2017 Magicicada Brood VI (17-Year)
Total Page：16
File Type：pdf, Size：1020Kb
Magicicada 2017 brood mapping project 12:00 PM 4/2/17 2017 Magicicada Brood VI (17-year) © 2017 Totoket Partners Page 1 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 © 2017 Totoket Partners LLC All rights reserved. This material may not be reproduced, displayed, modified or distributed in any form without the express prior written permission of the copyright holder. © 2017 Totoket Partners Page 2 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Table of Contents Introduction ........................................................................................... 4 Brood VI ....................................................................................................... 4 Emergence Timing ........................................................................................ 8 Distribution and abundance of Magicicada ............................................ 9 Species Information ............................................................................. 10 Magicicada cassini (Fisher 1851) .................................................................. 10 Magicicada septendecim (Linnaeus 1758) .................................................... 13 Magicicada septendecula Alexander and Moore 1962 ................................. 16 Brood Maps .......................................................................................... 19 Appendix 1: Planning a mapping route ................................................. 31 What to look for .......................................................................................... 32 Recording your data .................................................................................... 35 Appendix 2: Standard Data Sheet ......................................................... 38 Appendix 3: The GPS Datalogger .......................................................... 41 To use the Map-O-Matic device ................................................................... 42 Troubleshooting the GPS datalogger ........................................................... 48 Appendix 4: GPS Navigator Devices ...................................................... 50 Database records as Points of Interest (POI) ................................................ 50 Appendix 5: Locality Codes ................................................................... 53 Appendix 6: labeling specimens and specimen preservation ................. 55 Appendix 7: Practical Considerations .................................................... 56 Appendix 8: Important locations and contact information .................... 58 Literature ............................................................................................. 59 © 2017 Totoket Partners Page 3 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Introduction Periodical cicadas (Magicicada spp.) are among the most unusual of insects, with long life cycles, infrequent, periodic mass emergences, striking appearance, and noisy behaviors. Periodical cicadas are divided into broods, or synchronized regional communities sharing a common emergence schedule, with life cycles of either 13 or 17 years. Because brood and species formation may be triggered by climate fluctuations, the biogeography of periodical cicada populations, broods, and species is thought to reflect postglacial climate instability (Alexander and Moore 1962; Lloyd and Dybas 1966a, b; Lloyd and White 1976; White and Lloyd 1979; Karban 1982; Williams et al. 1993; Williams and Simon 1995; Kritsky and Simon 1996; Marshall et al. 2003; Marshall et al. 2011). Complicating matters, broods typically contain more than one species, and the ranges and evolutionary histories of species within broods may not be congruent (Simon and Lloyd 1982; Cooley et al. 2011; Sota et al. 2013). Brood VI Brood VI may be one of the smaller broods of 17-year periodical cicadas. According to verified records, the brood is confined to a “core” mountainous region of NC, SC, and northeastern GA. But the status of Brood VI is more complex than these records suggest. Marlatt’s map of Brood VI (Marlatt 1923) shows populations scattered over eastern North America, including extensive areas of emergence in the Philadelphia-New York corridor and in the Midwest. Some Marlatt records, such as those in Wisconsin, are supported by museum specimens (University of Wisconsin- Madison), though as with many older museum collections, specific information about collection date and locality is lacking. Simon’s (Simon 1988) revised map of Brood VI shows all but the “core” populations as doubtful. © 2017 Totoket Partners Page 4 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Marlatt Fig. 9 (Brood VI). Marlatt’s map includes the core distribution of Brood VI in NC, SC, and northeast GA as well as scattered emergences throughout the eastern US. Simon 1988 Fig I (Brood VI). Simon’s map shows all but the core records of Brood VI to be doubtful or unverifiable. Marshall (Marshall 2001) noted that many Brood VI records may be the products of biases in earlier mapping efforts; some biases have to do with the ways that records were compiled over generations, while others have to do with varying levels of effort to search for emergences. A key source of bias is the practice of assigning records to broods on the basis of expectation and timing, a problem compounded by a lack of emergence density data associated with such records. Periodical cicadas © 2017 Totoket Partners Page 5 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 have a propensity to emerge off-schedule or “straggle” in increments of 4 years (Lloyd and Dybas 1966b; Dybas 1969; Lloyd and White 1976; Simon and Lloyd 1982; Maier 1985; Kritsky 1988; Kritsky and Young 1992; Marshall et al. 2011). When broods in close physical proximity (such as II, VI, X, and XIV; Cooley et al. 2009; Cooley et al. 2011; Cooley et al. 2015) are offset by increments of 4 years, the brood membership of low-density populations or populations along the periphery of any one brood can be uncertain. Emerging cicadas could belong to the brood emerging in a particular year, or they could be a “shadow brood”—stragglers from the temporally and spatially related brood; moreover, such populations could be self-sustaining, or they could persist only because they are continually replenished by more stragglers (Lloyd and White 1976; Marshall 2001; Cooley et al. 2011). Shadow-brooding seems to be the best explanation for records of “Brood XV” which, if it existed, would emerge four years before Brood II (Lloyd and White 1976; Simon and Lloyd 1982; Cooley et al. 2011). Maier’s (Maier 1985) reports of cicadas in Connecticut emerging on the same schedule as Brood VI may have a related explanation, since they emerged four years after Brood II had emerged in the same areas. Because there are so many possibilities for shadow-brooding involving Brood VI, many of the records in Marlatt (Marlatt 1923) assigned to Brood VI may actually belong to other broods—they could just be “shadows” of them (Marshall 2001). Other records, such as those in Wisconsin, are not easily explainable as belonging to other broods, because they are nowhere near likely sources of stragglers (e.g., II, X, or XIV). Thus, the temporal and spatial context of Brood VI makes it especially challenging to map. Brood VI is one of the few broods of periodical cicadas not yet mapped using GPS technology. Marshall and Cooley (unpublished data) mapped the main body of the brood in 2000, marking paper maps and later transcribing them: © 2017 Totoket Partners Page 6 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Page from Marshall and Cooley field notes, 2000. These data were later published in Cooley et al. Fig. 10 (Cooley et al. 2011), shown modified below: © 2017 Totoket Partners Page 7 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Detailed, georeferenced maps are the key to understanding the evolutionary relationships of periodical cicada broods (Cooley et al. 2009). 2017 provides an opportunity to revisit the map of Brood VI using newer technologies (Cooley 2015). Mapping—and being ready to investigate disjunct populations, such as found for Broods I (Cooley 2015), II (Cooley et al. 2015), and most recently, V—is made more challenging by the possibility that Brood VI’s boundaries may be unusually dynamic (Kritsky 1987); interactions between neighboring broods offset by increments of four years may create the conditions in which one brood may replace another over time (Lloyd and White 1976; Kritsky 1988; Kritsky and Young 1992). In order to resolve some of these outstanding questions surrounding Brood VI, we will be mapping the 2017 emergence, taking special care to note population densities (Lloyd and White 1976; Marshall 2001; Cooley et al. 2011; Cooley et al. 2013) and to investigate areas where Brood II is in close proximity to other broods. Emergence Timing Locally, periodical cicada emergences occur when soil temperatures at a depth of 7-8 inches reach approximately 64°F (Heath 1968). 2017 Brood VI emergences in GA, SC, and NC are expected to occur in the month of May. © 2017 Totoket Partners Page 8 of 61 Magicicada 2017 brood mapping project 12:00 PM 4/2/17 Distribution and abundance of Magicicada Understanding the distributions of periodical cicada species and broods requires a more complete understanding of their ecology and their responses to environmental change. Although maps of periodical cicadas have existed for over a century, many current maps