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International audience; Faced with current health and environmental challenges, viticulture is directly concerned with the need to reduce pesticide use. Natural pest control services provided by bats have been demonstrated in other crops and is regularly mentioned as a way to reduce pesticide use. However, the trophic link between bats and grape pests as well as the effect of pest presence on bat activities remain largely unknown. To investigate the functional role of bats in vineyard landscapes, we used two independent approaches. We monitored the activities of bats and of the European grapevine moth (Lobesia botrana) in 23 vineyards located in the Bordeaux region (France). In parallel, we developed DNA primers to examine bat faeces from two regions, Bordeaux and Burgundy, for the presence of the three main species of grapevine moths. Our results demonstrate that bats significantly increase their hunting activity when European grapevine moths are present in vineyards. In addition, our molecular analysis of the faeces provides robust evidence that at least 10 species of bats predate the three grapevine moth species. Our results therefore suggest that bats can be natural enemies of grape pests in vineyard landscapes. Further research is now needed to investigate the consequences of predation of pests by bats on crop production as well as the effect of some management options at both the local and landscape scale to increase the level of pest control services provided by bats.

Global change is expected to modify the frequency and magnitude of defoliating insect outbreaks in forest ecosystems. Bats are increasingly acknowledged as effective biocontrol agents for pest insect populations. However, a better understanding is required of whether and how bat communities contribute to the resilience of forests to man- and climate-driven biotic disturbances.We studied the responses of forest insectivorous bats to a major pine defoliator, the pine processionary moth Thaumetopoea pityocampa, which is currently expanding its range in response to global warming [corrected]. We used pheromone traps and ultrasound bat recorders to estimate the abundance and activity of moths and predatory bats along the edge of infested pine stands. We used synthetic pheromone to evaluate the effects of experimentally increased moth availability on bat foraging activity. We also evaluated the top-down regulation of moth population by estimating T. pityocampa larval colonies abundance on the same edges the following winter. We observed a close spatio-temporal matching between emergent moths and foraging bats, with bat activity significantly increasing with moth abundance. The foraging activity of some bat species was significantly higher near pheromone lures, i.e. in areas of expected increased prey availability. Furthermore moth reproductive success significantly decreased with increasing bat activity during the flight period of adult moths. These findings suggest that bats, at least in condition of low prey density, exhibit numerical and functional responses to a specific and abundant prey, which may ultimately result in an effective top-down regulation of the population of the prey. These observations are consistent with bats being useful agents for the biocontrol of insect pest populations in plantation forests.

International audience; We compared the performances of the strip transect count method and the distancesampling method during colony surveys of large gulls to estimate the total number of nests. Ten colonieswere surveyed by both methods. Nest detection probabilities varied from 0.519 ± 0.064 to 0.706 ± 0.049and the average nest detection probability was 0.614 ± 0.015. Nest densities were highly variable, rangingfrom 77 nests/ha to 717 nests/ha. Estimates of the number of nests obtained by the strip transect countmethod averaged 9.3% lower than those obtained by distance sampling but by as much as 31% in somecolonies. Underestimation by the strip transect counts increased at high nest densities (Kendall t = −0.556,P = 0.032). The strip transect method needed on average 6.5 observers per colony surveyed, whereasthe distance sampling method required 1.4 observers per colony. In addition, the mean time spent percolony was 3 hours vs 1.7 hours for the strip transect and distance sampling methods respectively.Combining both these measures of effort, distance sampling required on average 87% less effort in thefield than the strip transect method. We strongly advocate the use of distance sampling for surveys oflarge gull colonies.