January 22, 2013

Do Butterflies Sleep?

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If you walk around the forest at night with a flashlight, you’ll quickly find the answer: 

Yes, kind of.


Here’s a collection of images of some ‘sleeping butterflies’ I’ve come across in Tambopata.


butterfly sleep amazon rainforest peru tambopata
'Sleeping' Butterflies


In general, there are a few common traits for this nighttime behavior
. They almost always ‘sleep’ hanging upside-down and underneath a leaf. This hanging requires minimal energy, as their tarsi (aka ‘claws’) can grasp on to the leaf with little effort, opposed to standing right side up. 


Why under a leaf?

Two main reasons. For one, they gain protection from rain that often falls at night. Secondly, they are more hidden from early-rising birds looking for a meal that may be active before the butterflies are warm enough to take off. 


I have often noted that butterflies with warning coloration (black and bright yellow, orange wings) sleep more exposed, for example under a thin twig rather than under a covering leaf. This coloration is there as a signal to warn birds that they may be poisonous to eat. So, it may work to the butterflies’ advantage to show their entire color signal (aka wings) to birds, rather than keep their wings partially hidden under a leaf, explaining why they may tend to sleep more in the open.


So, are they actually asleep? 


Depends on your definition of sleep. If you want to define sleep as an inactive, low metabolic state: yes.  This low metabolic state is often driven by the temperature in the air itself; ectothermic butterflies require outside heat-energy to become active. 


There’s really no use in being active at night for most butterflies- they can’t see each other to mate, and empty flowers are restocking themselves with nectar for the following day. So, it makes sense that they would go into this ‘sleep’ state which likely helps them digest the day’s feed, produce eggs/sperm, and basically take advantage of a time in which there is nothing better to do.


During this nocturnal state they are still capable of flying off if disturbed. Also, there are some butterflies that specialize in roosting together at night in groups, and others I’ve seen regularly in pairs. Some butterflies in temperate climates are capable of overwintering as an adult, which is basically a physiologically extreme version of this normal sleep, kind of similar to hibernation.


Now the obvious follow-up question: 


Do butterflies dream?

I think not.



January 20, 2013

Frog Weather

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Monkey frog peru amazon
Phyllomedusa palliata hanging from a leaf near Posada Amazonas.
Image by Phil Torres
Ask any field biologist who has worked with frogs: there is such a thing as frog weather. I have been on easily over 100 night surveys in the rainforest in search of frogs and it doesn’t take long to notice a pattern emerge uniting the weather with your success in the night’s excursion. 


Frog eggs with developing
tadpoles inside. Image by
Phil Torres
Frogs, especially here in the rainforest, require moisture for activity and flock temporary pools/swamps of water to reproduce and lay eggs. I was last here in Tambopata during the dry season when there were very few temporary pools, so many of the frogs were hard to spot and likely hanging out up in the canopy rather than being more visible closer the dry ground. But now, it is rainy season. Frog season.

The perfect weather scenario for frogs based upon my observations: No rain for two to three days. Then, moderate to heavy rain that day, clear weather for a couple hours as the sun sets, and no rain to light drizzle at night. I often look at the leaves to tell me how many frogs will be out- do the leaves look dry and dusty or dewy and glistening? If it’s the latter, you have a pretty good chance of spotting a frog- or dozens of frogs- that night. 

 If the rain is too heavy at night, there will be few frogs visible. The males come down closer to the ground at night and call to females to reproduce- what’s the point in calling for a mate if they can’t hear you through the rain? This also helps researchers- you can identify frogs and their activity based upon the amount of calling. 
tambopata frog peru amazon
Phyllomedusa camba
Image by Phil Torres
 So why should you go look for frogs? For one, they are quite photogenic, typically sit still, and make for great rainforest wildlife photos. Secondly, consider one of the reasons biologists go looking for them: frogs can be bioindicators. Meaning, a healthy frog population typically means a healthy environment. Many frogs breathe at least partially through their highly permeable skin, so if there are a lot of pollutants in the water the frog populations may be the first to be affected. 

Also, many species of frogs are in decline due the chytrid fungus. Thus, the sad reality is that the frog extinction rate is much higher than many other animals, so you may not have long to photograph some of the more unique or rare species. Tambopata has been tested recently and no chytrid fungus was detected, so you’ll be sure to encounter some spectacular hopping frogs during your visit.
 That being said, it is starting to rain here, so let’s hope for another night of frog weather. Happy frogging! 


January 18, 2013

Two Seconds In The Amazon

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Watch this amazing video put together by Rainforest Expeditions' photo tour guide Jeff Cremer.

Featuring the wildlife you can encounter in the Tambopata rainforests.





January 14, 2013

"Best" High Solar Halo Photos Ever Captured in Tambopata

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Solar halos seen in Tambopata.
 Image by Phil Torres



A boat ride down the Tambopata River in Peru this September took an incredible turn when rare optical phenomena, known as high altitude solar halos, were seen and photographed with what are being considered the best images of the halos ever recorded.

What appeared to be an upside-down rainbow at first glance out the side of the canoe ended up being part of the rainbow-filled display seen here. Biologist Phil Torres and photographer Jeff Cremer were there to document it in the images and video seen here while on a photo tour at the Tambopata Research Center.

What are high altitude solar halos?

According the atmospheric optics expert Les Cowley, these solar halos are caused by a very specific reflections and refractions of the sun's light with ice crystals located in cirrus clouds high in the atmosphere. Normal rainbows are created by interactions of the sunlight with low level rain drops rather than high altitude hexagonal crystals of ice.

Cowley also mentioned that after first sharing the photos with others in the field of study, the consensus was that these images are considered "the best high sun halo images seen" and are strikingly clear compared to other images of this phenomenon, possibly because of the tropical origin opposed to a more temperate one typically associated with the halos.


Solar ice halos seen in Tambopata. The fainter white halos are considered the most rare.
Image by Phil Torres

Image by Steve Gettle
Aren't these sun dogs?

No- many consider all 'rainbows around the sun' like these to be sun dogs, they are not. Sun dogs are a specific type of ice halo found closer to the horizon with paired glowing refractions horizontal with the sun, as seen here. The halos seen in Tambopata were considerably higher in the sky than a sun dog.

While many think these ice halos are found only in colder climates, Cowley says that they are actually present throughout the world.

Want to visit Tambopata for your chance to see these halos? Come along for the adventure and click here to find more information.

A full analysis of the display can be seen on Optics Picture of the Day.

Simulation of the phenomenon with names of corresponding ice halos seen in the images.
Image created by Les Cowley with HaloSim.
Image by Phil Torres.


January 08, 2013

The Elusive American Pygmy Kingfisher

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tambopata research center peru
American Pygmy Kingfisher, Chloroceryle aenea aenea, at the Tambopata Research Center
Photo by Phil Torres
For anyone that enjoys birding, getting a photo of a kingfisher is always quite a challenge. They are found along hard-to-access rivers or bodies of water, are very quick and strong flyers, and they always seem to take flight just moments before getting your camera into focus.

Kingfishers are known for their excellent fishing abilities. Their beak and body can dive into water head first in pursuit of fish with such a splash-free efficiency that kingfishers actually inspired the design of modern bullet trains in Japan!


I was lucky enough to come across this American Pygmy Kingfisher, one of the rarer species in Tambopata, as it roosted just after dusk. While many kingfishers are found along larger rivers like the Tambopata, others can be found along smaller streams or, in this case, a caiman-filled swamp.


The American Pygmy Kingfisher and the Ringed Kingfisher are unique amongst other tropical kingfishers in that they also "hawk" for insects- capturing and eating insects in flight- along with the fishing.



Tambopata Research Center Phil Torres Peru Rainforest Expeditions
Image by Phil Torres

January 03, 2013

Why are some animals so well camouflaged?

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Simply put, the detailed camouflage you can come across in the rainforest is astonishing. Whether it be a frog, an insect, or a lizard, camouflage is an essential part of survival in an ecosystem full of very intelligent predators. 

Here are some of the most impressive examples of camouflage we've come across in Tambopata.

Sphaenorhyncus lacteus, the greater hatchet-faced treefrog.
Photo by Phil Torres

A katydid.
Photo by Jeff Cremer.

A Plica plica tree runner camouflages against the bark of a large Ficus tree.
Photo by Phil Torres

Another related katydid- some camouflage against dead leaves, others against live, green leaves.
Photo by Jeff Cremer

Predators- like monkeys and birds- have remarkable visiion, pattern recognition, and learning abilities. Young birds can quickly learn which butterflies are distasteful or poisonous, and monkeys can learn which 'fake leaf,' like the katydids pictured, are actually edible insects.

Because of that learning ability, many of these camouflaged species are polymorphic- meaning the same species will come in a variety of different camouflage schemes. Within the above katyid species for example, some will look more like a live leaf while others have dead-leaf venation. The variation helps prevent monkeys from learning one single false-leaf pattern as food and makes it more difficult for them to find and eat these cryptic creatures.

Camouflage is one of many survival tactics that have evolved in the animals of the rainforest. While some species may focus on being poisonous, dangerous, or fast, these guys do an incredible job of looking more plant-like than animal-like, and it seems to pay off.


 
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