Spatial distribution of colonizing Listronotus maculicollis populations: implications for targeted management and host preference

We characterized the spatio-temporal distribution of emerging overwintered adult Listronotus maculicollis populations colonizing golf course fairways with Spatial Analyses by Distance IndicEs (SADIE) with the goal to better target management tactics and to test assumptions for weevil preference for annual bluegrass (Poa annua). Adults randomly colonized and moved throughout fairways. However, cumulative captures were significantly aggregated along fairway edges closest to overwintering sites demonstrating progressive movement through the edges. Spatial association analyses suggest that the spatial patterns of cumulative captures of adults rather than weekly patterns were strongly associated with larvae, indicating that the adults enter fairways from the edges and deposit eggs over the course of several weeks. We did not observe an effect of host species on the distribution of either adult or larval L. maculicollis which leads us to question traditional assumptions of host preference for short mown P. annua. Instead, we propose that the aggregated distribution of larvae is generated by a low encounter rate of short mown hosts, rather than preference for species or cultivar. This study indicates that caution need to be applied when using preference-performance criteria in host preference studies. Future behavioural studies need to address the contributions of encounter rate and host species on L. maculicollis host selection and oviposition.