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Temporal and spatial distribution patterns of a population of Talitrus saltator living on the Tyrrhenian coast of Tuscany (Italy) were studied. Bimonthly surveys were performed from March 1991 to January 1992 along transects using a standard system of pitfall traps and sieves for surface-active and burrowed individuals, respectively. Captured individuals were subdivided into sex and age classes (on the basis of the number of articles of the flagellum of the second antenna). Abundances were calculated for each sampling period and sex ratios were determined. For each sampling period the mean hour of surface activity was calculated together with the mean zonation of both surface-active and burrowing sandhoppers belonging to the different sex and age classes. Shifts in mean zonation between the resting and active phase were also determined. For each category of sex, age, and reproductive phase, simple and multiple regression analyses were used to find relationships of the mean zonation of surface-active animals with climatic data, and of the number of burrowed individuals with surface sand parameters recorded in correspondence to the sieves. On the whole, the results show that this Tyrrhenian population of T. saltator exhibited a bivoltine reproductive cycle and that the sex ratios of active sandhoppers were male or female biased according to the season. The variations in the mean hour of surface activity and in the zonation patterns of sandhoppers depended more on the age than on the sex. Furthermore distribution patterns were generally related to seasonal changes in the local climatic and substrate parameters. The observed differences between burrowing and activity zonations were interpreted on the basis of the nocturnal migrations of the different categories.

Spatial distributions of sand beach arthropods were studied at Zouara (Nefza), a beach dune system along the northwestern coast of Tunisia. Two transects with pitfall traps, perpendicular to the shoreline and placed from sea towards land, captured spontaneously crawling arthropods. The pitfalls were used to obtain data on horizontal zonations for 2 days during different seasons (April, October). In April, in order to assess local, long-shore distributions of surface-active beach invertebrates, ten transects with pitfall traps were placed every 100 m, for 2 days. Core samples were also taken in correspondence with each of the ten transects to obtain the distribution of burrowing individuals. Sand samples were taken for successive laboratory analyses (salinity, grain size and organic contents). Local climatic conditions were also recorded. One isopod (Tylos europaeus, subdivided into three different size classes), two amphipods (Talitrus saltator, Talorchestia brito and indistinguishable juveniles) and four coleopteran species (Eurynebria complanata, Scarites laevigatus, Phytosus nigriventris, Phaleria acuminata) were considered. Mean zonations perpendicular to the shoreline showed that crustaceans were found closer to the sea-line limits than coleopterans and that between seasons some species changed their mean zonation more than others. Local, long-shore distributions of active and burrowing individuals showed that most species were unevenly distributed along the shore. These discontinuous distributions differed according to the species and age class and were mainly related to specific microclimatic conditions and to nutrition.

The orientation of several Talitrus saltator sandhoppers that were moving spontaneously in the field at night were analyzed to determine the effects of astronomical and environmental cues on spontaneous movement. Analysis of the nocturnal spontaneous movement of sandhoppers indicated the presence of landward orientation after sunset and a seaward orientation at dawn. Feeding migration by the sandhoppers also occurred mostly at night while full moon night movements were seaward oriented.

An eco-ethological comparison of orientation experiments conducted on two different populations of the strand-living beetle Eurynebria complanata exhibits their response to sun compass cues. The beetles showed better orientation capacity in response to landscape cues in the presence of a visible sun. Height of silhouettes also influenced the orientation response.

The innateness and the possibility of modifying the orientation and responses of Mediterranean sandhoppers to substrate slopes and landscape. The sandhoppers, Talitrus saltator, either came from the beach or were reared in the laboratory prior to testing. Results indicate that orientation to substrate slope and landscape dishomogeneity are to some degree, innate and modifiable by experience. In the experiment, sandhopper were found to adopt a downslope orientation on dry substrate and an upward orientation on a wet substrate slope. The animal exhibited an innate orientation toward the black shape in the visual dishomogeneity condition.

The annual and daily patterns, together with zonation and direction of movements of Talitrus saltator were analyzed. The results showed that daily activity was mainly nocturnal but also dependent on climatic conditions. Zonation was observed to be different for juveniles andadults, and this was also dependent on climatic factors.