- Living with Spiders shows some of the webs, spiders, and prey on our house.
- No-See-Ums were fairly abundant this year and I noticed lots of them were caught by the spiders.
- I then wondered how useful or important spiders were in controlling and capturing the insects that feed on us, such as No-See-Ums, Black Flies and Mosquitoes.
- Most of their webs were associated with our windows. This makes sense since light from inside the house and general warmth probably attracts insects to the windows.
- I know some people clean the outside of their homes and purposely try to get rid of the spiders and their webs. Interesting to speculate, as far as, spiders controlling certain insects is this a good idea.
- I don't think any specific studies of this possibility have been done. But one could look at a few papers that discuss spiders and their prey and whether or not they benefit agriculture. Here are a couple to get you started:
These videos are free to use for educational purposes. To download them click on vimeo on the bottom right. To view them full screen click on the symbol next to the HD at the bottom. The bullets can be copied and pasted into a word document.
- Bog Cranberries (Vaccinium oxycoccos) is a video showing these plants from flowers to fruit and bears that feed on them. This video was filmed in Juneau, Alaska.
- For a quick look at some information available on this plant look at https://en.wikipedia.org/wiki/Vaccinium_oxycoccos
- Also interesting information can be found here https://www.fs.fed.us/database/feis/plants/shrub/vacoxy/all.html
- And in this article /sites/default/files/How%20Cranberry%20Bogs%20Work%20by%20Russel%20Avery.pdf
- I could not find any information about bears eating bog cranberries but this article might be a good start Constraints On Frugivory By Bears
- Of interest is it appears that the common name of this plant has recently (2018) been changed to Small Cranberry.
- I hope to continue work on these fascinating plants and update the video and information. I am especially interested in the various creatures that feed on these berries.
- Documenting Moth Visits with a Wingscapes TimeLapse Pro is an illustration of the value of using this camera for documenting the behavior of insects.
- This camera will focus as close as six inches to a subject, can take a photo or video as low as every 10 seconds all day and night.
- In general for documenting insect visits to flowers I have found a photo every 30 seconds or minute to be sufficient.
- It will also record the date and time each photo is taken.
- With lithium batteries and a 128 GB card it can last several days.
- The camera is waterproof and can be used in the rain.
- It costs as low as $115 here are some details:
- Looking for the Arctic Bristletail is a project I just started on and hope to improve in the future.
- The Arctic Bristletail (Petridiobius arcticus) is an amazing insect that lives in the upper intertidal zone in Southeast Alaska.
- It is a species of jumping bristletail in the family Machilidae. It is found in Europe & Northern Asia (excluding China) and North America.
- It has no wings but is capable of jumping up to 20 cm.
- I first discovered their presence in Juneau by seeing lots of their exoskeletons on a large rock along a shore in Juneau. It was fascinating how clustered together they were during the molting stage.
- Bristletails are small invertebrates that slightly resemble tiny lobsters. Petridiobius arcticus, is found from the Aleutian Islands to the Alaska panhandle where they live in cracks of bedrock just above the high tide line and feed on lichens.
- The following is from Matt Bowser, Fish and Wildlife Biologist on the Life history of Petridiobius arcticus:
First instar immatures hatch from eggs in early spring, April to May in Southcentral Alaska. These grow over the summer, molting a couple of times or so (I do not know exactly) so that they are nearly mature in the fall. They overwinter in cracks of rocks or under moss and reach maturity by the end of their second summer, when eggs are laid in the moss and other material among the rocks.
They are easy to raise from first instar to adulthood by feeding them lichens and providing water. They will lay eggs in captivity, but I have not been able to provide the correct conditions for eggs to hatch. I think these need to go through one winter before they will hatch.
In captivity the P. arcticus will eat almost any kind of lichen.
Petridiobius arcticus will be out in daylight. In particular, some will be out apparently sunning on warm days. They are mostly crepuscular/nocturnal, however. If you wait around at night with a deep red light to watch them you will see many bristetails emerging from the rocks.
There is much more to learn, though. No one has documented the mating behavior of this species, for example. We also have very little information on interactions with other species. I do not think that there is documentation of any predation on P. arcticus.
- To learn more about them look at http://archaeognatha.myspecies.info/taxonomy/term/148/descriptions
- Some interesting information about them can be found in the book Insects Their Natural History and Diversity by Stephen A. Marshall. The following information is taken from his book:
- These primitive, robust insects are easiest to observe along rocky seashores. Jumping Bristletails are such striking insects it is worth turning over a few rocks to see them.
- They feed on algae and lichens.
- The males do not mate directly with the females.
- Jumping bristletails .......sometimes use a silken line as a carrier thread on which the male deposits his sperm droplets before nudging the female into position to contact his sperm with the lip of her abdomen.
- In order to cast a skin to enable growth they use their own feces to anchor themselves down to solid surface, such as a rock.
- They also glue their eggs to rocks.
- Mandibles of jumping bristletails swing on a single pivot, much like a leg.
- The Dolly Varden Predator Control Program, in my opinion, was one of the greatest boondoggles in the history of Alaska's Fisheries.
- Supposidly more than 6 million Dolly Varden were destroyed.
- Bounties were paid for Dolly Varden tails turned in at 2.5 to 5 cents per tail.
- Studies showed that most of the tails turned in for bounty were from salmon and rainbow trout, the very species the program was supposed to benefit.
- Studies also showed that Dolly Varden do not eat significant numbers of salmon young. In fact the program was based on the feeding habits of another species, the Arctic charr.
- Further studies indicated that Dolly Varden benefit salmon by eating freshwater snails in lakes and loose salmon eggs in streams.
- These snails are an intermediate host of a parasite that causes blindness in coho and sockeye salmon.
- Loose salmon eggs eventually develop a fungus that can affect and destroy the eggs buried in the gravel.
- For information about the amazing migration behavior of Dolly Varden look at Migration of Anadromous Dolly Varden Charr in Southeastern Alaska--A Manager's Nightmare by Robert H. Armstrong
- For a good review of what is known about Dolly Varden look at Dolly Varden charr, Salvelinus malma by Robert H. Armstrong & James E. Morrow
- Also for informtion about them in Southeast Alaska look at Dolly Varden by Robert H. Armstrong and Marge Hermans
- We Like Mussels shows gulls swallowing mussels, sea stars, and urchins whole. Goldeneyes also swallow mussels whole.
- Ravens, crows, and oystercatchers also eat mussels but usually break open the shell first and eat the contents.
- To learn about gulls that forage extensively on mussels look at DIETARY CHANGES AND POOR REPRODUCTIVE PERFORMANCE IN GLAUCOUS-WINGED GULLS
- Also look at https://vimeo.com/298946148
- And https://www.naturebob.com/black-oystercatcher-eating-blue-mussels
- And https://www.naturebob.com/crows-dropping-mussels