The spool-and-line technique has been neglected in the study of the behavioural ecology of mammals. It has advantages over the more widely used method of radio tracking in terms of cost and depth of detail in the data obtained, despite its limitations. A spool and line was used to study habitat use of two species of Rattus on Santa Cruz Island, Galápagos, in areas of sympatry and allopatry. Significantly longer total spool lines were collected from R. rattus than R. norvegicus, and R. rattus also climbed trees significantly more. Significantly longer spool lines were collected from female than male R. rattus, and rats caught in the morning spent significantly more time on the ground than those caught at night. The method of handling and the occasion of capture (first, second, or third) had no significant effect on either the total length of spool line collected or the proportion of time spent on the ground. Arboreality in R. rattus was compared with that in R. norvegicus between areas of sympatry and allopatry, and a significant difference was found between sites in terms of both the total length of spool line collected and the proportion of time spent on the ground. Rattus rattus was least arboreal at site D, an area of allopatry, and most arboreal at site B, where the fewest trees occurred, suggesting that factors other than vegetation structure influence arboreality. The use of spool-and-line devices in the study of behavioural ecology is discussed.

The creation of new hedgerows offers novel habitats to rodent species which are considered to be agricultural pests. New hedgerows with four different treatments and established hedgerows ate considered in terms of small mammal species present. Results suggest use of new hedgerow areas is important with respect to possible pest potential.

Catches of Prostephanus truncatus (Hem) and Teretriosoma nigrescens Lewis from 205 pheromone trapping stations in Mexico were compared and related to climate and habitat. Prostephanus truncatus numbers differed between regions and over time with significant interaction between the two. An overall peak in captures occurred between August and November but this was not apparent in Veracruz and Chiapas. Catches of T. nigrescens also differed but effects were less distinct. The peak in P. truncatus catch was related to monthly rainfall and, with a time lag, minimum temperature in the drier, upland regions, but poorly matched in Chiapas and Veracruz. Prostephanus truncatus abundance was predicted from climatic and habitat data during the periods March to 3 July, and 31 July to November. A regression equation derived from temperature, humidity and rainfall, explained 82% of the variance in the P. truncatus catch in the later period. Local habitat made only a small addition to this model. The best correlate of T. nigrescens numbers was the catch of P. truncatus, but it was less abundant relative to P. truncatus as P. truncatus became more numerous and where annual r.h. was above 70%. Predicted abundance of P. truncatus from the regression model is compared with predictions from laboratory studies of reproductive potential under different climatic regimes. While laboratory studies predict high survival in hot, humid areas, the trap data showed higher catches in cooler, more temperate regions. Possible reasons for these differences and implications for the spread of P. truncatus in Africa are discussed.

A survey was carried out into the occurrence of insect pests infesting rural stores in five regions of Mexico. Stores were sampled using pheromone-baited crevice traps, bait-bags and maize samples every 28 d for an entire storage season. Maize and store temperatures, and grain moisture content were measured. The most numerous primary pests were Sitophilus zeamais Motsch., Sitotroga cerealella (Olivier) and Prostephanus truncatus (Horn). P. truncatus was more abundant in stores in the drier, temperature regions of Guanajuato, La Laguna and Jalisco than in the more tropical regions, Veracruz or Chiapas. In La Laguna (and to some extent in Jalisco), many more P. truncatus were detected in the store using the crevice trap than were counted in the maize samples, perhaps because crevice traps may attract beetles from outside the store. La Laguna and Chiapas had significantly fewer larvae of P. truncatus in the samples than other regions, probably a result of the lower grain moisture content. Grain damage levels were very low in La Laguna and they occurred later in Guanajuato than elsewhere. The three pest species causing most damage were S. zeamais, S. cerealella and P. truncatus. It is suggested that P. truncatus was important in causing damage primarily in Guanajuato, whereas S. zeamais and S. cerealella caused more damage elsewhere, particularly in more humid areas.

An assessment of the levels of field infestation of maize by stored-product pests was carried out in El Bajio, Central Mexico. Their presence was low at the initial harvest stage with only 0.76% of fields infested with either Prostephanus truncatus (Horn) or Sitophilus zeamais Motschulsky, but after several months of drying on site in stacks, 54.4% of fields were infested with P. truncatus and 63.6% with S. zeamais, with a corresponding increase in the infestation rate within individual fields. Numbers of Abasverus advena (Waltl) were also higher in the second sampling period and the moisture content had dropped, creating conditions more suitable for the development of stored-product pests. An initial infestation by P. truncatus was seen to increase the probability of further infestation within individual stacks over time. In Mexico, this drying stage allows easy access for stored-product pests, although subsequent farmer selection of uninfested cobs at storage reduces their effect.An investigation of insect migration into artificial stores indicated that P. truncatus is more attracted to P. truncatus-infested cobs, although the initial migration and subsequent build-up was slow. Other stored-product pests showed a tendency towards attacking uninfested cobs. These results indicate that storage pests can infest the crop at any time from field maturation to the storage period. However, particularly in the case of P. truncatus, the earlier they arrive the greater the risk of loss not only from the progeny of the original colonizers but also because further adults appear to be attracted to existing infestations.

Double-sided sticky traps were baited with polythene vials containing synthetic components of the aggregation pheromone of Prostephanus truncatus (Horn) and used to investigate the effect of time of day on capture of this insect. P. truncatus exhibited a bimodal pattern of flight activity with a major peak between 18.00 and 21.00 h, and a smaller peak between 07.00 and 09.00 h. The effective life of the pheromone bait was also investigated over 33 days. The highest numbers of P. truncatus were caught during the first 8 days and the majority of the beetles were caught within 14 days. Catches then showed a steady decline. Captures of the predatory histerid Teretriosoma nigrescens Lewis, were much lower than those of P. truncatus and showed fluctuations which did not appear related to numbers of its prey. Environmental factors such as rainfall, temperature, wind and trap positioning appeared to influence results, especially when considered over a short time scale.