Author: Marymegan Daly

Dynamics of Neo-Tropical Arachnids

Today’s post is a guest post by Andrew Mularo,  an undergraduate student in the Department of Evolution, Ecology and Organismal Biology. He is currently doing his Tropical Behavior Evolution and Ecology research project under Dr. Rachelle M. M. Adams and Dr. Jonathan Shik.

You may love them or you may fear them, but no one can deny the incredible ecological importance of spiders and scorpions. As an aspiring biologist, I have chosen to study the interactions between arachnids and their environment in the tropical rainforests of Panama for the 2017 Tropical Behavioral Evolution and Ecology course. The tropics are a biodiversity hotspot for the majority of the world’s organisms, so there are plenty of creatures to look at. From the smallest spiderling to the largest tarantula, I am curious to see how these cryptic and intriguing animals interact with their ecosystem.

For my project, I am doing an observational study where I am assessing the relationship between leaf litter and arachnid diversity and abundance. I am accomplishing this by creating several 50 meter transects in the Panamanian rainforest, sampling leaf litter with 1 square meter quadrants along each transect. For each quadrant, I take a measurement of leaf litter depth, and sift through the leaves to extract any organisms out of the area. Back at the lab, I sort through the organisms, first finding any arachnids in the sample, and then any other insect or invertebrate, such as ants, beetles, millipedes, snails, mites and many others. With these data, I hope to make a correlation between leaf litter abundance and arachnid diversity and abundance, as well as a correlation between the diversity of potential prey items and arachnid predators.

Naturally, the majority of the organisms that I have been assessing have been very small, from the size of a thumbnail to not even being visible to the human eye. However, there

Wandering Spider (Photo by A. Mularo)

are several occasions where I have observed some extremely imposing arachnids in the tropical forest. One of these includes the huntsman spider, an extremely large nocturnal species that does not rely on a web to capture its prey. This family of spiders is very poorly researched, and is largely unknown how dangerous the venom is for the majority of species. However, they are quite shy, and often scurry away at the sight or sound of a human.

Another fascinating group of organisms I see occasionally are scorpions. The two pictured below are from the genus Tityus, whose venom is very potent. I found the two in the picture below, which we believe to be different species, huddled in close quarters in the water well of a bromeliad. While potentially dangerous, these are a relatively uncommon sight in the rainforest. Nevertheless, it is always good to be careful where you step.

Tityus scorpions (photo by A. Mularo)

While many of them are feared, arachnids are some of the most fascinating organisms on the planet. They come in all shapes and sizes, and have a wide array of interesting characteristics that are of great interest to scientists. Being interested in biology since I was a child, I have always dreamed of coming to the tropics so I could study the vast diversity of organisms, and I could not have picked a better group of organisms to focus on!

Eyes and ears in the sea

NOAA Ship Okeanos Explorer berthed at the NOAA Ford Island facility located in the middle of Pearl Harbor, Hawaii. Image courtesy of NOAA Office of Ocean Exploration and Research.

NOAA Ship Okeanos Explorer berthed at the NOAA Ford Island facility located in the middle of Pearl Harbor, Hawaii. Image courtesy of NOAA Office of Ocean Exploration and Research.

In spring, the naturalist’s mind turns to bird watching, wildflower exploration, and other outdoor pursuits. The importance of observation cannot be underestimated: it is by watching and listening that we begin to make connections about the players and processes of the natural world.

This week marked the end of a voyage by the Okeanos Explorer, a research vessel owned and operated by the National Oceanographic and Atmospheric Administration (NOAA). Although the Okeanos Explorer does not collect specimens, its high-quality images, videos, and maps provide a glimpse into the biology and ecology of organisms that are often known only from museum specimens.

The videos and images from Okeanos Explorer are the eyes and ears of deep sea biologists, giving us vital information about where organisms live, how communities are structured, what organisms look like in life, and how organisms move and interact with one another.

Close up image of a glass sponge, with commensal anemones growing through its body. The anemones are as yet un-described members of the family Edwardsiidae. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana.

Close up image of a glass sponge, with commensal anemones growing through its body. The anemones are as yet un-described members of the family Edwardsiidae. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana.

My research focus is sea anemones. Footage from Okeanos Explorer shows that these are more abundant in deep sea communities than we might expect, given the number of specimens held by museums. In shallow habitats, sea anemones are important primary producers because they (like their relatives the stony corals) often harbor photosynthetic microorganisms.

Absent light in the deep sea, the biological role of sea anemones is less clear, but footage from Okeanos Explorer shows them crowding the branches of deep-sea sea fans, clinging to rocks, living in the bodies and skeletons of other animals, and dwelling in soft mud.

Benthic cnidarians are common in deep-sea canyons and seamounts. Here, octocorals, cup corals, and anemones share a rock at 1,459 meters depth in Hendrickson Canyon. Image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts.

Benthic cnidarians are common in deep-sea canyons and seamounts. Here, octocorals, cup corals, and anemones share a rock at 1,459 meters depth in Hendrickson Canyon. Image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts.

The Okeanos Explorer videos of anemones show subtle variation in color among specimens belonging to the same species. These kinds of insights are invaluable in filling in the blanks for animals otherwise known only from isolated, often damaged specimens. To learn more about the Okeanos Explorer and the habitats it surveys, go to http://oceanexplorer.noaa.gov/okeanos/welcome.html

This image of a pompom anemone is a very helpful complement to our understanding of this species. The tentacles have small muscles at their base and are often shed when the animal is disturbed, so most museum specimens have no or very few tentacles. Image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014.

This image of a pompom anemone is a very helpful complement to our understanding of this species. The tentacles have small muscles at their base and are often shed when the animal is disturbed, so most museum specimens have no or very few tentacles. Image courtesy of NOAA Okeanos Explorer Program, Our Deepwater Backyard: Exploring Atlantic Canyons and Seamounts 2014.

 

About the Author:  Dr. Marymegan Daly is an Associate Professor in the Department of Evolution, Ecology and Organismal Biology and Director of the OSU Fish Division.

Fish Face

 

Although any individual fish might be hard to pick out of its school photo,  fish faces can be  remarkably distinct.

 

About the Authors: This blog post is a collaboration between Dr. Meg Daly, Director of the Fish Division & Marc Kibbey, Associate Curator of the Fish Division.  All photos by Marc Kibbey.

 

Old collections, new tricks

 

Research collections are built through two primary avenues. Many specimens belonging to a single genus or family may be collected from a broad geographic area as part of a research project into the diversity, distribution, or biology of that lineage. Alternatively, specimens belonging to multiple lineages may be collected from a single place as part of studies into the diversity of a geographic region or drainage.

Field team leader Brian Zimmerman in his natural habitat: a boat! His expertise with the diversity and distribution of fish is invaluable as we survey new habitats. Photo by Paul Larson

Field team leader Brian Zimmerman in his natural habitat: a boat! His expertise with the diversity and distribution of fish is invaluable as we survey new habitats. Photo by Paul Larson

Our collaboration with the Ohio Division of Wildlife (https://obcp.osu.edu/) to assess the diversity of fishes in Ohio has followed both of these paths, exploring the distribution and genetic diversity of species of particular conservation concern across Ohio and capturing the diversity of particular rivers or drainages.

One of the “tricks of the trade” for our surveys has been to use diverse techniques. To make sure we have sampled all of the microhabitats within a waterway, we use everything from electrofishing to seines to trawls to snorkels.

This week we demo’ed a new net system in the Muskingum River and were pleased with the biomass and diversity of fish and other animals that we caught, including some HUGE flathead catfish as well as bycatch of softshell and snapping turtles. This is a new sampling method to us but has long been used by commercial fisherman and fisheries professionals alike. These nets will be part of our arsenal of methods as we establish baselines for the species diversity of the Muskingum River.

Collections manager Marc Kibbey mans the nets. The snapping turtle (left) and spiny softshell turtle (top) are released back into the river. The Northern Pike (middle) and Bowfin (bottom) are measured and recorded. Photo on left by Paul Larson; photos on right by Brian Zimmerman.

Collections manager Marc Kibbey mans the nets. The snapping turtle (left) and spiny softshell turtle (top) are released back into the river. The Northern Pike (middle) and Bowfin (bottom) are measured and recorded. Photo on left by Paul Larson; photos on right by Brian Zimmerman.

Our electronic database and tissue voucher collection means that we can record occurrence, size and abundance, and sample animals with the safest, most effective methods.

Most of the fish we catch are identified, measured, photographed, and released. Specimens belonging to species whose distribution, diversity, or identity are questioned and species not well represented in museum collections are brought back to the museum for further study.

A global database called “Fishnet” (http://www.fishnet2.net/aboutFishNet.html) integrates our database with those of other museums, making these collections visible, searchable, and accessible to scientists around the world.

 

About the Author:  Dr. Marymegan Daly is an Associate Professor in the Department of Evolution, Ecology and Organismal Biology and Director of the OSU Fish Division.