Reproductive habitat preferences of the endangered American burying beetle Nicrophorus americanus Ol

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Reproductive habitat preferences of the
endangered American burying beetle Nicrophorus
americanus Olivier (Coleoptera Silphidae)

• Amy Smith, Craig Clifford,
• Dan Howard, Hayley Dikeman, Jeff Howard

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Distribution In Oklahoma
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Issue

• Nicrophorus americanus (ABBs) are considered a
  habitat generalist
• Habitat loss and disturbance may not be as
  important as the loss of appropriately sized
  carcasses for feeding and reproduction (Sikes and
  Raithel 2002)

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Reproduction

• Male secretes pheromones
• Male and female move the carcass for burial
• After burial they strip away fur or feathers
• The female lays 10 to 30 eggs in a chamber
• The larvae hatch in days

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Reproduction

• Biparental care
• Adults remove fungi and secrete antibacterial
• After about a week, the larvae will have consumed
  the carcass
• Adults fly away
• Larva pupate and leave 1 month later

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Camp Gruber

• American burying beetles (ABB) exist at Camp
  Gruber Training Center in Braggs
• Large population
• Camp Gruber must survey annually to determine
  impacts of training on ABBs

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Data prior to 2005 was collected by Schnell and
Hoitt (2004).
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ABBs trapped during the 2006

• The greatest numbers collected at sites 19, 10,
  5, 34, and 26
• Note ABBS trapped at all but one site

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Questions

• Do ABBs have specific habitat requirements for
  reproduction?
• How far will carcasses be moved?
• What depth are carcasses buried?
• Does burial vary with soil characteristics?
• How many ABBs will emerge?
• When will emergence occur?

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Rat on a string

• 200 gram rats
• Limit use by other beetles
• Free-spooling fishing line
• Use line to find burial site

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Enclosures

• Enclosures made of 1/2 cm hardware cloth were
  placed over burial sites
• Monitored for emergence

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Habitats

• Nine different habitat types
• Two sites of each type
• Selection of sites based on
• Abundance of ABBs
• Access
• Soil varieties

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Excavation

• Burial site was excavated 15-16 August to
  determine chamber parameters.

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Soil sampling

• Soil compaction
• pH
• Temperature at 6 cm depth and 9 cm depth
• Top soil and subsoil samples collected for
  analysis of
• soil moisture
• Nitrate
• Phosphate
• Potassium
• organic matter
• soil texture (silt, sand, and clay).
• Samples were processed by Oklahoma State
  University Soil Lab.

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Results

• 60 rats presented, only 9 buried
• 6 different LCTA sites
• 72.39 km2 study area
• Only 1 site had ABBs emerge

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Burial of rats by beetles

• Carcasses were moved an average of 30.5 cm (range
  5-68 cm)
• Carcasses were buried an average of 15.9 cm
  (bottom of the chamber)
• The average width and length of the chamber was
  12.3 cm and 14.8 cm respectively.

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Soil impacts

• Burial of carcasses by beetles varied with
• Soil compaction (p0.003)
• Nitrogen (p0.004)
• Potassium (p0.005)
• Organic matter (p0.011)
• Clay (p0.019)
• Burial was more likely when these variables were
  low

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Emergence of beetles

• Parental ABBs emerged from 10C
• four newly eclosed ABBs emerged
• N. marginatus were more abundant
• A total of 47 N. marginatus emerged from three
  sites
• Eight N. marginatus emerged from the same site as
  ABBs

N. americanus
N. marginatus
Photos by Craig Clifford
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• N. marginatus trapped in 2006
• Most abundant at site 10

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Emergence of beetles

• Parental ABBs emerged twelve days after burial
• Newly eclosed ABBs emerged 31-42 days
• Newly eclosed N. marginatus emerged 18-48 days

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Emergence of beetles

• Varied with chamber depth (p0.030)
• Tended to emerge when carcasses at 23 cm
• Emergence varied with soil compaction (p0.038)
• Emergence of beetles varied with soil
  temperatures at 15.24 cm depth (p0.019)

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Emergence of beetles

• Emergence holes were located 11.5 cm from the
  chamber on average (range 0-25.4 cm).
• Beetles shared emergence holes.

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Conclusions

• 85 of rats were lost to scavengers
• Unable to determine habitat requirements
• Carcasses were carried by beetles 30cm
• Carcasses were buried 15cm deep
• Burial is more likely in loose soils with low
  organic matter, clay, N, and K

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Conclusions

• Four newly eclosed ABBs emerged at 10C
• Emergence of newly eclosed beetles occurred 18-48
  days after burial

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Special thanks to

• This project was funded by project number
  OK211840280 through Camp Gruber Training Center
  and the US Fish and Wildlife Service.

Erin Patrick Camp Gruber NSU Field Crew
Members Katey Kelley-Gifford Sarah Kelley-Gifford