Post date: Mar 13, 2017 3:22:25 PM
Goal: Measure CHC variation within and among populations and species of Lycaeides. We are focusing on CHC variation in caterpillars. Here, unbranched CHC are hypothesized to be important for desiccation tolerance. Branched CHC are more likely to be involved in communication, including communication with ants. We expect a greater proportion of long, unbranched CHCs at warmer drier sites.
Overview: We will conduct the rearing in two or three phases. We will focus on 10 populations, which have at least four females with five or more eggs. The populations are:
BNP BTB EML MRF PSP SKI SLA SNP VUH WLA
This includes five L. idas (admixed), three L. melissa, and two Sierran populations (SNP is Sonora Pass and EML is Lake Emma).
For round/phase 1 we will break diapause on two eggs from each of up to five females from each population. Depending on how many eggs hatch, we can supplement this. The goal is to have CHC data from 10-15 caterpillars per population.
Caterpillars will be submerged in hexane at 14-20 days (TBD). We may weigh caterpillars or try a desiccation experiment with a subset to get more information on the possible consequences of CHC variation.
Details:
Plant source and propagation: Alfalfa (M. sativa) were grown from seed in a pair of growth chambers (moved back and forth between them as growth was better in one than the other). All seeds were from a single maternal plant (), and were provided by M. Forister. Plants were started on xxx and grown at 27C under XX. Plants were watered as needed (e.g., ~ every 2-3 days).
Phase 1a: Eggs were placed individually in petri dishes, labelled and stored at 27C. We checked eggs daily (2-3 times) for hatching. The females used are highlighted here(x denotes phase 1a). Five additional eggs from each of five females were pulled out for a trial desiccation experiment (denoted d). Caterpillars were reared until 14 days of age and then weighed and frozen at -80C in glass vials. Rearing conditions were XX at 27C with plants in the same incubator. This increased the humidity substantially in the growth chamber, and I think had a positive affect on survival.
Phase 2: We placed an additional 3 eggs (or fewer if 3 were not available) from each female in individual petri dishes and followed the same protocol as for phase 1a. We did not include VUH and SLA as we have had no caterpillars emerge from these populations.
Results:
Sample information and rearing outcomes are tabulated here.