a problem in paradise: the vanishing picobar tree frog geoff hyde ncbs yeti 2009 bangalore
TRANSCRIPT
A problem in paradise: The vanishing Picobar Tree Frog
Geoff HydeNCBSYETI 2009Bangalore
Species Unique to Picobar346 plants209 insects37 birds14 mammals11 reptiles and amphibians
Picobar Tree Frog
Dyscophus picobari
DiurnalInsectivorousMid-altitudesPopulation declining
How can the population decline of the Picobar Tree Frog be halted?
Possible players in the population decline of the Picobar Tree Frog
Rat Snake(Ptyas mucosa)Introduced 1999
Picobar Lady Beetle(Harmonia picobari)Threatened by fungi
Is population decline due to increased predation or decreased prey?
If increased predation…..
… we should see snakes eating frogs
Objective 1: Do starved captive rat snakes eat Picobar Tree Frogs?
Preparation for exposure to frogs
27oC + 36oC
Replication : 20 snakes
Snakes offered two species of frogs
Snakes ate the brown frogs
Tree frogs uneaten after one week
What if snakes do not have a choice?
27oC
Tree frogs only, offered for one week
Snakes sometimes attacked tree frogs...
...but quickly spat them out.
After one week, no frogs eaten
Objective 1: Do starved captive rat snakes eat Picobar Tree Frogs?
No
If decreased prey, frogs should strongly prefer Lady Beetles
Objective 2: Do starved, captive Picobar Tree Frogs
strongly prefer Picobar Lady Beetles ?
27oC
Preparation for exposure to insects
Replication : 20 frogs
Frogs offered five species of insects
Frogs targeted the Lady Beetles
5% Lady Beetles, 75% Brown Beetles, 100% of other species remain after a week
27oC
What if frogs can't choose Lady Beetles?
Replication : 20 frogs
Frogs offered 4 species (no Lady Beetles)
45% of Brown Beetles, 100% of other species, remain after a week
Objective 2: Do starved, captive Picobar Tree Frogs strongly prefer Picobar Lady
Beetles ?
Yes
• Very unlikely due to Rat Snakes
Is decline of Picobar Tree Frogs due to increased Rat Snake predation or
decreased availability of Lady Beetles?
• Results support Lady Beetle hypothesis- need support from field studies - preliminary data is suggestive
• Breed fungal-resistant Lady Beetles
• Captive breeding program for tree frogs
Suggestions for management of population decline