The pollen beetle, Meligethes aeneus, changes egg production rate to match host quality

Abstract

Motivation-based models dominate current theory concerning host plant selection for oviposition by herbivorous insects. A female searching for a host plant will be more likely to accept a host which is of inferior quality for her offspring if motivation is high, e.g. a large eggload or long time since last oviposition. This implies that insects will accumulate eggs if exposed to hosts of low acceptability and after a time lay eggs on such hosts. An alternative strategy for insects when exposed to less acceptable hosts is to stop producing, instead of accumulating, eggs. Thus, resources would be saved until a more acceptable host is found. If this hypothesis is true, a herbivorous insect would cease egg production when exposed to hosts of low acceptability and resume egg production when exposed to hosts of high acceptability. Previous exposure should not affect oviposition rate when an insect encounters a new host of a different quality. In an earlier study pollen beetles, Meligethes aeneus (F.) (Coleoptera: Nitidulidae), did not accumulate eggs in the absence of high quality hosts. In this study we monitored the daily oviposition rate of female pollen beetles on hosts plants of low (Sinapis alba L.), intermediate (Brassica nigra Koch) or high (B. napus L.) acceptability over a 5-day period. Individuals were then switched to an oviposition resource of a different acceptability. Beetles moved from high- to low-acceptability plants reduced their oviposition rate considerably. In the opposite case, low to high acceptability, the rate of oviposition increased markedly after the switch. When M. aeneus were moved from the high-acceptability host to that of intermediate acceptability oviposition rate was modified accordingly. However, when moved to the intermediate host from a host of low acceptability oviposition on B. nigra was much less than would normally be expected. A possible mechanism for this finding is discussed. M. aeneus, by adjusting oviposition rate to host acceptability, maximizes the average host quality for offspring, even at the cost of a lower egg-laying rate.

Responses of Ovipositing Moths (Lepidoptera: Geometridae) to Host Plant Deprivation: Life-History Aspects and Implications for Population Dynamics

“…Accumulation of eggs in the absence of preferred hosts is predicted to lead to various changes in oviposition behavior (Miller and Strickler 1984, Courtney et al 1989, Minkenberg et al 1992, Mayhew 1997. Results of the current study, do, however, cast some doubt on the generality of the assumption that egg load is the central state variable modifying oviposition behavior (see also Hopkins and Ekbom 1999). In particular, theory predicts that females carrying higher egg loads should have higher motivation to accept unusual hosts.…”

Offering offspring as food to cannibals: oviposition strategies of Amazonian poison frogs (Dendrobates ventrimaculatus)

“…The ''oviposition-preference-offspring-performance'' hypothesis therefore predicts that female oviposition decisions are selected to maximize fitness by maximizing larval performance (Thompson 1988;Mayhew 1997). This hypothesis has been supported by many studies on insect parasitoids (Waage and Godfray 1985;Godfray 1987;Vet et al 1993;Brodeur et al 1998) and phytophagous insects (Hopkins and Ekbom 1999). However, there is growing evidence that, although female oviposition decisions are made to maximize their net fitness, female decisions may not match maximal performance of some or any offspring (Mayhew 1997).…”

Greater impact of host plant species on oviposition of a willow leaf beetle Plagiodera versicolora Laicharting (Coleoptera: Chrysomelidae) during the adult stage than in developing larval stage

“…In contrast to Lepidoptera, in groups such as Coleoptera and aphids, eggs or embryo initiation and maturation continue throughout the adult reproductive life (Dixon et al 1982;Hopkins and Ekbom 1999). In addition, females of Coleoptera and aphids resorb eggs for survival when the host plant quality is poor (Leather 1983;Sequeira and Dixon 1996;Ishihara and Ohgushi 2006).…”