Monday, April 23, 2012

Young Researchers Explore Costa Rican Rainforest - Part I: Invertebrate Bonanza

During the first two weeks of March students and staff from Forman School, Wamogo Regional High School and Litchfield High School, accompanied by CAS staff members Frank Gallo and Twan Leenders, headed to the Costa Rican rain forest again. For the 20th year in a row students got their chance to put the skills they learned in class in action and to test the research hypotheses they'd developed in class before traveling to the tropics. With guidance from their experienced project leaders these students studied the strength of local spider silk, recorded katydid calls, banded birds that winter in the rainforest but breed in temperate regions, tracked the recovery of several endangered frog species, documented the local moth diversity and much more. Below is a brief overview of some of the work these young scientists did, focusing on the three invertebrate-centered projects. Part 2 of this narrative will be posted on this blog tomorrow. If you would like to hear the whole story first-hand from the students themselves, they will be presenting their findings during the 20th anniversary Rainforest Project Dissertation Day on Friday April 27th starting at 9AM at the Forman School, 12 Norfolk Road, Litchfield. Everyone is welcome!

The Rainforest Project takes place in Selvatica and Rara Avis Rainforest Preserves, located in the buffer zone of the Braulio Carrillo National Park complex in northeastern Costa Rica. This park complex covers over 475 square kilometers (117,500 acres) of protected land ranging from near sea level to almost 3,000 m (9,850 ft) in elevation and contains several dormant volcanoes. On the way into our study area the group stopped briefly on one of those: Poas Volcano. 

Clouds cover the rim of Poas Volcano's main crater which still bears the signs of its most recent eruption. 
The clouds blow out for a few minutes exposing the main crater. It measures 1,320m in diameter and is some 300m deep with a green lake at the bottom. The crater lake's average temperature is around 110 degrees F and fumaroles spew sulphuric gasses constantly, making conditions in the crater pretty inhospitable for living creatures.    

A nearby old and inactive crater in the side of the mountain has meanwhile returned to cloud forest habitat

The Rainforest Project starts its research at the relatively low elevation Selvatica Preserve, at about 550 m above sea level. The research station is a converted penal colony that was operational in the 1960s and 70s but is now run by an international conservation organization.  
The main building at SelvaTica Preserve is called 'El Plastico' and is the administration building of an old prison colony. Convicts were forced to sleep outside under plastic tarps - hence the name. 
Upon arrival in the rainforest students set up their lab spaces and familiarize themselves with the overwhelming green-ness of the lowland rainforest habitat. No matter how much time they spent preparing for their individual projects and mentally trying to figure out where and how to find their study organisms, actually doing so in the forest is a whole different ballgame....

The Lowland Rain Forest in the preserve is overwhelmingly dense and lush.
However, students team up with their project leaders and head out into the jungle to set up their study plots and to collect data right away. 

The mountainous terrain in the area is full of rivers and streams. Navigating the slippery rocks and muddy streams can be challenging at times.

Every step of the way the view is worthy of a picture and the diversity of plant and animal life is truly mind-boggling

Students learn all sorts of new skills early on. Apart from their respective research subjects they learn how to read maps and navigate the extensive trail system, photograph and otherwise document their research and experiences for presentation during dissertation day and in their research papers to fine-tuning their observation skills. There is something to be seen every step of the way, and some of those things need to be seen in time - spines and thorns on plants, biting ants and spiky caterpillars and there is always the chance of running into a venomous snake...       
Mammal tracks and scat are often seen in the trails and tell us a lot about the local species and their habits. Wendy Welshans, director of the program, demonstrates the finer art of analyzing large cat scat. These fresh Jaguar or Puma droppings contained Peccary fur and bone fragments. 

Another good rainforest skill that students learned quickly is to read the weather patterns - especially useful if you want to dry your laundry....

One of the program's research projects focuses on investigating the potential use of spider silk in the pharmaceutical industry. Silk from the Golden Orb Weaver  (Nephila clavipes) is famously break-resistant and pound-for-pound can be considered stronger than steel. In addition it is lighter in weight and more elastic than any inorganic fiber equivalent. The project has been intent on developing a sustainable way to extract enough high-quality silk as to make this a viable home-industry that would revolve around the need to protect the spider's natural habitat. A type of 'spider-farming' set up in a way not unlike silk-worm farms, that can provide an alternative to destructive cattle ranching that locally takes a heavy toll on the forest.         

A female Agrioppe savignyi, an orb-weaving spider with a distinctive web design.

Students set up experiments with Golden-orb Weaver spiders (Nephila clavipes) moved into a small shed to simulate a farming setup.
A specially designed collection device is used to collect the spider silk from a Golden-orb Weaver
The amount of silk extracted from each spider, coloration of the silk and several other variables are carefully recorded
 A new project this year studies Orthoptera (grasshoppers, katydids and crickets) and Odonata (damselflies and dragonflies). Students working on this project study the diversity of these large groups in the local rainforest and also focus on bioacoustics: the characteristics and functions of the cricket and katydid calls that are a big part of the night sounds in the area.

A dazzling variety of orthopterans is found in the study area.
The variety of dragonflies and damselflies is equally stunning. 
 Since the animals in the target  groups are poorly known and no easy field guides for their identification exist, all sorts of measurements, photographs and drawings are collected for each individual that is found. Data will be shared with expert entomologists in hopes that we can help expand the knowledge of these animals.  
Each cricket, dragonfly and grasshopper collected is carefully documented and released back into its natural habitat. 
The students on this project developed a small, portable sound studio that can be wired with a microphone to record cricket and katydid calls onto a laptop computer. Several frustrating nights were spent waiting for a stubborn subject to start calling - something that did not always work. Luckily patience and some tweaks to the recording method paid off in the long run and the calls of several species could be reliably documented.  
Sound recordings were stored and edited on a laptop computer. The white box in the background is a make-shift sound recording studio.

When seen up-close, the subjects of this project display an amazing variety of shapes, colors and adaptations.

Artistic skills were a 'must' for these students since every new species found had to be documented with drawings illustrating the animal's diagnostic features.  
The project's resident artist hard at work
The following images show some of the animals encountered during our forays in the rainforest...
Immature praying mantis

A very well camouflaged stick insect seemingly covered in moss

Leaf-mimicking praying mantis (Choeradodis rhombicollis)
A large Cone-headed Katydid (Copiphora sp.)

A third project focusing on invertebrates is the moth project which has been documenting species diversity in the preserve for the past couple of years. Due to the full moon and heavy rainfall this year (both factors that keep the moth diversity and density down at night), the team was also looking into some other lepidoteran diversity: caterpillars found during the day.   
Home-made insect traps with a built-in UV 'black' light were placed in different locations in the rainforest or hoisted into trees at night to sample local moth populations  
On a good night the traps and sheets are full of moths and other insects, but this year those nights did not happen very often...

A canopy trap is lowered from the treetops and its contents examined

In addition to the traps, sheets with black lights are set up in strategic locations as well to attract moths

On busy nights the sheer number of insects present can be quite overwhelming!
Species not previously recorded in the area are carefully preserved and documented

 Here is a small sampling of some of the animals found:

Some moths are as colorful as their diurnal butterfly relatives.
Even the seemingly less colorful ones have beautiful subtle markings when viewed up-close, such as the metallic gold highlights on this small moth.
It is no surprise that very few moths are seen during the day, given their amazing camouflage patterns!
Other unusual visitors attracted to the black lights included this small yellow Dobson Fly.
And a large yellow flower-beetle

When moth activity was slow at times, the team shifted its focus to species that could be found during the day. Diurnal butterflies are fairly well-known in the area and the team decided to focus instead on their lesser-known larval stages - some of which are quite amazing!
A large sphingid moth larva with an intimidating spike on its back...
Many of these spiny caterpillars have to be handled with great care since they are often equipped with chemical defenses that can result in very painful stings! 

You really don't want to touch these!

Other species try to escape predation by disguising themselves as something as unappealing as a bird-dropping.
Although not a caterpillar, the bright coloration of this flatworm is probably advertising some unpleasant experience for any predator careless enough to eat it
A large Malachite Butterfly (Siproeta stelenes) hides from the rain

  Check back here tomorrow for part II of the Rainforest Project narrative describing the two remaining projects, studying migratory birds and rare amphibians and reptiles.

Twan Leenders
Conservation Biologist

All photos © Twan Leenders and not to be reproduced without explicit permission

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