Size, not temperature, drives cyclopoid copepod predation of invasive mosquito larvae

During range expansion, invasive species can experience new thermal
regimes. Differences between the thermal performance of local and invasive
species can alter species interactions, including predator-prey
interactions. The Asian tiger mosquito, Aedes albopictus, is a known
vector of several viral diseases of public health importance. It has
successfully invaded many regions across the globe and currently threatens
to invade regions of the UK where conditions would support seasonal
activity. We assessed the functional response and predation efficiency
(percentage of prey consumed) of the cyclopoid copepods Macrocyclops
albidus and Megacyclops viridis from South East England, UK against
newly-hatched French Ae. albopictus larvae across a relevant temperature
range (15, 20, and 25ºC). Predator-absent controls were included in all
experiments to account for background prey mortality. We found that both
M. albidus and M. viridis display type II functional response curves, and
that both would therefore be suitable biocontrol agents in the event of an
Ae. albopictus invasion in the UK. No significant effect of temperature on
the predation interaction was detected by either type of analysis.
However, the predation efficiency analysis did show differences due to
predator species. The results suggest that M. viridis would be a
superior predator against invasive Ae. albopictus larvae due to the larger
size of this copepod species, relative to M. albidus. Our work highlights
the importance of size relationships in predicting interactions between
invading prey and local predators.