Low oviposition stimuli reduce egg production in the pollen beetle Meligethes aeneus

Gravid female pollen beetles, Meligethes aeneus (F.) (Coleoptera: Nitidulidae), were exposed at different intervals to oviposition sites that varied in acceptability. The egg load of dissected individuals which had been deprived of oviposition sites was not greater than individuals which had been frequently exposed to oviposition sites. However, the egg load of individuals which had been exposed to highly acceptable host plants was greater than those exposed to a host plant of low acceptability. Over the experimental period the total number of eggs which an individual produced was lower for those that were either deprived of an oviposition site or frequently exposed to a low-quality host plant. There was no evidence of either increased oviposition probability or clutch size as the period since the last oviposition increased. It is concluded that low host quality and low host encounter rate reduce the egg production of M. aeneus. It is further concluded that the suppressed egg production reduces the accumulation of eggs, so that physiological motivation for the insect to oviposit is not increased. If low oviposition site quality acts to reduce oogenesis, as found here, then the probability of egg deposition on low-quality species may not increase over time and the effect of antixenotic resistance may be enhanced.