Cr. Bomar et Ja. Lockwood, OLFACTORY BASIS OF CANNIBALISM IN GRASSHOPPERS (ORTHOPTERA, ACRIDIDAE) .1. LABORATORY ASSESSMENT OF ATTRACTANTS, Journal of chemical ecology, 20(9), 1994, pp. 2249-2260
Two laboratory-reared and five field-collected species of grasshoppers
were assayed for behavioral responses to volatile chemicals emitted.
from grasshopper cadavers using a two-choice olfactometer with no stim
ulus as a control. Necrophilic and necrophobic responses to the stimul
i were dependent upon species, sex, development, starvation, crowding,
and attractant. Laboratory-reared Melanoplus differentialis (Thomas)
and field-collected Hadrotettix trifasciatus (Say) and Aulocara elliot
ti Thomas exhibited significant responses to the cadavers. Females of
these three species showed significant movement towards the cadavers,
but males were not significantly necrophilic. All tested developmental
stages of H. trifasciatus (fourth-instar nymphs through adults) showe
d significant attraction to cadavers. Fed M. differentialis adults and
H. trifasciatus adults and nymphs were significantly attracted to cad
avers, but starved individuals were either repelled or exhibited no si
gnificant response. Although female A. elliotti from an uncrowded popu
lation were significantly attracted to cadavers, females from a crowde
d population were significantly repelled from cadavers. Contraspecific
cadavers more frequently elicited a measurable response in adult M. s
anguinipes and H. trifasciatus than did conspecific cadavers, and only
contraspecific cadavers yielded a significant (necrophilic) response.
Although M. differentialis was necrophilic, neither males nor females
were significantly attracted to water.