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Opeapea The Hawaiian Hoary Bat

• Overview of the subspecies
• Upcoming Research
• Echolocation and moth auditory sensory evolution
• Ebola update

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Morphological Studies Suggest Relative of
Mainland Hoary bat

• Lasiurus cenerius cenerius (North American)
• L. c. vittosissimus (South American)
• L. c. semotus (Hawaiian)

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Hawaiian Hoary Forest Species

• Mainland species also forest species
• -utilizes tree roost in native forest
• -commonality still remains overtime
• -Hawaiian hoary could be good indicator species
• Strange findings in lava tube on Mauna Loa
• Variable habitat range
• -found in wet and dry areas of the island
• -from sea level to 13,000 ft
• Mean home range (consisting of several disjunct
  activity centers and the day roost)
• -males 121 ha
• -females 5.6ha

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Inaccurate population counts

• Most current population counts based on sightings
• Difficulties with Anabat II
• Future intraspecific echolocation analysis
• The importance of microphone location

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Mainland hoarys rather lengthy migration

• Only terrestrial mammals to reach Hawaii

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HawaiiA great place to study evolutionary trends
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Morphological Comparisons between L. c. cinerius
and L. c. semotus

• Character divergence
• -flight
• -feeding
• -45 decrease in body size

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Microchiropteran utilize echolocation during
hunting

• Potential drawbackMay alert prey of impending
  attack
• Researchers find it difficult to quantify
  information

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The Hawaiian archipelago is an ideal place to
examine moth hearing as a bat predation defense

• Only one bat species known to exist on the
  islands
• L. c. semotus exerted entire predatory selection
  pressure on the ears of sympatric moths.

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L. c. semotus prey preferences

• Endemic vs. adventive moths
• Why is H. euclidias preferred over similar sized
  endemic moths?
• Effects of artificial lighting

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Insect nervous system auditory processing center
evolution

• Ears have appeared 19 times in the class Insecta
• Fundamentally similar structures
• Common selection pressure (bat predation)

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Moth earsneurologically simple

• Consist of up to four auditory receptors
• It has been proposed that the closeness of the
  bat as perceived by the moth determines the
  bimodal defense flight behavior

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5 acoustic stages in foraging echolocation

1. Search
2. Approach
3. Tracking
4. Terminal Buzz (I)
5. Terminal Buzz (II)

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The moth also has certain neurological stages
that somewhat correlate to the approaching bat
behavior
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Stage 1 The most sensitive receptor, A1

• The moth directionally detects with its most
  sensitive receptor, A1, a foraging bat that is
  echolocating in a searching mode------
• responses of A1 evoke controlled directional
  flight away from the bat so that the bat does not
  have a chance to detect the moth.

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Second defense mode

• Bat echolocating in tracking or terminal buzz
  mode
• -As bat approaches target, alters the duration,
  intensity, frequency, and structure of calls
• - Acoustical reason for this (avoidance of
  pulse-echo overlap)
• A1 and less sensitive A2 receptor activated
• Triggers erratic flight pattern

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A1 receptors encodes bat calls as a near bat
until 100-200 ms before the attack

• disactivation of interneurons and a premature
  cessation of near-bat responses.
• -little selection pressure to maintain vigorous
  A1 response for the final ms of a moths life?
• -may be an adaptive tactic used by the bat to
  facilitate captured of eared moths

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A2 receptor may be vestigial and not used in
flight response

• May play a role in a different bat defensesound
  emission (echo jamming effect

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Function of the B cell

• may in fact be vestige of a homologous
  proprioceptor in thoracical earless moths
• persistence in eared noctuid moths is reflection
  of low evolutionary cost of simple nervous
  systems

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So if moths evolved ability to avoid bat
predation, shouldnt they eventually lose this
ability when relieved from bat predation
pressures?
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Four suggested conditions that must be met before
phenoypic effects of bat release will occur

1. Complete isolation from bats
2. Absense of alternative uses for ears
3. Genetic isolation from bat-exposed conspecifics
4. Sufficient evolutionary time in bat-released
   condition

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Bats in the news Ebola resevoirs?

• Scientists have long wondered where the ebola
  virus hides between outbreaks.
• -fast killer, so often covers tracks quickly
• -primates die from infection
• Maybe its the bats

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Researchers have injected bats with the virus and
they have survived, but only recently have 3
fruit bats been found in nature with genetic
sequences from the virus or evidence of an immune
response to it.Traces of the virus were found in
the animals' liver and spleen
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Maybe its the birds

• the outer protein shell of filoviruses, such
  as Ebola, have a biochemical structure similar to
  retroviruses carried by birds, making a common
  evolutionary origin more likely.

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Until more is known public education is important
in preventing the spread of the disease