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. >t Memoirs ofthe Museum ofVictoria 56(2):643-646 (1997) 28 February 1997 https://doi.org/10.24199/j.mmv.1997.56.63 PANZER MITES ON THE FOREST PHYLLOPLANE Vanessa M. Barnes Department ofEcology and Evolutionary Biology, Monash University, Clayton, Victoria, 3168, Australia Abstract Barnes, V.M., 1997. Panzer mites on the forest phylloplane. Memoirs ofthe Museum of Victoria 56(2): 643-646. Thedistributionandabundanceofthephylloplanespecialist,Apolyphyllos,appearstobe influenced by architectural complexities ofthe leaf. Introduction 1.5 Overthelastdecade,canopyfogginginavariety Adhaesozetes oftropical forestshaschangedourperceptionof polyphyllos the biodiversity of insects. However, most of these studies have probably underestimated Other both the abundance and species richness of a la Oribatids more obscure group of arthropods, the mites o (Acari) (Walter and O'Dowd, 1995a). Usually considered denizens ofthe soil and litter, these -3i.o tiny mites may exploit the wide variety offood •i— resources and microhabitats (ranging from the +a— leaf surface, or phylloplane, to bark crevices) JO •i—t available in the forest canopy (Walter et al., to-i 1994; Walter and O'Dowd, 1995b). For example,thediverseOribatidaor'Panzermites' (a German term referring to their 'tank-like' exoskeleton) are typically stereotyped as a soil- dwelling group. Yet, some Panzer mites may J2 0.5 lead arboreal lifestyles or even be microhabitat B specialists within the forest canopy (Walterand a Behan-Pelletier, 1993). In forests in southeastern Australia, I studied tmhieted,isAtdrhiabeutsioozneatlesecpoolloygpyhyolfloosne(Ascuacrhi:orOirbiabtai-d H-ot-> ii_ n tida: Licneremaeoidea) asking three questions: 1 Is A. polyphyllos a phylloplane specialist? 0.0 2. Doesthe morphologyofA. polyphylloscorre- Soil Bark Stem Leaf late with its arboreal lifestyle? A 3. Is polyphyllosahabitatspecialistatalarger Microhabitats scale, e.g., forest type? Figure 1. The mean number (± standard error) ofA. IsAdhaesozetes a phylloplane specialist? polyphyllos(nymphs and adults combined) and other TodeterminewhetherApolyphyllosspecialised oribatid mite species per cm ofmicrohabitat sample on any particular microhabitat in the forest per tree. The tree species (Musk Daisy-bush, Silver canopy, I compared itsdistribution with that of pBoaonlkesdi.a, Snowy Daisy-bush, and Lilly-pilly) are other oribatid species across microhabitats (bark,stem&leaves)onfourplantspeciesandin the soil (Fig. 1). From one plant, four soil and stant for the Musk Daisy-bush and the Snowy leaf litter cores (7 cm by 4 cm), four bark and Daisy-bush. However, the number of leaf moss strips (8 cm by 2 cm), four stem sections sampleswasincreasedto20foreachoftheLilly- (le1c2t-e1d.5 Tchmeinsalmepngltihn)gannudmebiegrhtslreaevmeasinweedreccoonl-- ppiolpluylpaltainotnsadnednstihteieSsilvweerreBanuknskinaopwlna.nts,Shaosottsh,e 643 644 V.M. BARNES approximately 7 cm in length, were collected Life on the phylloplane may also present dif- from the Silver Banksia to represent leaves as ficulties in obtaining adequate food, and in this plant species had considerably smaller avoidingcompetitionandpredation.Trichomes leaves than the other three species. may aid in trapping fungal spores, and compe- The four microhabitats within the tree were titionand predation maybereducedasthereare notdirectlycomparable.Onewaytoequalisethe fewer mites on the phylloplane compared with comparison was to transform the numbers of the soil. The thick, hard exoskeleton ofA. poly- mites per cm. As expected, the abundance and phyllos may protect adults from predators, and species richness oforibatid species was greatest the bothridial sensillum (thought to be an 'ane- in the soil. On a percm basis, the mean number moreceptor' sensing movement ofair currents) wasalmost ten timesgreaterin thesoil than any may enable these blind mites to sense move- ofthe plant microhabitats(bark, stem, and leaf) ments ofnearby predators. sampled. Ofthe oribatid species on the phyllo- The morphological characteristics ofA. poly- plane,A. polyphyllos(mean total length: male c. phyllosare consistent with otherarboreal oriba- 400 urn, female c. 430 um) was the most abun- tid species and distinct from soil-dwellingones, dant on all plant speciessampled. Furthermore, suggesting morphological correlates with an all lifestagesofA.polyphylloswereabundant on arboreal habit. Furthermore, these arboreal ori- the leaf surface and rare or absent in the other batid species are taxonomically distinct from microhabitats(Fig. 2). With theexceptionofthe their relatives in the soil. Lilly-pilly (Aanena smithii), which has smooth leaves, A. polyphyllos and its remains (exuviae) Is Adhaesozetes a habitat specialist at a larger were almost entirely restricted to the phyllo- scale? plane. My resultsand observationsshowthatA. Thearchitectural complexity ofthe phylloplane polyphyllos lives, eats, reproduces, and dies on appears to influence the distribution and abun- the forest phylloplane. dance of A, polyphyllos, but do habitat differ- Although A. polyphyllos occurred on the leaves of all plant species examined, its abun- epnlacyesanatimapolarrtgaenrtscraollee,?Tthoataniss,weforrethsitstqyupees,tiaolns,o dancevariedbetween plantspecies.Someofthis I sampled 20 leaves from eight Musk Daisy- variation could be explained by the differences bushes inwetsclerophyll forestand rainforestat in the leaf surface features. For example, the threedifferent sites. The distribution and abun- 'forest' of trichomes (leaf hairs) found on the dance of A. polyphyllos did not differ signifi- Musk Daisy-bush (Olearia argophylla). Silver cantly between forest habitats. The apparent Banksia(Banksia marginala)and Snowy Daisy- preference ofA. polyphyllos for the wet sclero- bush (Olearia lirata) may provide footholds for phyll forest (Fig. 3A) may be explained by the attachment, and protection from the elements distribution and abundance ofthe Musk Daisy- andpredators.Additionally,trichomesmaytrap fungal spores and pollen, which are important bush, a preferred plant species. It is a wet sclerophyll forest specialist and a coloniser of dis- foodsformany oribatid species. In contrast, the turbed areas, which are more common in wet smooth, 'desert-like' surface of the Lilly-pilly sclerophyll forest than rainforest. may not provide the architectural complexity that may be necessary for an arboreal lifestyle. In addition, I sampled a variety of plant species in threeforest types, drysclerophyll forest, wet sclerophyll forest, and warm temperate Does the morphology ofAdhaesozetes correlate rainforest. These results (Fig. 3B) differed only with its arboreal lifestyle? slightly from the above survey. All life stages of Lifeonthephylloplanepresentsseveralhurdles. A. polyphyllos were distributed across all three The morphological characteristics of A. poly- forest typesand itsabundancedid not differsig- phyllos may aid in its arboreal lifestyle. Firstly, nificantly between forest habitats. Independent its tarsal claws, and adhesive pulvilli may offoresttype,mitesandtheirexuviaeweremore anchorthe mite to the phylloplane by attaching common on plant species with leaf trichomes, to surface irregularities. Secondly, itsdorsoven- such as the Musk Daisy-bush and ferns. Thus, trally flattened body may help it to remain thedistributionandabundanceofA.polyphyllos within a narrow boundary layer, aiding with appears more strongly related to the fine-scale water balance. A flattened body shape would differencesin leafsurfacestructurewithin forest also reduce the chances ofdislodgment by wind typesthan coarse-scaledifferences inforest tvpe or by leaves rubbing together. itself. PAN/.F.R MII1S ON THE FOREST PHYLLOPLANE 645 Snowy Daisy-bush Musk Daisy-bush Adults 0.4 Nymphs 0.4 Exuviae 0.3 5 0.3 ft, ft, -o n ) 0.2 I ft, 0.1 o 0.1 X) B I 0.0 °-° 2 Soil Bark Stem Leaf v. Soil Bark Stem Leal Microhabitat Microhabilal Silver Banksia Lilly-pilly CD 4J 0.4 0.4 s u 3'-. 0.3 0.3 ! ft, ^a.. 0.2 C5 0.2 o ft, ft, -r O 0.1 o 0.1 u. v-< 11 0J £tu 1 Z6 0.0 Soil Hark Stem Leaf 2i^ 0.0 Soi1l Ba'rk SIt'elml1 L-eal Microhabitat Microhabilal SFi,lgvuerreB2.anTkhseiaab(uNnd-an3c)e, oSlnAo.wpyoDlayipshy-yblulsohS(&NM no.Ic)mandJtLrielely-p'i±llySE()NO0 .3h)e.Musk Daisy-buSh(N 15trees), Conclusions tarsal claws, adhesive pulvilli, club-shaped bothridial sensillum, and a dorsoventrally flat- Aa(edghsgpaseecsinoayzlmicsptthcsso,pnoaltnvhdpehaydlluelaloftsss)iuswrafenarceaer.abboAurlneladlalinmfteitosentaatgnhedes teTaehlneeosdnebbaaoptdpiyed)asrpceotcnoisbeiesstaceonnntdsidwsiitsttehinntcatnwiftarhrobmootrsheoaeilrl-ahdrawbbeoilrtl.-- pfasomuhcobogycuruglupnnelrhddsootapltslnihoancetgnerhicetac,.htaeolwtfFhhtuiehcrlerhtedxeaheeurefvavreceiomwtlateoeohrripeiferms,aoteninnmcyAits.citronhp(ofdeowhilaetvyhblippeildhht-uhyyadailtlelehslvs..oesspltwloTaeaphghrneaeeecdss ditaiinonbfggWufhinoetatnrdrvheeiaesnicn.cnhcaeoesmtlehiaosenrf,glfeAeorr.arafeiepssslottfelerdycutptcymhtpiyouedlrnslraolietsbhcxeoaaamnmndpiddilnseoetvxtdreihi,ietbnruyslt)io(inrioaeinnp-bcspalcaeutanadildre-d 646 V.M. BARNES (A) (B) Adults 200 Nymphs I 50 Exuviae I to X 150 •S 40 "^ §,30 ^ 100 X o o 20 <u ttJ 50 a c g 10 s I i 2<u n ;i'i Rf WS DS WS WTRf Habitat Habitat wFeitgusrcele3.ropIhhyellmefoarnestnu(mWbSe)r<oNf.-l.2p4oltyrpeheysllinoseapcerhtfroerees(tttySpEe)poonol(eAd)atchreoMssusthkreDeaisistye-s)b.u(sBh)iTnhreaianbfournedsatn(cRef)oafnAd. polyphyllos (mean number per tree ± SE) pooled across a variety ofplant species sampled in dry sclerophyll forest(DS),wet sclerophyll forest (WS)andwarmtemperaterainforest(WTRf)(N = 30treesineach forest type pooled across two sites). species than coarser seale differences in forest Walter. D.E. and O'Dowd. D.J., 1995a. Life on the type. Phylloplane specialists, like A. polyphyllos forestphylloplane: hairs,littlehouses,andmvriad appear to select those plant species that offer mites. Pp. 325-351 in Lowman. M. D. and N. M. them 'mite-sized' architectural complexity Nadkarni(eds.).Forestcanopies.AcademicPress: which may help them to overcome the substan- San Diego. tial hurdle ofa phylloplane existence. Walter. D.E. andO'Dowd, D.E. 1995b. Beneathbiod- iversity: factors influencing the diversity and References abundance of canopy mites. Selbyana 16' 12- 20. Walter, D.E. and Behan-Pelletier, V., 1943. System- aticsand ecology ofAdhaesozetespolyphyllos, sp. Walter. D.E..O'Dowd, D.J.and Barnes.V.. 1994.The nov. (Acari: Oribatida: Licneremaeoidea) leaf- forgotten arthropods: foliar mites in the forest inhabiting mites from Australian rainforests. canopy. Memoirs oftheQueensland Museum 36' CanadianJournalofZoology 71: 1024-1040. 221-226.