The periodical cicada / by Wm. J. Gerhard, Assoc. Curator of Insects.

no.4(1923)

Artificial diets for the production of natural enemies (predators and parasitoids) of greenhouse pest insects

The aim of this contract was to finalise in vitro rearing on artificial diets of entomophagous insects useful to control insect pests mainly in greenhouses through an analytical and rational approach. The work focuses on the development and optimisation of artificial diets for one coccinellid (Harmonia axyridis), two heteropteran predators (Orius laevigatus, Dicyphus tamaninii), and a braconid parasitoid of aphids (Aphidius ervi). The definition of the artificial diets was based on biochemical analyses of their natural food (aphids) or substitution food for the predators (Ephestia kuehniella eggs). Reliable quality control parameters of the entomophages produced were used in order to adjust dietary composition and formulation of the different diets tested.

The evolution of purinergic receptors involved in recognition of a blood meal by hematophagous insects

Many blood feeders use adenine nucleotides as cues for locating blood meal. Structure-activity relationship of adenine nucleotides as phagostimulants varies between closely-related species of blood feeders. It is suggested that a preexisting diverse pool of nucleotide-binding proteins present in all living cells, serves as a source of receptor proteins for the gustatory receptors involved in blood detection. It is proposed that the selection of any such nucleotide-binding protein is random.

Vitellogenesis in insects and other groups: a review

The eggs from oviparous organisms contain large amounts of vitellus, or yolk, wich are utilized by the growing embryo. Vitellogenesis is the process of vitellus accumulation and involves massive heterosynthetic synthesis of the protein vitellogenin (Vg) and its deposition in the oocyte. This work summarizes data on Vg structure, synthesis, uptake by oocytes and its fate during embryogenesis. The hormonal control of vitellogenesis and its tissue, sex and temporal regulation are also discussed. Where it is available, data on structure and expression of Vg-coding genes are reviewed. Insect vitellogenesis is priorized although other oviparous animal groups outside insects are also treated.

Interactions between parasites and insects vectors

This review stresses the importance of studies that will provide a basic understanding of the pathology of parasite-infected vector insects. This knowledge should be a vital component of the very focussed initiatives currently being funded in the areas of vector control. Vector fecundity reduction is discussed as an example of such pathology. Underlying mechanisms are being investigated in a model system, Hymenolepis diminuta-infected Tenebrio molitor and in Onchocerca-infected blackflies and Plasmodium-infected Anopheles stephensi. In all cases, host vitellogenesis is disrupted by the parasite and, in the tapeworm/beetle model, interaction between the parasite and the endocrine control of the insect's reproductive physiology has been demonstrated.

Development of specific ITS markers for plant DNA identification within herbivorous insects

DNA based techniques have proved to be very useful methods to study trophic relationships 17 between pests and their natural enemies. However, most predators are best defined as omnivores, 18 and the identification of plant-specific DNA should also allow the identification of the plant 19 species the predators have been feeding on. In this study, a PCR approach based on the 20 development of specific primers was developed as a self-marking technique to detect plant DNA 21 within the gut of one heteropteran omnivorous predator (Macrolophus pygmaeus) and two 22 lepidopteran pest species (Helicoverpa armigera and Tuta absoluta). Specific tomato primers 23 were designed from the ITS 1-2 region, which allowed the amplification of a tomato DNA 24 fragment of 332 bp within the three insect species tested in all cases (100% of detection at t = 0) 25 and did not detect DNA of other plants nor of the starved insects. Plant DNA half-lives at 25ºC 26 ranged from 5.8h, to 27.7h and 28.7h within M. pygmaeus, H. armigera and T. absoluta, 27 respectively. Tomato DNA detection within field collected M. pygmaeus suggests dietary mixing 28 in this omnivorous predator and showed a higher detection of tomato DNA in females and 29 nymphs than males. This study provides a useful tool to detect and to identify plant food sources 30 of arthropods and to evaluate crop colonization from surrounding vegetation in conservation 31 biological control programs.

A Preliminary Analysis of Insects of Medico-legal Importance in Curitiba, State of Paraná

A survey of the carrion fauna was made at two sites in Curitiba, State of Paraná, with the objective of describing the insects associated with carrion and setting up a preliminary data-base for medico-legal purposes in south Brazil. Vertebrate exclusion experiments were carried out in each season between 1994 and 1995 with a 250 g laboratory-bred rat (Rattus norvegicus). Five stages of decomposition were identified: fresh, bloated, decaying, dry and adipocere-like. Some species showed seasonal and site preference and so could be used to identify the probable place and season where death took place. Sarconesia chlorogaster (Diptera, Calliphoridae) was restricted to an open field site and to cooler months. Hemilucilia semidiaphana (Diptera, Calliphoridae) and Pattonella resona (Diptera, Sarcophagidae) were restricted to the forest site and warmer months. Phaenicia eximia (Diptera, Calliphoridae) and Oxyletrum discicolle (Coleoptera, Silphidae) were present at both sites throughout the year and could be useful for population level analysis. Dissochaetus murray (Coleoptera, Cholevidae) was present throughout the year at the forest site and was associated with the adipocere-like stage. Ants played an important role producing post-mortem injuries to the carcasses. Insects of 32 species are reported as being useful in community level approaches