Attributes of oviposition substrates affect fecundity in Rhodnius prolixus

Abstract

The effect of the oviposition substrate on the rate of egg laying was investigated in the haematophagous bug Rhodnius prolixus. Fresh or old hen feathers or corrugated cardboard were offered to ovipositing females. The insects showed significant differences in the number of eggs laid depending on the substrate. Egg laying was maximal on the fresh feathers and minimal on the cardboard. The variations cannot be explained by differences in the amount of blood ingested nor by differences in the mating frequency between treatments. The amount of blood necessary per laid egg exhibited an inverse relationship with the absolute fecundity. The dynamics of mating and egg-laying for groups having two different substrates (corrugated cardboard and hen feather) and different nutritional states (previously starved vs previously fed) was established throughout one month. After a single meal, previously starved insects having feathers as a substrate laid their eggs and reached an oviposition peak sooner (6 days) than previously starved insects on the cardboard substrate. For both nutritional states the lack of feathers decreased the cumulative number of eggs laid by one third. Results are discussed in relation to the mechanisms of ovarian regulation known at present.