The effect of arthropods on Dipodomys spectabilis food stores and storing behavior By: Amanda...
-
Upload
jayce-beetham -
Category
Documents
-
view
219 -
download
1
Transcript of The effect of arthropods on Dipodomys spectabilis food stores and storing behavior By: Amanda...
The effect of The effect of arthropods on arthropods on Dipodomys Dipodomys spectabilis spectabilis food food stores and storing stores and storing behaviorbehavior
By: Amanda SchauppBy: Amanda Schaupp
Mentor: Jose Herrera Mentor: Jose Herrera
What is a kangaroo rat?What is a kangaroo rat?
Granivorous rodentGranivorous rodent Desert grassland ecosystemDesert grassland ecosystem Are distributed in Are distributed in
Southwestern U.S and Mexico Southwestern U.S and Mexico Ecosystem engineers Ecosystem engineers Evolutionary adapted to use Evolutionary adapted to use
only metabolic wateronly metabolic water Seed diet Seed diet Morphological adaptations Morphological adaptations
Kangaroo rats on Kangaroo rats on SevilletaSevilleta
Dipodomys ordiiDipodomys ordii Dipodomys merriamiDipodomys merriami Dipodomys spectabilis Dipodomys spectabilis (banner-tail)(banner-tail)
Biggest in SevilletaBiggest in Sevilleta White-tipped tailWhite-tipped tail
Dipodomys ordiiDipodomys ordii
Dipodomys Dipodomys merriamimerriami
Dipodomys Dipodomys spectabilisspectabilis
Storing behavior of Storing behavior of banner-tail banner-tail
Store seed caches in moundsStore seed caches in mounds Stashed vertically inside wall of moundStashed vertically inside wall of mound Store seed caches for hibernation Store seed caches for hibernation
But how do they do this But how do they do this and why?and why?
Den Seed Caches
Hypothesis on storing Hypothesis on storing behavior of banner-tailbehavior of banner-tail
Preliminary hypothesis: banner-tail stick the stalk in their mouth, push it back quickly, bite, and do this continuously
Added onto hypothesis later: spit seed caches out and push forward onto inside wall of the mound
MethodsMethods
Trapped using Trapped using Sherman trapsSherman traps
Place 3 stalks of Place 3 stalks of Sporobolus Sporobolus cryptandrus cryptandrus (sand dropseed) (sand dropseed) in terrarium in terrarium
Conducted video Conducted video recordings using recordings using red light from red light from 4am-7am4am-7am
Why place the seeds Why place the seeds vertically?vertically? Fungal TheoryFungal Theory
Fungal growth caused by amount of Fungal growth caused by amount of moisture in denmoisture in den
Horizontally placed stacks containing Horizontally placed stacks containing seeds would imbibe waterseeds would imbibe water
Behavioral HypothesisBehavioral Hypothesis Vertically placed seed caches are more Vertically placed seed caches are more
difficult for ants and arthropods to difficult for ants and arthropods to harvest harvest
Den Seed Caches
What steals the seed What steals the seed caches?caches?
Ants are the primary seed stealersAnts are the primary seed stealers Watched them carry away seed Watched them carry away seed
stems and leave empty shellsstems and leave empty shells
Methods of behavioral Methods of behavioral hypothesishypothesis
Used kangaroo rat exclusion trap Used kangaroo rat exclusion trap and dug shallow hole in moundand dug shallow hole in mound
Seed caches placed in mound Seed caches placed in mound vertically, horizontally, and vertically, horizontally, and scatteredscattered
Kangaroo Rat Exclusion Trap
Vertical
Horizontal
Scattered
Hypothesis on arthropod Hypothesis on arthropod behavior behavior
Assumed that scattered seeds would be Assumed that scattered seeds would be taken first, followed by horizontal, and taken first, followed by horizontal, and then verticalthen vertical
Reasoning behind this is optimal Reasoning behind this is optimal foragingforaging
Results of arthropod Results of arthropod behaviorbehavior Used separate two-way ANOVAs Used separate two-way ANOVAs
with stalk orientation and den with stalk orientation and den activity as main factorsactivity as main factorsPercentage of Sporobolus cryptandrus caches taken
0
10
20
30
40
50
60
70
Vertical Horizontal Scattered
Orientation
Per
cen
tag
e ta
ken
Active
Inactive
Percentage of Sporobolus crytandrus caches taken
0
10
20
30
40
50
60
70
Vertical Horizontal Scattered
Orientation
Per
cen
tag
e ta
ken
Active
Inactive
Effect of orientation F=0.74, df=2, p=.48
Effect of den activity F=2.45, df=2, p=.1263
F=0.09, df=2, p=.9141
F=1.71, df=2, p=.1993
Trial 1 Trial 1 Trial 2Trial 2
ConclusionConclusion Kangaroo rats store seed caches Kangaroo rats store seed caches
vertically in moundvertically in mound Possible reasons arePossible reasons are
Fungal TheoryFungal Theory Behavioral HypothesisBehavioral Hypothesis Or maybe something else?Or maybe something else?
AcknowledgementsAcknowledgements University of New MexicoUniversity of New Mexico Sevilleta National Wildlife RefugeSevilleta National Wildlife Refuge Sevilleta LTERSevilleta LTER National Science FoundationNational Science Foundation US Fish and Wildlife ServiceUS Fish and Wildlife Service Jose Herrera and his studentsJose Herrera and his students Jennifer JohnsonJennifer Johnson 2009 Sevilleta REUs2009 Sevilleta REUs 2009 Sevilleta Interns 2009 Sevilleta Interns