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Conspecifics Enhance Attraction of Vespula germanica(Hymenoptera Vespidae) Foragers to Food BaitsAuthor(s) P Drsquoadamo M Lozada J CorleySource Annals of the Entomological Society of America 96(5)685-688 2003Published By Entomological Society of AmericaDOI httpdxdoiorg1016030013-8746(2003)096[0685CEAOVG]20CO2URL httpwwwbiooneorgdoifull1016030013-8746282003290965B06853ACEAOVG5D20CO3B2

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BEHAVIOR

Conspecifics Enhance Attraction of Vespula germanica (HymenopteraVespidae) Foragers to Food Baits

P DrsquoADAMO12 M LOZADA3 AND J CORLEY2

Ann Entomol Soc Am 96(5) 685ETH688 (2003)

ABSTRACT Local enhancement has been shown to occur in the socialwaspVespula germanica (F)a species that feeds on live insects as well as on dead animals Some studies suggest local enhancementis based on sight whereas others suggest that odors emanating from wasp bodies are more importantin attracting conspecifc workers to a food source We studied whether the attraction of V germanicaforagers to meat baits increases by the addition of live conspeciTHORNc foragers and analyzed which cues(olfactory and visual) elicit this attraction Our results show that the combination of meat and waspsstrongly enhances the attraction of conspeciTHORNc foragers Presenting both visual and olfactory cuestogether leads to a wasp response that is much greater than if isolated visual or isolated olfactory cueswere added suggesting some synergistic action of both cues

KEY WORDS social insect communication yellowjackets German wasp local enhancement ol-factory cues

THE CUES THAT foragingwasps use for prey location andchoice appears to depend on both the spatial scale inwhich the hunting takes place and on the type of prey(Raveret-Richter and Jeanne 1985) The variabilityobserved in foraging behavior suggests that the hunt-ing tactics of social wasps are likely to be facultativeand situation dependent (Raveret-Richter 2000)Some socialwasp species hovernear stationaryprey inresponse to visual cues and land in response to olfac-torycues (Raveret-Richter and Jeanne1985)whereasothers land in response to visual cues alone (Duncan1939 Jeanne 1972 Heinrich 1984) For instance var-ious species ofVespulaworkers scavenging on proteinorient in response to olfactory cues emanating fromthe resource (Rau 1944 Gaul 1952 Ross et al 1984)while foraging on arthropod prey is largely mediatedby visual cues (Brian and Brian 1952 Free 1970)Previous studies on mechanisms of meat discovery byV germanica (Fabricius) and V maculifrons (Buys-son) concluded that containers offering both visualand olfactory cues attracted more foragers than didcontainers offering either cue on its own (Reid et al1995)

Controversy exists on the capacity of V germanicato recruit conspeciTHORNcs toa food source(OvermyerandJeanne 1998) However it is a well-known fact thatforaging workers tend to land and feed on resourcesbeing exploited by conspeciTHORNcs rather than on emptypatches (Parrish and Fowler 1983 Reid et al 1995Raveret-Richter andTisch 1999DOtildeAdamoet al 2000)

For the same species Reid et al (1995) studied ag-gregation behavior of conspeciTHORNcs on a meat foodsource and found thatmorewaspswere at abaitmoreconspeciTHORNcs were attracted to it Recently DOtildeAdamoet al (2000) provided evidence that the attraction ofVgermanica foragers canbeelicitedbywasppresencealone and this might be mediated by odor cues pro-duced in glands located in the head (DOtildeAdamo et al2000)

Vespula germanica is a member of the V vulgarisgroup which commonly supplement arthropod preyby scavenging on vertebrate carrion to feed larvae(Akre and MacDonald 1986) This scavenging behav-ior can become a nuisance to people involved in var-ious economic and recreational activities such as bee-keeping tourism and horticulturism particularlyduring late summer and early fall when yellowjacketsare very abundant (Greene 1991) Vespula germanicaoriginally from Eurasia and Northern Africa has in-vaded several regions of the world and has become amajor pest (Edwards 1976 Akre and MacDonald1986) In Argentina it has rapidly spread throughoutthe country in the last 20 yr in one of the most out-standing insect invasions ever recorded for the region(Farji-Brener and Corley 1998)

In this study we analyzed whether the addition oflive conspeciTHORNcs to meat bait increases the attractionof V germanica foragers We also examined the rela-tive role that visual and olfactory cues have on landingbehavior of foraging wasps

Materials and Methods

The experimental design consisted of an array of sixclean plastic containers (8 cm diameter 10 cm high)

1 E-mail pdadamobarilocheintagovar2 Laboratorio de Ecologotildea de Insectos Forestales INTA EEA Bar-

iloche CC 277 - (8400) Bariloche Argentina3 Laboratorio Ecotono Universidad Nacional del Comahue Pasaje

Gutierrez 1125 - (8400) SC Bariloche Rotildeo Negro Argentina

0013-8746030685ETH0688$04000 2003 Entomological Society of America

faced down on the ground (DOtildeAdamo et al 2000)Some of these containers were depending on thetreatment perforated with small holes evenly distrib-uted around the sides Wasps could not enter or leavethe containers but the holes allowed the emission ofodors produced by bait andor trapped wasps Waspsinsideexperimental containerswere typicallyszligyingorwalking along container walls Each container wasassigned to one of the following treatments (1) Per-forated transparent container with six live wasps andbait inside (both bait and wasp odor and visual cues)(VO)(2)Closed transparentcontainerwith six livewasps and bait inside (both wasp bait and visual cuesonly) (V) (3) Perforated opaque container with sixlive wasps and bait inside (both wasp and bait odorcues only) (O) (4) Perforated transparent containerwith six live wasps (wasp odor and visual cues) (W)(5) Perforated transparent container with bait inside(bait odor and visual cues) (B) (6) Empty closedtransparent container (control) (C)

Baited containers all had 20 g of THORNsh-scented catfood bait (Whiskas Kal Kan Foods Verno CA) Eachassay consisted of counting simultaneously the num-ber of wasp visits to each of the six treatments Con-tainers were randomly placed in a straight line eachseparated by 60 cm Experiments were conducted atmidday hours on calm days in full sun crosswind andirrespective of nest location We considered any wasplanding on a container as a visit and the number ofvisits to each treatment was counted for 15 min afterthe THORNrst visit to the array occurred We included re-peated consecutive visits of the same wasp in ourcountbecause it allowed for the considerationofmorethan one treatment choice We replicated the exper-iment 31 times in different sites separated by 1 kmtoavoid theeffectsof trainingandassociative learningbothwhich have been shown to occur in V germanica(Free 1970) The number of visits to each type ofcontainer (treatment) was compared by means ofFriedmanOtildes test Paired comparisons were conductedby the Wilcoxon paired-sample test The study wascarried out close to the city of Bariloche Argentina(41 S 71 W) in gardens forests and open THORNeldsduring the austral summer of 2000

Results

SigniTHORNcant differences were found among wasp vis-its to the six treatments (FriedmanOtildes test 2 12517P 00001 n 31 df 5) (Table 1)When both odorand visual cues emanated from the test container thecombination of wasps and bait (VO) greatly in-creased the attraction of conspeciTHORNc wasps relative tothe treatments presenting either wasps (W) or bait(B) alone (Fig 1) The visual and olfactory cues frombait alone(B)wereequally attractive asolfactorycuesonly wasps bait (O) Wasps alone emanating odorand visual cues (W) recruited fewer wasps than theprevious treatments but more than wasps in contain-ers where they could only be seen (V) This lasttreatment differed signiTHORNcantly from the control (C)indicating a visual effect although slight on wasp

attraction Thus the treatment with wasp plus baitwhich allowed odor and visual cues attracted morewasp visits than any other treatment The odor effectwas higher than the visual stimulation on wasp attrac-tion and the combination of both cues was non-ad-ditive

Discussion

Our data show that foraging V germanica waspswere more attracted to the combination of bait andother live wasps than to either wasps or bait alonewhen both visual and olfactory cues were available tothem In addition we found that such attraction de-creaseswhen only olfactory cueswere offered but notas much as when only visual cues were available

Reidet al (1995) reporteda similar increaseofwaspattraction when both meat bait and forager waspswere combined in a container However in theirwork the roles of olfactory and visual cues were notdistinguished Other studies on local enhancement inV germanica suggest that this process is elicited by

Table 1 Wilcoxon matched pair tests among treatments

V O W B C

V O 494 457 482 435 494V 475 477 478 263O 330 182(NS) 471W 406 480B 478

Statistic (Z) is shown signiTHORNcant differences at P 0005 NSnonsigniTHORNcant N 31 V O container having bait and waspsoffering both visual and odor cues V container having bait andwasps offering only visual cues O container having bait andwaspsoffering only odor cues W container having wasps offering bothvisual and odor cues B container having bait offering both visualand odor cues C an empty container (control)

Fig 1 Mean number of wasp visits (SE) attracted toeach container of the array VO containers offer bothvisual and odor cues V containers offer only visual cuesO containers offer onlyodor cuesWB containers havewasps and bait W containers have wasps B containershave bait C an empty container (control) Different let-ters denote signiTHORNcant differences (P 005) among treat-ments while shared letters denote no signiTHORNcant differences(P 005)

686 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5

visual cues (Parrish and Fowler 1983 Raveret-Richterand Tisch 1999 but see DOtildeAdamo et al 2000) How-ever olfactory cues were not considered in thesestudies and probably in their absence visual cuesalone were likely to be sufTHORNcient to elicit local en-hancement (Raveret-Richter and Tisch 1999) In ad-dition in those studies local enhancement was testedon carbohydrate baits It is possible that wasps foragedifferently on protein resources which are used forbrood feeding than they do on carbohydrate re-sources necessary for providing energy to workers(Raveret-Richter and Tisch 1999 Raveret-Richter2000) In our experiment the number of visits tocontainers which had both stimuli was nearly fourtimes greater than when only olfactory cues wereavailable and nearly 50 times the number of visits tocontainers offering only visual cues These THORNndingssuggest that although visual cues play a role in thelocal enhancement process odor cues are also impor-tant and the combination of both cues increases for-agerOtildes attraction in a non-additive manner It is pos-sible that another cue such as movement could beenhancing the attraction when associated with bothodor and visual cues explaining such non-additiveincrease in the attraction

By studying the mechanisms of meat bait discoveryinV germanicaReid et al (1995) analyzed the role ofvisual and olfactory cues prevalent in this processThey found no difference between containers withmeat offering solely olfactory cues and those provid-ing only visual cues Although we found that contain-ers offering visual plus olfactory cues had signiTHORNcantlymore visits than containers offering either cue aloneour results show that olfactory cues alone recruitedsigniTHORNcantly more wasp foragers than did visual cuesalone The difference between our THORNndings and thoseof Reid et al (1995) may be explained by the fact thatin the latter work the containers had onlymeat whilein ours containers had meat and live wasps It shouldbe noted here that odor emanating from V germanicaforagersOtilde plays a central role in the local enhancementprocess (DOtildeAdamo et al 2000) In addition this couldalso help resolve the apparent contradiction betweenprevious studies that advance visually mediated localenhancement and the data of Maschwitz et al (1974)which suggest that resource discovery is notmediatedby visual cues

These results may help us understand the underly-ing mechanisms of bait discovery by V germanica andalso highlight the possibility of using a speciTHORNc attract-ant (ie conspeciTHORNc wasps) that could render itselfuseful in wasp population management Further stud-ies should focus on the discovery of the glands andsubstances responsible for conspeciTHORNc wasp attrac-tion

Acknowledgments

We thank Maite Chaves for THORNeld assistance and Damasiaand Andrew Schwartz as well as two anonymous reviewersfor critically reading themanuscript This studywas partiallyfunded through a grant from CONICET (PEI 30997) Uni-

versidad del Comahue (CRUB) and Coopreradora INTABariloche PD has a Graduate Research Fellowship(CONICET) and ML and JC are both supported byCONICET

References Cited

Akre R D and J F MacDonald 1986 Biology economicimportance and control of yellowjackets pp 353ETH412 InS B Vinson (ed) Economic impact and control of socialinsects Praeger New York

Brian M V and A D Brian 1952 The wasp Vespula syl-vestris Scopoli Feeding foraging and colony develop-ment Trans R Entomol Soc Lond 103 1ETH26

DrsquoAdamo P J Corley P Sackmann and M Lozada 2000Local enhancement in the wasp Vespula germanica arevisual cues all that matter Insectes Soc 47 289ETH291

DrsquoAdamo P J Corley and M Lozada 2001 Attraction ofVespula germanica (HymenopteraVespidae) foragers byconspeciTHORNc heads J Econ Entomol 94 852ETH854

Duncan C 1939 A contribution to the biology of NorthAmerican vespine wasps Stanford Univ Publ Biol Sci 81ETH272

Edwards R 1976 The world distribution pattern of theGerman wasp Paravespula germanica (HymenopteraVespidae) Entomol German 3 269ETH271

Farji-Brener A G and J C Corley 1998 Successful inva-sion of hymenopteran insects into NW Patagonia EcolAust 8 237ETH249

Free J B 1970 Thebehaviour ofwasps (Vespula germanicaL and V vulgaris L) when foraging Insectes Soc 1711ETH20

Gaul A T 1952 Additions to vespine biology X Foragingand chemotaxis Bull Brooklyn Entomol Soc 47 138ETH140

Greene A 1991 Dolichovespula and Vespula pp 263ETH305In K G Ross and R W Matthews (eds) The socialbiology of wasps Comstock Ithaca NY

Heinrich B 1984 Strategies of thermoregulation and for-aging in two vespid wasps Dolichovespula maculata andVespula vulgaris J Comp Physiol B154 175ETH180

Jeanne R L 1972 Social biology of the Neotropical waspMischocyttarus drewseni Bull Mus Comp Zool 144 63ETH150

Keyel R E 1983 Some aspects of niche relationshipsamong yellowjackets (Hymenoptera Vespidae) of thenortheastern United States PhD dissertation CornellUniversity Ithaca NY

Maschwitz U W Beier I Dietrich and I Keidel 1974Feeding communication in wasps of genus ParavespulaNaturwissenschaften 61 506 (in German)

Overmyer S L and R L Jeanne 1998 Recruitment tofood by the German yellowjacket Vespula germanicaBehav Ecol Sociobiol 42 17ETH21

ParrishMD andHGFowler 1983 Contrasting foragingrelated behaviours in two sympatric wasps (Vespulamaculiforns and V germanica) Ecol Entomol 8 185ETH190

RauP 1944 Afewnotes on thebehaviourofVespulamacu-lifrons Buys Bull Entomol Soc Am 39 177ETH178

Raveret-Richter M and R L Jeanne 1985 Predatory be-havior of Polybia sericea (Olivier) a tropical social wasp(Hymenoptera Vespidae) Behav Ecol Sociobiol 16165ETH170

Raveret-Richter M 1990 Hunting social wasp interactionsinszliguence of prey size arrival order and wasp speciesEcology 71 1018ETH1030

September 2003 DOtildeADAMO ET AL CONSPECIFIC ATTRACTION IN V germanica 687

Raveret-Richter M and V L Tisch 1999 Resource choiceof social wasps inszliguence of presence size and species ofresident wasps Insectes Soc 46 131ETH136

Raveret-Richter M 2000 Social wasp (HymenopteraVespidae) Foraging Behavior Annu Rev Entomol 45121ETH150

Reid B L J F MacDonald and D R Ross 1995 Foragingand spatial dispersion in protein-scavenging workers of

Vespula germanica and V maculifrons (HymenopteraVespidae) J Insect Behav 8 315ETH330

Ross D R R H Schukle and J F MacDonald 1984 Meatextracts attractive to scavenger Vespula in eastern NorthAmerica (Hymenoptera Vespidae) J Econ Entomol 77637ETH642

Received for publication 18 July 2001 accepted 3 June 2002

688 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5

faced down on the ground (DOtildeAdamo et al 2000)Some of these containers were depending on thetreatment perforated with small holes evenly distrib-uted around the sides Wasps could not enter or leavethe containers but the holes allowed the emission ofodors produced by bait andor trapped wasps Waspsinsideexperimental containerswere typicallyszligyingorwalking along container walls Each container wasassigned to one of the following treatments (1) Per-forated transparent container with six live wasps andbait inside (both bait and wasp odor and visual cues)(VO)(2)Closed transparentcontainerwith six livewasps and bait inside (both wasp bait and visual cuesonly) (V) (3) Perforated opaque container with sixlive wasps and bait inside (both wasp and bait odorcues only) (O) (4) Perforated transparent containerwith six live wasps (wasp odor and visual cues) (W)(5) Perforated transparent container with bait inside(bait odor and visual cues) (B) (6) Empty closedtransparent container (control) (C)

Baited containers all had 20 g of THORNsh-scented catfood bait (Whiskas Kal Kan Foods Verno CA) Eachassay consisted of counting simultaneously the num-ber of wasp visits to each of the six treatments Con-tainers were randomly placed in a straight line eachseparated by 60 cm Experiments were conducted atmidday hours on calm days in full sun crosswind andirrespective of nest location We considered any wasplanding on a container as a visit and the number ofvisits to each treatment was counted for 15 min afterthe THORNrst visit to the array occurred We included re-peated consecutive visits of the same wasp in ourcountbecause it allowed for the considerationofmorethan one treatment choice We replicated the exper-iment 31 times in different sites separated by 1 kmtoavoid theeffectsof trainingandassociative learningbothwhich have been shown to occur in V germanica(Free 1970) The number of visits to each type ofcontainer (treatment) was compared by means ofFriedmanOtildes test Paired comparisons were conductedby the Wilcoxon paired-sample test The study wascarried out close to the city of Bariloche Argentina(41 S 71 W) in gardens forests and open THORNeldsduring the austral summer of 2000

Results

SigniTHORNcant differences were found among wasp vis-its to the six treatments (FriedmanOtildes test 2 12517P 00001 n 31 df 5) (Table 1)When both odorand visual cues emanated from the test container thecombination of wasps and bait (VO) greatly in-creased the attraction of conspeciTHORNc wasps relative tothe treatments presenting either wasps (W) or bait(B) alone (Fig 1) The visual and olfactory cues frombait alone(B)wereequally attractive asolfactorycuesonly wasps bait (O) Wasps alone emanating odorand visual cues (W) recruited fewer wasps than theprevious treatments but more than wasps in contain-ers where they could only be seen (V) This lasttreatment differed signiTHORNcantly from the control (C)indicating a visual effect although slight on wasp

attraction Thus the treatment with wasp plus baitwhich allowed odor and visual cues attracted morewasp visits than any other treatment The odor effectwas higher than the visual stimulation on wasp attrac-tion and the combination of both cues was non-ad-ditive

Discussion

Our data show that foraging V germanica waspswere more attracted to the combination of bait andother live wasps than to either wasps or bait alonewhen both visual and olfactory cues were available tothem In addition we found that such attraction de-creaseswhen only olfactory cueswere offered but notas much as when only visual cues were available

Reidet al (1995) reporteda similar increaseofwaspattraction when both meat bait and forager waspswere combined in a container However in theirwork the roles of olfactory and visual cues were notdistinguished Other studies on local enhancement inV germanica suggest that this process is elicited by

Table 1 Wilcoxon matched pair tests among treatments

V O W B C

V O 494 457 482 435 494V 475 477 478 263O 330 182(NS) 471W 406 480B 478

Statistic (Z) is shown signiTHORNcant differences at P 0005 NSnonsigniTHORNcant N 31 V O container having bait and waspsoffering both visual and odor cues V container having bait andwasps offering only visual cues O container having bait andwaspsoffering only odor cues W container having wasps offering bothvisual and odor cues B container having bait offering both visualand odor cues C an empty container (control)

Fig 1 Mean number of wasp visits (SE) attracted toeach container of the array VO containers offer bothvisual and odor cues V containers offer only visual cuesO containers offer onlyodor cuesWB containers havewasps and bait W containers have wasps B containershave bait C an empty container (control) Different let-ters denote signiTHORNcant differences (P 005) among treat-ments while shared letters denote no signiTHORNcant differences(P 005)

686 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5

visual cues (Parrish and Fowler 1983 Raveret-Richterand Tisch 1999 but see DOtildeAdamo et al 2000) How-ever olfactory cues were not considered in thesestudies and probably in their absence visual cuesalone were likely to be sufTHORNcient to elicit local en-hancement (Raveret-Richter and Tisch 1999) In ad-dition in those studies local enhancement was testedon carbohydrate baits It is possible that wasps foragedifferently on protein resources which are used forbrood feeding than they do on carbohydrate re-sources necessary for providing energy to workers(Raveret-Richter and Tisch 1999 Raveret-Richter2000) In our experiment the number of visits tocontainers which had both stimuli was nearly fourtimes greater than when only olfactory cues wereavailable and nearly 50 times the number of visits tocontainers offering only visual cues These THORNndingssuggest that although visual cues play a role in thelocal enhancement process odor cues are also impor-tant and the combination of both cues increases for-agerOtildes attraction in a non-additive manner It is pos-sible that another cue such as movement could beenhancing the attraction when associated with bothodor and visual cues explaining such non-additiveincrease in the attraction

By studying the mechanisms of meat bait discoveryinV germanicaReid et al (1995) analyzed the role ofvisual and olfactory cues prevalent in this processThey found no difference between containers withmeat offering solely olfactory cues and those provid-ing only visual cues Although we found that contain-ers offering visual plus olfactory cues had signiTHORNcantlymore visits than containers offering either cue aloneour results show that olfactory cues alone recruitedsigniTHORNcantly more wasp foragers than did visual cuesalone The difference between our THORNndings and thoseof Reid et al (1995) may be explained by the fact thatin the latter work the containers had onlymeat whilein ours containers had meat and live wasps It shouldbe noted here that odor emanating from V germanicaforagersOtilde plays a central role in the local enhancementprocess (DOtildeAdamo et al 2000) In addition this couldalso help resolve the apparent contradiction betweenprevious studies that advance visually mediated localenhancement and the data of Maschwitz et al (1974)which suggest that resource discovery is notmediatedby visual cues

These results may help us understand the underly-ing mechanisms of bait discovery by V germanica andalso highlight the possibility of using a speciTHORNc attract-ant (ie conspeciTHORNc wasps) that could render itselfuseful in wasp population management Further stud-ies should focus on the discovery of the glands andsubstances responsible for conspeciTHORNc wasp attrac-tion

Acknowledgments

We thank Maite Chaves for THORNeld assistance and Damasiaand Andrew Schwartz as well as two anonymous reviewersfor critically reading themanuscript This studywas partiallyfunded through a grant from CONICET (PEI 30997) Uni-

versidad del Comahue (CRUB) and Coopreradora INTABariloche PD has a Graduate Research Fellowship(CONICET) and ML and JC are both supported byCONICET

References Cited

Akre R D and J F MacDonald 1986 Biology economicimportance and control of yellowjackets pp 353ETH412 InS B Vinson (ed) Economic impact and control of socialinsects Praeger New York

Brian M V and A D Brian 1952 The wasp Vespula syl-vestris Scopoli Feeding foraging and colony develop-ment Trans R Entomol Soc Lond 103 1ETH26

DrsquoAdamo P J Corley P Sackmann and M Lozada 2000Local enhancement in the wasp Vespula germanica arevisual cues all that matter Insectes Soc 47 289ETH291

DrsquoAdamo P J Corley and M Lozada 2001 Attraction ofVespula germanica (HymenopteraVespidae) foragers byconspeciTHORNc heads J Econ Entomol 94 852ETH854

Duncan C 1939 A contribution to the biology of NorthAmerican vespine wasps Stanford Univ Publ Biol Sci 81ETH272

Edwards R 1976 The world distribution pattern of theGerman wasp Paravespula germanica (HymenopteraVespidae) Entomol German 3 269ETH271

Farji-Brener A G and J C Corley 1998 Successful inva-sion of hymenopteran insects into NW Patagonia EcolAust 8 237ETH249

Free J B 1970 Thebehaviour ofwasps (Vespula germanicaL and V vulgaris L) when foraging Insectes Soc 1711ETH20

Gaul A T 1952 Additions to vespine biology X Foragingand chemotaxis Bull Brooklyn Entomol Soc 47 138ETH140

Greene A 1991 Dolichovespula and Vespula pp 263ETH305In K G Ross and R W Matthews (eds) The socialbiology of wasps Comstock Ithaca NY

Heinrich B 1984 Strategies of thermoregulation and for-aging in two vespid wasps Dolichovespula maculata andVespula vulgaris J Comp Physiol B154 175ETH180

Jeanne R L 1972 Social biology of the Neotropical waspMischocyttarus drewseni Bull Mus Comp Zool 144 63ETH150

Keyel R E 1983 Some aspects of niche relationshipsamong yellowjackets (Hymenoptera Vespidae) of thenortheastern United States PhD dissertation CornellUniversity Ithaca NY

Maschwitz U W Beier I Dietrich and I Keidel 1974Feeding communication in wasps of genus ParavespulaNaturwissenschaften 61 506 (in German)

Overmyer S L and R L Jeanne 1998 Recruitment tofood by the German yellowjacket Vespula germanicaBehav Ecol Sociobiol 42 17ETH21

ParrishMD andHGFowler 1983 Contrasting foragingrelated behaviours in two sympatric wasps (Vespulamaculiforns and V germanica) Ecol Entomol 8 185ETH190

RauP 1944 Afewnotes on thebehaviourofVespulamacu-lifrons Buys Bull Entomol Soc Am 39 177ETH178

Raveret-Richter M and R L Jeanne 1985 Predatory be-havior of Polybia sericea (Olivier) a tropical social wasp(Hymenoptera Vespidae) Behav Ecol Sociobiol 16165ETH170

Raveret-Richter M 1990 Hunting social wasp interactionsinszliguence of prey size arrival order and wasp speciesEcology 71 1018ETH1030

September 2003 DOtildeADAMO ET AL CONSPECIFIC ATTRACTION IN V germanica 687

Raveret-Richter M and V L Tisch 1999 Resource choiceof social wasps inszliguence of presence size and species ofresident wasps Insectes Soc 46 131ETH136

Raveret-Richter M 2000 Social wasp (HymenopteraVespidae) Foraging Behavior Annu Rev Entomol 45121ETH150

Reid B L J F MacDonald and D R Ross 1995 Foragingand spatial dispersion in protein-scavenging workers of

Vespula germanica and V maculifrons (HymenopteraVespidae) J Insect Behav 8 315ETH330

Ross D R R H Schukle and J F MacDonald 1984 Meatextracts attractive to scavenger Vespula in eastern NorthAmerica (Hymenoptera Vespidae) J Econ Entomol 77637ETH642

Received for publication 18 July 2001 accepted 3 June 2002

688 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5

visual cues (Parrish and Fowler 1983 Raveret-Richterand Tisch 1999 but see DOtildeAdamo et al 2000) How-ever olfactory cues were not considered in thesestudies and probably in their absence visual cuesalone were likely to be sufTHORNcient to elicit local en-hancement (Raveret-Richter and Tisch 1999) In ad-dition in those studies local enhancement was testedon carbohydrate baits It is possible that wasps foragedifferently on protein resources which are used forbrood feeding than they do on carbohydrate re-sources necessary for providing energy to workers(Raveret-Richter and Tisch 1999 Raveret-Richter2000) In our experiment the number of visits tocontainers which had both stimuli was nearly fourtimes greater than when only olfactory cues wereavailable and nearly 50 times the number of visits tocontainers offering only visual cues These THORNndingssuggest that although visual cues play a role in thelocal enhancement process odor cues are also impor-tant and the combination of both cues increases for-agerOtildes attraction in a non-additive manner It is pos-sible that another cue such as movement could beenhancing the attraction when associated with bothodor and visual cues explaining such non-additiveincrease in the attraction

By studying the mechanisms of meat bait discoveryinV germanicaReid et al (1995) analyzed the role ofvisual and olfactory cues prevalent in this processThey found no difference between containers withmeat offering solely olfactory cues and those provid-ing only visual cues Although we found that contain-ers offering visual plus olfactory cues had signiTHORNcantlymore visits than containers offering either cue aloneour results show that olfactory cues alone recruitedsigniTHORNcantly more wasp foragers than did visual cuesalone The difference between our THORNndings and thoseof Reid et al (1995) may be explained by the fact thatin the latter work the containers had onlymeat whilein ours containers had meat and live wasps It shouldbe noted here that odor emanating from V germanicaforagersOtilde plays a central role in the local enhancementprocess (DOtildeAdamo et al 2000) In addition this couldalso help resolve the apparent contradiction betweenprevious studies that advance visually mediated localenhancement and the data of Maschwitz et al (1974)which suggest that resource discovery is notmediatedby visual cues

These results may help us understand the underly-ing mechanisms of bait discovery by V germanica andalso highlight the possibility of using a speciTHORNc attract-ant (ie conspeciTHORNc wasps) that could render itselfuseful in wasp population management Further stud-ies should focus on the discovery of the glands andsubstances responsible for conspeciTHORNc wasp attrac-tion

Acknowledgments

We thank Maite Chaves for THORNeld assistance and Damasiaand Andrew Schwartz as well as two anonymous reviewersfor critically reading themanuscript This studywas partiallyfunded through a grant from CONICET (PEI 30997) Uni-

versidad del Comahue (CRUB) and Coopreradora INTABariloche PD has a Graduate Research Fellowship(CONICET) and ML and JC are both supported byCONICET

References Cited

Akre R D and J F MacDonald 1986 Biology economicimportance and control of yellowjackets pp 353ETH412 InS B Vinson (ed) Economic impact and control of socialinsects Praeger New York

Brian M V and A D Brian 1952 The wasp Vespula syl-vestris Scopoli Feeding foraging and colony develop-ment Trans R Entomol Soc Lond 103 1ETH26

DrsquoAdamo P J Corley P Sackmann and M Lozada 2000Local enhancement in the wasp Vespula germanica arevisual cues all that matter Insectes Soc 47 289ETH291

DrsquoAdamo P J Corley and M Lozada 2001 Attraction ofVespula germanica (HymenopteraVespidae) foragers byconspeciTHORNc heads J Econ Entomol 94 852ETH854

Duncan C 1939 A contribution to the biology of NorthAmerican vespine wasps Stanford Univ Publ Biol Sci 81ETH272

Edwards R 1976 The world distribution pattern of theGerman wasp Paravespula germanica (HymenopteraVespidae) Entomol German 3 269ETH271

Farji-Brener A G and J C Corley 1998 Successful inva-sion of hymenopteran insects into NW Patagonia EcolAust 8 237ETH249

Free J B 1970 Thebehaviour ofwasps (Vespula germanicaL and V vulgaris L) when foraging Insectes Soc 1711ETH20

Gaul A T 1952 Additions to vespine biology X Foragingand chemotaxis Bull Brooklyn Entomol Soc 47 138ETH140

Greene A 1991 Dolichovespula and Vespula pp 263ETH305In K G Ross and R W Matthews (eds) The socialbiology of wasps Comstock Ithaca NY

Heinrich B 1984 Strategies of thermoregulation and for-aging in two vespid wasps Dolichovespula maculata andVespula vulgaris J Comp Physiol B154 175ETH180

Jeanne R L 1972 Social biology of the Neotropical waspMischocyttarus drewseni Bull Mus Comp Zool 144 63ETH150

Keyel R E 1983 Some aspects of niche relationshipsamong yellowjackets (Hymenoptera Vespidae) of thenortheastern United States PhD dissertation CornellUniversity Ithaca NY

Maschwitz U W Beier I Dietrich and I Keidel 1974Feeding communication in wasps of genus ParavespulaNaturwissenschaften 61 506 (in German)

Overmyer S L and R L Jeanne 1998 Recruitment tofood by the German yellowjacket Vespula germanicaBehav Ecol Sociobiol 42 17ETH21

ParrishMD andHGFowler 1983 Contrasting foragingrelated behaviours in two sympatric wasps (Vespulamaculiforns and V germanica) Ecol Entomol 8 185ETH190

RauP 1944 Afewnotes on thebehaviourofVespulamacu-lifrons Buys Bull Entomol Soc Am 39 177ETH178

Raveret-Richter M and R L Jeanne 1985 Predatory be-havior of Polybia sericea (Olivier) a tropical social wasp(Hymenoptera Vespidae) Behav Ecol Sociobiol 16165ETH170

Raveret-Richter M 1990 Hunting social wasp interactionsinszliguence of prey size arrival order and wasp speciesEcology 71 1018ETH1030

September 2003 DOtildeADAMO ET AL CONSPECIFIC ATTRACTION IN V germanica 687

Raveret-Richter M and V L Tisch 1999 Resource choiceof social wasps inszliguence of presence size and species ofresident wasps Insectes Soc 46 131ETH136

Raveret-Richter M 2000 Social wasp (HymenopteraVespidae) Foraging Behavior Annu Rev Entomol 45121ETH150

Reid B L J F MacDonald and D R Ross 1995 Foragingand spatial dispersion in protein-scavenging workers of

Vespula germanica and V maculifrons (HymenopteraVespidae) J Insect Behav 8 315ETH330

Ross D R R H Schukle and J F MacDonald 1984 Meatextracts attractive to scavenger Vespula in eastern NorthAmerica (Hymenoptera Vespidae) J Econ Entomol 77637ETH642

Received for publication 18 July 2001 accepted 3 June 2002

688 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5

Raveret-Richter M and V L Tisch 1999 Resource choiceof social wasps inszliguence of presence size and species ofresident wasps Insectes Soc 46 131ETH136

Raveret-Richter M 2000 Social wasp (HymenopteraVespidae) Foraging Behavior Annu Rev Entomol 45121ETH150

Reid B L J F MacDonald and D R Ross 1995 Foragingand spatial dispersion in protein-scavenging workers of

Vespula germanica and V maculifrons (HymenopteraVespidae) J Insect Behav 8 315ETH330

Ross D R R H Schukle and J F MacDonald 1984 Meatextracts attractive to scavenger Vespula in eastern NorthAmerica (Hymenoptera Vespidae) J Econ Entomol 77637ETH642

Received for publication 18 July 2001 accepted 3 June 2002

688 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol 96 no 5