We investigate the effect of parasitoid phenology on host-parasitoid population cycles. Recent experimental research has shown that parasitized hosts can continue to interact with their unparasitized counterparts through competition. Parasitoid phenology, in particular the timing of emergence from the host, determines the duration of this competition. We construct a discrete-time host-parasitoi...

Chelonus inanitus (Braconidae) is a solitary egg-larval parasitoid which lays its eggs into eggs of Spodoptera littoralis (Noctuidae); the parasitoid larva then develops in the haemocoel of the host larva. Host embryonic development lasts approx. 3.5 days while parasitoid embryonic development lasts approx. 16 h. All stages of host eggs can be successfully parasitized, and we show here that eit...

Laboratory selection for fenvalerate resistance was conducted in two colonies of the parasitoid, Cotesia plutellae, reared on two colonies of its host, Plutella xylostella, which differed in resistance to the insecticide. In the selection regime, the insecticide was applied to the host larvae that harboured the parasitoid larvae. Compared with the unselected parasitoid colony, the parasitoid co...

Despite the diverse array of mating systems and life histories which characterise the parasitic Hymenoptera, sexual selection and sexual conflict in this taxon have been somewhat overlooked. For instance, parasitoid mating systems have typically been studied in terms of how mating structure affects sex allocation. In the past decade, however, some studies have sought to address sexual selection...

We explore the addition of Allee effects to single-species discrete-time models with overcompensatory density dependence. When the intrinsic growth rate of the population, r , is large, the population bifurcates into chaos. The population goes extinct if r is either below a threshold level or very large. The model is then used to study host–parasitoid interactions with and without Allee effects...

We tested the enemy hypothesis for gall morphology on a model system comprising two Diplolepis rose gall wasp species and their associated parasitoids. The enemy hypothesis predicts both that gall traits will influence parasitoid attack rates within species, and that galls with contrasting morphologies will support different parasitoid communities. This hypothesis is supported by studies at bot...

Anaphes iole Girault is a solitary egg parasitoid which attacks Lygus spp. In a low-parasitoid-density experiment (parasitoid:host ratio 5 1:40) 10.0% of available Lygus hesperus Knight eggs were superparasitized by A. iole. However, in experiments with a high parasitoid density (parasitoid:host ratio 5 1:9), superparasitism of L. hesperus eggs was 33.3, 66.7, and 82.2% after exposure for 2, 6,...

Host recognition and use in female parasitoids strongly relies on host fidelity, a plastic behavior which can significantly restrict the host preferences of parasitoids, thus reducing the gene flow between parasitoid populations attacking different insect hosts. However, the effect of migrant males on the genetic differentiation of populations has been frequently ignored in parasitoids, despite...

Parasitoid detection and identification is a necessary step in the development and implementation of fruit fly biological control strategies employing parasitoid augmentive release. In recent years, DNA-based methods have been used to identify natural enemies of pest species where morphological differentiation is problematic. Molecular techniques also offer a considerable advantage over traditi...

Many true parasites and parasitoids modify the behaviour of their host, and these changes are thought to be to the benefit of the parasites. However, field tests of this hypothesis are scarce, and it is often unclear whether the host or the parasite profits from the behavioural changes, or even if parasitism is a cause or consequence of the behaviour. We show that braconid parasitoids (Glyptapa...