distribution & habitat preferences of the scorpion, & habitat preferences of the scorpion,...
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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 4th 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
20% found on Pine Trees
1% found on Oak
54% found elsewhere (i.e. ground, pine needles, logs, etc.)
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Pine Oak Cabbage Palm Saw Palm Other
Habitat Preference
24% found on Saw Palmetto
1% found on Cabbage Palm
20% found on Pine Trees
1% found on Oak
54% found elsewhere (i.e. ground, pine needles, logs, etc.)
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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
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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