Avian Predation on Individual Neotropical Social Wasps (Hymenoptera, Vespidae) Outside Their Nests
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SAORT COMMUNICATIONS ORNrrOWGIA NEOTROPICAL 8: 89-92, 199¡ @ The Neotropical Ornithological Society AVIAN PREDATION ON INDIVIDUAL NEOTROPICAL SOCIAL WASPS (HYMENOPTERA, VESPIDAE) OUTSIDE THEIR NESTS Anthony Raw Departamento de Zoologia, Universidade de Brasília, Brasília DF, 70910, Brasil Key words: Birds, social wasps, adults, predation, Brazi, INTRODUCTION tivorous birds are found. Brasilia is located near the region's centre and more than 300 species of Socia1wasps are common in the Neotropics and birds, many of them insectivorous, have been their readiness to sting is a1l too well known. recorded in the Federal District of Brasilia; an Nonetheless, birds, bats and capuchin monkeys area 5,000 km2 (Antas & Cavalcanti 1988), have been reported to attack the nests (Schubart while, to date I have collected 62 speciesof social et al. 1965, Jeanne 1970, Terborgh 1983). Despite wasps there. the commonness of both the wasps and their Data were collected at numerous sites around predators, there are few reports of predation on Brasilia and also around the towns of Goiania individua1 wasps away from their nests. Further- and Goias in Goias State, and Xavantina in Mato more, those records which exist are questionable Grosso State which lie, respectively 180 km, 240 because they are based on the remains in regur- km and 480 km south-west and west of Brasilia, gitated pellets (Fry 1972) and in gut contents and near Patos de Minas in Minas Gerais State (Schubart et al. 1965) rather than on observation which is 380 km to the south of Brasilia. Obser- of the attack. This indirect evidence leavessome vations were made in various natural habitats doubt about whether the birds had attacked the and suburban girdens. The natural vegetation of wasps inside or away from the nest. The only much of central Brazil is cerrado which ranges certain means of knowing where a particular from herbaceous savannas to semideciduous speciesof bird attacked a wasp is by direct obser- forests with ribbons of evergreen forest along the vation, but this method involves a major restric- courses of streams (Eiten 1972). tion which is the reliable identification of both The names of the birds follow Schauensee the wasp and the bird. (1966). The specieswere identified with the help The paucity of information about attacks on of the volumes of Schauensee& Phelps (1978), wasps outside their nests raises questions about Dunning (1982), Sick (1984) and Antas & Caval- how frequent such predation might be and the canti (1988) and the instruction of colleagues. species of birds and wasps involved. In order to The names of the wasps follow Richards (1978) provide some evidence on these questions, my and Carpenter & Day (1988). record of birds' attacks on the wasps are pre- The relatively small number of reliable iden- sented here. tifications of social wasps captured by birds (30 of 65) was a result of doubts over identification STUDY AREAS AND METHODS in the field due to the extreme similarity in The observations reported here are of attacks on appearance of numerous species of wasps. The individual wasps which were hunting and forag- first stage in the process of identification is ing. They have been accumulated during some knowing which species to expect in a locality. 2,000 hours in the field over a period of 16 years With this knowledge, in many instances a group (1976 to 1993). All were made in central Brazil of visually similar species was identified easily, where many species of social wasps and insec- but sometimes difficulty arose in determining 89 GENERAL BIOLOG' the actual speciesof the group which a bird had On 30 occasions both the wasp and the caught. The flight and appearance of most predator were identified (Table 1). The recorded species of social wasps is relatively characteristic atttacks involved 16 species of birds and 18 of and identification was considered reliable (to my wasps. In all the instances that birds attacked satisfaction) only when the insect had been seen wasps the predator caught a live prey and in flight before is was captured by the bird. swallowed it. Four of the flycatchers (three of Tyrannus and Gubernetesyetapa), the two orioles RESULTS (Icteridae) and the oven-bird (Furnarius rufus) Predation on the wasps outside the nest was spent 10 to 35s beating each prey on a branch or ,observed on 65 occasions, giving an average of on the ground and examining is before swallow- qnly one sighting every 30 field hours. In addi- ing, while the Great Kiskadee (Pitangus sulphura- tion, once a small flycatcher (a species of Myiar- tus), Burrowing Owl (Speotyto cunicularia), chus) was stung in the mouth or throat by an Smooth-billed Ani ( Crotophaga ani), Rufous- unidentified, black wasp (possibly Palybia igno- tailed Jacamar (Galbula ruficauda) and White- bilis or Epipona tatua) and the insect escaped. eared Puffbird (Nystalus chacuru) spent 2 to 5s TABLE 1. Records from central Brazil of 30 attacks of 16 speciesof birds onindividals of 18 species of social wasps outside their nests. Number of Predator Waspspecies Locality observations Piaya cayana, Cuculidae Polistes erythrocephalus Goias GO Piaya cayana, Cuculidae Polybia striata Goias GO Piaya cayana, Cuculidae Agelaia flavipennis Goias GO Crotophaga ani, Cuculidae Polistes erythrocephalus Brasilia DF Crotophaga ani, Cuculidae Polistes versicolor Brasilia DF Guira guira, Cuculidae Polybia occidentalis Brasilia DF Speotyto cunicularia, Strigidae Polistes satan Brasilia DF Momotus momota, Momotidae Brachygastra moebiana Goias GO Galbula ruficauda, Galbulidae Polybia ignobilis Goias GO Galbula ruficauda, Galbulidae Polybia quadricincta Goias GO Galbula ruficauda, Galbulidae Polybia fastidiosuscula Goias GO 2 Galbula ruficauda, Galbulidae Epipona tatua Goias GO 1 Galbula ruficauda, Galbuliade Agelaia vicina Goias GO 4 Galbula ruficauda, Galbulidae Agelaia multipicta Goias GO 1 Nystalus chacuru, Bucconidae Polybia ruficeps Xavantina MT Nystalus chacuru, Bucconidae Chartergus globiventris Goias GO Colaptes campestris, Picidae Polistes lanio Brasilia DF Colaptes campestris, Picidae Polybia occidentalis Brasilia DF Furnarius rufus, Furnariidae Polybia occidentalis Goias GO Furnarius rufus, Furnariidae Metapolybia cingulata Goias GO Gubernetes yetapa, Tyrannidae Synoeca surinama Patos de Minas MG Pitangus sulphuratus, Tyrannidae Polybia occidentalis Brasilia DF Tyrannus melancholicus, Tyrannidae Polybia occidentalis Brasilia DF Tyrannus melancholicus, Tyrannidae Polybia fastidiosuscula Patos de Minas MG Tyrannus albogularis, Tyrannidae Polybia ruficeps Xavantina MT Tyrannus savana, Tyrannidae Polybia occidentalis Brasilia DF Tyrannus savana, Tyrannidae Polybia ruficeps Brasilia DF Gnorimopsar chopi, Icteridae Polybia occidentalis Goias GO Icterus icterus, Icteridae Polybia occidentalis Goias GO Icterus icterus, kteridae Polybia ignobilis Goias GO 90 SHORT COMMUNICATIONS beating the prey on a branch. In contrast, the sionally take social wasps which are away from kestrel (Falco sparverius), Blue-crowned Motmot their nests than those which attack a colony. (Momotus momota), two species of woodpeckers Very few attack were seen in relation to the (Picidae), two of the cuckoos (Piaya cayana and large numbers of wasps and birds which were Guira guira) and sometimes the rufous-tailed encountered during many hours in the field. jacamar and white-eared puffbird appeared to Furthermore, the wasps which were seen to be have no difficulty in swallowing the wasps imme- attacked are among the more common speciesof diately they captured them. the region (though records of this nature might At least one species, the Squirrel Cuckoo be expected). Most previous reports of social (Piaya cayana) eats other venomous insects in wasps outside the nest being the prey of birds .addition to hunting social wasps. On one occa- have been based on the questionable evidence of síon a squirrel cuckoo hunted systematically items that the birds had ingested (Fry 1972, through guava trees from which it gleaned and Schubart et al. 1965). ate more than a dozen larvae of the notorious Possibly the scarcity of attacks is due to the arctiid moth Eupseudosoma involutum (Sepp). ability of social wasps to defend themselves so The venom of this caterpillar is so strong that if that relatively few species of birds are able to its hairs touch the skin of an adult person the ingest them. Similarly there seem to be few avian pain is severe and often the person suffers from attacks on caterpillars of the family Arctiidae (which includes the Ctenuchinae). Many species delirium for several hours. of moths of this family sequester alkaloids from In addition to the observations on predation their host plants which results in the caterpillar on individual wasps outside the nest, two attacks being impalatable to potential predators (Watson were recorded on nests. Once a kestrel (Falco 1975). An additional variable to be considered in sparverius) opened a nest of Polybia occidentalis gaining an understanding of avian predation on near the town of Goiania, and a lineated wood- noxious insects is the ability of individual birds pecker (Dryocopus lineatus) discovered and to learn how to process a prey item prior to opened a nest of Metapolybia cingulata which ingestion. Such behaviour results in big differen- was attached to the trunk of a tree near the town ces in the speciesof insects taken -even among of Goias. On each occasion, the bird ate some individuals of a particular species of bird. Some- adult wasps and much of the brood while many times a bird learns to recognize particular types wasps flew about and seemed to have no means of insects and is able to manipulate the prey so of defending the colony. as to avoid the insect's defense system (Brown & The only other occasions observed of wasps Vasconcelos 1976). A bird can also learn to recog- being attacked by predators were two unidenti- nize a particular sex of an insect species. For fied species of robber-flies (Asilidae) which example, one White- throated Kingbird (Tyran- pounced on adult wasps which had alighted on nus albogularis caught and ate numerous O' of a leaf or a flower and immediately sank the sharp the solitary bee (Epicharis melanoxantha Moure), proboscis into the victim's body.