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