Archive for the 'Insects, Fish, Frogs' Category

Jul 21 2016

TBT: How to Swat a Fly

Published by under Insects, Fish, Frogs

House fly (photo by Alvesgasper from Wikimedia Commons)

House fly (photo by Alvesgasper from Wikimedia Commons)

It’s July and the house flies are getting more annoying.

My cat chases them around the house and when she fails I try to swat them — but they evade me.

On Throw Back Thursday (TBT) here’s a timely article on How to Swat a Fly.

How to Swat a Fly

 

(photo from Wikimedia Commons. Click on the image to see the original)

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Jul 18 2016

Bees and Electricity

Bumblebee on thistle with pollen grains (photo by Kate St. John)

Bumblebee on thistle with pollen grains (photo by Kate St. John)

Here’s an amazing thing: The hairs on a bumblebee’s body tell it where the flowers are.  It’s done with electricity.

Flowers use scent, patterns, nectar and even ultraviolet colors to attract insect pollinators.  Each flower also has an electric field that says, “I’m here!”  Scientists thought that insects picked up this communication, but how?  A study published in PNAS last May explains that bumblebees sense the electric field with their body hairs.

Bees and flowers are oppositely charged.  Without even trying, bees build up a positive charge on their bodies as they fly.  Flowers are negatively charged and that makes their pollen stick to bees through static electricity.  But the electric field is more than just that static charge.

Positive and negative electric fields: bee and flower (image from Wikimedia Commons)

Positive and negative electric fields: bee and flower (image from Wikimedia Commons)

In the diagram above, imagine that the bee is red and the flower blue.  As a bumblebee approaches the flower, a frisson of excitement passes along its body as its hairs bend in response to the flower’s electric field.  The bee feels the approach. Its hairs are pointing to the flower!

We humans can barely imagine this because we’re not sensitive to electric fields.  As we walk on a carpet we don’t feel the doorknob’s electric field until we touch it and are shocked at the discharge.  The best we can do is see our hair stand up after we rub a balloon on our head.  Here’s Emma at Emma’s Science Blog to show us how:

image linked from Emma's Science Blog: Emma does an experiment with static electricity, April 2014

from Emma’s Science Blog: Emma does an experiment with static electricity, April 2014

 

Now that we know about this communication between bumblebees and flowers, scientists think that lots of hairy insects sense electric fields, too.

I wonder if the house fly sees me with his hairs as well as his eyes as I approach to swat him.

 

Read more about bumblebees and electricity here at mashable.com.

(bumblebee photo by Kate St. John. electric field diagram from Wikimedia Commons.  Emma with balloon linked from Emma’s Science Blog. Click on the field and balloon to see the original images)

p.s. Thanks to Michelle Kienholz for alerting me to this story.

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Jul 13 2016

2016 Summer Slugfest

Published by under Insects, Fish, Frogs

Hosta leaves eaten by slugs (photo by Kate St. John)

Welcome to the 2016 Summer Slugfest.

The slugs are eating my hostas so this week I decided to kill them with kindness.  I bought them a beer.

Hosta leaves eaten by slugs (photo by Kate St. John)

Hosta leaves eaten by slugs (photo by Kate St. John)

Slugs love beer so much that when they get drunk they drown in it.  It’s the organic way to kill them.

Slug on the Laurel Highlands Hiking Trail, 10 Jul 2016. Not at me home, but you get the idea (photo by Kate St. John)

Slug on the Laurel Highlands Hiking Trail, 10 Jul 2016. Not in my garden… but you get the idea (photo by Kate St. John)

 

On Sunday afternoon I collected my tools:  small cat food cans, a trowel, garden gloves, and beer.  I don’t believe in wasting good beer on slugs so I keep a stash of old bottles just for them. This one is from December 2008.  My slugs drink “vintage” beer.

Slugfest tools: beer, small catfood cans, trowel, garden gloves (photo by Kate St. John)

Slugfest tools: beer, small catfood cans, trowel, garden gloves (photo by Kate St. John)

For each can I dug a hole to place the rim at dirt level.  I set one can under the most-eaten hosta and the other in a central location.  Then I poured beer to the rims.

Beer trap for slugs (photo by Kate St. John)

Beer trap for slugs (photo by Kate St. John)

The next morning there were 13 dead slugs in my two beer traps.  Great attendance!

Slugs in the beer trap (photo by Kate St. John)

Slugs in the beer trap (photo by Kate St. John)

I’ve added two more cans and am now offering vintage brew in four locations.

The 2016 Summer Slugfest is very successful. I’m gonna run out of beer. 😉

 

(photos by Kate St. John)

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Jul 12 2016

Gone But Not Forgotten

Cicada damage on an oak tree (photo by Kate St. John)

Cicada damage on an oak tree (photo by Kate St. John)

After weeks of roaring in late May and June, the 17-year periodical cicadas (Magicicadas, Brood V) are gone but not forgotten.

During the mating frenzy the females used their ovipositors to slit the bark near the ends of twigs and deposit up to 600 eggs per slit. Weeks later the adults are dead but they’ve left their mark on the trees.  The slits killed the leafy branch tips.

Everywhere you go in cicada country the trees are green inside and brown at the tips.  (This is called “flagging.”)

Cicada damage on an oak tree (photo by Kate St. John)

Cicada damage on an oak tree (photo by Kate St. John)

The trees look as if someone has sprayed defoliant on this year’s new growth.  Fortunately that’s not the case!

Cicada damage on an oak tree (photo by Kate St. John)

Cicada damage on an oak tree (photo by Kate St. John)

The trees will be fine.  They have plenty of time to recover before Brood V reappears in 2033.

If you lived through the cicada invasion this summer, you won’t soon forget their roar.

If you missed them, your next big chance near Pittsburgh will be Brood VIII in 2019.

 

(photos by Kate St. John)

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Jun 24 2016

Sneaky Orchids

Most flowers offer food to attract pollinators.  Trumpet vine, for instance, provides nectar for hummingbirds who incidentally pick up pollen and transport it to the next flower.

But some orchids have no food to offer.  Instead they look and smell like sexy female insects so the males will attempt to mate with them.  In doing so the orchids’ pollen clumps (pollinia) become stuck to the male insects and are taken to the next flower.

Watch the video above from BBCWorldwide to see how it’s done.

Sneaky orchids!

 

Thanks to Bonnie Isaac, President of the Botanical Society of Western Pennsylvania, for pointing out this cool video in the Society’s second quarter bulletin.

(video from BBCWorldwide on Youtube)

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Jun 03 2016

Magic Cicadas

Published by under Insects, Fish, Frogs

Periodical 17-year cicada, Washington Cemetery, Washington, PA, 30 May 2016 (photo by Kate St. John)

Periodical 17-year cicada, Washington Cemetery, Washington, PA, 30 May 2016 (photo by Kate St. John)

I had to see them for myself.

Thousands and thousands of very loud bugs the size of my thumb with bright red eyes.  They’ve spent 17 years of their youth underground to emerge as adults, en masse, for only 4-8 weeks.  I didn’t want to miss the spectacle so I drove down to Washington, PA last Monday to see …

17-year cicadas (Magicicada sp.), unique to eastern North America, are so tasty to birds and mammals that they survive by emerging in overwhelming numbers on a prime-number cycle.  There are 13 regional Broods with different cycles.  This one, Brood V (i.e. 5), lives in parts of West Virginia, Ohio and the bottom left corner of Pennsylvania(*).  (Click here for the list of all Broods and regions, and here for Pennsylvania by county.)

There are lots of cool facts about these bugs:

  • In the spring of their 17th year the nymphs dig tunnels that stop just below the surface … and then they wait. The moment of their emergence depends on soil temperature and perhaps on their ability to hear each other making sounds that mean “I’m ready.”  (read more here)
  • They emerge at night and crawl up on trees, plants and walls to shed their exoskeletons and dry their wings.  At this point they are very soft and tasty to predators.
Adults and cast-off shells of Periodical 17-year cicadas, Brood V, Washington, PA, 30 May 2016 (photo by Kate St. John)

Adults and cast-off shells of Periodical 17-year cicadas, Brood V, Washington, PA, 30 May 2016 (photo by Kate St. John)

Periodical 17-year cicada. Brood V, 30 May 2016. Wings did not unfurl properly. (photo by Kate St. John)

Periodical 17-year cicada – wings did not unfurl properly. Washington, PA, 30 May 2016. Its . (photo by Kate St. John)

  • There are so many of them that later arrivals knock the old shells off to the ground.
Periodical 17-year cicada shells, Washington Cemetery, Washington, PA, 30 May 2016 (photo by Kate St. John)

Periodical 17-year cicada shells, Washington Cemetery, Washington, PA, 30 May 2016 (photo by Kate St. John)

  • It takes about a week for their bodies to stiffen enough to make their distinctive call.  When they’re ready the males congregate in trees and vibrate their tymbals to attract the females.  Each bug is individually loud. Thousands of them are overwhelming.  Here’s the sound from a cicada-filled tree.  The audio sounds like a hiss but it’s actually bugs.

  • After they mate the females rip a long slit in the bark of a twig and lay up to 600 eggs.  Weeks later, the eggs hatch and the nymphs fall to the dirt where they burrow underground to live for 17 years.
  • Later this summer you’ll know cicadas were here when you see brown leaves on branch tips.
Brown tips on tree branches because of cicada egg-laying (photo from Wikimedia Commons)

Brown tips on tree branches because of cicada egg-laying (photo from Wikimedia Commons)

 

For lots more information about cicadas, visit the Cicada Mania website or this Allegheny Front episode Everything You Need to Know About This Year’s Mass Cicada Emergence.

Magicicadas are weird and magical.

 

p.s.  Watch this cool video of the cicadas’ life cycle, billed on Facebook as “Cicada Time-Lapse Video Will Make You Cry.

(cicada photos and video by Kate St. John. photo of tree with brown tips from Wikimedia Commons)

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May 09 2016

Nature’s Perfect Partners: PBS NATURE May 11

Barbell fish clean hippo's skin and teeth (photo courtesy PBS Nature © Mark Deeble/Vicky Stone)

Barbell fish clean hippo’s skin and teeth (photo courtesy PBS Nature © Mark Deeble/Vicky Stone)

Oh my!  Is the hippo eating these fish?!?

No. He could eat them if he wanted to but these barbell fish are his helpers.  They eat ticks from his skin and food from his teeth.  It’s a symbiotic relationship.

The hippo and the barbell fish are just one example of the unlikely partnerships animals make with other species.  Watch the premiere of Nature’s Perfect Partners on Wednesday May 11 to learn about many more — lizards with lions, a fish with a blind shrimp, toads with tarantulas.

Here’s a preview:

Don’t miss Nature’s Perfect Partners this Wednesday May 11 at 8pm EDT/ 9pm CDT on PBS.  In Pittsburgh it’s on WQED.

 

(photo courtesy PBS NATURE © Mark Deeble/Vicky Stone)

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Jan 08 2016

Natural Born Hustlers: PBS NATURE

Are humans the only species that fools others to survive, find food, and mate?  Not at all!

This month PBS NATURE premieres a new three-part series, Natural Born Hustlers, airing on PBS on Wednesdays, January 13, 20 and 27 at 8:00pm (ET) (check local listings).

Episode One, Staying Alive, focuses on survival techniques:  camouflage, dominance tricks, audio mimics and playing dead.  Early on I was amazed to learn how zebras’ stripes create an optical illusion.  You have to see them in motion to believe it!

Other fascinating finds are the amazing skin-morphing camouflage of cuttlefish, the lizard that walks like a stinky beetle, and the white-faced capuchin monkeys who calculate whether they’re needed in battle.  “More capuchins are killed by their own kind than by predators,” says the episode.  What an unfortunate trait to have in common with humans.

The video excerpt above gives you a good idea of animals’ ingenuity.  California ground squirrels use their enemy’s scent as protective camouflage.  Their arch enemy is the rattlesnake, so if you hate to look at snakes this video will make you flinch.

And fair warning to those afraid of snakes:  Staying Alive has quite a few snakes in it including a match-up in North Carolina of a harmless species that mimics the coral snake.  The bonus is that you can identify birds by song on the audio track.

 

(Natural Born Hustlers trailer from PBS NATURE)

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Jan 06 2016

The Living Bridge

Published by under Insects, Fish, Frogs

A “living bridge” of army ants, species Eciton hamatum. (photo courtesy of Matthew Lutz, Princeton University, and Chris Reid, University of Sydney)

Now that the Greenfield Bridge is gone over the Parkway East, my neighbors are joking that we need a zip line to get to Schenley Park.  If we were army ants, we could build a bridge of our bodies to solve the problem.

Native to the tropical rainforest, army ants are famous for their foraging habits.  The colony has no permanent home and is always on the move like an army, killing and eating other insects and raiding their nests.  The columns of workers are so focused on their task that they overcome obstacles by building living bridges of their bodies across the gaps.

How big a gap will the ants bridge? How do they modify it for different conditions?  To learn more about their behavior, Matthew Lutz of Princeton University and Chris Reid of the University of Sydney studied Eciton hamatum in Panama.  They inserted the apparatus shown below into army ant paths and varied the angle — 12, 20, 40, and 60 degrees — to see what the ants would do.  It turns out that ant bridges are more sophisticated than anyone knew.

Researchers found that the ants start from the narrowest point and work toward the widest point, expanding the bridge as they go. (Courtesy of Matthew Lutz, Princeton University, and Chris Reid, University of Sydney)

For instance, the bridges are typically 10-20 ant-lengths but the ants don’t start building at the widest spot.  Instead, they start from the narrowest point and make the bridge longer to shorten the overall path.  They also give up on a bridge if it ties up too many workers to make one. As Iain Couzin, Lutz’s graduate adviser, explains:

“They don’t know how many other ants are in the bridge, or what the overall traffic situation is. They only know about their local connections to others, and the sense of ants moving over their bodies,” Couzin said. “Yet, they have evolved simple rules that allow them to keep reconfiguring until, collectively, they have made a structure of an appropriate size for the prevailing conditions.

Could we humans bridge the Parkway East with our bodies?  No.  We aren’t long enough and we don’t have enough legs to hold onto each other.  Besides, some of us are afraid of heights.

Army ants aren’t afraid of heights. They’re blind (!) and have no idea how far they’d fall if they failed.

 

(*)Read more about the study here at Princeton University news.

(photo courtesy of Matthew Lutz, Princeton University, and Chris Reid, University of Sydney)

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Dec 27 2015

Galling

Oak gall, Washington County, PA, November 2015 (photo by Kate St. John)

Oak gall, Washington County, PA, November 2015 (photo by Kate St. John)

Back in November I found these round hairy growths on the backs of many oak leaves at Hillman State Park in Washington County, PA.

From above they look furry but up close I can see that they’re fibrous.

Close-up of oak gall, Washington County, PA, November 2015 (photo by Kate St. John)

Close-up of oak gall, Washington County, PA, November 2015 (photo by Kate St. John)

No doubt these are galls, structures grown by the tree itself in response to chemicals deposited by a tiny insect that laid eggs on the underside of the leaf.  The insects are usually gall wasps (Cynipidae) whose larvae are protected by the gall.

There are 750 species of Cynipidae in North America, best identified by the characteristics of the gall and the plant it’s growing on.  What does the gall look like?  What species is it growing on?  Where is the plant located (geographically)?  What part of the plant is the gall growing on?  If on a leaf, is it on the upper or under side?  Is it on a twig?  A bud?  Etc. etc.

Extensive searches of bugguide.net produced similar photos but no final identification.  The closest was this one:  A gall wasp (Cynipidae) in the genus Acraspis, photographed in Guelph, Ontario.

So I’m back where I started.  I know the name of the wasp (as far as I care to know) but what is the name of the gall?

 

(photos by Kate St. John)

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