28,482 pp.
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WILSON,R.S. 1996. A practical key to the genera of
Pupal Exuviae of the Brit~sh Chjronomidae (Diptera: Insecta) with an account of the CPET method or warer quality arsessment. Country Pr~nt. UK. 98 pp, Accepted 23 Augids1J999.
