Nature Blog Network

Friday, September 19, 2014

Scelionidae Wasp Hatching


Mark Bower sent me these pictures last month, a good example of what you can find with curiosity.....and a good photographer.  These eggs are 1mm in diameter (1/25 of an inch), hard to see with a magnifier and impossible to photograph.  I asked him to describe his find.
"These eggs were deposited on a wooden post on our front porch. When the first one emerged, it stayed with the eggs constantly. When others hatched, the first one watched intently, and immediately either attacked or mated with them. I say two "hatchlings" get attacked and expelled from the egg cluster, one gets mated with, and several others die (why?) before they could get out (after opening their eggs). Not sure what all was going on there; it all seemed sort of odd."
We sent this to Chris Barnhart who explained that "these are parasitoid wasps, emerging from eggs of hemiptera. The wasp is likely in the Scelionidae family."  Hemiptera are the order of "true bugs", the order that contains aphids, planthoppers, leafhoppers, shield bugs, and stink bugs that often plague your garden.  In this closeup Youtube video by Mark, at 1:03 you can see a wasp emerging from a hemipteran egg and an immediate attempted mating by a newly emerged male who was waiting for her to come out.

Not all species are black
The scelionidae family contains over 3000 species of parasitoid wasps.  They all lay their eggs on the eggs of insects or spiders where their young grow by using their host  as food.  Generally they are careful to eat only nonessential parts at first, prolonging the life of the host to obtain maximal nutrition.

These wasps and the eggs they attack are tiny!
Antennae with 9 visible segments
A typical scelionid wasp is black and slender although some are various colors and shapes.  In general they have long elbowed antennae with 9 or 10 segments.  These are tiny creatures, ant sized, and could be mistaken for them without magnification.  Most are winged except for some species that parasitize wingless beetles.

Winged scelionid wasp
We tend to be judgmental about plants and animals, classifying them as "good" or  "bad" by our personal criteria.  In ecological terms, many "bad" bugs and plants are just misplaced, located where it is inconvenient or problematic for us.   Eating our garden or the caterpillars of butterflies we treasure labels them "bad".   Meanwhile they are, to paraphrase Arthur Dent in Hitchhikers Guide to the Galaxy, "just these bugs, you know", making babies the best they can.  And if you look closely, they can even be a little cute.

Cute? -  Compound eyes, "The better to see many of you with."

Thursday, September 18, 2014

Monarch Migration

Monarch emerged, dry and ready to take off
Chrysalis before emerging
As we watch the last of our monarch butterflies from Linda Bower emerge from their chrysalids to head south to Mexico, we are reminded of the challenges facing them.  First there is the emergence from the dried skin of the chrysalis itself.  They must hang on while pumping blood down into the veins of their deflated wings, expanding them with the help of gravity until they dry.  Falling or failure to hang properly can lead to deformity that sentences them to a brief stationary existence.

Failed wing expansion
Once their wings have dried and we release them from the rearing cage, they have to warm up their flight muscles, not easy on these last few cool, overcast rainy days.  Under these conditions they take off later and land earlier, frequently dependent upon the sun.   An observer from Ontario a few days ago reported, "We conservatively counted 1,000 monarchs from 11 a.m. to 2 p.m., at 4 - 8 per minute. Then the sun went behind clouds and all stopped!"*

Migration progress 9/17/2014 - Learner.org
You can follow the progress of migration thanks to citizen science reports on
Learner.org  including some day to day personal observations from Canada and the northern states as the migration begins.  The Learner.org maps show the day to day progress of the wave of monarchs heading to their winter quarters in Mexico.  Other maps show the location of adult butterflies, eggs and larvae, and fall roosts.

The migration of species has always been of interest to nature lovers, but now with the tools of the Internet, we have the ability to follow their journey.  Citizen scientists all over the US reporting their sightings of monarch butterflies and hummingbirds allows us to see the big picture as well as understand changing patterns of migration brought on by human activity and climate change.  Someday there may be tiny chips that allow us to follow the monarchs we raise.  Waaay too much information!

Friday, September 12, 2014

Hummingbird Predator


Not much eats a hummingbird between their speed and their aversion to sitting still.  Still every creature and plant has a place in the food web, including humans.  In the case below it was truly a food "web".

I was hiking along Bull Creek and noticed a few cardinal flowers down stream, a brilliant flash of bright red on a cloudy evening at sunset.  I went down to photograph them, and while trying to focus in the low light I saw something move off to the side.  It was a large yellow spider busily wrapping up its prey, suspended from a single silk "baseline" stretched between two branches of bushes.  It had the coloration of the common yellow garden spider,  Argiope aurantia,  discussed in a previous blog but was not quite a match.  This one was the banded Argiope, Argiope trifasciata.

As I was taking pictures, I suddenly focused on a long slender beak protruding from the silk wrapping.  On the other side I could just make out the iridescent green of a hummingbird's wing under the silk cloak.  There was no ruby throat so it must have been a female or juvenile. The web had been suspended in front of the cardinal flowers which just happened to appeal to a ruby-throated hummingbird.  It is possible however that the hummingbird wasn't an entirely innocent victim.
"Hummingbirds use spider webs as a source of spider's silk in nest construction, being necessary to bind the nest to the tree branch or other substrate and to hold the nest together. Even so, the hummingbird must be careful when removing the pieces of webbing, for it may become entangled and be trapped there. Spider's silk has a tensile strength comparable to steel on a weight basis. In one report, a ruby-throated hummingbird was caught in an active web, and quickly wrapped and encased by the spider, much as an insect might be." Hummingbirdsociety.org
Spider web construction varies with the species and many spiders don't even bother to make one.  The initial strand in web construction of Argiopes' is called the "baseline."  It then drops a single line in a "Y" and builds the radials before adding the sticky web.  Most lose stickiness after a day and are eaten by the spider who then, in the ultimate in recycling, uses the ingested silk to reconstruct the web.  Details and diagrams of their techniques are at spiderzrule.com.


When most prey hits the web, the spider rushes out and bites it, killing it before its thrashing allows it to escape.  With some venomous insects like wasps they just carefully wrap it in silk. Once our Argiope realized I was intruding it slowly made its way along the single strand of baseline to the anchoring branch.  The baseline is incredibly strong and it was stretched a foot as I pulled the mummified humming bird off the strand, before the baseline snapped back in place without damage.

Most things in nature have a purpose, even if we can't guess what that is.  A recent study on the Web Orientation of the Banded Garden Spider, Argiope Trifaciata found that they oriented their webs in an east-west direction, and then suspended their ventral (underside) surface to the south, picking up the maximum sun rays.  This surface is dark on A. trifaciata, which increases its heat absorption.
"The spiders grow throughout the summer, reaching full-size in late August and September. The males, which are much smaller than the females and do not produce webs, roam around the vegetation and mate the females in late summer. The female then lays one or more egg sacks, that appear somewhat like a small kettle drum with a tough papery cover and may contain 1000 eggs apiece. The spiders die after frost and there is only one generation produced each year."  Colostate.edu
 Stabilimentum-Wikimedia
Argiopes seem to be proud of their webs, creating a beautiful radial pattern and some species even construct a "stabilimentum" decoration along the vertical axis of the web.  There are many theories about the purpose of this structure which are discussed at this site.  Even before "some pig" appeared in Charlotte's Web, folk tales said that if you saw your name in the web, you were about to die.   I don't know how to spell "hummingbird" in bird-speak, but it may be a zig-zag.


And yes, the hummingbird had gone to that big sugar water feeder in the sky.

Monday, September 8, 2014

Butterfly House Update


Chris Barnhart sent me this update on the Dr. Bill Roston Native Butterfly House at the Botanical Center Gardens in Close Memorial Park.

The milder weather and the rain last week really perked up everything in the park. We’ve got great variety in the Butterfly House (BH) right now. All of the swallowtail species are in there now, and all life stages of each.  Monarch chrysalides have nearly all hatched, but more larvae are maturing. There are several Polyphemus and Io moths in the cage. Also have lots of hatchling Io cats, so we haven’t seen the last of those. However, the days are getting shorter, and these should be the last broods of the year for most of our resident butterflies and moths. The chrysalides and cocoons of the current caterpillars will diapause (enter in to a period of suspended development) and not hatch till spring.

Cloudless sulphur caterpillar- Wikimedia
 Cloudless- Wikimedia
One of the late summer arrivals is the cloudless sulphur (Phoebis sennae). Mike Martin caught several in the park last week and they are laying eggs on the Cassia (senna) on the NE side in the BH. This is the fairly tall, woody legume with the long seed pods. The eggs are very tiny, but I collected a dozen in just a few minutes. The caterpillars and chrysalides are very colorful and interesting, so keep fingers crossed. Here is a link to the species on the U. Florida website. 

The cloudless sulphur is a southern species that moves north each summer, and then migrates or dies out in the fall. They tend to start moving south now, and you may notice that they will go to the SE corner of the BH in the afternoon, while the monarchs will go to the SW corner, as we move into fall.  (A fascinating observation- Ed.)
Questionmark butterfly (Polygonia interrogationis) - CB
I’ll just mention one other butterfly that will be evident over the next couple of weeks - the questionmark (Polygonia interrogationis). You’ve probably noticed lots of cats of these on the elm and hackberry, and we have a bunch of chrysalides. These will hatch next week and should be the fall form that will overwinter as adult butterflies. They look different from the summer broods, having hindwings orange on top instead of black, and violet edges on the wings. Look for them roosting in the trees and visiting the fermenting fruit above the doors.

Wednesday, September 3, 2014

Raising Monarchs Part. 2

Monarchs begin with an egg - LB
We recently wrote about Saving Monarchs, the butterfly whose annual migration is in jeopardy.  In the next few blogs Linda Bower will discuss how to raise monarch butterflies, grow milkweed for host plants, and recognize the plants pests.

Got Milkweed? By Linda Bower
We can help the declining monarch population by simply growing milkweed. We can help even more by rearing them in a protected environment. Their natural survival rates are low, with only about 5% surviving to form a chrysalis. The others are killed by a variety of predators, including ants, spiders, true bugs, beetles, and lacewing larvae. Fewer reach adulthood to mate. Now add pesticides, herbicides, traffic and loss of habitat to the equation and its little wonder any monarchs are still with us.
 

It doesn’t take much time to rear monarch caterpillars, they grow up fast. According to the book, How to Raise Monarch Butterflies, if we grew at the same rate, we would be 30' tall in 2 weeks! With just a little understanding of their life cycle and a little bit of equipment we can make a big difference.


The Egg
Monarch females lay their eggs on the underside of a leaf, usually only one egg per plant. They look like a tiny white bump when first deposited. It will take 4-5 days for them to hatch. You will see a black dot in the egg when they are about ready. Their first meal is the egg case and then they will be still for as long as 24 hours.

Cat heads out - MB
Tight squeeze - MB









When you find an egg on your milkweed, simply place the leaf in a small plastic container with a tight lid. You do not need to punch holes in the container. Line the bottom with a paper towel or coffee filter. You will know when the caterpillar has eaten its first bit of leaf by the hole and frass (poop) left behind.
 

The Caterpillar 

Caterpillars need to be fed every day for 10-14 days. Cut the old leaf around the caterpillar and place it on top of a fresh leaf. Caterpillars have 6 pairs of eyes, but poor vision. They can still find the fresh leaves you place in the container, you don’t need to intervene. Also replace the paper daily as the frass will be plentiful and must be removed to avoid mold.
View from the top - MB
Hiding under leaf - MB








Brother, where art thou?

They eat voraciously during the last few days, so watch carefully. An average caterpillar will devour 20-30 leaves. When it is ready to form a chrysalis, the plump caterpillar will go to the top of the container, spin a patch of silk and attach by its rear end via a support hook and hang down in the shape of a “J” for around 18 hours. Lining the lid with a paper towel or coffee filter will make it easy to move the chrysalis to a netted container where the adult will be able to emerge safely.

Later instar - LB
The Chrysalis
It usually takes 15-20 hours for the new chrysalis skin to harden. Even a blowing leaf can slice into it at this point, so do not touch it! Once the chrysalis is formed it will take 1-2 weeks for the adult to emerge. You can tell a monarch’s gender by examining the chrysalis. Look near the support hook (cremaster) and you will see paired black dots. Females have a vertical line in the segment below the paired dots.


The chrysalis - CB
Emerging from chrysalis
When the monarch emerges, it will take about two hours for the wings to unfold and harden. If it falls during this time the wings will be damaged and it will not be able to fly. It is ready to release when it begins flapping its wings. Just let it go! Monarchs that emerge in late summer are no longer mating but concentrate on fattening up on nectar for their migration. Those born in early to mid-summer don’t migrate; they live 2-6 weeks to mate and lay eggs.




Grown and ready to mate - CB
These instructions are printable in this PDF.
Answers to many monarch questions are at MyMonarchGuide.com.

Visit www.monarchwatch.org for more information or www.monarchparasites.org for troubleshooting if death occurs at any stage.
Photographs by Linda Bower (LB), Mark Bower (MB) and Chris Barnhart (CB)

Monarch Migration Threatened

Migration starts as an egg - Linda Bower
Linda Bower dropped off some of her 300+ monarch eggs and caterpillars for adoption.  Raising them appears easy relative to the teenagers who pupated from our house years ago.  In this case it just needs a steady supply of milkweed and removing the frass (insect poop) from the container at regular intervals.  On second thought, our little Frick and Frack below are not that far different from a newborn.
Frick, Frack and frass- REK
Why bother raising monarchs aside from curiosity and abiding interest in nature?  The fact that you are reading this blog suggests that you probably aware of the crisis that monarchs face.  In the last 20 years the monarch population has declined by 90%.  Their summer breeding grounds have decreased by 165 million acres.  The latest news this week:
"The Center for Biological Diversity and Center for Food Safety as co-lead petitioners joined by the Xerces Society and renowned monarch scientist Dr. Lincoln Brower filed a legal petition today to the U.S. Fish and Wildlife Service seeking Endangered Species Act protection for monarch butterflies."
Many experts feel that the monarch is not threatened with extinction as it would survive in small numbers in Mexico and our border states.  What would likely disappear is the famous annual migration.  They depend upon milkweed to reproduce 3-4 times along the migration route, and it is rapidly disappearing.  A common "weed" in and along agricultural fields, it has virtually disappeared over many square miles of the migration, the victim of Roundup ready crops.  Meanwhile, the remaining land is being urbanization, neighborhoods, golf courses and rural homes with 10 acre lots, all mowed and weeded.

While looking for some large scale answers, you can start to help the migration in your own small way.
  1. Plant milkweed in your garden, land, ditches and roadsides.  The time to plant is in the fall as the seeds have to cold stratify (freeze and thaw) to germinate.
  2. Avoid the use of insecticides on flowers where butterflies obtain nectar.
  3. Consider raising Monarch butterflies.  There is a high mortality in nature on their journey from egg and caterpillar to adulthood, much of which can be avoided by home rearing.
Soon we will be describing methods to help you support the Monarch population. 

Sunday, August 31, 2014

Pandora Sphinx Moth


  Photo by Drew Albert
Drew Albert of our Master Naturalist chapter found this beauty hanging out in a tower of the National Weather Service where he works.  This was a restricted area and it wasn't wearing an ID, but he turned a blind eye and a camera onto the trespasser.

This is a Pandora or Pandorus sphinx moth, Eumorpha pandorusIt seems appropriate that it was hanging out at the airport as it resembles a stealth bomber that is painted in jungle camo, like Mother Nature had been watching too many Rambo movies that day.  They fly predominately at dusk on green to brown wings that can span 4.5 inches.  Their wing shape looks a lot like the somewhat smaller hog sphinx moth.


Hog sphinx, Darapsa myron - Chris Barnhart
Pandorus Sphinx Moth Pupa - Eumorpha pandorus
  Janice Stiefel
The larvae are just as impressive as the adult.  They grow up to 4 inches long by feeding on grape species (Vitis) as well as Virginia creeper.  There is considerable variation in the colors of their various instars.  The last instar climbs down to the ground and burrows into the loose soil.  There it will pupate in the fall, forming the cocoon that will be its home until it emerges next year as a beautiful moth.

caterpillar - Eumorpha pandorus
  Fifth instar - gkmarsh
The caterpillars will go through five molts, called instars.  Early instars have a horn like most sphinx moths, for example the familiar tomato horn worm.  Unlike their cousins, the Pandora's horn has a cute little curl.  This disappears in the fourth instar, replaced by a little eye mark.

Pandorus Sphinx - Eumorpha pandorus
Early instar - Erik Blosser

Pandorus Sphinx Moth Larva - Eumorpha pandorus
 Head tuck - Janice Stiefel*
Like many other caterpillars, their prolegs have special hooks which allow them to feed upside down, clinging to the underside of a leaf to hide from predators.  At times they will tuck their two front segments into the third, giving the otherwise some what pointed head a blunt appearance.  When they are threatened they use a vulture-like defense, vomiting up a sticky substance.

Pandorus Sphinx with parasites and wasp - Eumorpha pandorus

Pandora sphinx with parasites and wasp emerging - Jo Ann Poe-McGavin
It doesn't always turn out well for caterpillars.  In addition to their contributions to the food chain for birds, insects and even snakes, there are various parasites that utilize them as a nursery for their young.  The specimen above is still alive, but just barely.  It was infested by the eggs of a parasitic wasp whose young have just pupated and emerged.  The parasites preserve all the caterpillar's vital functions until the last minute to maintain their food source.  You can see a little wasp at the bottom, presumably newly emerged from the pupa.
 
 *  The late Jan Stiefel had submitted 779 photographs to Bugguide.net and over 129 Door County, Wisconsin moth records, which are documented with the state. She had served as editor of the "Wisconsin Entomological Society Newsletter" since 1999.

There is more information at the  uwm.edu/ website.