Ambient temperature affects the utility of plasticine caterpillar models as a tool to measure activity of predators across latitudinal and elevational gradients

Publication date: Available online 15 November 2018Source: Biological ControlAuthor(s): Kanyata Muchula, Gang Xie, Geoff M. GurrAbstractPredation is a key ecosystem process and central to the practice of biological control. Artificial caterpillars moulded from plasticine have been widely used to compare attack rates in a variety of field settings. A recent study extended their use to latitudinal and elevational gradients and concluded that herbivores at lower latitudes and elevations suffer higher rates of attack by invertebrate predators. The present laboratory study examined effect of ambient temperature on the capacity of plasticine caterpillars to be marked by either a simulated attack of standardised force or by minute-long exposure to live ants. The effect of temperature on ease of marking of plasticine caterpillars was tested by preparing the plasticine at 2, 4, 8, 16, and 32 °C. The first three experiments tested the prepared plasticine at room temperature, immediately after removal of model prey from the preparation temperature and before it reached room temperature. A fourth experiment tested the plasticine caterpillars at the same temperatures at which they were prepared (i.e., 2, 4, 8, 16, and 32 °C), exposing the plasticine caterpillars to live ants. In all studies, the plasticine caterpillars were subsequently inspected for visible impressions by nine independent assessors who were unaware of the experimental aim or treatments. The assessors designated individ...
Source: Biological Control - Category: Biology Source Type: research