Ovipositing adults

Probing for oviposition Adults Sitophilus oryzae, Cereals... 

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]. 

Experimental studies with southern armyworm larvae and thiocyanate — one of the in vivo cyanide metabolites — showed that 5000 mg thiocyanate/kg diet reduced pupation by 77%, completely inhibited oviposition, and reduced adult emergence by 80% (Brattsten et al. 1983), strongly suggesting that thiocyanate poisoning is the primary effect of high dietary cyanide levels in southern army worms. 

This beetle is found on a wide range of foods, but develops best on animal feeds, whole grains, pollen, and various processed food commodities such as egg noodles and wheat germ (Partida and Strong, 1975). Adults are short lived and oviposition peaks after a few days and then declines rapidly. Eggs are laid singly either loosely or in crevices. This species has a larval diapause similar to T. granarium. 

The isolation of the ovipositional factor for adult gravid female hornworms (M. sexta) is still on-going research and is not as far along as the two previously discussed topics. Nevertheless several interesting chemical and biological points have been revealed and are worthy of discussion. 

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). 

The eggs of B. germanica contain the same types of hydrocarbons as the hemolymph, HDLp, and cuticle of the adult female. Only 150 pg of hydrocarbons accumulate on the epicuticular surface whereas up to 450 pg accumulate within the female during the period of egg maturation (Fan et al., 2002). The internal hydrocarbons are divided primarily between the ovaries, fat body, and 150 pg of HDLp-bound hydrocarbons in the hemolymph. During oocyte maturation ovarian hydrocarbons increase by more than 65-fold - from 3.5 pg on day-1 to 232 pg on day-8 (Fan et al., 2002). However, after oviposition on day-9, ovarian hydrocarbons decline to only 8.2 pg, demonstrating that hydrocarbons were associated with the ovulated oocytes. Radiotracing results indicate that they serve as components of the cuticular lipids of the embryos and first instars (Fan and Schal, unpublished results). 

Lam, K., Babora, D Duthiea, D Babora, E.M., Moorea, M. and Gries, G. (2007). Proliferating bacterial symbionts on house fly eggs affect oviposition behaviour of adult flies. Anim. Behav., 74, 81-92. 

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. 

Contact and stomach action, not translocated in the plant. Inhibits moulting of nymphs and larvae, leading to death. Also suppresses oviposition by adults, treated insects lay sterile eggs... 

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