Table Of ContentOdonatologica27(2): 225-237 June 1. 1998
Terrestrial andaquatic matingterritories in
Somatochloraflavomaculata(Vander Linden)
(Anisoptera: Corduliidae)*
H.Wildermuth
Haltbergstrasse43.CH8630 Rüti,Switzerland
Received March 18, 1997/ RevisedandAcceptedOctober2, 1997
Insearchofreceptivefemales,the malesofmanycorduliids patroloveropenwater.
Additionally,somespeciesexhibit localizedpatrolflightsalso overterrestrial sites.In
openfen habitats,Somatochloraflavomaculatamaybeanextremecaseinthisrespect
as it conspicuously patrolsoften away from water. In consideration ofits possible
function the terrestrial patrolflightswereinvestigatedinadescriptiveandexperimen-
tal field study and comparedwiththose ataquatic sites.Typically,themalespatrolled
close tovertical structures such astrees and bushes oroverfootpaths in glades of
reedbeds. No relevant differences between thepatrol fligthsataquaticand terrestrial
localities werefound.Bothtypes offlightwereterritorial infunction asconspecific
males werevigorouslydrivenaway. Itisspeculatedthatthemalesestablishterritories
away frompondsbecause the occurrenceoffemales is unpredictable,thepreferred
ovipostion sites (shallowand largelyovergrownpuddles) beingscattered overlarge
areas.Hence,thebeststrategyformalesforinterceptingmateswouldbe topatrolnear
vertical structures servingaslandmarks and guidelinesforarrivingfemales.
INTRODUCTION
Territoriality,connectedwithreproduction, is suggested tobea widespread phe-
nomenon in corduliid dragonflies. However, this behaviourand its variability is
poorly understood, as ithasbeen investigated intensely inonly very fewspecies.
Epitheca cynosura (Say) was the first to be studied in detail in this respect
(KORMONDY, 1959).Malesoccupy fixedareas atlakeshores, aggressively expel
conspecific intrudersandmate witharriving females.Theflightpatternis charac-
terizedby extendedperiodsofhovering,considerablemanoeuveringandnoalight-
ing. In contrast tothesexual patrol flight,thefeeding flightoccursaway from the
*Thispaperisdedicatedtothe memory ofthelateDrP.L. Mi 11er.
226 H. Wildermuth
water,andthereis muchhorizontaland vertical displacement, almost noarea lo-
calisation, littleorno hoveringandnoaggressive interactionsbetweenindividuals.
Corduliashurtleffi Scudderwas showntopatrol for shortperiods about 15mof
shorelineatabog pond, attempting to driveawayany rivals (HILTON, 1983).By
way ofcontrast, territorialindividuals ofHemicorduliaaustraliae(Rambur) are
extremely site-fixed, spending mostoftheirtimehovering inavery smallvolume
(ROWE, 1988).CorduliaaeneaamurensisSelys becomesterritorialatpondsonly
if male density exceeds a given value. Otherwise the males search for females
along the shore over long distances, lacking aggression towards conspecifics
(UBUKATA, 1975).In bothspecies malesinitiatecopulation exclusively atwater
by intercepting femaleswhichvisitthe siteforoviposition.
In some corduliidslocalizationofmalesready to mate may depend on thetype
ofhabitat.At ponds male Procorduliasmithii(White) intercept females over the
water,whereasatlakescopulation is initiatedaway fromtheshore(ROWE, 1988).
Hence, this species may use alternativemate finding strategies. Somatochlora
flavomaculata (VanderLinden)maybean extreme case withrespect toterritorial
behaviour.Anumberofauthorshave stressed that adults wouldavoidareas with
open water, thus almostexclusively using terrestrial sites for patrol flights (e.g.
RIS, 1885;SCHIEMENZ, 1957;ROBERT, 1959). Referring to S.flavomaculata,
ST.QUENTIN (1932, 1964)distinguished betweenterritoriesatwaterandterrito-
ries away from water ("Wasserreviere” und "Landreviere"). He consideredsite-
-fixedpatrolling individualsatterrestrial locationsunambiguously toholdfeeding
territories("Jagdreviere"). However, thefunctionofthe terrestrial patrol flights
remainedunclearas itwas not demonstratedwhatresources weredefended.
Inthis study theterrestrial patrol flightsofS.flavomaculata are describedand
compared withthoseataquatic sites withrespectto thehypotheses thattheformer
primarily serve mating, andnot feeding. Itwill be speculated that theestablish-
mentofmating territoriesawayfromwater maybe connectedwithecological con-
straints, i.e. thespecific geometryoftheoviposition sites.
STUDYSITE, METHODSANDDEFINITIONS
STUDY SITE.- This field study was conducted from 1995to 1997near Wetzikon (47°16'45"N/
8°48'11"E, 540malt.),20kmESE ofthecity ofZurich(Switzerland).The areaconsists ofamosaicof
elongatedand gentlysloped hills(drumlins),mostly covered with woods, and correspondingly shal-
low valleyslayingbetweenthem,comprisingmoorland, meadows, hedges,small woods and scattered
groups oftrees and bushes (WILDERMUTHet al., 1982).Most investigationswerecarriedoutatthe
Bbndlerried (Ambitzgi),a broad and shallowdepression withbogand fen vegetation,peat ponds,
ditchesand denselyovergrown puddles (Fig. 1;forfurtherdetailscf.WILDERMUTH, 1992).Addi-
tional observations were madeatthe Oberhbflerried as well as atforestedges,wood clearingsand
treefall gaps, allinthe vicinityofthemain study locality. Supplementaldata werecollectednear
Ribnica(Slovenia)atanextendedfenareaalonga dammedriver.
METHODS.- Flightvelocityofpatrollingindividuals aswellasflightandrest periodsweredeter-
mined withastopwatch, Selected examples offlightcoursesweresimultaneouslywatched and out-
Terrestrial andaquatic matingterritories inSomatochloraflavomaculata 227
lined on paper. Atthepeak ofthe flightseasonall territorial males in the study areaweremappedon
two selected dayswith idealweatherconditions. Anumberofmales weremarked individuallywith
nail varnish.
FortheexperimentsI netted malesand females. Theyweresubsequentlyreleased individuallyin
front ofpatrollingmales atterrestrialterritories. Fishing-lineexperimentswerecarriedoutwithmales
of S.flavomaculataand Libellulaquadrimaculataaswell as small pieces ofround stick(7cm in
length, 0.5 cm in diameter),tethered to athin thread ofca 1mwhich was fastened toarod. The
animals werefixedat thethorax in amannerwhichallowed themtofly asfreelyaspossible.
Inordertomimicwater(andthusovipositionsites),blackplasticfoil ordarkbrownperspex(Ixlm),
usuallycombined with aluminium foil ordifferentlycoloured plasticsheets,wereplaced sideby side
on dryvegetationinthe vicinityofaditchwhereS.flavomaculatamalesoccasionallypatrolled.The
responses tothe dummiesofalldragonflyspeciespresent attheexperimentalsite wererecorded asin
aprevious study(WILDERMUTH & SPINNER, 1991).
For microscopicstudiesthree patrollingmales were captured atterrestrial sites and dissectedin
Ringersolution. I investigated sperm vesicles and testes separately withrespect tomature sperm
under the microscopeusingphase contrast.
DEFINITIONS.- The termpatrolflightis used here for site-fixedimaginaladultscruisingback
andforth overaspecificbeatorflyingslowly criss-cross foratleast someminutesinaconfinedand
narrow spaceat acertain level above ground.These areasare defended by the residents against
conspecific intruders and therefore areconsidered asterritories.
PATROLFLIGHTS
SEX. - Individualsperforming patrol flights were males in allcontrolledcases
(65 animalsnetted). Femalescouldonly bewatchedcopulating andovipositing.
SITE.- Theplaces wherethelocalizedmalesstayed were distinguishedby con-
spicuous topographic features such as trees or shrubsobviously serving as land-
marks.Strongly site-fixedadultswere neverrecordedinwideandopenspacelack-
ing any verticalstructure. They preferred theimmediatevicinityofsingle bushes
or trees as well as rowsand groupsofwoody plants,hedges, woods,forestedges,
forestclearings, treefallgapsinforestsand glades or footpaths inreedbeds.
Territorialmaleswereencountered ator nearthe breeding sites, butoftencom-
pletely away fromany waterbody.However, thepatrol areaswere situatedatmost
somehundredmetresaway fromthenearest possible larval habitat.Aquaticterri-
torieswere situatedatpeat-diggings and ditchesas wellas partlyovergrownareas
ofpuddles withopenwaterclearlyvisibleforthehumanobserver fromtheair.At
theterresrialterritoriesthegroundconsistedofmoistordrysoil withdensewetland
or heath or hay-meadow vegetation, evenwithgrass freshly cut,or ofgraveland
clay withoutor withsparse shortvegetation. In afew cases itwas impossible to
differentiateclearly betweenterrestrialandaquatic territories, sincethemales pa-
trolledover water-logged vegetation with very littleor no openwater visible. At
thepeak ofthereproductive period acensus inthestudy area yielded 29terrestrial
and 15aquaticterritorialmales(Fig. 1).Althoughthepotentialterrestrialterritorial
sitesoutnumberedtheaquatic sites,not alloftheoviposition placesavailablewere
occupied.
228 H.Wildermuth
Certainplaces seemedtobepreferred toothers,astheywere nearly permanently
occupied duringtheflying season. Thesewereglades or footpaths betweenwalls
ofreed orbush rows, meadowcorners confinedby woods, andbays at hedge or
forestedges 2to6mindiameteradjacent toareas withlow vegetation, overlooking
openspace. Generally theindividualspatrolled inthesunandparallel totheverti-
calstructures,but flightcourses perpendicular tothewoodsedges, radially tothe
centres ofsingle shrubs, andbetweenbushesor treeswerealsorecorded.Atambi-
ent temperaturesof C theanimalsflew partly in theshadow.
At coherentand homogeneously structuredoviposition sites larger than 1/20ha
(open waterwithdensevegetation ofCarexelataorEquisetum fluviatile),themales
were not clearly site fixed. Instead, they slowly criss-crossed over thearea, thus
activelysearching forfemales.Thisbehaviourwasobservedoutsidethemainstudy
site.
durationOFSTAY. - As no individualswere marked andthe residents some-
timeslefttheirterritoriesduringaerialfights whilechasing anintruder, itwas im-
possible to determinewhichofthecontestants returned.Thereforethedurationof
stayforaresidentmalecouldnot be determinedexactly, especially duringthepeak
oftheflying season whenintraspecific competition was heavy. However, towards
theendofthereproduction periodthefrequencyofinterferenceswithconspecifics
Fig. 1. Distributionofaquatic andterrestrial territories inthe study areaonJuly 23, 1996, 12:00-
14:30 h CEST.Note the close vicinityofthe territories to shrubs and trees. Each black circle or
triangleindicatesonesite-fixed male.
Terrestrial andaquatic matingterritoriesinSomatochloraflavomaculata 229
decreasedandterritorialmalescouldbeobserved uninterruptedly forhalfanhour
ormore atthesameplace. Maximumperiods forfiveindividualswere 40,45,55,
60, and70min. Other individuals interrupted their patrol flights and perched on
plantstems. Inonerecordedcase flights lasted15-130s(mean= 59s,n= 15) and
rests 10-435s(mean= 81s,n= 18).
FLIGHTALTITUDE. - At ditchesandponds withoutemergent vegetation theani-
malspatrolled 0.3 - 0.5mabovethewater surface. Inthe presenceofwaterplants
(e.g. Equisetum fluviatile) the distance was 0.5 - 1.5m.On average males kept
aboutthesameheight forlongerperiods. They loweredtheirflightaltitudeatinter-
valsorraiseditforshortinstances, sometimesdashing ataninsectabovethem.On
terrestrial territories the constant flight height was occasionally only 0.2m over
gravel or freshly cut grass.However,flightbetween0.8- 1.5mwas alsoobserved
atthesesites.Theflightheight was usually0.7-1.2mabove ground inplaces where
thegrassor herbaceousvegetation hadnot beencutyet. Overpuddles withsparse
vegetation aflight heightof0.5-1.0mwas found.
RANGE AND FLIGHT COURSE. - Atterrestrialsites the individualscruisedback
andforth over a specific beat using thethe samehorizontalline dozens oftimes
subsequently (Fig.2).The distancebetweentwo turns was individual,but moreor
less constant for the same male at one site. It varied from 3 to 10m.Insteadof
straight lines also irregular zigzag or curved courses were seen, e.g. at areas of
2x3m(adjacent tobush), 1.5x1.5mand2x15m(footpath betweenreedbeds), 4x5m
(puddle area withdensevegetation). Atditches andpeat-diggings theanimalskept
ratherclosetothe water.
FLIGHTvelocity.- The flightspeedwas only measuredinindividualskeeping
periodically astraightflightcourse atterrestrialterritories.Patrolflights wererather
slow,ranging from0(hovering) to4m/s.Averagespeed was2.0-2.5m/s.Oneindi-
vidualwhichpatrolledevenly covered1600min 12min(0v=2.2m/s). Theflight
velocity ofindividualspatrolling a straight line was occasionally differentback
and forth,e.g. 1.9m/sfromStoN(n=21)and4.1m/sfromNtoS(n=21). Insome
cases thiswas duetothewind,butthereasons forthedifferenceswere not always
obvious.
FLIGHTSTYLE.- Patrollingmalesadvancedwithalternating wingbeatsandturned
back abruptly attheendsoftheirflightstretches.Otherindividualsshowedzigzag
courses withsharp turns orwide curves. Glidingwas regularly observed,however
mostly for short distances of0.1 - 0.3m only, rarely up to 2m. Returning from
pursuits or inspection flights up to 10mupward, the males flewwide loops and
glided over distancesof4-5m. Hoveringonthespot was afrequentcomponentof
patrol flightsand usually lasted0.5- 3s (0 1.6s, range0.5- 20s, n= 112). Many
individualspatrolledfor 15minor longerwithoutinterruptionandwithoutasingle
hoverstop.
FEEDING DURINGPATROLFLIGHTS. - Cruisingmalesnowandthendashedatsome
objects abovethemwhichsometimescouldbeidentifiedas smallflying insects.
230 H. Wildermuth
However,only onfew occasions Iclearly saw thattheprey itemwas captured and
thatdetachedparts of themdropped afterashortinstant.
REACTIONSTOWARDSFLYINGNON-PREY OBJECTS.- Territorialmales dashed at
any fast flying objects ofa certain size, even though itwas not suitableas prey.
Targets suchas butterflies, dragonflies andfalling tree leaveswereapproached for
Fig. 2. Flightcoursesofsite-fixed males. (1)Twoadjacentterrestrial territories inlane between rows
oftreesandbushes (B),viewfromabove;- (2)terrestrial territorybetween bushes (B),view fromthe
side; - (3)terrestrial territoryoverfen vegetation;- (4)terrestrial territoryoverdirtpath(PA) with
rainwaterpuddle(PU)ingladeofreed bed(Phragmitesaustralis PH),blackdotsindicatehoverstops;
- (5)aquaticterritoryoverditch(D);- (6)aquatic territoryoverpeat pond(PD);(3)to(6)view from
above.
Terrestrial andaquatic matingterritories inSomatochlora flavomaculala 231
closerexaminationwithacceleratedspeed. Thiswas observed atboth aquatic and
terrestrialsites. However, theresidentshardly showedany reactionstowards drag-
onfliesandbutterfliespassing atlowspeed. Fast flyingdragonflies were detected
atdistancesupto 12m, approached closely butonly occasionally chased.
REACTIONS towards CONSPECIF1CS. - Encounters between conspecific males
proceeded inthesamemanner atbothaquatic andterrestrialterritories.In allcases
which were watched (n = 24) the resident dartedimmediately atthe intruderas
soonas hewasdetectedandattackedhimfrombelowor fromtheside.Generally
thenewcomerretreated. Sometimesthelatterwas chasedfarbeyond the territory.
Typically aerial fights started about 1mabove ground or water, thecontestants
facingeachotherwithbody axesheldobliquely andspirallingupward upto6-12m
(Fig.3). Occasionally they extendedalllegs for short grapples withbody contact.
Chases couldalsobeperformedatahorizontalplane,theanimalsswiftly curving
orcircling severaltimes.The pursuerfollowedtheescaping opponentveryclosely
(Fig. 3). Some chases ended up far away from theterritory and one individual
occasionally returnedtothesite after15-30s.As pursuitsoccurred athigh speed it
was difficultrecognise details.Thereforeitis possible thatoneor theotherofthe
chasedindividualswas afemale.However,definiteencounters betweenterritorial
malesandfemalescouldberecorded
neither at aquatic nor at terrestrial
locations.
FEEDINGFLIGHTSOFNON-TERRITO-
RIAL individuals. - Besidesstrictly
localizedpatrolling males,adultsalso
were observed which performed
flights usingwiderspacesandshow-
ingadifferentflightstyle, interpreted
asfeeding flights. Inonetypical case
recorded,theindividualpatrolled on
a small sunlit forest clearing. It
hunted uninterruptedly at altitudes Fig.3.Examplesofflightcoursesduringaerialfights
between I and 10m above ground, ofmaleS.flavomaculataatterrestrial territories.
overanareaof30 x 40m.The flight
was characteristicallyerraticandundulating, alternating withcalmflightandglid-
ing stretches along straight linesandperiodically interrupted by dartsupwards or
sidewards,presumably directed toward smallinsects. Occasionally prey items or
parts ofthemwere seen dropping against the sunlight. The individualwas obvi-
ouslyfeeding. Neitherhoverstopsnor interactionswithotherdragonfliescouldbe
recorded.
232 H. Wildermuth
EXPERIMENTS
FISHING-LINE EXPERIMENTS. - Six tetheredmalesofS.flavomaculata werere-
leasedin the territoriesofpatrolling males approaching theexperimentalist on a
straight flight course. They elicitedimmediateattacks by theresidenttowardsthe
fleeing individual,followedby shortbut vigorous clashes.Thecontestants circled
3 to5s, occasionally grappling with perceivable clattering ofwings. Soonafter-
wards theterritoryowner mostly leftthesite. Malesflying inan untypical manner
or staying motionlesswereonly approached forshortinspections or not noticedat
all.On theotherhand,thereactions were thestrongerthefasterthetetheredindi-
vidualtried to escape. Flying males ofLibellulaquadrimaculata tetheredto the
fishing-line were approached uptoca0.2m,andthen nolonger noticed.Repeated
releases didnotevoke furtherreactions.
Patrollingmalesalsopursued asmallpiece ofwoodtetheredtothefishing-line,
swiftly circling around theexperimentalist (n = 8).The strongest reactions were
obtainedwhen theobject passed horizontally at high speed in frontand slightly
abovetheapproaching male.The dummy was followed2 to3m, insomecases up
toacomplete turn.Thenthemalesresumedthepatrol flight.However,thisexperi-
mentwas successful only afewtimessubsequently withthesameindividual.After
two or threeboutsofswinging, theresidents didnolonger showpositivereactions.
Malesataquatic territoriesreactedexactly thesameas thoseatterrestrialsites.
EXPERIMENTS with untethered MALES AND females. - Six males were re-
leasedindividually atsixdifferentterrestrialterritories.Theyfledswiftly upwards
andwereimmediately chasedbytheresidentuptoca 10m. Subsequently the latter
returned to his territory. Corresponding experiments were carried out with five
females. The males reactedpromptly and tried to intercept them. In four cases
tandemformationcouldbewatched.However,only threepairs completed copula-
tion. One femaledived into a bush nearby and remained motionless.The male
hovered 20 cm infront ofher during ca. 20s but did not recognize her.Thesame
experimentwas conductedby L. Bdrzsbny (pers. comm.)atafen near Munich.He
obtainedsimilarresults.
REACTIONS TOWARDSOVIPOSITIONSITEDUMMIES. - In contrast to Libellula
quadrimaculata andL. depressa, S.flavomaculata showedonly weakreactionsto
theplastic material.Inthecourse of 45 experimental sessions (distributed over 3
years,in Juneandearly July,eachsession lasting 2-4h)thelibellulidsexhibited ca
1800positive reactions, whereasin5. flavomaculata only 7 clearreactions could
berecorded.Themalesexaminedthesheets very shortly froma closedistanceand
subsequently movedon.Somereturnedonceor twice.Noindividualstayedlonger
than afewseconds atthesite.
Terrestrial andaquatic matingterritoriesin Somatochloraflavomaculata 233
SPERMVESICLECONTENTS OF MALESATEXTRA
AQUATICTERRITORIES
In order to learn whether the males patrolling away fromthe water hadtheir
spermvesicle filledwith spermand thereforewere ready tocopulate, patrolling
individualswere captured andthenmicroscopically studiedinthelaboratory. The
sperm storageorgansofevery malecontainedmature spermcells. Presumably S.
flavomaculata fills the sperm vesicle before the patrol flight as described for
Corduliaaenea(UBUKATA, 1984).
DISCUSSION
According to BROWN's (1964)concept ofeconomic defendability, the estab-
lishmentofaterritoryis only rewarding ifthebenefitsofpriorityofaccess tothe
site-fixedresource exceed thecostssuch as timeandenergyexpenditure. Hypo-
thetically, theresources whichS.flavomaculata malesclaimforexclusive access
mightcomprise food,locationsforthermoregulation, oviposition sites, orfemales.
Combinedfunctionsmaynot beexcluded.
Inthecaseofaquatic territoriesfoodas aresource withexclusive access maybe
leftoutofconsideration,sincetheresidentsonly occasionally feed. Thesites may
be regularly visited for egg deposition. Indeed, oviposition couldbe witnessed
only rarely, butexuviaewere found atmostwaters wherethemalesoccasionally
patrolled (WILDERMUTH, 1997).Hence,thedefendedaquatic sites willatleast
partly serve as rendezvous, as described for other corduliids such as Cordulia
aenea(UBUKATA 1975) and Procordulia smithii(ROWE, 1988). However, as
demonstratedbytheexperiments withplasticsheets mimickingpossible oviposition
sites, areas with open water do not prove specially attractive for male S.
flavomaculata. This is in contrast to S. arctica (WILDERMUTH & SPINNER,
1991). Terrestrial territories, on the other hand, may be completely excluded as
resources rewarding defence with respect to egg deposition, since femaleshave
only been observed to oviposit into open water (e.g. SCHMIDT, 1990;
BUCHWALD, 1983; ULLRICH, 1995). At the study site theseare shallowand
densely overgrownpuddles onorganic mudground, ditches,andsmallpeatponds
(WILDERMUTH, 1997).
ST. QUENTIN (1932, 1964) interpreted the terrestrial territories of S.
flavomaculata as defendedfeeding sites. However,iftheindividualsclaimedfood
resources, itshouldbeexpected thattheprey itemswereclumped andstationary,at
least for a certaintime.In thefield no such concentrationsofprey insects were
present atthe territory sites. Furthermore, the femaleshaving considerablefood
requirements foreggproductionshouldalsobeterritorial.However, noterritorial
females have been reported. As mentionedabove, hunting individualsdifferin
theirflightstyle frompatrollers. Regular oroccasionalfeeding ofterritorialmales
234 H. Wildermuth
may be explained by the fact that S. flavomaculata is a "flier" sensu CORBET
(1962), staying onthewing forlong periodsandthereforeconsuming correspond-
ing amounts ofenergy. On the other hand,occasional prey capture was alsore-
corded in territorial males of Libellulaquadrimaculata, considered a typical
"percher", and thereforesupposed to havelesser energy requirements (MOORE,
1960;personal observations).
Many locations where males patrolled were characterized by favourable
microclimaticalconditionsdueto high insolationand/orwindsheltersuggesting a
thermoregulatory functionoftheterrestrialterritories.Hence,themaleswouldgain
maximumagility for encounters with females.This mightbe true for "perchers”
which regulate their body temperatureto a great extent by behavioural means.
However, "fliers" will hardly seek thesites in orderto warm uptheir body since
they rely on endothermicheatgeneration (HEINRICH, 1993).Onthecontrary, at
high ambienttemperaturesthey maybe faced withoverheating problems. Strik-
ingly, malesofS.flavomaculata patrolled partly in theshadowwhen theairtem-
peratureexceeded28°C, hardly showing anyhoverstops. Atlowertemperatures
theterritorialflights were performed exclusively inthesun, and hoveringwas fre-
quently interspersed, as recordedinEpitheca cynosura (MAY, 1987).
Themostlikely functionoftheterrestrialterritoriesis sexual.Thisassumption is
supported by anumberoffacts: (1) The territorialbehaviouris exclusively per-
formedby males.(2) Themalesare readyto mate,astheir spermvesicleis filled
with sperm.(3) Intruding conspecific malesare vigorously drivenoff, to a lesser
extent alsoother dragonflies species. (4) Released or tetheredconspecific males
arevigorously attackedby theterritoryowner.(5)Any passing insectsofa certain
sizeand dummiesswiftly sweeping through theairare dashedatandapproached
for close inspection. (6)Feeding duringpatrol flights is ratherinfrequent andthe
flightstyle is differentfromtypical foraging flights. (7) Conspecific femalesre-
leasedwithinterrestrialterritoriesare immediatelyseized, followedby tandemand
wheelformation.(8)There isnorelevantdilferenceinterritorialbehaviourataquatic
andterrestrialsites.
Direct evidence forthe reproductive functionofthe terrestrialterritories with
receptive femalesrewarding defencewouldbetherecordofmating. Althoughpairs
adopting tandemor wheel position were seen at some occasions at or near the
territories(L.Borzsony, pers.comm.;thisstudy),thecomplete sequenceofmating
has not been recorded atterrestrial sites. However, it may not be excluded that
seizure and tandemformationhave not been witnessed because the procedures
occur suddenly, rapidly, after a short pursuit andthereforeaway from territory.
Thismight have happened when a terrestrialterritory stayed empty fora while
afterawildchasewith theprosecuted individualpossibly being afemale.Never-
theless, WEBEL (1932) observed on forestpaths thatmalesgrasped femalesand
flewrapidly totheponds nearby.
Mostcorduliidsso farstudiedpatrol atselectedsectionsofpond or lakeshores
