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Second hymenopteran attendants differ in tenacity of attendance. 
Components of these differences include fidelity and constancy of 
attendance, foraging strategy, and temporal activity pattern. Para- 
chartergus fraternus showed high fidelity during our observation 
period, i.e., the same individuals tended the same homopteran 
groups. Similar behavior is known for Polistes fuscatus (Barrows 
1979). In general, wasps tend to forage as individuals (Barrows 
1979, Schremmer 1978, and this study), whereas social bees, like 
ants, more often recruit (Cortopassi-Laurino 1977, Schuster 1981). 
Both wasps and bees remain with homopterans for long periods 
interrupted only by short forays to the nest. Honeydew foraging 
activities of wasps and bees are always diurnal (Schremmer 1978 
and this study). 
Third, hymenopteran attendants also differ in quality. It is now 
well established that hymenopteran attendance enhances the fitness 
of homopterans (Bristow 1984, Fritz 1982). However, the quality of 
hymenopteran services varies widely in terms of the effectiveness of 
sanitation, enhancement of growth rate, and defense. At least in a 
few studies with ants and aphids (Banks and Nixon 1958, El-Ziady 
1960), rapid rate of honeydew excretion indicates an increased rate 
of assimilation of essential nutrients, higher growth rate, and higher 
fecundity in homopterans. In our study, sanitation was maintained 
by most attendants, but wasp attendance could potentially increase 
the fitness of homopterans through providing better defense and 
enhancing growth rates. Jiron P. and Salas D. (1975), on the other 
hand, report no evidence that the presence of bees and wasps deter 
scale predators but observe benefits due to site sanitation. Bombus 
bifarius may not enhance aphid growth rates, but its leaf-gleaning 
activities can disrupt potential enemies (Wagner and Cameron 
1985). 
Fourth, homopterans may show preference for certain attend- 
ants. Benefits to homopterans from hymenopteran attendants may 
not be equal and certain Homoptera-Hymenoptera associations 
may be favored (Addicott 1979, Bristow 1984, Messina 1981). In 
this study, we documented differential responses of A. reticulatum 
to various hymenopteran attendants. In the presence of P. fraternus, 
aetalionids behaved defensively and provided little, if any, honey- 
dew to soliciting ants. Furthermore, under wasp solicitation, aetali- 
onids produced significantly larger quantities of honeydew. This 
