Biology and Reproductive Behavior of Dilophus Sayi (Diptera: Bibionidae)

Randy Thornhill


The eggs of Dilophus sayi (Hardy) are laid in the soil and require 16-22 days to hatch. Aggregates of up to 300 larvae are found on or near the surface of the soil among the roots of grasses. Pupation occurs in the soil. Males hover over emergence areas in the morning and afternoon. Females are intercepted immediately upon emergence as they fly through swarms of hovering males. Copulation takes place on the grass and is accomplished in a mean of 30 min. At the termination of a copulation males rejoin the hovering swarm; females disperse from the emergence area. Both males and females may mate more than once. Under laboratory conditions, females live about 72 hr and males about 92 hr. The behavior of D. sayi adults is somewhat similar to that of the lovebug, Plecia nearctica Hardy.

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