Photons and foraging: Artificial light at night generates avoidance behaviour in male, but not female, New Zealand weta.

Avoiding foraging under increased predation risk is a common anti-predator behaviour. Using artificial light to amplify predation risk at ecologically valuable sites has been proposed to deter introduced mice (Mus musculus) and ship rats (Rattus rattus) from degrading biodiversity in island ecosystems. However, light may adversely affect native species; in particular, little is known about invertebrate responses to altered lighting regimes. We investigated how endemic orthopterans responded to artificial light at Maungatautari Ecological Island (Waikato, New Zealand). We predicted that based on their nocturnal behaviour, ecology and evolutionary history, tree weta (Hemideina thoracica) and cave weta (Rhaphidophoridae) would reduce their activity under illumination. Experimental stations (n = 15) experienced three evenings under each treatment (order randomised): (a) light (illuminated LED fixture), (b) dark (unilluminated LED fixture) and (c) baseline (no lighting fixture). Weta visitation rates were analysed from images captured on infra-red trail cameras set up at each station. Light significantly reduced the number of observations of cave (71.7% reduction) and tree weta (87.5% reduction). In observations where sex was distinguishable (53% of all visits), male tree weta were observed significantly more often (85% of visits) than females (15% of visits) and while males avoided illuminated sites, no detectable difference was observed across treatments for females. Sex could not be distinguished for cave weta. Our findings have implications for the use of light as a novel pest management strategy, and for the conservation of invertebrate diversity and abundance within natural and urban ecosystems worldwide that may be affected by light pollution.

Seasonal variation of biomass and bioactive alkaloid content of goldenseal, Hydrastis canadensis.

Seasonal variations in biomass and alkaloid contents of goldenseal (Hydrastis canadensis) were investigated. Five-year-old plants gave 5x the yield of roots and rhizomes of two-year-old plants, and summer growth gave significant increases in root biomass but not rhizomes. Berberine contents of roots plus rhizomes did not vary significantly and were >3.4% in all samples. Hydrastine contents of 5 y roots plus rhizomes showed significant seasonal variation. These variations were due to significant changes in the hydrastine contents of the roots (1.3-1.9%), but not the rhizomes (2.2-2.8%). Goldenseal leaves plus stems had lower contents of hydrastine (0.4-0.8%) and berberine (1.0-1.5%).