Distribution & Habitat Preferences of the scorpion, Centruroides hentzi in central Florida State Parks Abraham Miller PhD & Jennifer Fernandes University of Tampa St. Petersburg College, Tarpon Springs
Scorpion Background Approx. 1500 species worldwide All are nocturnal predators Glow green under UV light Give birth to live young Long lived (5+ years) All are venomous Paruroctonus boreus under blacklight Photo by Ryan Stork
Scorpion Background Major constituent of desert Biomass (Polis 1990) With exception of ants and termites, they have the greatest arthropod biomass Their biomass is higher than most vertebrates in the desert Paruroctonus boreus under blacklight Photo by Ryan Stork
Importance in Florida Scorpions are major invertebrate predators May represent healthy environment Don t disperse well Require other invertebrates May be a source for biological control Centruroides hentzi from Highlands Hammock State Park
Why C. hentzi in State parks? Photo: Guy E. Crauwels (C) www.ntnu.no/ub/scorpion-files/gallery.php
Lack of Information
Public Information in the Western US
Corey & Stout 1990
Corey & Stout 1990 Sampled 12 sites 6 arachnid orders; 14 species Scorpion: C. hentzi 4 th most abundant of all taxa 86% collected between July-September Juveniles in September No correlation with ground cover
Shelley & Sissom 1995
Questions What Florida State Parks have scorpions? How common are scorpions in Florida? What habitats do they occupy? What do they prey on?
Methods Blacklight collecting at night between Feb - Nov Used GPS to mark location Scorpion locations were recorded Amount of Moonlight Vegetation Type Vertical height Distance to nearest Pine Tree Distance to nearest Oak Tree Distance to nearest saw palmetto Laboratory Trial of Tree Preference Scorpions were placed in a large plastic container filled with sand Oak Log & Pine Log were placed vertically in the sand Scorpion location was recorded
What Florida State Parks have scorpions? 5 parks sampled in Central region
What Florida State Parks have scorpions? 7 parks sampled in Southwest region
Highlands Hammock S.P.
Highlands Hammock S.P.
Highlands Hammock S.P.
Highlands Hammock S.P.
Highlands Hammock S.P.
Habitat Preference 24% found on Saw Palmetto 1% found on Cabbage Palm 120 100 80 20% found on Pine Trees 1% found on Oak 60 40 20 54% found elsewhere (i.e. ground, pine needles, logs, etc.) 0 Pine Oak Cabbage Palm Saw Palm Other
Habitat Preference 24% found on Saw Palmetto 1% found on Cabbage Palm 120 100 80 20% found on Pine Trees 1% found on Oak 60 40 20 54% found elsewhere (i.e. ground, pine needles, logs, etc.) 0 Pine Oak Cabbage Palm Saw Palm Other
Experiment: Habitat Preference
Experiment: Habitat Preference Experimental set-up needs to be revised Scorpions disappeared for days at a time, which heavily skewed data Scorpions were seen (active) every 3-14 days Scorpions came out to feed 3-5% of Scorpions are active on any night (Polis 1990)
Experiment: Habitat Preference
Results: Negative Phototaxis 85% of scorpions collected were located in the shadow of the moon 160 140 120 100 143 80 60 40 20 0 13 14 shadow partial shadow moonlight
Other Results Temporal Variation Full Moon at St. Sebastian 3/7-3/8/12 7 scorpions clear conditions 3 scorpions after rain Waning Moon at St. Sebastian 5/21/11 15 captured Moon had not risen yet Prey Spiders Caterpillars Solpugids Moths Crickets Lacewings Unaffected by fire
Other Results Vertical Stratification Do not burrow Have been seen at 5 meters up a pine tree Gravid Females Found in all areas Females carrying young All found associated with rotting logs on the ground Most (if not all) have termites Possible Food Source
Discussion Pine Trees & Saw Palmettos like offer the best refugia Poorly drained areas decrease dispersal capabilities There appears to be seasonality Abiotic Factors Biotic Factors Abundance Observed 30+/hr along 100m trail
Why not C. hentzi Walk?
CETL Funding Used to set up a lab at the TS campus to get SPC AA and BS students involved in scientific research Need to purchase Black lights Housing containers Building materials for behavioral studies and other experimental supplies Crickets and a terrarium to breed them Light timers Sand Dissecting microscope
Acknowledgements St Petersburg College Florida Biology Class for field help CETL Florida Department of Environmental Protection Collecting Permit
Thanks & Questions