do the dimensions of male adanal suckers and tritonymphal female docking papillae correlate in

14 Pages·2017·2.49 MB·English

Like a glove: do the dimensions of male adanal suckers
and tritonymphal female docking papillae correlate in
the Proctophyllodidae (Astigmata: Analgoidea)?
K.A. Byers, H.C. Proctor
To cite this version:
K.A. Byers, H.C. Proctor. Like a glove: do the dimensions of male adanal suckers and tritonymphal
female docking papillae correlate in the Proctophyllodidae (Astigmata: Analgoidea)?. Acarologia,
2014, 54 (1), pp.3-14. ￿10.1051/acarologia/20142110￿. ￿hal-01565225￿
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Acarologia54(1):3–14(2014)
DOI:10.1051/acarologia/20142110
LIKEAGLOVE:DOTHEDIMENSIONSOFMALEADANALSUCKERSAND
TRITONYMPHALFEMALEDOCKINGPAPILLAECORRELATEINTHE
PROCTOPHYLLODIDAE(ASTIGMATA:ANALGOIDEA)?
KayleeA. BYERS* andHeatherC. PROCTOR
(Received05June2013;accepted05November2013;publishedonline28March2014)
DepartmentofBiologicalSciences,UniversityofAlberta,CW405BiologicalSciencesBuilding,Edmonton,Alberta,CanadaT6G2E9.
[email protected](*CorrespondingAuthor);[email protected].
ABSTRACT— Precopulatoryguardingoftritonymphalfemalesbyadultmalesiscommoninfeathermites(Acari:Astig-
mata).WithintheProctophyllodidae(Astigmata:Analgoidea),somegenerapossessmorphologicalfeaturesinbothsexes
thathavebeensuggestedtoenhancemaleattachment. Onesuchstructureintritonymphalfemalesisthedevelopment
ofapairoffleshylobe-likedockingpapillae,whilemalespossessapairofventraladanalsuckersthatareproposedto
fitovertopoftheseprojections. Todeterminewhetherthesestructuresarestronglycorrelatedinsize,wemeasuredthe
dimensionsofthemaleadanalsuckersandtritonymphalfemaledockingpapillaeinthreegeneraofmites:Neodectesspp.
ParkandAtyeo,1971,Proterothrixspp. Gaud,1968(Proctophyllodidae: Pterodectinae),andProctophyllodesspp. Robin,
1877(Proctophyllodidae: Proctophyllodinae). Welookedforcorrelationsinthesemeasurementsasanindicationofse-
lectivecooperation.Ourresultsdidnotrevealstrongpositivecorrelationsbetweenthedimensionsofthesestructuresin
tritonymphalfemalesandadultmales. Weproposeseveralreasonsforwhywemaynothavedetectedstrongevidence
ofagoodfitbetweenanalsuckersandtritonymphalpapillaethatarerelatedtothebiologyoffeathermites,andsuggest
stepstoexpandonthisresearchinfuture.
KEYWORDS—Acari;cooperative;correlatedmorphology;feathermites;precopulatoryguarding
INTRODUCTION to store sperm; these qualities encourage males to
stakeaclaimtounreceptivefemalesbeforetheybe-
come receptive (Parker, 1974; Grafen and Ridley,
The mating strategies of precopulatory and post-
1983). Incontrast,postcopulatorymateguardingis
copulatory mate guarding are common tactics em-
predictedwhenfemalesmaterepeatedlyandarere-
ployed by males to overcome sperm competi-
ceptivetoadditionalmalesfollowinganinitialcop-
tion (Parker, 1970). Although both strategies aim
ulation(Parker, 1974). Inthecaseofprecopulatory
to maximize male fertilization success, these be-
mate guarding, the fitness gained by guarding an
haviours are predicted under different reproduc-
unreceptivefemaleexceedsthatwhichisgainedin
tiveconditions. Precopulatorymateguardingisex-
a continued search for mates (Parker, 1974). This
pectedwhenfemalesmateonlyonce,whenfemales
formofmateguardingisarguedbySimmons(2001)
mate for a limited time (a brief fertilization win-
to function more as a means of monopolizing fe-
dow), or when there is little ability of the female
http://www1.montpellier.inra.fr/CBGP/acarologia/ 3
ISSN0044-586-X(print).ISSN2107-7207(electronic)
ByersK.A.andProctorH.C.
males until they are receptive than as a tactic to tritonymphal females possess a pair of dorsal,
avoidsperm-competition. fleshy protuberances which are hypothesized to fit
into the male adanal suckers (Atyeo and Braasch,
While mate guarding has been widely re-
1966), which are particularly elongated in this
ported throughout the animal kingdom (beetles:
genus. The protuberances of Proctophyllodes spp.
Alcock, 1991; birds: Birkhead, 1979; Hammers
and Psoroptes spp. Gervais, 1841 (Astigmata:
et al., 2009; cephalopods: Huffard et al., 2008;
Psoroptidae)havebeendescribedindetailbyWital-
lizards: Cuadrado, 1998; mammals: Schubert et
in´ski et al. (1992) whose findings suggest that the
al.,2009),precopulatoryguardingisespeciallycom-
dimensionsofthedockingpapillaeandtheadanal
mon among invertebrates (Deinert et al., 1994; Bel-
suckers correspond in length, diameter and axis-
Venner and Venner, 2006; Arnqvist et al., 2007;
to-axis distance. A comparable mechanism for at-
Parker and Vahed, 2010; Takeshita and Henmi,
tachmenthasbeenillustratedinthebeaverfur-mite
2010). Severalstudiesinarthropodsdocumentthat
Schizocarpus mingaudi Trouessart, 1896 (Astimgata:
the onset of precopulatory mate guarding occurs
Chirodiscidae) whereby the larval cuticle is drawn
whenfemalesarestilljuveniles(Evstigneeva,1993;
into a conical depression in the male’s soft cuticle
Fiers, 1998; HoldsworthandMorse, 2000; Zhuand
(Fainetal.,1984).Somefurmiteshaveanadditional
Tanaka, 2002; Oku, 2009; Estrada et al., 2010; Jones
attachment site between the male’s adanal suckers
et al., 2010). In some taxa this guarding is cued
and discs on the immature female mite; in this in-
by the emission of pheromones by the immature
stance, the discs are considerably larger than the
female that announce her stage in the moult cy-
adanal suckers, which makes their insertion into
cle to potential mates (Dunham, 1978; Thompson
thesuckershighlyunlikely(Fainetal.,1984).
andManning, 1981). Someimmaturefemalemites
(Arachnida: Acari) also emit pheromones termed
"arrestants" that stimulate guarding behaviour in
conspecificadultmales(Sonenshine,1985).
Morphologicaltraitsassociatedwithcopulation
In mites, precopulatory guarding has been
and intromission are often correlated between the
found in many taxa where males guard the penul-
sexes(Eberhard,2004). Thesecorrelatedcharacters
timatefemalestage,whichdependingontaxoncan
canarisethroughantagonisticcoevolutionwherein
bethedeutonymph(Helle, 1967; Potteretal., 1976;
the sexes engage in an evolutionary arms race to
Yasui, 1988; Oku, 2009) or the tritonymph (Wital-
gain control of reproduction (Rowe and Arnqvist,
in´ski et al., 1992; Bochkov and OConnor, 2005).
2002; Bergsten and Miller, 2007; Tatarnic and Cas-
Some male spider mites (Tetranychidae: Neonidu-
sis, 2010); or these traits may be "selectively coop-
lus Beard and Walter, 2010) have enlarged legs I to
erative" arising through sexual selection by female
guardnymphalfemales(D.E.Walter,RoyalAlberta
choice (Eberhard, 1985). In this study, we mea-
Museum, pers. obs.). Likewise, many male Astig-
sured the dimensions of the male adanal suckers
mata possess enlarged legs III and/or legs IV to
and the tritonymphal female docking papillae in
aidinguardingnymphalfemales(KrantzandWal-
representatives of three genera of Proctophyllodi-
ter, 2009), whileothersuseapairofventraladanal
dae (Neodectes spp. Park and Atyeo, 1971, Procto-
suckers to attach to immature and/or mature fe-
phyllodes spp., and Proterothrix spp. Gaud, 1968).
males (Witalin´ski et al., 1992). In most male Astig-
Thesetraitsaresupposedlybeneficialtobothsexes,
mata,thesesuckersarecomposedofathickexocu-
as efficient coupling may increase the fertilization
ticle that forms slightly concave sucker plates that
success of both sexes, and potentially reduce dam-
are covered by a flexible procuticle encompassing
agetothefemale’sintegumentbylocalizingattach-
the sucker periphery, which facilitates attachment
ment to a particular area. As such, we hypoth-
ofthesexesthroughsuction(Witalin´ski,1990).
esized that these traits would be strongly corre-
In the feather mite genus Proctophyllodes latedtoimproveattachmentoftheadultmaletothe
Robin, 1877 (Astigmata: Proctophyllodidae), the tritonymphalfemale.
4
Acarologia54(1):3–14(2014)
MATERIALS AND METHODS authors (HP). For these birds, mites were removed
in two ways: if hosts were prepared as dry skins,
Specimencollection the skins were ruffled over a sheet of white paper
andthemiteswerepickedoutwithfineforcepsand
We collected three genera of mites in the family
placed into 80 % ethanol; if birds were preserved
Proctophyllodidae, including Neodectes spp., Pro-
in ethanol, mites were sucked up from the bottom
terothrix spp. (Proctophyllodidae: Pterodectinae),
of the container using a syringe. Birds collected in
and Proctophyllodes spp. (Proctophyllodidae: Proc-
Canadawerestoredindividuallyaftercaptureat-20
tophyllodinae). Miteswerecollectedfrom31avian
°CuntilprocessingbyHPorKB.Frozenbirdswere
hosts captured in Australia, Canada, China, the
thawed and then washed in a container with (cid:39) 15
Philippines, and Spain (Table 1). Mites were re-
mL of 95 % ethanol, (cid:39) 10 mL of Palmolive® dish
trieved using a variety of methods depending on
detergentandsufficientwatertosubmergethebird.
thehost’splaceofcapture. BirdscollectedinChina
Wemassagedeachbirdthoroughlywithinsolution
and the Philippines were mist-netted and mites
toremovemitesfromthebody, wingfeathers, and
wereremovedbyeyefromthedeadhost. InSpain,
retrices. We rinsed the bird body and poured the
feathers were plucked from live birds and soaked
washingsolutionthroughaFisher-Scientific53-µm
in70%ethanoltorehydratespecimens(seeGalván
meshfilter. Miteswerewashedfromthesievewith
etal.,2008). InAustralia,preservedbirdspecimens
80 % ethanol and stored in 75 mL screw-cap con-
were sampled from either the Western Australian
tainers. ForbirdscaughtinCanadaandSpain, the
MuseumortheQueenslandMuseumbyoneofthe
TABLE1:TaxonomicauthoritiesandlocalitydataforavianhostsofNeodectesspp.,Proctophyllodesspp.,andProterothrixspp.(Analgoidea:
Proctophyllodidae).Thepresenceorabsenceofdockingpapillaeintritonymphsisindicatedforeachtaxon.
Docking papillae 
Mite taxonomy and authority Host genus Host species Authority Locality
present
Neodectes spp. Park & Atyeo, 1971 Acanthisitta chloris (Sparman, 1787) No data Yes
Pachycephala philippinensis (Walden, 1872) Aurora Memorial Park, Philippines Yes
Sitta frontalis Swainson, 1820 Philippines Yes
Proctophyllodes spp. Robin, 1877 Acanthis hornemanni  (Hoiboil, 1843) Smith, AB, Canada No
Bombycilla cedrorum Vieillot, 1808 Athabasca, AB, Canada No
Carpodacus purpureus (Gmelin, 1789) Athabasca, AB, Canada Yes
Catharus ustulatus (Nuttall, 1840) Edmonton, AB, Canada Yes
Certhia americana Bonaparte, 1838 Edmonton, AB, Canada Yes
Cincloramphus cruralis (Vigors and Horsfield, 1827) Outcamp Creek, Australia Yes
Cyornis herioti Ramsay, 1886 Mt. Cagua, Philippines Yes
Melospiza melodia (A. Wilson, 1810) AB, Canada Yes
Pica hudsonia (Sabine, 1823) Edmonton, AB, Canada Yes
Sitta canadensis Linnaeus, 1766 Spruce Grove, AB, Canada Yes
Turdus migratorius Linnaeus, 1766 Edmonton, AB, Canada Yes
P. glandarius (Koch, 1840) Bombycilla garrulus (Linnaeus, 1758) AB, Canada No
P. megaphyllus Trouessart, 1885 Plectrophenax nivalis (Linnaeus, 1758) Barrhead, AB, Canada Yes
P. microcaulus Gaud, 1957 Eremophila alpestris (Linnaeus, 1758) Manyberries, AB, Canada Yes
P. musicus Vitzthum, 1922 Turdus migratorius Linnaeus, 1766 Edmonton, AB, Canada Yes
P. pennifer (Trouessart and  Neumann, 1888) Cinclidium leucurum (Hodgson, 1845) Jing Xin, China No
P. schoenicli Atyeo and Braasch, 1966 Emberiza  schoeniclus (Linnaeus, 1758) Spain Yes
P. sylviae Gaud, 1957 Sylvia atricapilla (Linnaeus, 1758) Spain Yes
P. vesca Atyeo and Braasch, 1966 Myadestes townsendi (Audubon, 1838) Camp Creek, AB, Canada No
Proterothrix spp. Gaud, 1968 Rhipidura cyaniceps (Cassin, 1855) Aurora Memorial Park, Philippines Yes
Orthonyx temminckii Ranzani, 1822 Wilson’s Peak, Killarney, Australia Yes
Cracticus quoyi (Lesson, 1827) Gunn Point, Australia No
Keys to Proterothrix spp. Gaud, 1968 Conopophila rufogularis (Gould, 1843) Derby‐West Kimberley, Australia Yes
Cyornis herioti Ramsay, 1886 Angat & Mt. Cagua, Philippines Yes
5
ByersK.A.andProctorH.C.
FIGURE1:LengthoftheidiosomainProctophyllodesspp.inA.femaletritonymphs,B.adultfemalesandC.adultmales.Measurements
(dashedline)weretakenfromthemarginoftheprodorsumtotheposteriormarginofthebody.Infemaletritonymphswemeasured
thelaterallength(A),mediallength(B),andwidth(C)ofthedockingpapillae.Inadultmales(D;ventral),wemeasuredthedistal(D)
andbasal(E)widthsoftheadanalsuckersaswellassuckerdepth(F).LinedrawingsaremodeledafterProctophyllodesglandarinus
foradultsandfromProctophyllodesparifortritonymphs(AtyeoandBraasch,1996). Diagramsofthedockingpapillaeandadanal
suckersaredrawnafterscanningelectronimagespublishedinWitalin´skietal.(1992).
6
Acarologia54(1):3–14(2014)
ethanol solution was examined at 20-40X magnifi- mensions of the male adanal suckers and female
cationusingaLeicaMZ16dissectingmicroscope. tritonymphaldockingpapillaewerecorrelated.
We mostly selected pairs of mites that were in
precopula (i.e., male and tritonymphal female) for
slide mounting. Mites were cleared in lactic acid
Proctophyllodestroncatusmeasurements
overnightandmountedinPVAmountingmedium
(BioQuipProducts; RanchoDominguez, CA,USA)
In the literature, ’docking papillae’ have been as-
on glass slides. Slides were cured on a warm-
sociated with the female tritonymph of Proctophyl-
ing tray at 45 °C for a minimum of four days and
lodes spp. (Atyeo and Braasch, 1966); however,
werethenexaminedat400XonaLeicaDMLBcom-
whether or not females are the only sex to pos-
pound microscope (Leica Microsystems Inc., Rich-
sess these papillae has not been tested. To clar-
mondHill,ON,Canada)usingdifferentialinterfer-
ify whether docking papillae were restricted to fe-
encecontrast(DIC).Miteswereidentifiedtogenus
male tritonymphs and not to any other nymphal
in all cases and species when possible using rele-
stage or sex, we measured the length of the id-
vanttaxonomicliterature(AtyeoandBraasch,1966;
iosoma in adult male, adult female and nymphal
Gaud and Atyeo, 1996). Most proctophyllodids
ProctophyllodestroncatusRobin, 1877capturedfrom
from hosts outside of Europe and North America
house sparrows (Passer domesticus (Linnaeus)) in
areundescribed, andarenotedsimplyas’sp.’. Ex-
Romania (Figure 1). We measured a total of 20
emplars of each taxon are deposited in the E.H.
adult male and female P. troncatus, as well as 196
Strickland Entomological Museum at the Univer-
nymphal P. troncatus. Ideally we would have been
sityofAlberta.
able to use the number of genital papillae to dif-
ferentiate between protonymphs (which have one
Correlationmeasurementsandanalysis
pair) and tritonymphs (which have two pairs), but
To analyze whether the male adanal suckers and the slightly degraded nature of the specimens ren-
tritonymphal female docking papillae correlated dered the nymphal genital papillae essentially in-
morphologically,wetookdigitalimagesat200and visible even under DIC lighting. The presence of
400Xofadultmalesandtritonymphalfemalesfrom twoadditionalpairofventralsetaemightalsohave
each bird using Image Capture (Apple Computer, been used for differentiating tritonymphs from
Cupertino,CA,USA)andaCanonPowerShotS40. protonymphs (Gaud and Atyeo, 1996); however,
Images were uploaded to ImageJ (National Insti- these setae were also difficult to observe, making
tutes of Health, Bethesda, Maryland) and mea- theirconsistentuseproblematic.Forallnymphswe
sured for male and tritonymph body size as well determinedwhetherdockingpapillaewerepresent.
as for dimensions of the male adanal suckers and We grouped mites into categories for adult males,
tritonymphal docking papillae. For both sexes we adult females, nymphs with docking papillae, and
measured the length of the idiosoma from the an- nymphs without docking papillae and analyzed
terior margin of the prodorsum to the posterior of the distribution in a histogram produced in SPSS.
the body excluding the opisthosomal lamellae in We tested for differences in size between the adult
males(seeFigure1a,b,c). Fortritonymphs,wetook sexes as well as between nymphs with and with-
three measurements of the docking papillae: the outdockingpapillaeusingunpairedt-tests. Wehy-
width, the longest (medial) length and the short- pothesizedthatadultfemaleswouldbelargerthan
est(lateral) length(Figure1a). For males, wemea- adultmales, thatadultmaleswouldbelargerthan
sured the width at the adanal sucker tip and at nymphs and that, if nymphs with docking papil-
the base as well as the depth of the sucker (Fig- lae were tritonymphal females, that these nymphs
ure 1d). Spearman’s correlation coefficient analy- should be on average larger than nymphs without
ses were performed in SPSS version 20 (SPSS Inc., dockingpapillae(predictedtobenymphalmalesor
Chicago, IL, USA) to determine whether the di- protonymphalfemales).
7
ByersK.A.andProctorH.C.
FIGURE2: Correlationbetweenadultmaleandtritonymphalfemalebodylength(µm)inNeodectesspp.,Proctophyllodesspp.,andPro-
terothrixspp. (Astigmata: Proctophyllodidae). Lengthoftheidiosomawasmeasuredfromtheanteriormarginoftheprodorsum
totheposteriorregionofthebodyexcludingtheopisthosomallamellaeinmales. Bodysizewaspositivelycorrelatedbetweenthe
sexes(rs=0.66,n=32,P<0.01)wherebylargertritonymphalfemaleswerepairedwithlargerconspecificmales.
TABLE2:Spearman’scorrelationcoefficients(rs)andsignificance(P)ofcorrelationsbetweenmeasurementsofmaleadanalsuckersand
tritonymphaldockingpapillaeinthegeneraNeodectesspp.,Proctophyllodesspp.,andProterothrixspp. (Analgoidea:Proctophyllodi-
dae).
Male Adanal sucker Adanal sucker Adanal sucker
Female tritonymph morphology
morphology distal width basal width length
n r P n r P n r P
s s s
Docking papillae width 19 0,47 0,85 18 0,43 0,07 17 -0,43 0,06
Docking papillae medial length 19 0,36 0,13 18 0,2 0,42 17 0,38 0,13
Docking papillae lateral length 19 0,06 0,81 18 -0,21 0,41 17 0,24 0,35
RESULTS tritonymphal females measured, four Proterothrix
spp., one Neodectes spp. and eight Proctophyllodes
Correlationanalysis
spp. individualsdidnothavedockingpapillae. For
correlationanalysesweomittedspecimenswithout
Of the 49 pairs of mites analyzed, 17 were omitted
dockingpapillae(n=13)toremovetheinfluenceof
astheindividualswerestillfirmlyinprecopulaand
zerocounts. Wealsoomittedmaleswherewewere
thedockingpapillaewerenotobservable. Inthere-
unabletomeasureadanalsuckerlength(n=2of19
maining pairs, body size was positively correlated
pairs)orbasalareaofthesucker(n=1of19pairs).
between adult males and tritonymphal females (r
s
Therewerenocorrelationsbetweenthedimensions
= 0.66, n = 32, P < 0.01) (Figure 2). Among the
8
Acarologia54(1):3–14(2014)
of tritonymphal docking papillae and male adanal ingpapillaeandthemaleadanalsuckers. Inarthro-
suckers(Table2). Themedialandlaterallengthsof pods,severalstudieshavedocumentedcorrelations
the female docking papillae did not correlate with between the sexes in reproductive characters both
maleadanalsuckerlength(r >0.24,n=17,P>0.13; internally (e.g. the genitalia of Apamea Ochsen-
s
seeFigure3);norwaswidthofthedockingpapillae heimer, 1816 moths (Mikkola, 1992)), and exter-
correlatedwiththedistal(r =0.05,n=19,P=0.85) nally(e.g. thegroovesandpitsonfemalekatydids
s
or basal (r = 0.43, n = 18, P = 0.07) widths of the which facilitate grasping by male clasping struc-
s
adanalsuckers(Figure3). tures (Rentz, 1972)). In their study of Proctophyl-
lodes and Psoroptes spp. mites, Witalin´ski et al.
Proctophyllodestroncatusmeasurements (1992) report size similarities between the docking
papillae and male adanal suckers; however, these
Distributions of body length for P. troncatus adult
results were strongly categorical, whereby lengths
males,adultfemales,andnymphsaredisplayedin
anddiametersofthesestructureswerecomparedas
Figure4. Adultmalesrangedinsizefrom250–285
ranges.Wedidnotfindanyquantitativecorrelation
µm in length and were significantly smaller than
between these structures in our study. Given that
adult females in length which were 330 – 380 µm
the mode of precopulatory attachment is likely the
(t =22.6, P<0.001). Fornymphs, thereweretwo
38 sucking force between the adanal suckers and the
distinctsizeclusters;nymphswithdockingpapillae
dockingpapillae(Witalin´skietal.,1992),onewould
(n=81)rangedinsizefrom240–375µminlength
expectthatcloselycorrelateddimensionswouldbe
andweresignificantlylargerthannymphswithout
integraltopromotingacohesivecoupling. Theab-
dockingpapillae(n=115)whichwere175–255µm
senceofcorrelationbetweentritonymphsandadult
inlength(t =20.6,P<0.001).
194 males in dimensions of the docking papillae and
adanalsuckersmayindicatethatsizeisnottheonly
DISCUSSION characteristicthatmatters.
Although copulation occurs between adult astig-
It is possible that we did not measure the size
matan feather mites, it is common for males to
of the papillae as they would be when held within
couple with tritonymphal females prior to mating
the adanal suckers. Witalin´ski et al. (1992) sug-
(Atyeo and Braasch, 1966; Witalin´ski et al., 1992).
gest that the docking papillae swell during attach-
In our study of Neodectes spp. and Proterothrix
ment due to increased haemolymph pressure in-
spp. (Proctophyllodidae: Pterodectinae) and Proc-
duced from suction of the male suckers. A sim-
tophyllodes spp. (Proctophyllodidae: Proctophyl-
ilar suction-based mechanism of maintaining con-
lodinae) we observed dorsal docking papillae in
tactbetweenadultmalesandimmaturesishypoth-
tritonymphsofallgenerasimilartothosedescribed
esized in Schizocarpus spp. Trouessart, 1896 fur
by Witalin´ski et al. (1992) in Proctophyllodes stylifer
mites (Fain et al., 1984). If this is so, then it is pos-
(Buchholz, 1869), Proctophyllodespicae(Koch, 1840),
sible that the papillae of independent tritonymphs
Psoroptescuniculi(Delafond,1859),andPsoroptesna-
are not representative of their size when swollen
talensis Hirst, 1919. Surprisingly, not all nymphs
in copula. However, we would also expect that
that we observed in precopula possessed docking
the width of the papillae would be consistently
papillae. This may be due to either intrageneric
smaller than that of the adanal suckers, which we
variability in the presence of docking papillae, or
did not find. In some instances, the width of the
aresultofmalesaccidentallygrabbinganymphof
tritonymphaldockingpapillaewasgreaterthanthe
the wrong sex or stage, a phenomenon which has
width of the distal adanal sucker, a result which is
been reported in male tarsonemids (Garga et al.,
in contradiction to our hypothesis. Another con-
1997).
sideration is the role of glandular secretions in the
It was surprising that we did not find a corre- attachment of males to females. In some uropo-
lation between the dimensions of the female dock- did mites, the phoretic deutonymph uses glandu-
9
ByersK.A.andProctorH.C.
FIGURE3:CorrelationsinmorphologybetweenadultmaleandtritonymphalfemaleNeodectesspp.,Proctophyllodesspp.,andProterothrix
spp.feathermites(Astigmata:Proctophyllodidae).Correlationsareillustratedbetweenwidths(A-B)andlengths(C-D)ofthemale
adanalsuckersandthefemaledockingpapillae. R2 valuesindicatehowwellvariationinonevariableispredictedbythatofthe
othervariable.
10