A Potential Cost of Monandry in the Lekking Sandfly Lutzomyia Longipalpis

Multiple mating by females is a subject of considerable controversy. In some species, however, females appear to mate only once, and the potential costs and benefits of this behavior are equally intriguing. When male mating success is highly skewed, monandrous females potentially risk mating with a sperm depleted male. In lek-breeding species, a male may gain up to 80% of available matings, yet few studies have explored whether these highly successful males suffer sperm depletion. These points are investigated in a series of laboratory experiments on the lekking sandfly, Lutzomyia longipalpis. It is shown that females may actively reject males prior to and after genital contact and that mated females do not remate within a single egg-laying cycle regardless of the refractory period between the first and subsequent matings. Males mate multiply and suffer from the effects of sperm depletion after their fifth copulation. Despite this, they continue to court and copulate females with equal vigor and females do not appear to detect sperm-depleted males: they lay similar numbers of eggs irrespective of the number of females their mate has previously copulated with. The implications of a single mating for L. longipalpis females in natural and laboratory leks are discussed.