Washing is recommended for nectar collection from flowers with low nectar volumes in the field (with the understanding that one wash underestimates the amounts of sugars present in a flower), as is immediate analysis of sugar mass. In view of the great variation in results depending on nectar collection and storage methods, caution should be exercised in their choice, and their accuracy should be evaluated. The use of pulsed amperometric detection, more specific than refractive index detection, may improve the accuracy of nectar sugar analysis.

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Parasites often induce behavioural changes in their host. However, it is not necessarily easy to determine whether these changes are representative of an adaptation of the parasite (parasite manipulation), an adaptive response of the host or a side-effect of infection. In a solitary parasitoid of Drosophila larvae (Leptopilina boulardi), viral particles (LbFV) modify the host acceptance behaviour of infected females by increasing their tendency to superparasitize. This behavioural alteration allows for the horizontal transmission of the virus within superparasitized Drosophila larvae. To add support for or against the 'manipulation hypothesis', we investigated whether other behavioural components of the parasitoid are affected by viral infection, and whether other forms of horizontal transmission exist. Neither the ability of females to locate host kairomones nor their daily rhythm of locomotor activity was affected by viral infection. However, infected females showed a lower rate of locomotor activity, suggesting a physiological cost of infection. The searching paths of females were also unaffected. Males from infected and uninfected lines showed the same ability to locate females'sexual pheromones. Moreover, alternative modes of horizontal transmission (through food consumption and/or contact with the same Drosophila larvae) did not lead to viral contamination of the parasitoid. The overall specificity of behavioural alteration and of viral horizontal transmission is consistent with the hypothesis that the virus manipulates the behaviour of the parasitoid.

Two bat species, Leptonyrteris curasoae and Glossophaga longirostris, are the principal pollinators of at least two of the three species of columnar cacti that grow on the semiarid island of Curaçao, Netherlands Antilles. I examined the importance of the cacti in the diets of the bats and found that 85–91 percent of their diet samples contained cactus pollen and seeds. At least 43 percent of the samples from each species contained cactus pollen andlor seeds exclusively. Leptonycteris curasoae consumes nectar and pollen of Ceiba pentandra and Agave spp. at the beginning of the dry season and G. longirostris also consumes a few other plant products in the wet season, but both bat species depend nutritionally on cacti. Female bats give birth to one pup per year, and the periods of parturition and lactation in each species correspond to peaks in the reproductive phenology of the two most abundant columnar cactus species. From personal observations and a review of the literature, I determined that bats were unlikely to fly to the mainland to feed, although L. curasoae may do so. I conclude that the interdependence of bats and cacti is suggestive of coevolution, and that columnar cacti are critical for the survival and persistence of nectar‐feeding bats on Curaçao.

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To maximise bat retention in urban environments, efficient bat monitoring is needed, but the factors that influence survey results for urban bats are unclear. We used echolocation call detectors (n = 378 detector-nights from November 2005 to October 2006) to assess bat activity among different sites in the Adelaide City parklands, temporal variations in activity (hourly, nightly, monthly), and responses to weather and light (artificial and moon). Bat species did not occur evenly in urban conditions; dark parks were more important for bat diversity and activity (six species groups in the darkest park) than were artificially lit parkland areas (three species groups in the flood-lit park). Gould’s wattled bat (Chalinolobus gouldii) and Mormopterus species 4 (94% of calls) were advantaged in urban parklands, being the only species recorded when lights were on at sports parks, whereas five species groups occurred when the lights were off. Minimal bat activity was recorded in the first 2 h after civil twilight, suggesting that bats may roost outside the city and commute nightly into parklands. Bat activity increased with temperature, with a burst in activity occurring after 7°C. Rainfall (>1 mm/24 h) and moon illumination at midnight did not influence activity. Urban environments should provide diversity to attract a diverse assemblage of bat species. Activity fluctuated among sites, nights, and across the year, indicating that large sample sizes over long periods of time are required to monitor and survey bats reliably with detectors.

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