Host oviposition

Once the ovipositor penetrates the host, the decision to accept the host as an oviposition site is made. Although this has been referred to as host acceptance, the term acceptance is ambiguous. The host s heart beat has been suggested as a stimulus for host oviposition (Edwards, 1954) but its importance has not been confirmed. Chemicals appear to play a role in host oviposition. Arthur et al. (1972) reported that certain amino acids and MgCl are important in inducing oviposition in Itoplectis conqwsitor. 

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Unlike parasitoids of other insect orders that have host-seeking larvae, most parasitic hymenoptera lay their eggs on, in, or very close to a host individual [11]. This requires the adult female to find a suitable host, often with the aid of chemical cues from host frass, pheromones, plant volatiles emitted upon host feeding or egg-deposition, silk, honeydew and other secretions. She may then chemically mark the host following oviposition to reduce superparasitism by herself or intra- and inter-specific insects [11]. 

Host marking pheromones are important in many species of parasitic hymen-optera, because they ensure that a female parasitoid focuses on non-parasitized hosts. This, in turn, ensures a more effective use of limited host resources. Marking pheromones can be internal (injected into the host at the time of oviposition) or external (applied to the host during inspection and/or ovipo-sition). The internal markers can be detected by sensory hairs on the parasitoid ovipositor [11]. The internal markers often also delay the development of the host. 

Konstantopoulou M A, Krokos F D and Mazomenos B E (2002), Chemical stimuli from corn plants affect host selection and oviposition behavior of Sesamia nonagrioides (Lepidoptera Noctuidae) , J Econ Entomol, 95, 1289-1293. 

Glabrous soybeans supported a higher population of fabae and had a higher Incidence of oviposition than pubescent varieties (25, 26). This same observation has been made on other pubescent host plants (17). The differences in populations of E. fabae... 

The host range of the tobacco hornworm (Manduca sexta) is limited to selected members of the family Solanaceae. In an effort to better understand the chemical basis for the host plant selection process, we have undertaken an examination of both hornworm preferred and non-preferred members of the Solanaceae. Our investigations have shown this tc be a complex system involving the subtle interaction between such behavioral modulators as (1) Ovipositional stimulants (2) Feeding stimulants and imprinters (3) Anti-feedants (A) Repel-lants (5) Insecticides. The results of these investigations will be discussed. 

Although the ovipositional stimulant and the phagostlmulant are necessary to illicit their respective responses, they may not be sufficient to account for host-plant selection. In the case of Nicandra physaloldes, a member of the Solanaceae not preferred as a host plant by M. sexta, we have shown that aqueous extracts... 

About 85% of all Insects are holometabolous, and the food plants of larval and adult stages often differ (28). In most holometabolous insects host recognition may have been predetermined for the larva by the ovipositing female ]). In some cases it has been demonstrated that the larva prefers to eat the food upon which they are initially fed (Induction), even if it s not the appropriate host (29). 

A number of resistance factors influence behavioral processes and hence determine an insect s preference or non-preference for a particular plant. Hosts which do not contain the proper kairo-monal compounds are often totally rejected as food plants and by ovipositing females. Dethier (29) noted, however, that plants are almost never neutral, but are aTmost always either attractive or repellant. As previously observed, the ovipositional choice of the female imago and the food choice of the larvae usually coincide ( ). 

Harrington, E. A. and Barbosa, P. (1978). Host habitat influences on oviposition by Parasetigena silvestris (R-D) (Diptera-Tachinidae), a larval parasite of gypsy moth (Lepidoptera-Lymantriidae). Environmental Entomology 7 466-468. 

Landolt, P. J. (1993). Effects of host plant leaf damage on cabbage-looper moth attraction and oviposition. Entomologia Experimentalis etApplicata 67 79-85. 

One perceives from the world only what one has been prepared to perceive. In humans and in most mammals, different senses are used to make sense of life. In contrast, in insects, chemical senses involving odorants and contact chemosensory molecules play a vital role. The olfactory system is the primary sense insects use in analyzing the environment, in crucial tasks such as finding food, nesting, mating and in conspecifics. Contact chemosensation is used especially to analyze specific substrates to assist in the identification of suitable oviposition sites, the recognition of host plants, the selection of tastants and the search for further nutrient chemicals. Dedicated to survival, both olfactory and contact chemosensory systems in insects have developed to extremely high levels of sensitivity and selectivity. 

Richter, I. and Krain, H. (1980). Cuticular lipid constituents of cabbage seedpod weevils and host plant oviposition sites as potential pheromones. Lipids, 15, 580-586. 

STAEDLER, E., Chemoreceptions of host plant chemicals by ovipositing females of Delia (Hylemya) brassicae., Entomol. Exp. Appl., 1978,24, 511-520. 

NAIR, K.S.S., MCEWEN, F.L., Host selection by the adult cabbage maggot, Hylemya brassicae (Diptera Anthomyiidae) Effect of glucosinolates and common nutrients on oviposition., Can. Entomol., 1976,108, 1021-1030. 

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