Dactylanthus flower visitation by New Zealand lesser short-tailed bats appears to be influenced by daily rainfall

The unique relationship between Dactylanthus taylorii and its pollinator, the New Zealand lesser short-tailed bat (Mystacina tuberculata), is poorly understood despite both species being threatened. We used data collected over two summers (2016 and 2017) to determine if mean ambient temperature and total daily rainfall during the flowering period affected flower visitation by bats. We placed dataloggers around D. taylorii inflorescences to monitor bats with implanted passive integrated transponders (PIT-tags). We determined that flower visitation and bat activity was negatively correlated with daily rainfall but not temperature. Further, we found that juveniles and adult males were much more common visitors, with only four visits from adult females in two years. There is still much to learn about the unique and vulnerable relationship between these two New Zealand species, but it appears that rainfall may play a larger role than previously thought.