Cold Temperature Tolerance of the Green Porcelain ’s Egg Production and Development in its Non-Native Range

Juliana Ventresca

GPMB The University of Charleston, South Carolina

Background Methods Results Field Sampling 120 35 • Biweekly monitoring of abundance, size distribution, and assemblage composition of resident • Invasive are non-natives whose introduction causes or is likely 100 30

to cause harm. on intertidal oyster reef near Grice Marine Lab (November 1, 2018 - November 1, 2020) C) (Figure 3; Figure 4). 25 ° 80 • Global climate change and ocean warming reduce thermal barriers to • Trays placed in mid-intertidal zone. Crabs identified to species, measured, and egg-bearing poleward range expansion. 20 status noted. 60 • The green , armatus, is an invasive, • Egg stages recorded to document ratios of early- to late-stage eggs in association with water 15 anomuran crab that disrupts trophic interactions (Figure 1; Figure 2; temperatures. Ovigerous % 40

Hollebone and Hay 2008). 10 Water Temperature ( Temperature Water

• P. armatus was first discovered in Charleston, SC, in mid 1990s (Knott Low-Temperature Tolerance Experiments 20 5 et al. 2000). • Female crabs held in cold incubators at 23oC, 20oC, 17oC, and 15oC to mimic conditions in Charleston Harbor from spring (~23°C) to fall (~15oC). 0 0 • P. armatus experiences sublethal effects at 6°C and lethal effects Sep '18 Oct '18 Nov '18 Dec '18 Jan '19 Feb '19 Mar '19 Apr '19 May '19 Jun '19 Jul '19 below 6°C (Mack 2017). • Monitor ovigery status, larval presence, and activity level of each female. • Crabs collected from Grice Marine Laboratory, North Inlet, and Bluffton, South Carolina to Figure 5. Mean monthly ovigery rates (+ standard error) and temperature • P. armatus reproduces year-round in native range, but primarily in determine if northern population can reproduce successfully at colder temperatures than variation from September, 2018 - July, 2019. Samples collected at Grice spring and summer near Charleston area (Wassick et al. 2017). Marine Lab. Temperature data provided by USGS. southern population. Figure 6. Stage 3 egg. Concentration of cells with germinal disc (pale, yolk-free area) forming at side of egg. Yolk broken up. Eggs dark brown/black.

Figure 7. Stage 6 egg. Eye pigmentation increased to irregularly-rounded darkened area (almost 10% of embryo). Eggs light brown.

Discussion • Recording egg stages will document delayed development, signified by higher late-stage egg rates, and associated water temperatures. Figure 1. An adult Petrolisthes armatus. Figure 2. Map of the invasive • Field observations of ovigery status provide documentation of spawning (blue dotted line) range of P. armatus (Mack et al. 2018) and a portion of season relative to increasing spring temperatures and decreasing fall its native (red line). temperatures (Figure 5). • Experiments will establish lower range limit of P. armatus’ reproductive thermotolerance, through egg development, egg hatching, and larval Objectives mobility. Acknowledgements Figure 3. Biweekly monitoring sample being sorted in the lab. Figure 4. Petrolisthes armatus from • • Document ovigery rates with relation to temperature variation biweekly monitoring sample. My advisors, Dr. Dara Wilber and Dr. Robert Podolsky through biweekly data collection on intertidal oyster reef at Grice. • My committee, Dr. Melissa Hughes and Dr. Virginia Shervette • Teresa Popp, for past data collection. Larval Temperature Tolerances • Determine lower temperature range limit preventing egg • Larvae from low-temperature tolerance experiment placed into temperature gradient block (6 - References development and hatching. 13°C). Hollebone AL, Hay ME (2008) An invasive crab alters interaction webs in a marine community. Biol Invasions. 10:347–358 • Mobility of larvae checked and scored over several minutes under dissecting microscope. Knott D, Boyko C, and Harvey A (2000) Introduction of the green porcelain crab, Petrolisthes armatus (Gibbes, • Compare low temperature tolerances of larvae hatched at different 1850) into the South Atlantic Bight. In "Marine Bioinvasions: Proceedings of the First National Conference, January 24-27, 1999", (J. Pederson, ed.), p. 404. MIT Sea Grant College Program. Cambridge, MA. water temperatures. Mapping Egg Stages Mack KJ, Podolsky RD, Shervette V, Fowler AE, Wilber DH (2018) Spatial and Temporal Associations Between • Male and non-ovigerous female crabs held in 1:1 ratio until breeding occurs. Native Crabs and the Invading Green Porcelain Crab, Petrolisthes armatus, Throughout Its Northernmost Invaded Range. Estuaries and Coasts 42.2: 537-547. • Create outline of succession of green porcelain crab’s egg • Eggs removed daily and viewed using compound microscope until development is completed Mack KJ (2017) Populations of the green porcelain crab, Petrolisthes armatus, vary in cold tolerance within the development. species’ northernmost invaded range. Masters thesis, College of Charleston, Charleston, SC. 91pp. and hatching occurs. Turra A, Leite FPP (2007) Embryonic development and duration of incubation period of tropical intertidal hermit • Egg stages determined based on stages described in Turra and Leite, 2007 (Figure 6; Figure 7). crabs (, ). Revista Brasileira de Zoologia. 24(3): 677-686. Wassick A, Baeza JA, Fowler A, Wilber DH (2017) Reproductive performance of the marine green porcelain crab Petrolisthes armatus Gibbes, 1850 in its introduced range favors further range expansion . Aquatic Invasions 12.4: 469-485.