HOMOPTERAN ATTENDANCE BY WASPS AND ANTS: 
THE STOCHASTIC NATURE OF INTERACTIONS 
By Deborah K. Letourneau 1 and Jae C. Choe 2 
Associations of Hymenoptera with Homoptera have intrigued 
ecologists and evolutionary biologists as model systems of mutual- 
ism. The extensive body of literature, however, tends to be skewed 
to the interactions between ants and homopteran trophobionts in 
the Aphidae or Coccoidea (e.g., Kloft et al. 1965, Nixon 1951, Way 
1963, Wilson 1971). In the following account we document a web of 
multispecies interactions within and between trophic levels, in- 
volving a species of wasp, several species of ants, and two 
species of Homoptera. This account is unique in the literature on 
Hymenoptera-Homoptera associations because it (1) addresses 
observable interference between hymenopteran attendants, (2) 
reports behavioral preference by homopterans for certain hymenop- 
teran attendants, and (3) describes an interaction between a polis- 
tine wasp and an aetalionid planthopper. In addition, this study has 
general implications about the quality of diffuse and multiple asso- 
ciations between Homoptera and their honeydew foragers. 
Materials and Methods 
Ten aggregations of feeding Aconophora ferruginea Fowler 
(Homoptera: Membracidae) and four of Aetalion reticulatum (L.) 
(Homoptera: Aetalionidae) were located in the tropical wet forest 
along the Quebrada Camaronal at La Sirena, Parque Nacional de 
Corcovado, Osa Peninsula, Costa Rica. Both species of Homoptera 
are common in Costa Rica, ranging from Mexico and from Costa 
Rica to Brazil, respectively, and possessing wide ranges of host 
plants (Ballou 1935, 1936, Wood 1984). They are generally sessile, 
mating and depositing egg masses at the feeding site (Wood 1984). 
'Board of Environmental Studies, 407 Kerr Hall, University of California, Santa 
Cruz, California 95064. 
2 The Biological Laboratories, Department of Organismic and Evolutionary Biology, 
Harvard University, Cambridge, Mass. 02138 
Manuscript received by the editor February 3, 1987. 
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