THE EFFECT OF THE CORPORA ALLATA ON THE MATING BEHAVIOR OF THE MALE MIGRATORY LOCUST, LOCUSTA MIGRATORIA MIGRATORIOIDES [R. & F.]

ABSTRACT

Males of the African migratory locust were allatectomized in the last (5th) nymphal instar. Observations were carried out on the sexual behavior of the adults obtained from the allatectomized nymphs. Sham operated and unoperated males were used as controls. Observations on the sexual behavior were based on quantitative methods and were performed during the whole lifetime of the adults. Sexual behavior exhibited towards females, towards differently treated males and towards similarly treated males was investigated separately, but comparatively, in allatectomized and control males. Intensity of sexual behavior exhibited by allatectomized males was considerably lower than that observed in control males. Presence or absence of additional locusts (females, differently treated males) markedly affected the intensity of the sexual behavior in allatectomized males and less markedly (but differently) in control males. Allatectomized males exhibited mild sexual behavior in absence of additional locusts and their sexual behavior was even less intensive in the presence of females. Almost no sexual behavior was exhibited by allatectomized males in the presence of control males. The life span of the allatectomized males was nearly twice that of the control males.

It was concluded that although the corpora allata have a marked effect on male sexual behavior, these glands do not exercise a complete control on the mating behavior of the males of Locusta migratoria migratorioides. The timing of allatectomy within several days before or after the moult to adult stage does not substantially influence the effect of the corpora allata on male sexual behavior in this subspecies. The controversial results obtained by different authors on the effect of the corpora allata on male sexual behavior in the species Locusta migratoria were discussed in the light of the findings of the present paper.