Abundance of Latrodectus katipo Powell, 1871 is affected by vegetation type and season

Abstract

The seasonal abundance of Latrodectus katipo Powell, 1871, a declining spider species endemic to coastal dunes in New Zealand, was observed in two different plant communities: an endemic sedge, Ficinia spiralis A. Rich. and an exotic grass, Ammophila arenaria (L.) Link. Using artificial cover objects (ACOs), presence/absence data was collected for L. katipo in the two plant communities. ACOs were positioned at Kaitorete Spit, which supports a healthy population of L. katipo, adjacent to F. spiralis or A. arenaria. ACOs were checked over four seasons. L. katipo were found significantly more often in ACOs placed next to F. spiralis as opposed to A. arenaria and its presence was highest in summer. Conserving L. katipo will involve reducing the amount of A. arenaria in New Zealand’s sand dunes. Studies monitoring L. katipo population dynamics should do so in summer when they are most abundant.