76 
Psyche 
[Vol. 90 
Discussion 
The defensive adaptations of the immature and adult stages of E. 
canadensis are quite different even though they occur in the same 
microhabitats, overlap in their seasonal occurrences, and encounter 
similar predators. The cases that cover the eggs and larvae appear to 
deter most, if not all, of the several invertebrate predators that 
forage on goldenrods (see Messina 1982 for a list). Wallace (1970) 
has found that the case of another chlamisine, Neochlamisus gibbo- 
sus (F.) (= Anthrochlamys plicata F.), protects the larvae from 
imported fire ants. The defenses of adult chlamisines require further 
investigation. Nevertheless, it seems obvious that a variety of escape 
mechanisms are derived from the adults’ morphology. As a conse- 
quence of their hard, compact body form, adults are well-armored 
against the initial thrusts of predators and they are more likely to 
tumble into a refuge after dropping from the foliage. Furthermore, 
because of their resemblance to caterpillar frass, adults may be over- 
looked by many predators that rely on vision (Jenks 1940). 
Many chrysomelids are chemically defended against predators 
(e.g. Meinwald et al. 1977; Howard et al. 1982). Adults in the camp- 
tosomate group, however, lack the defense glands found in most 
chrysomelid subfamilies (Deroe and Pasteels 1982). This suggests 
that chlamisine adults must rely primarily on the mechanical and 
behavioral defenses discussed above. 
The major enemies of E. canadensis are the parasitoids, S. albi- 
frons and T. chlamytis. Specialized parasitoids have been highly 
successful in overcoming most of the defenses (e.g. reflex bleeding, 
fecal shields, glandular secretions) employed by chrysomelid larvae 
to deter predators (Eisner et al. 1967; Wallace 1970; Matsuda and 
Sugawara 1980). 
Several characteristics of E. canadensis can be grouped into an 
adaptive syndrome that is associated with the case-bearing habit. 
This coordinated set of traits includes the bowed posture, long legs, 
and other morphological adaptations that accommodate the larvae 
to life within the confinement of a case. In addition, casebearing 
probably influences other aspects of the natural history. For 
instance, the time and case-building material that the female must 
invest in each egg may result in a lowered reproductive rate. We 
observed that 30 females laid an average of only 1.2 eggs per day 
over a six-day period; Karren (1972) reports similar oviposition 
