26 April 2012

Vouchers for early (and late) dates

We recently received a query about collecting vouchers that do not represent new records for a county, but are the first of the season.

I think having first-of-season specimens (and last, as well) in the collection are very worthwhile. They are especially important to provide baseline as well as ongoing data on phenology fluctuations due to climate change -- something researchers are already doing with herbarium specimens.

Unfortunately, with Odonata there hasn't been too much motivation or incentive to make sure the entire flight period of each species is represented by specimens. It may be that some species that fly during the summer months will have the best data, since collectors are out and about during peak season and more likely to get individuals from throughout the entire period. Species that arrive early in the spring or linger later in the fall may be flying when folks are not out with their nets.

Darrin and I have always made an effort to at least collect individuals that are earlier or later than any others of their species in the MOS database, if not the first or last of a species in each season. Darrin went through and created a spreadsheet of first and last dates for all species in the counties we usually collect in. This is a little tedious, so Mark and I are looking into incorporating a Julian date field in the database. This way, records could be searched and sorted by day-of-year...great for volunteer users and also for making phenology graphs for the atlas.

Meanwhile, vouchering first-of-the-year for a variety of species is a decent strategy and can really add to the knowledge we have about flight periods and changes in the timing of emergence and arrival of migrants. We're happy to have these records to add to the database.