1980] Tietjen — Sanitary Behavior of Malios gregalis 
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nature, however, one would not expect a secondary colony to be 
formed beneath the primary colony since in the laboratory such 
associations are rarely seen. The data do indicate, however, that 
within-colony fouling could occur if M. gregalis did not exhibit 
sanitary behavior. 
Excreta produced by M. gregalis do not provide chemical messages, 
as spiders are neither attracted to nor are they repelled from 
conspecific excreta (Tietjen, unpubl. data). It is possible, however, 
that excreta could disrupt other modes of communication. A large 
amount of excreta on the web surface may make adjacent silk threads 
stick together, possibly affecting the vibration characteristics of the 
web. Such contamination may directly affect communication among 
nest mates as suggested by the work of Burgess (1979). Deposition of 
excreta outside the normal areas of habitation may reduce this 
potential problem. 
Localized excretion sites are, however, only one aspect of sanitary 
behavior. During the summer months in North Carolina, for 
example, it is surprising that prey carcasses in the web are not 
associated with bacterial or fungal growth, as similar organic matter 
outside the web provides an excellent growth medium for such 
colonies. Perhaps the venom and/or the digestive fluids of M. 
gregalis serve an additional function analogous to the agents found in 
honey which discourage bacterial growth (Morse, 1972). In addition 
to incorporating prey remains into the nest structure, exuviae and 
dead spiders are often seen in the web matrix. Rarely do the dead 
spiders exhibit evidence of bacterial or fungal growth and often do 
these spiders appear as if they have been fed upon (e.g they are dried 
and shrunken). Jackson (1979) reports two instances of cannibalism 
in M. gregalis and others in this laboratory have observed similar 
behavior (Hollar and Scarboro, personal communication; Tietjen, 
unpublished obervation). If only injured or dead individuals are 
cannibalized (this has not been determined, as cases of cannibalism 
are very rare) then this behavior may be similar in function to the 
cannibalistic nest cleaning behavior observed in bees and ants 
(Wilson, 1971). In a similar vein, I have recorded the distribution of 
dead spiders within and outside the webs of four colonies confined in 
glass containers (13 cm dia, 17 cm height) and found that 14 of the 29 
dead spiders were found outside the web area on the bottom surface 
of the containers. Data presented in this paper (Model 3) would 
predict that the majority of dead individuals should be associated 
