Table Of ContentHYM. RES.
J.
Vol. 3, 1994, pp. 133-143
Colony Densities and Preferences for Nest Habitats of Some Social Wasps in
Mato Grosso State, Brazil (Hymenoptera, Vespidae)
IVONE R. DiNIZ AND KlNITI KlTAYAMA
DepartamentodeZoologia, Institutede Biologia
UniversidadedeBrasilia, 70910-900Brasilia DF, BRAZIL
—
Abstract Studiesofcolonydensitiesandpreferencesfornest habitatsofsomesocialwaspswereconductedincerrado
vegetation inSouthernMatoGrossostateinCentral Brazil.Waspcolonydensitieswereestimated inthreehabitats(campo
umido,cerradosensu-strictoand gallery forest). Regarding thewasp nesthabitatspreferences, we found 100coloniesof30
speciesin 15genera nestinginsixdifferenthabitatsinSouthernMatoGrosso. InNorthernMatoGrosso,basedonRichards
(1978),wefound 199coloniesof51 speciesin14generanestinginsixdifferenthabitats.Considering bothregionstogether,
wecameoutwith 299coloniesof61 species in 16genera nesting in ninedifferent habitats.
INTRODUCTION METHODS ANDSTUDY AREA
Theeffectivenessandefficacyofpredationby- The studywasconducted in cerrado vegeta-
social wasps on many insects (Gobbi et al. 1984, tion during a five week survey (August, October
Gobbi and Machado 1985, Machado et al. 1987, throughDecember 1988 andJune 1989) at theRio
Raw 1988)confersonthema fundamental impor- Manso Hydroelectric Power Station (HPS-Rio
tance as biological control agents. Nonetheless, Manso) (14°52' S and 55°50' W), in the Chapada
the study of thenests ofthese insectshas focused dos Guimaraes county, southern Mato Grosso
mainlyon theirarchitecture (Jeanne 1975, Kojima State in central Brazil.
1982)andonthenumbersofindividualspercolony Cerrado sensu-lato is a semideciduous
(Richards 1978), with few reports on pairsofspe- xeromorphicvegetation dominantinCentralBra-
cies nesting close together (Windsor 1972, Starr zil, occupying about 20% of the wholecountry. It
1988). occurs in various structures from closed forest-
Information on preferences for nest habitats likeforms topuregrasslands (Eiten 1972). "Habi-
(Richards 1978, Reed and Vinson 1979, Forsyth tat" is used here to refer to a vegetation subtype
1980)andoncolonydensities(Rau1942,Kitayama within the cerradosensu-lato.
etal. 1989) ofneotropical social wasps is still very The censuses of social wasp colonies (nests
scarce. IncentralBrazil, 130speciesofwaspshave with resident adults) were conducted in campo
been collected (Richards 1978, Raw pers. comm. umido, vereda, campo sujo, cerradosensu-stricto,
and our own collections), but studies on their galleryforestand surroundingdirtroads.Charac-
ecology are very fragmentary. terizingthesehabitatsverybriefly itcouldbesaid
The aim of this report is to add new informa- that campo umido is a wet grassland without
tion on colony densities and preference for nest visible woody plants (Fig. 1); vereda is a broad
habitatsofsocialwaspsinthecerradosensu-latoof marshy valleybottomgrassland with buriti palm
Central Brazil. (Mauritiavinifera)galleries(Fig. 2);camposujoisa
cerrado grassland with a few, very scattered, low
conspicuousshrubsoracaulescentpalms (Fig. 3);
134 Journalof Hymenoptera Research
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a--S^^Ss
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1
Fig. 1. Area of 100nvofcampoumidowherewasp nestsweresurveyed.
Fig. 2. AreaofVereda (Photoby Dr. RobertoCavalcante)
135
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1
Fig. 3. Areaofcamposujo.
Fig.4. Areaofcerradosensu-stricto (PhotobyDr. RobertoCavalcante).
136 Journalof Hymenoptera Research
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Fig. 5. Areaofgallery forest (PhotobyDr. RobertoCavalcante).
cerradosensu-strictoincludes formswiththe total 1972),galleryforestanddryforest (deciduousand
woody plant cover of about 30-40% and with a semi deciduous mesophytic forest, Eiten 1972).
canopy generally less than seven meters (Fig. 4) Forthestudyoncolonydensity,knownareas
m
and gallery forest is usually a narrow evergreen were sampled, in gallery formest (7500 2) and in
mesophytic forest following the streams (Fig. 5) cerrado sensu-stricto (10000 2). Nests were lo-
(Eiten 1972). catedamongleaves,onbranches,onthetrunksof
Searches for nests were conducted in four treesandinholesintree-trunksandintheground.
different months, covering two seasons: dry sea- Binocularswereusedtolocatenestsinthecanopy.
m
son (June and August) and wet season (October In addition, five squares of 100 2 each were
and December) in six habitats. Each habitat re- surveyed incampo timido, where nests ofwasps
ceivedthesameintensityofsearchingduringeach were sought among tufts of grasses and sedges
ofthese seasons.
(Fig.l).
Fromeachnest,adultwaspswerecollectedto The survey for estimates of the density of
guarantee identification of the species. All the colonies, within the study area, was done during
nests and insects sampled are deposited in the thewetseason.Threepeoplespentapproximately
Laboratorio de Zoologia, Departamento de 360 hours searching for nests. In each habitat the
Zoologia in the Universidade de Brasilia. time spent per square meter was about one per-
ThedataonXavantinaandSerradoCachimbo son-minute.
(10°50'S and 51°47'W), in northern Mato Grosso For the estimates of density of adult wasps/
state were compiled from Professor Richards' ha, thenumberofadultswithinsomeofthenests
(1978) species descriptions of nest habitats using were counted and also, for some species, data
only the data where there was no doubt on the from Richards (1978) were compiled.
location of the nests). Richards' censuses were In each table the habitats, when it was pos-
conductedincamposujo,dirtroadsandclearings, sible, were arranged in order of increasing com-
cerrado sensu-stricto, Cerradao (the medium tall plexityofstructurebecausethismakes iteasierto
arboreal form of cerrado with a closed or semi- see general patterns in species preferences for
opencanopywith30-40% treecrowncover, Eiten habitats.
Volume 3. 1994 137
RESULTS AND DISCUSSION seven in four and three in five habitats (Table 3).
Theareasurveyedwasdifferentineachhabitat so
1. Nesting Habitat Preference ofWasps thenumberofcoloniesfounddonotrepresentone
absolute abundance but the relative habitat pref-
A total of 100colonies, comprising30species erence fornesting.
in 15 genera of wasps were encountered in six Of the total number of colonies recorded by
differenthabitatsinChapadadosGuimaraes(Table Richards and us from Mato Grosso, the species
1). Among them, 18 species nested in only one with the largest number of colonies was Polybia
habitat,nineintwo—,andthree(Polybia(Myrapetra) ruficeps(14%),followedbyPolybiaoccidentalis(9%),
ruficepsSchrottky averycommonspeciesofthe Polybiajurinei(6%),Polybia(Myrapetra)erythrothorax
region, Chartergus chartarius (Olivier) and Richards(5%),Polybiaignobilis(5%),Paraclmrtergus
Clwrtegelhis communis Richards) in three habitats fratemus (Gribodo) (4%) and Epipona tatua (4%).
(Table 1). Of the species that nested in only one The genus Polybia represents 60% of the colonies
habitat, most were found in cerrado sensu-stricto reported from the two regions of Mato Grosso
(sevenspecies), ingalleryforest (fivespecies)and State(Table3),rangingfrom67%inXavantinaand
incampoumido(fourspecies) (Table 1).Ofthe30 Serra doCachimbo (Table2) to45% in RioManso
species collected in this study, only Polistes (Table 1). Amongallthecoloniesofthe 19species
(Epicnemius) pacificus liliaciosus de Saussure was of Polybia collected, 58% were found in cerrado
not collected by Richards (Table 1 and 2). This sensu-stricto (Table 3) ranging from 31% in Rio
subspecies has been collected only rarely in cen- Manso and 55% in Xavantina and Serra do
tral Brazil and, until Richards' 1978 record, its Cachimbo (Tables 1 and 2).
distribution was thought tobe restricted in Brazil Richards (1978) suggested that the choice of
totheNorth(Amazonas,Amapaand Parastates). habitat for nesting is very characteristic and less
Polybiaruficepswasthecommonestspeciesofwasp diversethanthatused forforaging. Hisopinionis
atRio-Mansowith23colonies,ofwhich70%were confirmed in our survey at Rio Manso. For ex-
foundincerradosensu-stricto.Threeotherspecies, ample, both Synoeca suririama (L), which nests in
Epipona tatua (Cuvier), Synoeca surinama (L) and gallery forest, and Polybia (Trichothorax) sericea
Oiartergus chartarius, with eight colonies each, (Olivier) in cerrado sensu-stricto, were collected
were also common (Table 1). when theyhunted ingallery forest,cerradosensu-
Richards (1978) recorded 199 colonies com- stricto, campo sujo and campo umido. Of the 30
prising51 speciesin 14generanesting insixhabi- species of wasps at Rio Manso, 21 (70%) were
tats (Table2). Most ofthespecieshecollected (25 encountered foraginginmorethanonehabitat(in
of the51), were found nesting only in one habitat preparation).
(eight of them in dry forest), 12 species nested in Awatersource isimportantforwaspstonest
two habitats, eight nested in three habitats, three successfully, (Rau 1942, Forsyth 1980). The latter
nestedinfour,andonespeciesPolybia(Myrapetra) authorconcluded that the greatercolony density
platycephala Richards nested in five habitats. In of wasps in gallery forest was due mainly to the
Xavantina and Serra do Cachimbo, Polybia presence of water. Wet habitats at Rio Manso
(Myrapetra) occidentalis (Olivier) with 24 colonies (galleryforest,eight/haandcampoumido60/ha)
(12%),wasthemostabundant,followedbyPolybia also had higher colony densities than did dry
ruficeps (10%), Polybia (Apopolybia) jurinei de habitats (cerrado sensu-stricto five/ha). Polistes
Saussure (8%), Polybia (Trichothorax) ignobilis (Epicnemius) subsericeus de Saussure and
(Haliday) (7%) and Polybia (Formicicola) rejecta (F) Mischocyttarus (Mischocyttarus) drewseni de
(5%) (Table 2). Saussure which nest in campo umido, had higher
ThedatacollectedbyusandbyRichardswere colonydensitycompared tootherspecies in drier
combinedandforthesametypeofhabitatthedata habitats,suchascerradosensu-stricto.Availability
were lumped (Table 3 representing the sum of ofwaterallyearroundandnestprotectionbytufts
Tables 1 and 2). At the nine habitats 299colonies, of grasses and sedges, could be the cause of that
comprising 61 species and 16 genera, were col- high density.
lected. Twentyeightspecies (46%)nested inonly Most animals have preferences forparticular
one habitat, 13 species nested in two, 10 in three, habitats (Partridge, 1978). In Mato Grosso ap-
138 Journalof Hymenoptera Research
Table 1. Wasps nesting habitats in Rio Manso Chapada dos Guimaraes: Mato
Grosso, Brazil.
Species
Volume 3, 1994 139
Table 2. Wasp nesting habitats of Xavantina and Serra do Cachimbo: Mato
Grosso, Brazil (Data from Richards, 1978)
Species
140 Journalof Hymenoptera Research
CS DC CE CD GF DF TT
Species
Stelopolybia angulata
Volume 3. 1994 141
CU VE CS OF DC CE CD GF DF TT
Species
Polistes cinerascens
142 Journalof Hymenoptera Research
Table4. WaspcoloniesdensityinthreedifferenthabitatsinRioManso-Chapadados
Guimaraes: MatoGrosso, Brazil.
Campo Cerrado Gallery
umido sensu stricto forest
Area (m2
)
