LeafCutter Ants at Hornsby Bend

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Leaf-Cutter Ants at Hornsby Bend

• Locations and Interactions

Team members Bryan Lai Andrew Horton
Michael Murphy Ryan Thomas Peg Wallace
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Project Goals

• Find and map Leaf-cutter Ant colonies
• Map extent of colonies plot in relation to major
  trees and other landmarks
• Observe interactions between ants the environment
  
• Evaluate impacts of past land-use on
  presence/absence of ants
• Map general distributions and monitor
  interactions of other ant species and insects
  found during this study, specifically harvester
  ants, carpenter ants, fire ants, and digger bees.

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Accomplishments

• Created a map detailing Leaf-Cutter Ant colony
  locations and their relation to other species of
  ants
• Established a possible correlation between nest
  sites and past
  land use
• Photographic documentation
  of ant activity
• Observed interactions with
  other ant species
• Production of a web site
• Class presentation

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Overview of Leaf-cutter species

• Fungus growers
• Prefer disturbed/cleared areas
• Important ecologically
• Leafcutters forage on many kinds of plants
• Range may depend on
• -rainfall patterns
• -vegetation
• -temperature

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Map of colony in Tract C
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Behavioral Observations

• Mostly a mystery!
• No clear cut connection to light levels
• Preferred moderate temperatures
• Some days we saw activity, most days we didnt

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Species Interactions

• No real problem with fire ants
• Found all three species in close proximity to
  each other
• No clear competition between different species
  located close to each other

Fire Ant
Harvester Ants
Leaf-cutter ant
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Food Foraging

• Plant species gathered include wild geraniums,
  elm, hackberry, and dewberry
• Pile of leaves at the base
• of the elm tree a mystery

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Interactions with Soil

• Water infiltration experiment

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Land Use

• Leaf-cutters seem to prefer cleared/disturbed
  areas and edges

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Other Ant Species

• Fire, Pyramid, Carpenter, and Harvester ants

Harvester ants
Carpenter ants
Pyramid ants
Fire ants
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Problems Encountered

• Scheduling Our scheduled field work has not
  necessarily coincided with the ants peak
  activity
• Weather Can and has occasionally been wholly
  uncooperative, resulting in minimal ant activity
• Other insects
• Poison ivy

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Surprises!
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Digger bees

• Were an accidental find
• Observed lots of interesting interactions
  including mating, males patrolling, bees
  gathering pollen, flies emerging from bee holes

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Digger bees

• There are parasitic and non-parasitic species.
• They burrow in the ground
• The bees are solitary but nest in colonies
• They line their burrows with a waxy substance

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Course Strands - Ecological Interactions

• ants are important in an ecosystem
• they stimulate plant growth and add organic
  matter to the topsoil

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Course Strands - Communication and Collaboration
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Course Strands - Sustainability

• The ants sustain themselves by foraging, cleaning
  out the nest, etc.
• By working the soil, they contribute to the
  sustainability of the whole system
• They prefer land with some human disturbance
• Clearing the fields for hay and the existence of
  the road dont seem to pose a problem for ant
  sustainability. However, the gravel mines might
  hinder the ants from building nests

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Humans and sustainability

• With Kevin, we learned about planting trees and
  forest restoration efforts at Hornsby
• Hornsby Bend is a reservoir of biodiversity
• The treatment of biosolids at Hornsby sustains
  bird populations and allows for the reuse of
  human waste as dillo dirt

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What else would we do?

• More time observing
• Observe during different seasons throughout the
  year - we were only there during the Spring
• Dig up the nest chamber to observe the fungus

Photo from TAMU website http//www-viz.tamu.edu/f
aculty/lurleen/main/attamain.htm
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Leaf-Cutter Ants at Hornsby Bend

• A Field Study

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This project was planned as a field experience
for the undergrads. The ants were just something
to focus on the real objective was to learn what
field work is really like.
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What did we learn?

• Since this was an unscripted project, we
  learned to
• Observe
• Pay attention to small details
• Wait for the Ah-Hah!! moments, and to recognize
  them when they came!

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We learned some new skills and ways to observe
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We learned by experimenting
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We did some measuring, and made some maps
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We made lots of up close and personal
observations
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And probably most importantly, we learned by just
BEING THERE!!!