Category Archives: Insects, Fish, Frogs

The Capelin Are Rolling!

Capelin rolling in on the waves at Witless Bay, NL, 10 July 2018 (photo by Kate St. John)
Capelin rolling on the waves at Witless Bay, NL, 10 July 2018 (photo by Kate St. John)

Last Tuesday morning, 10 July 2018, I took a walk before breakfast at Witless Bay, Newfoundland to take in the scenery and watch the birds. When I stopped by the shore I never noticed the amazing spectacle at my feet.  It was high tide and the waves were full of fish.

As I stood gazing out to sea, a local man pulled up in a jeep to see what I was looking at.  He got out of the jeep and looked at the waves.  “It’s good to see the capelin,” he said.

I didn’t understand what he was saying.  “Pardon me?”

“Do you know about the capelin?”

“No,” I said.  So he explained.

Capelin (Mallotus villosus) are small fish in the smelt family that form dense schools as they feed on plankton and krill.  Their numbers attract the attention of everything that eats them — seabirds, mackerel and cod — and the whales that eat what capelin eat.

In Newfoundland the capelin come ashore every year in July but the exact date varies. People wait and watch for the spectacle to begin. Wikipedia explains:

Capelin spawn on sand and gravel bottoms or sandy beaches at the age of 2–6 years, and have an extremely high mortality rate on the beaches after spawning, for males close to 100%.

The waves are full of capelin at Witless Bay, 10 July 2018 (photo by Kate St. John)
The waves are full of capelin at Witless Bay, 10 July 2018 (photo by Kate St. John)

The fish flip-flop in shallow water as the females lay eggs and the males distribute sperm.

Capelin spawning at Witless Bay, 10 July 2018 (photo by Kate St. John)
Capelin spawning at Witless Bay, 10 July 2018 (photo by Kate St. John)

The number of capelin eggs is incredible.  All the white spheres among these stones are capelin eggs, not grains of sand!  The eggs can be food for shorebirds.

The rocky sand is full of capelin eggs, Witless Bay, 10 July 2018 (photo by Kate St. John)
The rocky sand is full of capelin eggs, Witless Bay, 10 July 2018 (photo by Kate St. John)

Some of the capelin don’t make it back to sea and are stranded, dying on shore. This provides on-shore food for scavengers including bald eagles, crows and foxes.

Capelin on shore after high tide, Witless Bay, 10 July 2018 (photo by Kate St. John)
Capelin on shore after high tide, Witless Bay, 10 July 2018 (photo by Kate St. John)

The waves are full of fish, but so is the sea. Here’s my video of the capelin-filled waves with black-legged kittiwakes flocking and diving on them before the capelin can reach shore.

Who else eats capelin?  Half a million Atlantic puffins that nest at the Witless Bay puffin colony. Though this bird was photographed at the Faroe Islands, it shows how puffins can carry 8-10 capelin-sized fish in their beaks.

Atlantic puffin bringing home food for its chick (photo from Wikimedia Commons)
Atlantic puffin bringing home food for its chick (photo from Wikimedia Commons)

July 10 was the first morning the capelin had come back to Witless Bay and word of their arrival spread quickly.  When our birding group came down after breakfast many villagers were already there.  Some came to watch the capelin roll. Others brought buckets to collect fish to fertilize in their gardens.  Some eat capelin, some don’t.

Come down to the bay.  The capelin are rolling!

 

 

(Puffin photo from Wikimedia Commons; click on the image to see the original. All other photos and videos by Kate St. John)

Common Whitetail

Common whitetail dragonfly, Huntley Meadows Park, VA (photo from Wikimedia Commons)
Common whitetail dragonfly, Huntley Meadows Park, VA (photo from Wikimedia Commons)

If you’ve been outdoors near water lately, you’ve seen this pretty dragonfly.

His name is the common whitetail (Plathemis lydia) and he’s very territorial.  This pose is one way he threatens his competition.

Learn about his threat display and see a photo of his lady — she looks very different! — at this Throw Back Thursday article: Threat Display.

 

(photo from Wikimedia Commons; click on the image to see the original)

Malaria Makes You Smell Better

Anopheles gambiae Mosquito, vector for malaria (photo by Muhammad Mahdi Karim via Wikimedia Commons)
Anopheles gambiae Mosquito, vector for malaria (photo by Muhammad Mahdi Karim via Wikimedia Commons)

By a cruel twist of fate, malaria makes you smell better to mosquitoes.

In a study published last April in the Proceedings of the National Academy of Sciences, scientists in Kenya tested whether mosquitoes were attracted differently to those with transmissible malaria versus those without.

Malaria is caused by Plasmodium parasites that infect the victims’ blood.  Rather than subject humans to mosquito bites and potential infection, the researchers tested a group of children for malaria, then placed socks the children had worn into different boxes based on the results.  Then they released mosquitoes into a tube connecting the boxes and watched what happened.

Diagram of malaria attraction test, drawn by Kate St. John based on Science Magazine article
Diagram of malaria attraction test, drawn by Kate St. John based on Science Magazine article

60% of the mosquitoes flew to the socks worn by children with transmissible malaria.  When the children were cured of malaria, the mosquitoes shunned them as much as those who never had the disease.

So what is it about malaria that attracts mosquitoes?

Since mosquitoes are attracted to scent, the researchers tested foot odor samples of the infected children for a handful of chemicals that turn on mosquitoes and were found at higher levels in the infected children.  As Science Magazine explains:

The test zeroed in on … a class of chemicals called aldehydes, including heptanal, octanal, and nonanal. Those chemicals easily vaporize and are common additives in perfumes. Several are described as having a “fruity” odor, including heptanal, which is found in allspice.

So that’s what it is. The malaria parasite is very sneaky. People with the disease smell good to mosquitoes — as if they are wearing perfume. Mosquitoes bite those people more often and thus spread the disease.  Grrrr!

Read a summary here in Science Magazine or the full study at Plos One.

 

(photo by Muhammad Mahdi Karim via Wikimedia Commons; click on the image to see the original and its license. Diagram drawn by Kate St. John based on the April 16, 2018 Science Magazine article.)

A Bee Backs Out

Last weekend in Virginia Beach I saw a bit of black at the tip of a tightly closed yellow flower.

The flower was making a buzzing sound. What next?

As I watched a bumblebee backed out.  In the last photo you can see that she was in the flower upside down.

 

p.s. Do you know what flower this is?  Is it False Foxglove? It was growing in sandy soil by the Long Creek Trail at First Landing State Park, Virginia Beach, VA.

(photos by Kate St. John)

Amaze Your Friends

Yellow poplar weevil on black locust, Schenley Park, 8 June 2018 (photo by Kate St. John)
Yellow poplar weevil on black locust, Schenley Park, 8 June 2018 (photo by Kate St. John)

At this time of year the weevils appear.  I found one on black locust leaves in Schenley Park on Friday June 8.

At first, they hang out on plants but they can fly.  In a “big year” they spread everywhere, landing on buildings and people and just about anything.  By late June people are freaking out.  They think they’re ticks.

But you won’t freak out. You’ll know what they are.

This is a yellow poplar weevil (Odontopus calceatus), a vegetarian that feasts on yellow poplars, tuliptrees, sassafras and cucumber magnolia trees.  He’s usually kept in check by predatory insects but in “big years” there aren’t enough predators and his population goes wild.

The weevil’s body structure shows why he’s not a tick:

  • Ticks have 8 legs (they’re related to spiders). Weevils have 6.
  • Ticks don’t have wings.  Weevils have wings under their elytra (wing covers). Though they don’t fly much you may see one raise his wing covers and zoom away.
  • Ticks do not have snouts.  Weevils have snouts like inflexible elephants’ trunks and 2 antennas on the snout.
  • Ticks never swarm.  Weevils swarm in June because they’re mating.
Yellow poplar weevil is not a tick (photo by Kate St. John)
Yellow poplar weevil is not a tick (photo by Kate St. John)

Later in June when the weevils swarm, amaze your friends . “Nope, it’s not a tick.”

 

(photos by Kate St. John)

Where The Color Comes From

Indigo bunting (photo by Marcy Cunkelman, May 2015)
Indigo bunting (photo by Marcy Cunkelman, May 2015)

Why does the indigo bunting (Passerina cyanea) look so blue?  It isn’t from the color of his feathers.  In dull light he looks gray!

Last month when I wrote about blue morpho butterflies I learned that their color comes not from pigments but from the structures of their scales that reflect blue light.

This same color trick is what makes indigo buntings’ feathers so blue.

Watch the Deep Look video below to learn how it works.

 

(photo of indigo bunting by Marcy Cunkelman, video from Deep Look on YouTube)

First Cabbage Whites

Cabbage white butterfly (photo from Wikimedia Commons)
Cabbage white butterfly (photo from Wikimedia Commons)

During mid April’s hot weather I saw my first cabbage white butterfly of the year.

Cabbage whites (Pieris rapae) overwinter in the chrysalis but are quick to emerge when the weather warms up. They’re one of the first butterflies to emerge in the spring.

You might think they look boring because they’re simply white but these butterflies have an amazing color we can’t see.

On Throw Back Thursday, read how cabbage whites communicate in color in this vintage article:  If Only We Could See.

Cabbage white butterfly reflects UV light (photo by Nathan Morehouse in Science Magazine)
Cabbage white butterfly reflects UV light (photo by Nathan Morehouse in Science Magazine)

 

(photo at top from Wikimedia Commons, white-and-purple image by Nathan Morehouse in Science Magazine. Click on the images to see full photo credits.)

Time Slowed Down

Dorsal and ventral views of museum specimen, Morpho menelaus, Peru (photo from Wikimedia Commons)
Dorsal and ventral views of museum specimen, Morpho menelaus, subspecies from Peru (photo from Wikimedia Commons)

The most beautiful butterfly I have ever seen lives in the jungles of Central and South America.

The blue morpho (Morpho menelaus) is as large as my open hand, iridescent blue above and patterned brown below.  When it flies, sunlight winks blue on its open wings.  On the upstroke it shines gold.

In Panama we were transfixed when blue morphos appeared one by one above the road, floating toward and over us.  They defied our efforts at photography so I looked for a video on YouTube.

Slow motion videos are the only ones that match my memory of morphos. (We did not see the black-blue butterfly in this video, only the all-blue one.)

 

In fact they flew rather fast.  You can see in this video how hard it is to keep up with one.

 

My memory of these butterflies is in slow motion because my brain was busy processing the new and beautiful experience.  This happens to all of us when we focus on new information.  (Read more here about our perception of time. )

Perhaps that’s why I enjoy the beauty of nature.

When I watch blue morphos time slows down.

 

(photo from Wikimedia Commons; click on the image to see the original.  All videos from YouTube; click on the YouTube logos to see the videos full screen)

Something To Be Thankful For

Living with Alligators PSA 2018 from My FWC on Vimeo.

April 4, 2018:

Spring is on hold again as the temperature falls to 26 degrees F tonight — but here’s something Pittsburghers can be thankful for 😉

Yes, it’s cold in Pennsylvania and spring takes too long to get here but we don’t have to worry about this message from the Florida Fish and Wildlife Commission.

However, if you live in Florida or plan to visit please pay attention.

Tweeted last week by @MyFWC:  Warmer spring weather means #alligators are more active. Here’s how to stay safe: ow.ly/ULpK30ja6V4 #Florida

Alligator safety message from Florida WFC
Alligator safety message from Florida WFC

 

(message, video and poster from Florida Fish and Wildlife Commission)