The behavioural response of Triatoma pseudomaculata to chemical substances present in their faeces or cuticle (footprints) was analyzed. Groups of larvae were simultaneously exposed to a clean filter paper and to another paper impregnated with a chemical stimulus in a circular arena. In these choice experiments, the insects aggregated significantly around papers impregnated with dry faeces. In ...

The ultrastructure of the 'cuticle' of Dipylidium caninum is described. The presence of mitochondria within the 'cuticle' and the connexion between it and subcuticular cells indicates that the outer covering of this cestode is of living cells forming an epidermis. On its external surface the epidermis is folded into finger-like microthriches and its thickness is pierced in places by pore-canals...

An account of the patterns of clones induced on the head cuticle of Drosophila melanogaster is given. The system was studied using mitotic recombination, induced by X-rays at certain developmental stages. In agreement with the findings of a computer model devised to simulate growth in the head imaginal disc, cuticle clones are found to have a characteristic pattern, sweeping round the central, ...

Earthworms (Lumbricus terrestris) produce a chemical substance that is readily detected by and serves as an attractant for garter snakes (Thamnophis sirtalis). This chemoattractant is sensed by the vomeronasal system of snakes. Amino acid analysis of the chemoattractant revealed a high hydroxyproline/proline ratio and large amounts of serine and threonine. More than one-third of the residues we...

The ultrastructural features of the gill epithelium of adult Daphnia magna are consistent with their dual function of ion transport from the surrounding medium to the hemolymph and transport of macromolecules from the hemolymph towards the cuticle. The thin cuticle of the gill epithelium displays short, thin epicuticular tubercles and pits. Silver grains penetrate the cuticle in AgNO3 treated s...

Precise ultrastructural localization of Drosophila melanogaster pupal cuticle proteins (PCPs) was achieved by the immunogold labeling of frozen thin sections. PCPs were found in lamellate cuticle and intracellular vesicles but, curiously, were absent from the assembly zone of the cuticle. Antibodies that distinguish between the two classes of PCPs--low molecular weight (L-PCPs) and high molecul...

The sequencing of numerous insect genomes has revealed dynamic changes in the number and identity of cytochrome P450 genes in different insects. In the evolutionary sense, the rapid birth and death of many P450 genes is observed, with only a small number of P450 genes showing orthology between insects with sequenced genomes. It is likely that these conserved P450s function in conserved pathways...

IN three earlier papers (Wigglesworth, 1933, 1945, 1947a) the structure and deposition of the cuticle of Rhodnius proltxus have been described. The main conclusions reached were as follows. The epicuticle is a composite structure made up of four layers: (i) a 'cuticulin' layer composed of a condensed lipoprotein subsequently tanned by quinones; (ii) a layer of material rich in dihydroxyphenols;...